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  • Inorganic Chemistry  (5,240)
  • Genetics  (1,010)
  • Wiley-Blackwell  (6,250)
  • 1990-1994  (4,623)
  • 1950-1954  (1,627)
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  • 1
    Electronic Resource
    Electronic Resource
    Embryonic expression of the single Tribolium engrailed homolog (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 7-18 
    Details
    ISSN: 0192-253X
    Keywords: Tribolium ; engrailed ; embryogenesis ; segmentation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have cloned and sequenced the single Tribolium homolog of the Drosophila engrailed gene. The predicted protein contains a homeobox and several domains conserved among all engrailed genes identified to date. In addition it contains several features specific to the invected homologs of Bombyx and Drosophila, indicating that these features most likely were present in the ancestral gene in the common ancestor of holometabolous insects. We used the cross-reacting monoclonal antibody, 4D9, to follow the expression of the Engrailed protein during segmentation in Tribolium embryos. As in other insects, Engrailed accumulates in the nuclei of cells along the posterior margin of each segment. The first Engrailed stripe appears as the embryonic rudiment condenses. Then as the rudiment elongates into a germ band, Engrailed stripes appear in an anterior to posterior progression, just prior to morphological evidence of the formation of each segment. As in Drosophila (a long germ insect), expression of engrailed in Tribolium (classified as a short germ insect) is preceeded by the expression of several homologous segmentation genes, suggesting that similar genetic regulatory mechanisms are shared by diverse developmental types. © 1994 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150103
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  • 2
    Electronic Resource
    Electronic Resource
    Developmental evolution: New paradigms and paradoxes (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 1-6 
    Details
    ISSN: 0192-253X
    Keywords: Evolution ; homeobox gene ; body plan ; comparative method ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150102
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  • 3
    Electronic Resource
    Electronic Resource
    Homeotic gene expression in the locust Schistocerca: An antibody that detects conserved epitopes in ultrabithorax and abdominal-A proteins (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 19-31 
    Details
    ISSN: 0192-253X
    Keywords: Homeobox ; Ultrabithorax ; abdominal-A ; short germ development ; grasshopper ; evolution ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To investigate what role homeotic genes may play in morphological evolution, we are comparing homeotic gene expression in two very different insects, Drosophila (Diptera) and Schistocerca (Orthoptera). In this paper we describe a monoclonal antibody, FP6.87, that recognizes the products of both the Ultrabithorax (Ubx) and abdominal-A (abd-A) genes in Drosophila, via an epitope common to the carboxy terminal region of these two proteins. This antibody recognizes nuclear antigens present in the posterior thorax and abdomen of Schistocerca. We infer that it recognizes the Schistocerca homolog of UBX protein, and probably also of ABD-A. As the distribution of Schistocerca ABD-A protein is already known, we can use this reagent to map the expression of Schistocerca UBX in the thorax and anterior abdomen, where ABD-A is not expressed. Both the general domain, and many of the details, of UBX exp ression are remarkably conserved compared with Drosophila. Thus UBX expression extends back from T2 in the ectoderm (including the CNS), but only from A1 in the mesoderm. As noted for other bithorax complex genes in Schistocerca, expression begins in the abdomen, at or shortly before the time of segmentation. It only later spreads anteriorly to the thorax. For much of embryogene-sis, the expression of UBX in the thoracic epidermis is largely restricted to the T3 limb. Inthis limb, UBX is strikingly regulated, in a complex pattern that reflects limb segmentation.Reviewing these and earlier observations, we conclude that evolutionary changes affect both the precise regulation of homeotic genes within segments, and probably also the spectrum of downstream genes that respond to homeotic gene expression in a given tissue. Overall domains of homeotic gene expression appear to be well conserved between different insect groups, though a change in the extent and timing of homeotic gene expression may underlie the modification of the posterior abdomen in different insect groups. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150104
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  • 4
    Electronic Resource
    Electronic Resource
    Characterization and expression of C/EBP-like genes in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone-induced metamorphosis (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 366-377 
    Details
    ISSN: 0192-253X
    Keywords: C/EBP ; thyroid hormone ; metamorphosis ; gene expression ; Rana cafesbeiana ; bZlP proteins ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Tissue-specific changes in gene expression occur in the liver of Rana cafesbeiana tadpoles undergoing metamorphosis. Many of these changes can be induced precociously by administration of thyroid hormone (TH) to a tadpole or to cultured tadpole liver. While the precise molecular means by which TH exerts a tissue-specific response is unknown, recent studies suggest that the expression of genes which are liver-specific and characteristic of the adult liver phenotype may rely on TH-induction of tissue-specific transcription factors, as well as the thyroid hormone receptor proteins. Guided by this notion, we screened our Rana catesbeiana liver cDNA library and isolated clones, RcC/EBP-1 and -2, encoding Rana homologues of a mammalian transcription factor, C/EBP (CCAAT/enhancer core binding protein), implicated in the expression of liver-specific genes and terminal differentiation of hepatocytes. Gel mobility shift assays demonstrate that the proteins synthesized from these cDNAs bind specifically to the consensus binding site for C/EBP-related proteins. Characterization of the amino acid sequence in the bZlP DNA-binding domains of these proteins suggests that RcC/EBP-1 and -2 encode Rana homologues of C/EBPα and δ, respectively. Hybridization analyses demonstrate that the amount of RcC/EBP-2 mRNAs in tadpole liver remains constant throughout metamorphosis, whereas RcC/EBP-1 mRNAs are up-regulated during both spontaneous and TH-induced metamorphosis. The TH-induced up-regulation of RcC/ EBP-1 mRNAs precedes the up-regulation of liver-specific urea cycle enzyme mRNAs by 6 to 12 hours. These results, coupled with in situ hybridization studies, suggest that RcC/EBP-1 mRNAs encode a transcription factor which may play an early role(s) in the terminal differentiation and/or reprogramming of gene expression in this tadpole's liver cells during both spontaneous and TH-induced metamorphosis. ©1994 WiIey-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150408
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  • 5
    Electronic Resource
    Electronic Resource
    Interactions between tassel seed genes and other sex determining genes in maize (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 155-171 
    Details
    ISSN: 0192-253X
    Keywords: Sex determination ; epistasis ; floral development ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The tassel seed mutations of maize cause sex reversal of the florets of the tassel, such that the normally staminate florets develop pistils. Although these mutations have been recognized for many years, little is known about how they act. We have tested the hypothesis that the tassel seed genes interact directly with each other and with other genes controlling sex determination in a single genetic pathway by the construction and analysis of double mutants. On the basis of the phenotypes of the double mutants, the tassel seed mutations were placed into two groups: ts1, ts2, Ts5 and ts4, Ts6. Both groups of tassel seed mutations were additive with the masculinizing mutation dwarf, indicating independent modes of action. Interactions of tassel seed mutations with silkless varied, allowing the ordering of the action of the various tassel seed mutations relative to silkless. Both groups of tassel seed mutations were epistatic with regard to sex expression to mutations that alter both architecture of the plant and distribution of male and female florets, Teopod 1, terminal ear, and teosinte branched. Thus, there are at least two separate genetic pathways that control the sex of florets in maize tassels. In addition, analysis of double mutants revealec that all tassel seed genes tested play a role in the regulation of flower morphogenesis as well as pistil suppression. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150206
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  • 6
    Electronic Resource
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    Sex determination and differentiation (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 201-204 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150302
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  • 7
    Electronic Resource
    Electronic Resource
    Genetics of sex determination in flowering plants (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 214-230 
    Details
    ISSN: 0192-253X
    Keywords: Sex determination ; angiosperms ; genetics ; white campion ; sex chromosomes ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Most flowering plant species are hermaphroditic, but a small number of species in most plant families are unisexual (i.e., an individ-ual will produce only male or female gametes). Because species with unisexual flowers have evolved repeatedly from hermaphroditic progenitors, the mechanisms controlling sex determination in flowering plants are extremely diverse. Sex is most strongly determined by genotype in all species but the mechanisms range from a single controlling locus to sex chromosomes bearing several linked locirequired for sex determination. Plant hormones also influence sex expression with variable effects from species to species. Here, we review the genetic control of sex determination from a number of plant species to illustrate the variety of extant mechanisms. We emphasize species that are now used as models to investigate the molecular biology of sex determination. We also present our own investigations of the structure of plant sex chromosomes of white campion (Silene latifolia - Melan-drium album). The cytogenetic basis of sex determination in white campion is similar to mammals in that it has a male-specific Y-chromosome that carries dominant male determining genes. If one copy of this chromosome is in the genome, the plant is male. Otherwise it is female. Like mammalian Y-chromosomes, the white campion Y-chromosome is rich in repetitive DNA. We isolated repetitive sequences from microdissected Y-chromosomes of white campion to study the distribution of homologous repeated sequences on the Y-chromosome and the other chromosomes. We found the Y to be especially rich in repetitive sequences that were generally dispersed over all the white campion chromosomes. Despite its repetitive character, the Y-chromosome is mainly euchromatic. This may be due to the relatively recent evolution of the white campion sex chromosomes compared to the sex chromosomes of animals. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/dvg.1020150304
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  • 8
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994) 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150401
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  • 9
    Electronic Resource
    Electronic Resource
    Tissue-specific regulation by ecdysone: Distinct patterns of Eip28/29 expression are controlled by different ecdysone response elements (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 320-331 
    Details
    ISSN: 0192-253X
    Keywords: Drosophila melanogaster ; ecdysone ; steroid ; Eip28/29 ; EcREs ; lacZ ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The Eip28/29 gene of Drosophila is an example of a tissue- and stage-specific ecdysone-responsive gene. Its diverse patterns of expression during the third larval instar and a synopsis of those patterns in terms of expression groups have been reported previously. Here we have studied the expression (in transgenic flies) of reporter genes controlled by Eip28/29-derived flanking DNA. During the middle and late third instar, most tissues exhibit normal expression patterns when controlled by one of two classes of regulatory sequences. Class A sequences include only 657 Np of 5′ flanking DNA from Eip28/29. Class B sequences include an extended 3′ flanking region and a minimal (≤93 Np) 5′ flanking region. The class B sequences include all those elements known to be important for ecdvsone induction in cultured cells. They are sufficient to direct the normal premetamorphic induction of Eip28/29 in the lymph glands, hemocytes, proventriculus, and Malpighian tubules. This is consistent with our suggestion that Kc cells are derived from embryonic hematopoietic cells. It is remarkable that the epidermis requires only class A sequences. These are sufficient to up-regulate expression at medinstar and to down-regulate expression at metamorphosis. It follows that the epidermis uses EcREs distinct from those that function in Kc cells. It is possible that the Upstream EcRE, which is nearly silent in Kc cells, is active in the epidermis. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/dvg.1020150403
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  • 10
    Electronic Resource
    Electronic Resource
    Upregulation of AP-2 in the skin of Xenopus laevis during thyroid hormone-induced metamorphosis (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 356-365 
    Details
    ISSN: 0192-253X
    Keywords: Thyroid hormone ; AP-2 ; Xenopus luevis ; metamorphosis ; 63 kDa keratin gene ; epidermal differentiation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: During amphibian metamorphosis dramatic changes occur in the morphogenesis and differentiation of the epidermis. Concurrently with these changes, the 63 kDa keratin geneis upregulated from low basal levels to high levels. What makes these processes unique is that they are controlled by triiodothyronine (T3) and can be duplicated in cultures of purified epidermal cells. Since there is a 2 day lag period between the addition of T3 and the upregulation of keratin gene expression and terminal differentiation, recent studies have focused on identifying the genes activated during the lag period. We assume that the transcription factors required for upregulation of the keratin gene are induced by T3 during the lag period, and therefore we have cloned the keratin gene so that promoter analyses can be conducted. S1 mapping assays have shown that the same transcription start sites are used during premetamorphosis when the keratin gene is basally expressed, during metamorphosis when it is T3-upregulated, and in the adult epidermis where it is expressed independently of T3. During the early part of the lag period TRP and AP-2 mRNA levels are upregulated in the epidermis by T3. The transcription factor AP-2 is expressed at high levels in the skin of premetamorphic larvae and induced about fivefold by T3 but is not induced in an epithelial cell line (XL-177). Since the keratin mRNA, AP-2 rnRNA, and other genes induced during the lag period are expressed in premetamorphic larvae it appears that T3 functions by upregulating the expression of genes previously activated by a T3-independent process. This preprogramming may account for the tissue specificity of T3 action during metamorphosis. © 1994 WiIey. Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150407
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  • 11
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994) 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150501
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  • 12
    Electronic Resource
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    Developmental arrest of fertilized eggs from the B6.YDOM sex-reversed female mouse (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 435-442 
    Details
    ISSN: 0192-253X
    Keywords: Fertility ; sex-reversal ; XY ovary ; XY oocyte ; mouse ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: When the Y chromosome of a Mus musculus domesticus mouse strain is placed onto the C57BL/6J (B6) inbred background, the XY progeny develop ovaries or ovotestes but never normal testes during fetal life. While some of the hermaphroditic males become fertile, none of the XY females produces litters. Here, we examined the fertility and development of oocytes derived from the XY female mouse. With or without preceding injection of gonadotropins, female mice were mated with normal B6 males, and their embryos were recovered at various developmental stages. In vitro fertilization was performed with the eggs recovered from the oviduct after treatment with go-nadotropins. Development of embryos was examined by both light and electron microscopy. The results indicate that the oocytes released from the B6.YDOM ovary were efficiently fertilized and often initiated the first cell cleavage, but all embryos died during early preimplantation periods. Even when oocytes were fertilized in vitro, minimizing their exposure to the XY oviduct/uterus environment, most embryos died at the 1- or 2-cell stage. A few exceptional embryos reached the 4- or 8-cell stage, but abnormalities were evident in both nuclear and cytoplasmic structures of all embryos. After cleavage, neighbouring blastomeres were only loosely associated, and microvilli were abundant at the intercellular interfaces. We postulate that oocytes of the B.6.YDOM female mouse become defective during XY ovarian differentiation, and, hence, fail to proceed through normal embryonic development. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150506
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  • 13
    Electronic Resource
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    Heterochronic expression of an adult muscle actin gene during ascidian larval development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 51-63 
    Details
    ISSN: 0192-253X
    Keywords: Actin ; ascidian development ; gene expression ; heterochrony ; muscle actin gene ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Adultation is a hetercchronic mode of development in which adult tissues and organs differentiate precociously during the larval phase. We have investigated the expression of an adult muscle actin gene during adultation in the ascidian Molgula citrina. Ascidians contain multiple muscle actin genes which are expressed in the larva, the adult, or during both phases of the life cycle. In ascidian species with conventional larval development, the larval mesenchyme cells, which are believed to be progenitors of the adult mesoderm, remain undifferentiated and do not express the muscle actin genes. In M. citrina, the mesen-chyme cells differentiate precociously during larval development, suggesting a role in adultation. An adult muscle actin gene from M. citrina was obtained by screening a mantle cDNA library with a probe containing the coding region of SpMAl, a Styela plicata adult muscle actin gene. The screen yielded a cDNA clone designated McMAl, which contained virtually the complete coding and 3′ noncoding regions of a muscle actin gene. The deduced McMAl and SpMAl proteins exhibit 97% identity in amino acid sequence and may be encoded by homologous genes. The McMAl gene is expressed in juveniles and adults, but not in larval tail muscle cells, suggesting that it is an adult muscle actin gene. In situ hybridization with a 3′ non-coding region probe was used to determine whether the McMAl gene is expressed during adultation in M. citrina. McMAl mRNA was first detected exclusively in the mesenchyme cells during the late tailbud stage and continued to accumulate in these cells during their migration into the future body cavity and heart primordium in the hatched larva. The McMAl transcripts persisted in mesenchyme cells after larval metamorphosis. It is concluded that an adult muscle actin gene shows a heterochronic shift of expression into the larval phase during adultation in M. citrina.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150107
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  • 14
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994) 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150201
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  • 15
    Electronic Resource
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    Action of the Tunicate locus on maize floral development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 176-187 
    Details
    ISSN: 0192-253X
    Keywords: Floral development ; floral genetics ; Tunicate maize ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The co-dominant Tunicate (Tu) mutation in maize causes nonreproductive structures in both the male and female inflorescences to be enlarged. This mutation also affects sex determination, permitting the development of pistils in the normally staminate tassel. In order to characterize the role of the normal tu gene product, we have analysed genetic interaction between Tu and other mutations that perturb specific stages of floral development. Synergistic interactions observed suggested that the tu product functions in at least three stages of floral development-determination of spikelet primordia, differentiation of non-reproductive organs and pistil abortion in the tassel. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150208
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  • 16
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    Advantages of sexual reproduction (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 205-213 
    Details
    ISSN: 0192-253X
    Keywords: Sex ; sexual reproduction ; recombination ; diploidy ; anisogamy ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Despite the obvious efficiencies of many forms of asexual reproduction, sexual reproduction abounds. Asexual species, for the most part, are relatively short-lived offshoots of sexual ancestors. From the nineteenth century, it has been recognized that, since there is no obvious advantage to the individuals involved, the advantages of sexual reproduction must be evolutionary. Furthermore, the advantage must be substantial; for example, producing males entails a two-fold cost, compared to dispensing with them and reproducing by parthenogenetic females.There are a large number of plausible hypotheses. To me the most convincing of these are two. The first hypothesis, and the oldest, is that sexual reproduction offers the opportunity to produce recombinant types that can make the population better able to keep up with changes in the environment. Although the subject of a great deal of work, and despite its great plausibility, the hypothesis has been very difficult to test by critical observations or experiments.Second, species with recombination can bunch harmful mutations together and eliminate several in a single “genetic death.” Asexual species, can eliminate them only in the same genotype in which they occurred. If the rate of occurrence of deleterious mutations is one or more per zygote, some mechanism for eliminating them efficiently must exist. A test of this mutation load hypothesis for sexual reproduction, then, is to find whether deleterious mutation rates in general are this high-as Drosophila data argue. Unfortunately, although molecular and evolutionary studies can give information on the total mutation rate, they cannot determine what fraction are deleterious.In addition, there are short discussions of the advantages of diploidy, anisogamy, and separate sexes. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/dvg.1020150303
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  • 17
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    Temperature-dependent sex determination in reptiles: Proximate mechanisms, ultimate outcomes, and practical applications (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 297-312 
    Details
    ISSN: 0192-253X
    Keywords: Sex determination ; sexual differentiation ; reptiles ; temperature-dependent sex determination ; behavior ; steroidogenic enzymes ; aromatase ; reductase ; estrogen ; androgen ; steroid hormone receptors ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In many egg-laying reptiles, the incubation temperature of the egg determines the sex of the offspring, a process known as temperature-dependent sex determination (TSD). In TSD sex determination is an “all or none” process and intersexes are rarely formed. How is the external signal of temperature transduced into a genetic signal that determines gonadal sex and channels sexual development? Studies with the red-eared slider turtle have focused on the physiological, biochemical, and molecular cascades initiated by the temperature signal. Both male and female development are active processes - rather than the crganized/default system characteristic of vertebrates with genotypic sex determination - that require simultaneous activation and suppression of testis- and ovary-determining cascades for normal sex determination. It appears that temperature accomplishes this end by acting on genes encoaing for steroidogenic enzymes and steroid hormone receptors and modifying the endocrine microenvironment in the embryo. The temperature experienced in development also has long-term functional outcomes in addition to sex determination. Research with the leopard gecko indicates that incubation temperature as well as steroid hormones serve as organizers in shaping the adult phenotype, with temperature modulating sex hormone action in sexual differentiation. Finally, practical applications of this research have emerged for the conservation and restoration of endangered egg-laying reptiles as well as the embryonic development of reptiles as biomarkers to monitor the estrogenic effects of common environmental contaminants. © 1994 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/dvg.1020150310
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  • 18
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    Developmental significance of epigenetic impositions on the plant genome: A paragenetic function for chromosomes (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 523-532 
    Details
    ISSN: 0192-253X
    Keywords: Epigenetic ; paramutation ; cosuppression ; pattern elaboration ; flower pigmentation ; plant morphogenesis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Developmental and physiological factors can impose heritable metastable changes on the plant genome, a fact that was established by maize geneticists during the 1950s and 1960s, largely through the efforts of R. Alexander Brink and Barbara McClintock. This paper describes a transgenic reporter system that monitors genomic impositions as changes in morphogenetically-determined flower color patterns. The observations reported here on the metastable properties of plant transgenes illustrate the proposals of Brink and McClintock that chromosomal impositions occur during normal development as ordered sequences of events which contribute to the elaboration of complex developmental patterns. The relationship between this process and some recent findings about the control of gene expression in transgenic plants is also discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/dvg.1020150611
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  • 19
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    Correlated evolution of the cis-acting regulatory elements and developmental expression of the Drosophila Gld gene in seven species from the subgroup melanogaster (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 38-50 
    Details
    ISSN: 0192-253X
    Keywords: Evolution ; Drosophila ; promoter ; glucose dehydrogenase ; development ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The tissue-specific expression patterns of glucose dehydrogenase (GLD) exhibit a high degree of inter specific variation in the adult reproductive tract among the species in the genus Drosophila. We chose to focus on the evolution of GLD expression and the evolution of the Gld promoter in seven closely related species in the mela-nogaster subgroup as a means of elucidating the relationship of changes in cis-acting regulatory elements in the Gld promoter region with changes in tissue-specific expression. Although little variation in tissue-specific patterns of GLD was found in nonreproductive tissues during development, a surprisingly high level of variation was observed in the expression of GLD in both developing and ma-ture reproductive organs. In some cases this variation is correlated with changes in sequence elements in the Gld promoter which were previously shown to direct tissue-specific expression in the reproductive tract. In particular D. teissieri adult males do not express GLD in their ejaculatory ducts, atypical of the melanogaster subgroup species. The Gld promoter region of D. teissieri specifically lacks all three of the TTAGA regulatory elements present in D. melanogaster. The TTAGA elements were previously shown to direct reporter gene expression to the ejaculatory duct. Together these data suggest the absence or presence of the TTAGA elements may be responsible for variation in the absence or presence of GLD in the ejaculatory duct among species. © 1994 Wiley-Liss, Inc.
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    Ontogeny of gene expression in Pomoxis (pisces: Centrarchidae) (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 119-128 
    Details
    ISSN: 0192-253X
    Keywords: Embryogenesis ; gene expression ; isozymes ; Pomoxis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The regulation of gene expression during embryogenesis was investigated in white and black crappie (Pomoxis spp.) and their reciprocal interspecific F1 hybrids. The schedule of morphological development and the timing of isozyme expression were compared among the two species and both reciprocal maternal half-sibling F1 hybrids. Although absolute rates of morphological development differed in response to incubation temperature, relative rates of morphological development (normalized to the onset of retinal pigment deposition) were similar among all crosses. Furthermore, these relative rates were similar to those previously documented for other centrarchid species. To assess differences in ontogenetic patterns of gene expression among the crosses, we examined expression for 39 enzymeencoding loci. Expression was not detected in the embryos for 16 loci due to low or nonexistent activity. Enzymatic activity from eight other loci were continuously detected throughout embryogenesis as a result of maternal enzyme in the egg. However, 15 loci initiated expression during the early development period investigated (fertilization through yolk sac absorption). We observed temporal variability in expression of these 15 loci among the crosses, either in the form of differential expression between parental species or as disturbances in the ontogeny of expression in interspecific hybrids. Such variability in expression suggests that some of the gene regulating mechanisms have diverged since Pomoxis species shared a common ancestral genome. © 1994 Wiley-Liss, Inc.
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    Zfy is transcribed in the normal mouse epididymis and in the XXSxr (“sex reversed”) testis (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 129-138 
    Details
    ISSN: 0192-253X
    Keywords: Zinc finger Y ; sex reversed ; epididymis ; sex differentiation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The presence of the mutation Sex reversed (Sxr), a copy of a Y-chromosomal segment that gets transferred to an X chromosome, causes the resulting XXSxr mice to develop as apparent males. However, several features of male sexual development are abnormal in these animals. The testes are small and aspermatogenic, and the epididymides lack the initial segment. Testes and epididymides show abnormalities of extracellular matrix. In this study we examined transcription of the conserved Y chromosomal gene Zfy, which has an X-chromosomal homologue (Zfx). Northern blotting showed Zfy to be expressed in the testes of XXSxr animals, except for those that carry the coat-marker gene Tabby (Ta), despite the lack of germ cells in XXSxr mice. Reverse transcription polymerase chain reaction (RT-PCR) studies detected Zfy in mRNA in testes even when Ta was present. RT-PCR also demonstrated Zfy transcription in epididymides of normal males, though not in XXSxr mice. Previous authors reported an absence of Zfy transcription in XXSxr testes; Zfy transcription in normal testes has been ascribed to germ cells. Our observation indicates that this idea requires re-evaluation. The occurrence of Zfy transcription in the normal epididymis is similarly a novel finding that may help explain those aspects of epididymal development that occur in the absence of androgen. © 1994 Wiley-Liss, Inc.
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    Cell cycle mutation in Paramecium tetraurelia discriminates between sexual and vegetative functions (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 172-175 
    Details
    ISSN: 0192-253X
    Keywords: Paramecium ; DNA synthesis ; sexual pathways ; vegetative pathways ; cell cycle ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The temperature-sensitive mutation cc1 blocks a number of cell cycle processes in Paramecium including macronuclear DNA synthesis, oral morphogenesis, and the later stages of micronuclear mitosis. Oral morphogenesis and micronuclear mitosis also occur in the sexual pathway. This study shows that cc1 cells can proceed through conjugation or autogamy under restrictive conditions; neither stomatogenesis nor micronuclear mitosis is blocked. Fertilization and macronuclear determination occur normally, but DNA synthesis in macronuclear anlagen is blocked. Therefore, this mutation discriminates between oral replacement during meiosis and vegetative prefission stomatogenesis, and between mitotic spindle elongation during the pregamic and postzygotic divisions and spindle elongation during the vegetative cell cycle. These results point to a fundamental regulatory difference between morphogenesis in the vegetative and sexual pathways. © 1994 Wiley-Liss, Inc.
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    Sxl in the germline of Drosophila: A target for somatic late induction (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 265-274 
    Details
    ISSN: 0192-253X
    Keywords: Germ cells ; Inductive signals ; Sex determination ; Sex-lethal ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In Drosophila, the sex of germ cells is determined by autonomous and inductive signals. Somatic inductive signals can drive XX germ cells into oogenesis or into spermatogenesis. An autonomous signal makes XY germ cells male and unresponsive to sex determination by induction. The elements forming the X:A ratio in the soma and the genes tra, tra2, dsx, and ix that determine the sex of somatic cells have no similar role in the germline. The gene Sxl, however, is required for female differentiation of somatic and germ cells. Inductive signals that are dependent on somatic tra and dsx expression already affect the sex-specific development of germ cells of first instar larvae. At this early stage, however, germline expression of Sxl does not appear to affect the sexual characteristics of germ cells. Since inductive signals dependent on tra and dsx nevertheless influence the choice of sex-specific splicing of Sxl, it can be concluded that Sxl is a target of the inductive signal, but that its product is required late for oogenesis. Other genes must therefore control the early sexual dimorphism of larval germ cells. © 1994 Wiley-Liss, Inc.
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    Behavioral and neurobiological implications of sex-determining factors in Drosophila (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 275-296 
    Details
    ISSN: 0192-253X
    Keywords: Reproductive behavior ; courtship song ; Sex-specific internal anatomy ; doublesex mutants ; transformer mutants ; intersex mutant ; fruitless mutants ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The function of the central nervous system as it controls sex-specific behaviors in Drosophila has been studied with renewed intensity, in the context of genetic factors that influence the development of sexually differentiated aspects of this insect. Three categories of genetic variations that cause anomalies in courtship and mating behaviors are discussed: (1) mutants isolated with regard to courtship defects, of which putatively courtship-specific variants such as the fruitless mutant are a subset; (2) general behavioral and neurological variants (including sensory and learning mutants), whose defects include subnormal reproductive performance; and (3) mutations of genes within the sex-determination regulatory hierarchy of Drosophila, the analysis of which has included studies of reproductive behavior. Recent studies of mutations in two of these categories have provided new insights into the control of neuronally based aspects of sex-specific behavior. The doublesex gene, the final factor acting in the sex-determination hierarchy, had been previously thought to regulate all aspects of sexual differentiation. Yet, it has been recently shown that doublesex does not control at least one neuronally-determined feature of sex-specific anatomy - a muscle in the male's abdomen, whose normal development is, however, dependent on the action of fruitless. These considerations prompted us to examine further (and in some cases re-examine) the influences exerted by sex-determination hierarchy genes on behavior. Our results - notably those obtained from assessments of doublesex mutations' effects on general reproductive actions and on a particular component of the courtship sequence (male “singing” behavior) - lead to the suggestion that there is a previously unrecognized branch within the sexdetermination hierarchy, which controls the differentiation of the male- and female- specific phenotypes of Drosophila. This new branch separates from the doublesex-related one immediately before the action of that gene (just after fransformer and transformer-2) and appears to control as least some aspects of neuronally determined sexual differentiation of males. © 1994 Wiley-Liss, Inc.
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    Establishment of the dorsoventral axis in nemertean embryos: Evolutionary considerations of spiralian development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 64-78 
    Details
    ISSN: 0192-253X
    Keywords: Spiralians ; Nemertea ; development ; cell lineage ; evolution ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The Nemertea represent one of a number of invertebrate phyla that display a highly conserved pattern of cell division known as spiral cleavage. The fates of the early blastomeres are known for representatives of some spiralian phyla (i.e., molluscs and annelids) and in these species there appears to be a high degree of conservation in the ultimate fates of particular embryonic cells. The first two cleavage planes bear an invariant relationship to the symmetry properties of the future larval and adult body plan. To investigate whether these properties of spiralian embryo-genesis are shared (conserved) amongst members of other spiralian phyla, individual blastomeres in two- and four-cell embryos of the nemertean, Nemertopsis bivittata, were microinjected with bi-otinylated dextran lineage tracers. N. bivittata is a direct-developing hoplonemertean that forms a nonfeeding larva. When individual blastomeres are injected at the two-cell stage, two sets of complementary labeling patterns (a total of four different patterns) were observed in the ectoderm of the larvae. When cells were injected at the four-cell stage, four different patterns were observed that represented subsets of the four patterns observed in the previous experiment. Unlike the case in the annelids and molluscs, in which the first cleavage plane bears a strict 45° angular relationship to the future dorsoventral axis, the first cleavage plane in N. bivittata can bear one of two different relationships relative to the larval/adult dorsoventral axis. In half the cases examined, the first cleavage plane corresponded roughly to the plane of bilateral symmetry, and in the rest, it lay along a frontal plane. A similar result was observed for the embryos of the indirect-developing heteronemertean, Cerebratutus lacteus. These results indicate that the fates of the four cell quadrants in nemerteans are not directly homologous to those in other spira-lians, such as the annelids and molluscs. For instance, no single cell quadrant appears to contribute a greater share to the formation of ectoderm, as is the case in the formation of the post-trochal region by the D-cell quadrant in annelids and mol-luscs. Rather, two adjacent cell quadrants contribute nearly equally to the formation of dorsal or ventral ectoderm in the larvae. Possible explanations for the determination of dorsoventrality in nemerte-ans, as well as implications of these findings regarding the evolution of spiralian development, are discussed. © 1994 Wiley-Liss, Inc.
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    Developmental quantitative genetic models of evolutionary change (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 92-103 
    Details
    ISSN: 0192-253X
    Keywords: Developmental quantitative genetics ; development ; epigenetic ; evolution ; genetic models ; effects ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Discussions about evolutionary change in developmental processes or morphological structures are predicated on specific quantitative genetic models whose parameters predict whether evolutionary change can occur, its relative rate and direction, and if correlated change will occur in other related and unrelated structures. The appropriate genetic model should reflect the relevant genetical and developmental biology of the organisms, yet be simple enough in its parameters so that deductions can be made and hypotheses tested. As a consequence, the choice of the most appropriate genetic model for polygenically controlled traits is a complex tissue and the eventual choice of model is often a compromise between completeness of the model and computational expediency. Herein, we discuss several developmental quantitative genetic models for the evolution of development and morphology. The models range from the classical direct effects model to complex epigenetic models. Further, we demonstrate the algebraic equivalency of the Cowley and Atchley epigenetic model and Wagner's developmental mapping model. Finally, we propose a new multivariate model for continuous growth trajectories. The relative efficacy of these various models for understanding evolutionary change in developmental and morphological traits is discussed. © 1994 Wiley-Liss, Inc.
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    The Knotted leaf blade is a mosaic of blade, sheath, and auricle identities (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 401-414 
    Details
    ISSN: 0192-253X
    Keywords: Mosaic of cell identities ; knotted leaf ; homeobox gene ; cell fates ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The dominant Knotted-1 mutations in maize alter development of the leaf blade. Sporadic patches of localized growth, or knots, and fringes of ectopic ligule occur along lateral veins of mutant leaf blades. In addition, bundle sheaths do not completely encircle lateral veins on mutant leaf blades. We have compared mutant leaf blades with wild-type leaves to determine the precise nature of the perturbed regions. Our analysis includes characterization of epidermal cell shapes, localization of photosynthetic proteins and histology of the leaf. We show that mutant leaf blades are a mosaic of leaf organ components. Affected regions of mutant leaf blades resemble either sheath or auricle tissue in both external and internal features. This conversion of blade cells represents an acropetal shift of more basal parts of the leaf blade region and correlates with previously identified ectopic expression of the Knotted-1 protein in the leaf blade. We propose that inappropriate expression of Kn1 interferes with the process of establishment of cell identities, resulting in early termination of the normal blade development program or precocious expression of the sheath and auricle development programs. © 1994 Wiley-Liss, Inc.
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    Epigenetics: An overview (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 453-457 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150602
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    Masthead (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994) 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150101
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    Expression patterns of twist and snail in Tribolium (Coleoptera) suggest a homologous formation of mesoderm in long and short germ band insects (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 32-37 
    Details
    ISSN: 0192-253X
    Keywords: Pattern formation ; mesoderm specification ; short germ band insect embryogenesis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The mesodermal region in Drosophila is determined by a maternally derived morphogenetic gradient system which specifies the different cell fates along the dorsoventral axis, including the prospective mesodermal cells at the ventral side of the embryo. There are at least two zygotic target genes, twist and snail, which are required for mesoderm formation in Drosophila. To analyze whether a similar mode of mesoderm specification might also apply to short germ band insect embryos, we have cloned twist and snail- related gene fragments from the flour beetle Tri-bolium and have analyzed their expression pattern. Both genes are expressed in a ventral stripe at early blastoderm stage, which is restricted to the region of the developing germ rudiment. The cells expressing the two genes are those that invaginate during gastrulation, indicating that the early stages of mesoderm specification are indeed very similar between the two species. Interestingly, both genes are also expressed during germband extension in a subregion of the growth zone of the embryo which forms the mesodermal cells. This suggests that the expression of the two genes is required for mesoderm formation both at early blastoderm stage and during germband elongation until the end of the segmental growth process. © 1994 Wiley-Liss, Inc.
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    Quantitative genetics of butterfly wing color patterns (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 79-91 
    Details
    ISSN: 0192-253X
    Keywords: Butterfly wing patterns ; developmental constraints ; genetic correlations ; nymphalid groundplan ; quantitative genetics ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Developmental processes exert their influence on the evolution of complex morphologies through the genetic correlations they engender between traits. Butterfly wing color patterns provide a model system to examine this connection between development and evolution. In butterflies, the nymphalid groundplan is a framework used to decompose complex wing patterns into their component pattern elements. The first goal of this work has been to determine whether the components of the nymphalid groundplan are the products of independent developmental processes. To test this hypothesis, the genetic correlation matrices for two species of butterflies, Precis coenia and Precis evarete, were estimated for 27 wing pattern characters. The second purpose was to test the hypothesis that the differentiation of serial homologs lowers their genetic correlations. The “eyespots” found serially repeated across the fore- and hindwing and on the dorsal and ventral wing surfaces provided an opportunity to test this hypothesis. The genetic correlation matrices of both species were very similar. The pattern of genetic correlation measured between the different types of pattern elements and between the homologous repeats of a pattern element supported the first hypothesis of developmental independence among the elements of the groundplan. The correlation pattern among the differentiated serial homologs was similarly found to support the second hypothesis: pairs of eyespots that had differentiated had lower genetic correlations than pairs that were similar in morphology. The implications of this study are twofold: First, the apparent developmental independence among the distinct elements of wing pattern has facilitated the vast diversification in morphology found in butterflies. Second, the lower genetic correlations betweendifferentiated homologs demonstrates that developmental constraints can in fact be broken. The extent to which genetic correlations readily change, however, remains unknown. © 1994 Wiley-Liss, Inc.
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    Diverse programs of ascus development in pseudohomothallic species of Neurospora, Gelasinospora, and Podospora (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 104-118 
    Details
    ISSN: 0192-253X
    Keywords: Ascus development ; spindle pole ; body plaque ; spindle orientation ; heterokaryotic ascospore ; pseudohomothallism ; Neurospora fetrasperma ; Gelasinospora tetrasperma ; Podospora anserina ; Podospora fefraspora ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Meiosis and ascospore development in the four-spored pseudohomothallic ascomycetes Neurospora tetrasperma, Gelasinospora tetrasperma, Podospora anserina, and P. fefraspora have been reexamined, highlighting differences that reflect independent origins of the four-spored condition in the different genera. In these species, as in the heterothallic eight-spored N. crassa, fusion of haploid nuclei is followed directly by meiosis and a postmeiotic mitosis. These divisions take place within a single unpartitioned giant cell, the ascus, which attains a length of 〉0.1 mm before nuclei are enclosed by ascospore walls. Two basically different modes underlie the delivery of opposite mating type nuclei into each of the four ascospores in the different genera. In N. tefrasperma on the one hand, the mating type locus is closely centromere-linked. Mating types therefore segregate at the first meiotic division. The second division spindles of N. tefrasperma overlap and are usually parallel to one another, in contrast to the their tandem arrangement in N. crassa. As a result, nonsister nuclei of opposite mating type are placed close together in each half-ascus and a pair is enclosed in each ascospore. In the Podospora and Gelasinospora species on the other hand, the second-division spindles are in tandem, with sister nuclei of opposite mating type associated as a pair in each half-ascus. It is established for P. anserina and inferred for P. fetraspora and G. fefrasperma that a single reciprocal crossing over almost always occurs in the mating type-centromere interval, ensuring that mating types segregate at the second meiotic division and that nuclei of opposite mating type are enclosed in each ascospore.Other differences are also seen that are less fundamental. Neurospora tetrasperma differs from the other species in the orientation of chromosomes and spindle pole body plaques at interphase (I.) Third-division spindles are oriented parallel to the ascus wall in Gelasinospora but across the ascus in Podospora and Neurospora. The two Podospora species differ from one another in nuclear behavior following mitosis in the young ascospores. In P. tefraspora, two of the four nuclei migrate into the tail cell, which degenerates, leaving one functional nucleus of each mating type. In P. anserina, by contrast, only one of the four nuclei moves into the tail cell, leaving the germinating ascospore with two functional nuclei of one mating type and one of the other.The pseudohomothallic condition with its heterokaryotic vegetative phase has significant consequences for both the individual organism and the breeding system. Genetic controls of development and recombination are complex. Inbreeding is not obligatory. © 1994 WiIey-Liss, Inc.
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    Developmentally regulated expression of fibroblast growth factor receptor genes and splice variants by murine embryonic stem and embryonal carcinoma cells (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 148-154 
    Details
    ISSN: 0192-253X
    Keywords: Fibroblast growth factor ; receptor ; gene expression ; RNA splicing ; embryonic stem cells ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The expression of the four fibroblast growth factor receptor (FGF-R) genes was examined in murine embryonic stem (ES) cells, embryonal carcinoma (EC) cells, and their differentiated derivatives. FGF-R1 and FGF-R4 were found to be expressed constitutively in all samples examined. The expression of FGF-R2 and FGF-R3 was, however found to increase significantly upon differentiation of both ES and EC cells. Examination of splice variants of the third immunoglobulin domain (Iglll) of the extracellular region of the FGF-R2 revealed that whilst Iglllc transcripts were expressed upon ES cell differentiation, Iglllb transcripts (which confer specificity for the ligand FGF-7) were expressed in both ES cells and their differentiated progeny. FGF-R3 transcripts were also expressed in ES cells, but variont FGF-R3 transcripts containing the Iglllb region were expressed upon differentiation. The findings suggest that the repertoire of FGF-R expression in embryonic cell types is developmentally regulated at the level of both gene expression, and alternative splicing and different members of the FGF-R family can exhibit distinct patterns of both gene and splice variant expression. © 1994 Wiley-Liss, Inc.
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    Masthead (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994) 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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    Regulatory rearrangements and smg-sensitive allels of the C. elegans sex-determining gene tra-1 (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 240-250 
    Details
    ISSN: 0192-253X
    Keywords: Sex determination ; zinc fingers ; C elegans ; smg mutations ; tra-1 ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The tra-1 gene is the terminal regulator in the sex determination pathway in C. elegans, directing all aspects of somatic sexual differentiation. Recessive loss-of-function (If) mutations in tra-1 masculinize XX animals (normally somatically female), while dominant gain-of-function mutations feminize XO animals (normally male). Most tra-1(If) mutations can be fitted into a simple allelic series of somatic masculinization, but a small number of If alleles do not fit into this series. Here we show that three of these mutations are associated with DNA rearrangements 5′ to the coding region. One allele is an inversion that may be subject to a position effect. We also report the isolation of a new class of tra-1 alleles that are responsive to mutations in the smg system of RNA surveillance. We show that two of these express RNAs of aberrant size. We suggest that the smg-sensitive mutations may identify a carboxy-terminal domain required for negative regulation of tra-1 activity. © 1994 Wiley-Liss, Inc.
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    Metamorphosis: Model systems for studying gene expression in postembryonic development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 313-319 
    Details
    ISSN: 0192-253X
    Keywords: Metamorphosis ; postembryonic development ; thyroid hormones ; ecdysteroids ; amphibians ; insects ; fish ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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    S6 phosphorylation results from prothoracicotropic hormone stimulation of insect prothoracic glands: A role for S6 kinase (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 332-338 
    Details
    ISSN: 0192-253X
    Keywords: Insect molting ; ecdysteroid ; S6 kinase ; rapamycin ; immunosuppressant ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The insect prothoracic glands are the source of steroidal molting hormone precursors and the glands are stimulated by a brain neuropeptide, prothoracicotropic hormone (PTTH). Previous work from this laboratory revealed that PTTH acts via a cascade including Ca2+/calmodulin activation of adenylate cyclase, protein kinase A, and the subsequent phosphorylation of a 34 kDa protein (p34) hypothesized, but not proven, to be the 56 protein of the 40S ribosomal subunit. The jmmunosuppressive macrolide, rapamycin, is a potent inhibitor of cell proliferation, a signal transduction blocker, and also prevents ribosomal S6 phosphorylation in mammalian systems. We demonstrate here that rapamycin inhibited PTTH-stimulated ecdysteroidogenesis in vitro by the prothoracic glands of the tobacco hornworm, Manduca sexta, with half-maximal inhibition at a concentration of about 5 nM. At concentrations above 5 nM, there was a 75% inhibition of ecdysteroid biosynthesis. Similar results, were observed with the calcium ionophore (A23187), a known stimulator of ecdysteroidogenesis. Most importantly, the inhibition of ecdysteroid biosynthesis was accompanied by the specific inhibition of the phosphorylation of p34, indicating that p34 indeed is ribosomal protein S6. In vivo assays revealed that injection of rapamycin into day 6 fifth instar larvae resulted in a decreased hemolymph ecdysteroid titer and a dose-dependent delay in molting and metamor-phosis. When S6 kinase (S6K) activity was examined using rapamycin-treated prothoracic glands as the enzyme source and a synthetic peptide (S6-21) or a 40S ribosomal subunit fraction from Manduca tissues as substrate, the date revealed that rapamycin inhibited S6K activity. The composite data suggest that rapamycin inhibits a signal transduction element leading to p34 phosphorylation that is necessary for PTTH-stimulated ecdysteroidogenesis in this insect endocrine gland, and lend further support to the concept that p34 is S6. © 1994 Wiley-Liss, Inc.
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    Cloning of thyroid hormone receptor genes expressed in metamorphosing flounder (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 378-382 
    Details
    ISSN: 0192-253X
    Keywords: Thyroid hormone receptor ; metamorphosis ; fish ; cDNA cloning ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two distinct cDNAs encoding thyroid hormone receptors (THRs) were cloned from a λ gtl0 library prepared from the whole bodies of metamorphosing flounder larvae (Paralichfhys olivaceus). Deduced amino acid sequences of the two isolated cDNAs shared 96% and 92% homologies in their DNA- and hormone-binding domains, respectively. These were highly conserved when compared to THRs for other vertebrates: 88-96% in the DNA-binding domain and 84-94% in the hormone-binding domain. Other receptors in the nuclear receptor family showed lower homologies than those of THRs. Both THRs for the flounder had higher homologies with the α-type THRs of other vertebrates than with the β-type. Thus, the two THRs for flounder were designated as fTHRαA and fTHRαB. © 1994 Wiiey-Liss, Inc.
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    Regulation of juvenile hormone esterase gene transcription by juvenile hormone (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 391-400 
    Details
    ISSN: 0192-253X
    Keywords: Juvenile hormone ; juvenile hormone esterase ; transcription ; Trichoplusiani ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Juvenile hormone (JH) is a major hormone regulating insect development. We have obtained a cDNA and a genomic clone for juvenile hormone esterase (JHE), the enzyme that is involved in the degradation of juvenile hormone and which is critical for insect development. Analysis of the regulation of JHE during the final larval stadium in the cabbage looper, Trichoplusia ni, showed that the JHE mRNA levels are maximal on days 2 and 4 of the final stadium. Nuclear run-on analyses demonstrated that changes in JHE mRNA levels are primarily due to changes in the transcription rate of the gene, which may be a single copy in the genome. Treatment with a JH analog resulted in induction of JHE gene transcription, which could be detected within three hours after treatment. Salient features present in the 5′ flanking region of this JH-sensitive gene are presented, including the presence of sequences closely resembling binding sites for members of the family of nuclear receptors. This report is the first direct demonstration, by nuclear run-on analysis, of JH induction of gene transcription. © 1994 Wiley-Liss, Inc.
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    Masthead (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994) 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150601
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    Reactivation of inactive X-linked genes (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 504-514 
    Details
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150609
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    Experimental embryological analysis of genetic imprinting in mouse development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 515-522 
    Details
    ISSN: 0192-253X
    Keywords: Genetic imprinting ; androgenesis ; parthenogenesis ; development ; chimeras ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1002/dvg.1020150610
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    DNA sequence requirements for the regulation of immobilization antigen a expression in Paramecium tetraurelia (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 443-451 
    Details
    ISSN: 0192-253X
    Keywords: Paramecium tetraurelia ; immobilization antigen ; gene expression ; promoter ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The Paramecium surface proteins (immobilization antigens) are expressed in a mutually exclusive manner; only one antigen is found on the cell surface at a time. Expression of these proteins is regulated in response to environmental cues such as temperature and pH. This regulation has been shown to be controlled at the level of mRNA abundance by transcriptional and post-transcriptional mechanisms. Here, we have studied the transcription and regulated expression of the immobilization antign A gene in Paramecium tetraurelia by transforming an A -deficient strain, d12, with cloned portions of the A gene viamicroinjection. The A gene is approximately 8 kilobases (kb) long with the transcription start site at postion -9 or -8 and the start of translation at position +1. Paramecia transformed with cloned DNA containing A-gene sequences beginning at position -264 and ending 63 base pairs (bp) past the gene's polyadenylation site show properly regulated expression of immobilization antigen A. Lines derived from paramecia transformed with a plasmid containing A-gene sequences starting at position -211, however, show markedly reduced A-gene mRNA levels, and rarely express the A antigen. Nevertheless, cells that do express the A protein exhibit mutual exclusion and normal responses to environmental stimuli. Thus, the 54 bp between -264 and -211, while important for transcription, are not involved in the control of mutual exclusion and responses to environmental chages. Further deletion to position -151 yields similar, but more extreme, results. Therefore, the start of the A-gene promoter lies within the region -264 to -211, with additional sequences affecting transcriptional regulation present between base pairs -211 and -151. Sequences controlling environmental responses and mutual exclusion must be located downstream of position -211. Thus, we have defined regions of DNA necessary for immobilization antigen A expression and have located the approximate position of the A-gene promoter in Paramecium. This work paves the way for a precise mutational analysis of these regions and the first detailed molecular characterization of a Paramecium promoter. © 1994 Wiley-Liss, Inc.
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    Inheritance of chromatin states (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 463-470 
    Details
    ISSN: 0192-253X
    Keywords: Transcription factor ; histone ; nucleosome ; heterochromatin ; replication ; chromodomain protein ; transcription ; methylation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1002/dvg.1020150604
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    Positional information and pattern formation in development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 485-490 
    Details
    ISSN: 0192-253X
    Keywords: Pattern formation ; positional information ; periodic structures ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A widely used mechanism for pattern formation is based on positional information: cells acquire positional identities as in a coordinate system and then interpret this information according to their genetic constitution and developmental history. In Drosophila maternal factors establish the axes and set up a maternal system of positional information on which further patterning is built. There is a cascade of gene activity which leads both to the development of periodic structures, the segments, and to their acquiring a unique identity. This involves the binding of transcription factors to regulatory regions of genes to produce sharp thresholds. Many of the genes involved in these processes, particularly the Hox complex, are also involved in specifying the body axis and limbs of vertebrates. There are striking similarities in the mechanisms for spcifying and recording positional identity in Drosophila and vertebrates. © 1994 Wiley-Liss, Inc.
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    IME1 gene encodes a transcription factor which is required to induce meiosis in Saccharomyces cerevisiae (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 139-147 
    Details
    ISSN: 0192-253X
    Keywords: IME1 ; meiosis ; transcriptional activator ; S. cerevisiae ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Previous studies have shown that the IME1 gene is required for sporulation and the expression of meiosis specific genes in Saccharomyces cerevisiae. However, sequence analysis has not revealed the precise functional role of the Ime1 protein. By engineering constructs which express various portions of the Ime1p fused to either the DNA binding or transcriptional activation domains of GAL4, we have conclusively demonstrated that IME1 is a transcription factor, apparently required for sporulation to activate the transcription of meiosis specific genes. The full Ime1p, when fused to the GAL4 DNA binding domain, can both activate GAL1-IacZ expression, and complement Ime1-0 (a null allele) for the ability to sporulate, and transcriptionally activate IME2, a meiosis specific gene. As successively larger portions of the encoded Ime1p N-terminus are deleted from the GAL4(bd)-IME1 construct, the encoded fusion proteins retain the ability to complement an ime1 null allele, despite a decreasing ability to activate GAL1-lacZ transcription. However, a fusion construct which retains only the last 45 C-terminal amino acids of IME1 provides neither transcriptional activation of GAL1-lacZ nor complementation of ime1-0. Fusion of a GAL4 activation domain to this portion of IME1, results in a construct with a restored ability to complement an ime1-0 cllele. This restored ability is dependent upon galactose induction. We conclude, therefore, that IME1 functions in meiosis as a transcriptional activator. © 1994 Wiley-Liss, Inc.
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    Sex determination in Drosophila melanogaster: X-linked genes involved in the initial step of Sex-lethal activation (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 251-264 
    Details
    ISSN: 0192-253X
    Keywords: Drosophila ; sex determination ; X:A signal ; Sex-lethal activation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sex determination is the commitment of an embryo to either the female or the male developmental pathway. The ratio of X chromosomes to sets of autosomes is the primary genetic signal that determines sex in Drosophila, by triggering the functional state of the gene Sex-lethal: in females (2X;2A) Sxl will be ON, whereas in males (X;2A) Sxl will be OFF. Genetic and molecuar studies have defined a set of genes involved in the formation of the X:A signal, as well as other genes, with either maternal or zygotic effects, which are also involved in regulating the initial step of Sex-lethal activation. We review these data and present new data on two more regions of the X chromosome that define other genes needed for Sxl activation. In addition, we report on the interaction between some of the genes regulating Sxl activation. © 1994 Wiley-Liss, Inc.
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    Cloning of a thyroid hormone-responsive Rana catesbeiana c-erbA-β gene (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 339-346 
    Details
    ISSN: 0192-253X
    Keywords: 3,5,3′-Triiodothyronine ; thyroxine ; thyroid hormone β receptor gene ; Rana catesbeiana ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two types of thyroid hormone receptor (c-erbA) gene have been identified in mammals and in lower species including chickens and the amphibian Xenopus laevis. The two genes are located on different chromosomes and have been named TRα and TRβ We have described previously the cloning of a TRβ cDNA from Rana catesbeiana (RC) tissues (RC15) and we now report the cloning of a TRβ cDNA from this species. The cloning strategy employed utilized the polymerase chain reaction (PCR), with primers based on the sequences of the X. laevis TRβ cDNA (XenTRβ) and an RCTRβ genomic clone, which, by analogy with XenTRβ, contains some of the 3′ end of the open reading frame together with 3′-untranslated sequences. At the nucleotide and amino acid levels, respectively, the cloned RCTRβ cDNA is 90% and 98% homologous with XenTRβ, and 72% and 76% homologous with RC15. Following in vitro transcription and translation, the cDNA was shown to encode a 48 kilodalton protein which binds 3,5, 3′-triiodothyronine (T3) with high affinity (mean Kd: 0.032 nM). Samples of total or poly(A)+RNA from tadpoles at different stages of metamorphosis and from adult frogs were analyzed for the presence ofTRβ-specific transcripts by slot blot analysis using as probe a 258 bp section of the RCTRβ cDNA. This section of the cDNA does not hybridize to the corresponding section of RC15. In confirmation of previous findings, β-specific transcripts were not detected in RNA from tadpole red blood cells (RBCs) and none was found in RBCs from adult frogs. However, β-specific transcripts were detected in RNA from tail, skin, and liver of stage XIII tadpoles, and the levels were greatly increased in these tissues during metamorphic climax. In the adult frog, the level was minimal in all tissues studied. In other studies using stage XII tadpoles and a reverse transcription-polymerase chain reaction assay, β-specific transcripts were readily detected in tail, skin, kidney, leg, heart, intestine, and eye but minimal or absent in liver, brain, and RBCs. Within 2 days of injection of T3, the level of β-specific transcripts was markedly increased in all tissues. These findings strongly suggest that the expression of the RCTRβ gene is regulated developmentally and/or by thyroid hormone in most tissues of the RC tadpole. © 1994 Wiley-Liss, Inc.
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    Epigenetic effects in eukaryotic gene expression (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 458-462 
    Details
    ISSN: 0192-253X
    Keywords: Epigenetic phenomena ; chromatin structure ; eukaryotes ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the broadest terms, epigenetic phenomena in eukaryotes depend on the interaction of alleles or repeated sequences or on the mitotic inheritance of chromatin states or methylation patterns. One of the most exciting aspects of the study of epigenetic phenomena is the insight that can be gained into the structure and assembly of higher-order chromatin structures, an important subject that has proved refractory to current biochemical methodologies. Rapid progress in the study of gene inactivation in fungi, plants, and invertebrates will provide new hypotheses to be tested in mammals. © 1994 Wiley-Liss, Inc.
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    Spreading the silence: Epigenetic transcriptional regulation during Drosophila development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 478-484 
    Details
    ISSN: 0192-253X
    Keywords: Drosophila development ; transcription regulation ; pattern formation ; chromatin structure ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In early Drosophila development a complex cascade of diffusible transcription factors generates an intricate expression pattern of developmental regulators such as the homeotic genes. The mechanism which subsequently maintains the pattern during the rest of development is mainly using epigenetic features for its function. Evidence comes from the analysis of the Polycomb-group (Pc-G), a class of genes which is responsible for maintaining the inactive state of expression. The Pc-G was found to share many parallels to genes involved in heterochromatin formation. Different members of the Pc-G interact in large multiprotein complexes, which apparently can cover and inactivate large chromosomal domains. Specific DNA elements have been identified that are used by the Pc-G proteins to nucleate these specialized domains of silent chromatin. Thus, the Pc-G proteins appear to permanently inactivate genes by generating heterochromatin-like structures which could then be inherited by the daughter cells in an epigenetic manner. Heritable gene silencing is an important but little understood mechanism in pattern formation. Phenomenologically related effects have been observed in many organisms. These range from the transcriptional silencing of the inactive mating type loci in yeast to parental imprinting phenomena and X-chromosome inactivation in mammals. Analysis of these functions in Drosophila provides an excellent model system for studying the molecular basis of such epigenetic mechanisms that use higher order chromatin structures for transcriptional repression. © 1994 Wiley-Liss, Inc.
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    Function of the her-1 gene is required for maintenance of male differentiation in adult tissues of C. elegans (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 231-239 
    Details
    ISSN: 0192-253X
    Keywords: Commitment ; differentiation ; sex determination ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Function of the sex-determining gene her-1 is required in XO embryos cf C. elegans to specify male development. Using a temperature-sensitive mutant of her-1, we show that when XO males reared at a permissive temperature are shifted as adults to a nonpermissive temperature, they initiate vitellogenin synthesis in the intestine and oocyte production in the germline. A similar shift has no effect on her-1(+) males. We conclude that sexual differentiation of the intestine and germline is plastic, requiring her-1 expression throughout adulthood for maintenance of the male state. © 1994 Wiley-Liss, Inc.
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    Isolation of silencer-containing sequences causing a tissue-specific position effect on alcohol dehydrogenase expression in Drosophila melanogaster (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 188-200 
    Details
    ISSN: 0192-253X
    Keywords: Alcohol dehydrogenase ; silencer ; tissue-specific position effect ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A transient expression assay has been used to investigate the cause of a tissuespecific position effect on Adh expression from a transgene insertion in Drosophila. A 15.4-kb genomic clone containing the 3.2-kb Adh insert along with flanking regions of genomic DNA is expressed in this assay in a tissue-specific pattern resembling the abnormal expression pattern of the position effect. The 3.2-kb Adh insert is expressed normally without the flanking sequences. A silencer element is located upstream of the Adh gene within a 2-kb fragment that acts in both orientations and at a distance of at least 6.5 kb from the larval Adh promoter to suppress ADH expression in a nontissue specific fashion. The DNA sequence of the 2-kb fragment indicates that it is a noncoding region. A 17-bp sequence is repeated within this region and may be associated with the silencer activity, since subclones from the 2-kb fragment, each containing one of the repeated regions, both retain full silencer activity. This silencer fails to suppress expression from an α1-tubulin promoter-LacZ fusion construct or an hsp70 promoter-Ach fusion construct. In addition to the silencer, another element is located downstream of the Adh gene that produces a higher level of anterior than posterior midgut expression. These results suggest that the 5′ silencer and the 3′ element act together to create the tissue specific pcsition effect characteristic of the GC-1 line. © 1994 Wiley-Liss, Inc.
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    Hemoglobin switching in Rana/Xenopus erythroid heterokaryons: Factors mediating the metamorphic hemoglobin switch are conserved (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 347-355 
    Details
    ISSN: 0192-253X
    Keywords: Hemoglobin switching ; metamorphic Hb switch ; hemoglobins ; development ; Rana catesbeiana ; Xenopus laevis ; erythroid cell differentiation ; heterokaryons ; cell fusion ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hemoglobin switching, which occurs in all classes of vertebrates as well as in certain invertebrates, is due to developmental regulation of different globin genes which are typically arranged in clustered families. By fusing erythroid cells of different developmental programs, trans-acting factors that regulate this switch in gene expression have been detected [Ramseyer et al. (1989): Dev Biol 133:262-271]. Adult erythroid cells of one anuran species, Xenopus laevis, were fused with tadpole erythroid cells of another frog, Rana catesbeiana, creating developmental erythroid heterokaryons that synthesize adult Rana globin mRNA and hemoglobins. The results show that factors from adult Xenopus erythroid cells are capable of inducing adult Rana globin gene expression in the Rana tadpole erythroid cell nucleus. We have used the cross-induction of adult Rana hemoglobin synthesis in these adult Xenopus/Rana tadpole erythroid heterokaryons to address two practical questions, answers to which may be helpful in isolating developmental stage-specific globin gene regulatory proteins: (1) Are erythroblasts which are actively expressing globin mRNAs and hemoglobins richer in specific globin-inducing activities than other stages of erythroid cellular differentiation? (2) Do mature, circulating erythrocytes still have the activities necessary to mediate the cross-induction of Hb synthesis? The results reported here show that the answers to both questions are affirmative and show that quiescent, fully differentiated adult erythroid cells are still capable of expressing the trans-activator(s). These findings show that factors which mediate the metamorphic hemoglobin switch are conserved between these two genera of frogs. © 1994 Wiley-Liss, Inc.
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    Screen for enhancers of Polycomb and Polycomblike in Drosophila melanogaster (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 425-434 
    Details
    ISSN: 0192-253X
    Keywords: Polycomb group ; homeotic ; spalt ; devenir ; Su(Pc)37D ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: There are 11 Polycomb group genes known in Drosophila. These genes are negative regulators of homeotic gene expression, and may act by modifying chromatin structure. It is not clear how many members of the Polycomb group of genes exist. Many were discovered because of their homeotic phenotypes, or because they enhance homeotic mutations. Systematic screens for enhancers of Polycomb have identified previously known members of the Polycomb group. In an attempt to discover cytological locations of new Polycomb group genes, we crossed deletions uncovering about 20% of the genome to Polycomb-like and Polycomb and scored for enhancement of the extra sex combs phenotype. Haploidy for four regions, 36F7-37A, 43E18; 44B5-9, 70C2-6, and 70C6-15; 70D enhanced the extra sex comb phenotype associated with strong Polycomb group mutations. These regions have homeotic phenotypes either as homozygous embryos or heterozy-gous adults, or both. We also show that spalt enhances Polycomb group mutations. These results are discussed with respect to previous estimates of Polycomb group gene number. © 1994 Wiley-Liss, Inc.
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    Analysis of multiple classes of abscisic acid-responsive genes during embryogenesis in zea mays (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 415-424 
    Details
    ISSN: 0192-253X
    Keywords: Plant embryogenesis ; seed development ; maize ; phytohormone ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have examined the effects of the plant growth regulator abscisic acid (ABA), on the accumulation of three transcripts during maize embryogenesis. The Emb5 and Rab -17 transcripts were first detected during mid embryogenesis and accumulated to high levels during late embryogenesis. In an ABA-deficient mutant, both transcripts were accumulated at very low levels. Treatment with μM ABA during early and mid embryogenesis, but not during late embryogenesis, in the wild type and the ABA-deficient mutant enhanced the accumulation of the Emb5 and Rab-17 transcripts. The oleosin KD18 transcript was detected at moderate levels during early embryogenesis, reached a peak during mid embryogenesis and then declined gradually. Embryos incubated in the absence of ABA exhibited a rapid loss of the oleosin KD18 transcript whereas a high level of accumulation of this transcript was maintained by incubation with nM ABA. Interestingly, the oleosin KD18 transcript was accumulated at high levels in the ABA-deficient mutant and was also detected, albeit at low levels, in an ABA-insensitive mutant. In addition, the Rab-17 transcript could be stimulated to accumulate in vegetative tissue by either ABA or water stress. Similar treatment of vegetative tissue did not induce the accumulation of Emb5 or oleosin KD18 transcripts. These results suggest that ABA-responsive genes expressed during maize embryo-genesis are regulated by multiple mechanisms. © 1994 Wiley-Liss, Inc.
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    Epigenetics and the maintenance of gene activity states in Caenorhabditis elegans (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 471-477 
    Details
    ISSN: 0192-253X
    Keywords: Epigenetics ; Caenorhabditis elegans ; imprinting ; regulatory circuits ; sex determination ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The nematode Caenorhabditis elegans has been the subject of many detailed investigations in developmental biology. Molecular analyses have failed to detect covalent alterations to DNA, such as methylation or rearrangement, during development of C. elegans. Genetic experiments indicate that imprinting of gamete genomes does not occur to any significant extent. The maintenance of gene activity states in this organism may depend predominantly on regulatory gene circuitry. Some possible examples of maintenance circuits are discussed. © 1994 Wiley-Liss, Inc.
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    Expression of an X-linked HMG-lacZ transgene in mouse embryos: Implication of chromosomal imprinting and lineage-specific X-chromosome activity (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 491-503 
    Details
    ISSN: 0192-253X
    Keywords: X chromosome ; X inactivation ; lacZ transgene ; cell lineage ; mouse embryo ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: X-chromosome activity in female mouse embryos was studied at the cellular level using an X-linked lacZ transgene which encodes β-galactosidase (β-Gal). Translation of maternal RNA in oocytes is seen as β-Gal activity that persists into early cleavage-stages. Zygotic transcription of the transgene from the maternal X chromosome (Xm) is first found at about the 8-cell stage. By contrast, expression of the lacZ transgene on the paternal X chromosome (Xp) is not seen until later at the 16-32-cell stage. Preferential inactivation of Xp occurs in the mural trophectoderm, the primitive endoderm, and derivatives of the polar trophectoderm, but a small number of cells in these lineages may still retain an active paternal X chromosome. X inactivation begins at 3.5 days in the inner cell mass but contrary to previous findings the process is not completed in the embryonic ectoderm by 5.5 to 6.0 days. Regional variation in β-Gal activity is also observed in the embryonic ectoderm during gastrulation which may be related to the specification of cell fates. Random inactivation of Xp and Xm ensues in all somatic tissues but the process is completed at different times in different tissues. The slower progression of X inactivation in tissues such as the notochord, the heart, and the embryonic gut is primarily due to the persistent maintenance of two active X chromosomes in a significant fraction of cells in these tissues. Recent findings on the methylation of endogenous X-linked genes suggest that the prolonged expression of β-Gal might also be due to the different rate of spreading of inactivation along the X chromosome to the lacZ transgene locus in different tissues. © 1994 Wiley-Liss, Inc.
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    frizzled Gene expression and development of tissue polarity in the Drosophila wing (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 383-389 
    Details
    ISSN: 0192-253X
    Keywords: Tissue polarity ; Drosophila ; wing ; frizzled ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Almost every cell in the Drosophila pupal wing forms a single, distally pointing cuticular hair. The function of the frizzled (fz) gene is essential for the elaboration of the normal wing hair pattern. In the absence of fz function hairs develop, but they display an abnormal polarity. We have examined the developmental expression of the fi gene at the RNA level via in situ hybridization and at the protein level via Western blotting. We have found that fz is expressed in all regions of the epidermis before, during, and after the fz cold sensitive period. We have also found that fz function is not required for normal fi expression. We have further found that mutations in several other tissue polarity genes do not noticeably alter the expression or the modification state of the Fz protein. © 1994 Wiley-Liss, Inc.
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    N(B(NMe2)2)(Si(NMe2)3)(Ti(NMe2)3), [N(Si(NMe2)3)(Ti(NMe2)2)]2 und N(SiMe3)(Si(NMe2)3)(Ti(NMe2)3)  -  Synthese und Charakterisierung neuer molekularer Einkomponentenvorläufer für nitridische und carbonitridische Keramiken (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 366-370 
    Details
    ISSN: 0044-2313
    Keywords: Bis(dimethylamino)boryl-tris(dimethylamino)silyl-tris(dimethylamino)titanylamin ; N,N′-Bis(tris(dimethylamino)-silyl)-1,1,3,3-tetrakis(dimethylamino)cyclobistitanazan, Trimethylsilyl-tris(dimethylamino)silyl-tris(dimethylamino)titanylamin ; Trimethylsilyl-tris(dimethylamino)-silylamin ; synthesis ; nmr spectra ; mass spectra ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N(B(NMe2)2)(Si(NMe2)3) (Ti(NMe2)3), [N(Si(NMe2)3)(Ti(NMe2)2)]2 und N(SiMe3)(Si(NMe2)3)(Ti(NMe2)3)  -  Synthesis and Characterization of New Molecular Single-source Precursors for Nitride and Carbonitride CeramicsSynthesis and spectroscopic data of the title compounds are reported. [N(Si(NMe2)3)(Ti(NMe2)2)]2 crystallizes in the space group P1, a = 8.406(7), b = 10.673(8), c = 10.872(6) Å, α = 68.45(4)°, β = 71.72(4)°, γ = 78.11(7)°, 2 877 diffractometer data (Fo ≥ 2σFo), R = 0.051. The compound is characterized by a planar four-membered Ti2N2-ring with exocyclic tris(dimethylamino)silyl substituents attached to the nitrogen atoms of the ring.
    Notes: Darstellung, kernresonanz- und massenspektroskopische Daten der Titelverbindungen werden mitgeteilt. [N(Si(NMe2)3)(Ti(NMe2)2)]2 kristallisiert in der Raumgruppe P1 mit den Gitterkonstanten a = 8,406(7), b = 10,673(8), c = 10,872(6) Å, α = 68,45(4)°, β = 71,72(4)°, γ = 78,11(7)°. 2 877 Diffraktometerdaten (Fo ≥ 2σFo), R = 0,051. Die Verbindung besitzt einen planaren Ti2N2-Vierring mit exocyclischen Tris(dimethylamino)silylsubstituenten an den Stickstoffatomen des Rings.
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    Masthead (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/zaac.19946200301
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    Darstellung und Strukturen einiger N-(Tri-t-butoxysilyl)anilin-Derivate (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 377-384 
    Details
    ISSN: 0044-2313
    Keywords: One-pot reactions of tri-t-butoxychlorosilane, K-t-butanolate and substituted anilines. Crystal structure analyses of N-(tri-t-butoxysilyl)-aniline, C18H33NO3Si ; N-(tri-t-butoxysilyl)-p-nitroaniline, C18H32N2O5Si ; N-Methyl-(N-tri-t-butoxysilyl)-p-nitroaniline C19H34N2O5Si ; N-(tri-t-butoxysilyl)-p-cyanoaniline, C19H32N2O3Si ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Structures of N-(tri-t-butoxysilyl)aniline CompoundsPara-substituted N-(tri-t-butoxysilyl)anilines (t-BuO)3SiNRC4H4X-p, R = H, CH3, with substituents of high electron affinity (X = CN, NO2) were prepared by a one-pot reaction of tri-t-butoxychlorsilane, potassium t-butanolate and substituted anilines. Corresponding compounds with substituents of low electron affinity (X = OMe, H) preferably were prepared by metalation of anilines with sodium amide. Four crystal structures were determined. N-(tri-t-butoxysilyl)-p-nitro-aniline, N-methyl-(N-tri-t-butoxysilyl)-p-nitroaniline and N-(tri-t-butoxysilyl)-p-cyanoaniline crystallize at 298 K monoclinically, N-(tri-t-butoxysilyl)aniline crystallizes orthorhombically.
    Notes: Derivate des para-substituierten N-(Tri-t-butoxysilyl)anilins (t-BuO)3SiNRC6H4X-p, R = H, CH3 mit Substituenten hoher Elektronenaffinität (X = CN, NO2) wurden nach einem neuen Eintopfverfahren aus Tri-t-butoxychlorsilan, Kalium-t-butanolat und dem entsprechend substituierten Anilin dargestellt. Für Substituenten niederer Elektronenaffinität (X = OMe, H) wird die Methode der Metallierung von Anilinen mit Natriumamid bevorzugt. Vier Kristallstrukturen wurden bestimmt. N-(Tri-t-butoxysilyl)-p-nitroanilin, N-Methyl-(N-tri-t-butoxysilyl)-p-nitroanilin und N-(Tri-t-butoxysilyl)-p-cyanoanilin kristallisieren bei 298 K monoklin, N-(Tri-t-butoxysilyl)anilin kristallisiert orthorhombisch.
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    Densities of Melts of the System KF—K2MoO4—B2O3 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 385-388 
    Details
    ISSN: 0044-2313
    Keywords: Density of melts ; system potassium fluoride/potassium molybdate/boron oxide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dichte der Schmelzen des System KF/K2MoO4/B2O3Die Dichte der Schmelzen des Systems KF/K2MoO4/B2O3 wurden gemessen. Das Molvolumen des binären Systems KF/K2MoO4 weicht nur wenig vom idealen Verlauf ab, was die starke thermische Dissoziation des kongruent schmelzenden K3FMoO4 anzeigt. Im System KF/B2O3 führt die Bildung von KBF4 und K2B4O7 zur Volumenzunahme, wie auch im System K2MoO4/B2O3. In letzterem kann die Volumenzunahme durch die Bildung des Heteropolyanions [BMo6O24]9- beschrieben werden. Die deutliche Abweichung vom idealen Verhalten des Systems KF/K2MoO4/B2O3 weist auf eine ausgeprägte ternäre Wechselwirkung, wahrscheinlich auf die Substitution von Sauerstoff in der Koordinationssphäre des Heteropolyanions durch Fluor.
    Notes: The density of melts of the system KF—K2MoO4—B2O3 was measured. The molar volume in the binary system KF—K2MoO4 deviates only little from the ideal course, which indicates the extended thermal dissociation of the congruently melting additive compound K3FMoO4.In the KF—B2O3 binary system the formation of KBF4 and K2B4O7 leads to the volume expansion, like in the K2MoO4—B2O3 system, where the volume expansion may be described by the formation of the heteropolyanions [BMo6O24]9-. The significant deviation from the ideal behaviour in the ternary system KF—K2MoO4—B2O3 refers to the pronounced interaction, most probably due to the substitution of oxygen atoms in the coordination sphere of the heteropolyanion with the fluorine ones.
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    Synthesis and Crystal Structure of Hg5Sb2I6 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 389-392 
    Details
    ISSN: 0044-2313
    Keywords: Mercury antinionide iodide, Hg5Sb2I6 ; Preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese und Kristallstruktur von Hg5Sb2I6Das Antimonid-Iodid von Quecksilber, Hg5Sb2I6, früher irrtümlich als Hg3Sb2I4 formuliert, wurde in Standardampullen synthetisiert. Einkristalle wurden mittels Transport über die Gasphase erhalten. Hg5Sb2I6: Raumgruppe Pc21n, Gitterparameter: a = 8,108(1), b = 10,702(1), c = 21,295(1) Å. Die Struktur (Einkristall) ist aus [HgSbI3]-Tetraedern und [HgSbI2]-Dreiecken aufgebaut. Alle Antimonatome sind paarweise zu Sb24--Hanteln verbunden. Die Struktur wird mit anderen Strukturen, die Sb24--Hanteln enthalten, verglichen.
    Notes: Mercury antimonide iodide, Hg5Sb2I6, previously and erroneously reported as Hg3Sb2I4 was synthesized using standard ampoule technique. A gas-phase transport reaction was applied for preparation of single crystals. Hg5Sb2I6 crystallizes in the space group Pc21n (No. 33) with unit cell dimensions: a = 8.108(1), b = 10.702(1), c = 21.295(1) Å. Crystal structure solved using single crystal X-ray data is built of [HgSbI3] tetrahedra and [HgSbI2] triangles. All antimony atoms are joined into Sb24- dumbbells. The structure is compared with ones containing similar Sb24- dumbbells.
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    Alkylidinphosphane und -arsane. I [P ≡ C—S]-[Li(dme)3]+ - Synthese und StrukturProfessor Reinhard Schmutzler zum 60. Geburtstage gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 405-417 
    Details
    ISSN: 0044-2313
    Keywords: Tris(1,2-dimethoxyethane-O,O′)lithium 2λ3-phosphaethynylsulfanide ; [P≡C—S]--anion ; [Li(dme)3]+-cation ; heteroatom-substituted λ3-phosphaalkynes ; nmr and ir data ; X-ray structure determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylidynephosphanes and -arsanes. I [P ≡ C—S]-[Li(dme)3]+ - Synthesis and StructureO,O′-Diethyl thiocarbonate and bis(tetrahydrofuran)-lithium bis(trimethylsilyl)phosphanide dissolved in 1,2-dimethoxyethane, react below 0°C to give ethoxy trimethylsilane and tris(1,2-dimethoxyethane-O,O′)lithium 2λ3-phosphaethynylsulfanide - [P≡C—S]- [Li(dme)3]+ - (1a). Apart from bis(trimethylsilyl)sulfane or carbon oxide sulfide, dark red concentrated solutions of λ3-phosphaalkyne 1 are also obtained from reactions of carbon disulfide with bis(tetrahydrofuran)-lithium bis(trimethylsilyl)phosphanide or with the homologous lithoxy-methylidynephosphane (2) [1]. The ir spectrum shows two absorptions at 1762 and 747 cm-1 characteristic for the P≡C and C—S stretching vibrations. The nmr parameters {δ(31P) - 121.3; δ(13C) 190.8 ppm; 1JCP 18.2 Hz} resemble much more values of diorganylamino-2λ3-phosphaalkynes than those of bis(1,2-dimethoxyethane-O,O′)lithoxy-methylidyne-phosphane (2a). As found by an X-ray structure analysis (P21/c; a = 1192.6(16); b = 1239.1(19); c = 1414.8(26) pm; β = 105.91(13)° at -100 ± 3°C; Z = 4 formula units; wR = 0.064) of pale yellow crystals (mp. + 16°C) isolated from the reaction with O,O′-diethyl thiocarbonate, the solid is built up of separate [P≡C—S]- and [Li(dme)3]+ ions. Typical bond lengths and angles are: P≡C 155.5(11); C—S 162.0(11); Li—O 206.4(17) to 220.3(20) pm; P≡C—S 178.9(7)°.
    Notes: O,O′-Diethylthiocarbonat setzt sich mit Bis-(tetrahydrofuran)lithium-bis(trimethylsilyl)phosphanid in 1,2-Dimethoxyethan unterhalb 0°C zu Ethoxy-trimethylsilan und Tris(1,2-dimethoxyethan-O,O′)lithium-2λ3-phosphaethinylsulfanid - [P≡C—S]-[Li(dme)3]+ - (1a)1,2-Dimethoxyethan (dme); Tetrahydrofuran (thf); Bis(2-methoxyethyl)ether (diglyme). Den λ3-Phosphaalkinen P≡C—S—Li und P≡C—O—Li werden unabhängig vom Gehalt an koordinierendem Solvens und der Konstitution die Ziffern 1 und 2 zugeordnet; bei den röntgenstrukturanalytisch untersuchten Komplexen [P≡C—S]-[Li(dme)3]+ und P≡C—O—Li(dme)2 kommt das Suffix a hinzu. um. Das als dunkelrote, konzentrierte Lösung erhaltene λ3-Phosphaalkin 1 entsteht neben Bis(trimethylsilyl)sulfan bzw. Kohlenstoffoxidsulfid auch bei den Umsetzungen von Kohlenstoffdisulfid mit Bis(tetrahydrofuran)lithium-bis(trimethylsilyl)phosphanid oder dem homologen Lithoxy-methylidinphosphan P≡C—O—Li (2) [1]. Das IR-Spektrum weist die für eine P≡C- und C—S-Valenzschwingung charakteristischen Absorptionen bei 1762 und 747 cm-1 auf; die NMR-Parameter {δ(31P) - 121,3; δ(13C) 190,8 ppm; 1JCP 18,2 Hz} gleichen mehr den Werten der Diorganylamino-2λ3-phosphaalkine als des Bis(1,2-dimethoxyethan-O,O′)-lithoxy-methylidinphosphans (2a). Nach den Ergebnissen einer Röntgenstrukturanalyse (P21/c; a = 1192,6(16); b = 1239,1(19); c = 1414,8(26) pm; β = 105,91(13)° bei -100 ± 3°C; Z = 4 Formeleinheiten; wR = 0,064) an blaßgelben, aus einem Ansatz mit O,O′-Diethylthiocarbonat isolierten Kristallen (Schmp. + 16°C) liegen im Festkörper getrennte [P≡C—S]-- und [Li(dme)3]+-Ionen vor. Charakteristische Bindungslängen und -winkel sind: P≡C 155,5(11); C—S 162,0(11); Li—O 206,4(17) bis 220,3(20) pm; P≡C—S 178,9(7)°.
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    Pr(CH3COO)3, ein wasserfreies Selten-Erd-Acetat mit Netzwerkstruktur (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 438-443 
    Details
    ISSN: 0044-2313
    Keywords: Praseodymium(III) Acetate ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pr(CH3COO)3, an Anhydrous Rare-Earth Acetate with a Network StructurePr(CH3COO)3 may be prepared by dehydration of Pr(CH3COO)3 · 1,5 H2O at 180°C as an amorphous green powder. Single crystals were grown from the powder by addition of (NH4)CH3COO as „mineralisator“ at 180°C in a sealed glass ampoule. The crystal structure (tetragonal, P421c (no. 114), Z = 24, a = 2106.5(3), c = 1323.6(1) pm, Vm = 147.39(3) cm3/mol, R = 0.055, Rw = 0.029) was determined from four-circle-diffractometer data. The Pr3+ ions occupy three crystallographically independent positions and are surrounded by 9 and 10 oxygen atoms, respectively. Acetate ions connect the cations to a complicated three-dimensional network.
    Notes: Pr(CH3COO)3 entsteht beim Entwässern von Pr(CH3COO)3 · 1,5 H2O bei 180°C als amorphes Pulver. Einkristalle konnten daraus mit Hilfe von (NH4)CH3COO als „Mineralisator“ ebenfalls bei 180°C in einer geschlossenen Glasampulle gezüchtet werden. Die Kristallstruktur (tetragonal, P421c (Nr. 114), Z = 24, a = 2106,5(3), c = 1323,6(1) pm, Vm = 147,39(3) cm3/mol, R = 0,055, Rw = 0,029) wurde anhand von Vierkreis-Diffraktometerdaten bestimmt. Pr3+-Ionen besetzen drei unterschiedliche kristallographische Positionen und sind von 9 bzw. 10 Sauerstoffatomen umgeben. Acetationen verbinden die Kationen auf unterschiedliche Weise zu einem komplizierten dreidimensionalen Netzwerk.
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    Die Chloride Na3xM2-xCl6 (M = La—Sm) und NaM2Cl6 (M = Nd, Sm): Derivate des UCl3-Typs. Synthese, Kristallstruktur und Röntgenabsorptionsspektroskopie (XANES) (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 444-450 
    Details
    ISSN: 0044-2313
    Keywords: Chlorides ; lanthanides ; synthesis ; crystal structure ; X-ray absorption spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Chlorides Na3xM2-xCl6 (M = La—Sm) and NaM2Cl6 (M = Nd, Sm): Derivatives of the UCl3-Type of Structure. Synthesis, Crystal Structure and X-Ray Absorption Spectroscopy (XANES)Single crystals of the derivatives of the UCl3-type structure Na3xM2-xCl6 (M = La/x = 0.364(4); Ce/0.349(5); Pr/0.318(8); Nd/0.305(5); Sm/0.246(4)) and NaSm2Cl6 were grown by different methods generally under reducing conditions. They are addition [Na(Sm2)Cl6] and addition/substitution variants [Na2x(NaxM2-x)Cl6] of the UCl3 structure type [□(U2)Cl6]. X-Ray Absorption Spectroscopy (XANES) at the LIII edge characterizes NaSm2Cl6 and NaNd2Cl6 as mixed-valence compounds with valences of +2 and +3 in statistical distribution (approximately 1:1) for Sm and Nd, respectively.
    Notes: Einkristalle der Derivate des UCl3-Typs Na3xM2-xCl6 (M = La/x = 0,364(4); Ce/0,349(5); Pr/0,318(8); Nd/0,305(5); Sm/0,246(4)) sowie von NaSm2Cl6 wurden auf unterschiedlichen Wegen, im allgemeinen unter reduzierenden Bedingungen erhalten. Sie sind Additions- [Na(Sm2)Cl6] bzw. Additions- / Substitutionsvarianten [Na2x(NaxM2-x)Cl6] des UCl3-Strukturtyps [□(U2)Cl6]. Röntgenabsorptionsspektren (XANES) an der Lm-Kante charakterisieren NaSm2Cl6 und NaNd2Cl6 als gemischtvalente Verbindungen mit Valenzen von +2 und +3 in statistischer Verteilung (etwa 1:1) für Sm bzw. Nd.
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    Synthesis, structures and luminescence of two new Europium(II) Silicate-Chlorides, Eu2SiO3Cl2 and Eu5SiO4Cl6 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 451-456 
    Details
    ISSN: 0044-2313
    Keywords: Silicates ; crystal structure ; europium ; luminescence ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese, Strukturen und Lumineszenz von zwei neuen Europium(II)-silicat-chloriden, Eu2SiO3Cl2 und Eu5SiO4Cl6Eu2SiO3Cl2 und Eu5SiO4Cl6 wurden durch Erhitzen von EuCl2 mit EuSiO3 bzw. Eu2SiO4 gewonnen, Sr2SiO3Cl2:Eu2+ aus einem Gemenge von SrCO3, Eu2O3, SrCl2 · 6H2O und SiO2 unter reduzierenden Bedingungen. Die Kristallstrukturen von Eu2SiO3Cl2 [a = 1118,7(5), c = 952,6(1) pm, tetragonal, I4/m, Z = 8, R = 3,3, Rw = 3,0%] und Eu5SiO4Cl6 [a = 900,4(1), b = 1401,7(2), c = 1112,3(2) pm, β = 103,51(1)°, monoklin, C2/c, Z = 4, R = 3,6, Rw = 2,6%] wurden aus Einkristall-Vierkreisdiffraktometer-Daten bestimmt und mit verwandten Verbindungen verglichen. Die Lumineszenzeigenschaften wurden bei 300 K und bei 4,2 K untersucht; sämtliche Verbindungen zeigen eine intensive blaugrüne Photolumineszenz. Sr2SiO3Cl2:Eu2+ zeigt Thermolumineszenz.
    Notes: Eu2SiO3Cl2 and Eu5SiO4Cl6 were prepared by reaction of EuCl2 with EuSiO3 and Eu2SiO4, respectively, Sr2SiO3Cl2: Eu2+ from mixtures of SrCO3, Eu2O3, SrCl2 · 6H2O and SiO2 under reducing conditions. The crystal structures of Eu2SiO3Cl2 [a = 1118.7(5), c = 952.6(1) pm, tetragonal, I4/m, Z = 8, R = 3.3, Rw = 3.0%] and Eu5SiO4Cl6 [a = 900.4(1), b = 1401.7(2), c = 1112.3(2) pm, β = 103.51(1)°, monoclinic, C2/c, Z = 4, R = 3.6, Rw = 2.6%] were determined from four-circle diffractometer data and compared with related compounds. The luminescence properties were investigated at 300 K and at 4.2 K; all compounds show intense bluish-green photoluminescence. Sr2SiO3Cl2:Eu2+ shows thermoluminescence.
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    Synthetic and structural Studies on Organomolybdenum-Bismuth Halide Complexes (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 457-466 
    Details
    ISSN: 0044-2313
    Keywords: Organomolybdenum-bismuth halide complexes ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchungen zur Synthese und Struktur von Organomolybdän-Bismuthalogenid-KomplexenDie Reaktionen von BiBr2Ph mit Na/K[Mo(CO)3(η—C5H5)], von [BiPh{Mo(CO)3(η—C5H5)}2] mit BiBr2Ph oder BiBr3 und BiPh3 mit [Bi{Mo(CO)3(η—C5H5)}3] ergeben den Komplex [BiBrPh{Mo(CO)3(η—C5H5)}] 1, der röntgenographisch charakterisiert worden ist. Der Komplex 1 besteht aus einem Bismutzentrum mit einem Bromatom, einer Phenylgruppe und einer Mo(CO)3(η—C5H5)-Einheit. Eine intermolekulare Wechselwirkung besteht zum Bromatom eines benachbarten Moleküls, wodurch sich eine eindimensionale polymere Struktur ergibt. Bei der Umsetzung mit einer Bromidabgebenden Verbindung wird zunächst der anionische Komplex [BiBr2Ph{Mo(CO)3(η—C5H5)}2]- 3- und bei längerer Reaktion [BiBr2{Mo(CO)3(η—C5H5)}2]- 5- gebildet, das als [Ph4P]+-Salz röntgenographisch charakterisiert wurde. Der Komplex 5-, der am Bi zwei Br und zwei Mo(CO)3(η—C5H5)-Einheiten enthält, liegt in einer Struktur zwischen unvollständig trigonal-pyramidal und tetraedrisch vor. Der Komplex [PPN]2[Bi2Cl6{Mo(CO)3(η—C5H5)}2] 8 wurde ebenfalls dargestellt und röntgenographisch charakterisiert. Es liegt ein dimeres Anion vor, das aus zwei quadratischen Pyramiden mit einer gemeinsamen Kante besteht, in denen die Chloratome in der Basisebene und die zwei Mo(CO)3(η—C5H5)-Einheiten sich an den Spitzen in gegenüberliegenden Positionen befinden.
    Notes: The reactions between either BiBr2Ph and Na/K[Mo(CO)3(η—C5H5)], [BiPh{Mo(CO)3(η—C5H5)}2] and BiBr2Ph, or BiBr3 and BiPh3 and [Bi{Mo(CO)3(η—C5H5)}3] afford the complex [BiBrPh{Mo(CO)3(η—C5H5)}] 1 which has been characterised by X-ray crystallography. Complex 1 comprises a bismuth centre bonded to a bromine atom, a phenyl group and a Mo(CO)3(η—C5H5) fragment together with a longer secondary intermolecular interaction between a bromine from an adjacent molecule which results in a one-dimensional polymeric structure. Addition of a source of bromide anion to 1 affords the anionic complex [BiBr2Ph{Mo(CO)3(η—C5H5)}]- 3- although prolonged reaction results in the complex [BiBr2{Mo(CO)3(η—C5H5)}2]- 5- which was characterised by X-ray crystallography as its [Ph4P]+ salt. Complex 5- comprises a mononuclear bismuth centre bonded to two bromine atoms and two Mo(CO)3(η—C5H5) fragments in a geometry which lies between equatorially vacant trigonal bipyramidal and tetrahedral. The complex [PPN]2[Bi2Cl6{Mo(CO)3(η—C5H5)}2] 8 has also been synthesised and characterised by X-ray crystallography. A dimeric dianion is observed which can be viewed as two edge-shared square-based pyramids with chlorine atoms in the basal planes and Mo(CO)3(η—C5H5) fragments in the apical positions on opposite sides of the Bi2Cl6 plane.
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    The Molybdenum Stannide MoSn2In memoriam Konrad Schubert (1915-1992) (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 467-470 
    Details
    ISSN: 0044-2313
    Keywords: MoSn2 ; crystal structure ; Pauli paramagnetism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Das Molybdän-Stannid MoSn2Die Titelverbindung wurde durch Tempern von Molybdän-Pulver mit einem Überschuß von Zinn hergestellt. Einkristalle wurden durch Auflösen der zinnreichen Matrix in Salzsäure erhalten. Sie sind Pauli-paramagnetisch. Die Kristallstruktur wurde aus Einkristall-Röntgen-Diffraktometer-Daten bestimmt: P6222, a = 548,8(1) pm, c = 1417,1(2) pm, Z = 6, R = 0,036 für 18 variable Parameter und 389 Strukturfaktoren. MoSn2 ist erst der zweite Vertreter der hexagonalen Mg2Ni-Struktur. Die Beziehung der Struktur zum CuAl2-Typ wird diskutiert.
    Notes: The title compound was prepared by annealing molybdenum powder with an excess of tin. Single-crystals were obtained by dissolving the tin-rich matrix in hydrochloric acid. They are Pauli paramagnetic. The crystal structure was determined from single-crystal X-ray diffractometer data: P6222, a = 548.8(1) pm, c = 1417.1(2) pm, Z = 6, R = 0.036 for 18 variable parameters and 389 structure factors. MoSn2 is only the second representative of the hexagonal Mg2Ni-type structure. The relation of the structure to the CuAl2-type is discussed.
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    Spektroskopische und röntgenographische Untersuchungen an Dichlormethyl-QuecksilberverbindungenProfessor Wolfgang Sawodny zum 60. Geburtstage gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 625-631 
    Details
    ISSN: 0044-2313
    Keywords: Bis(dichloromethyl)mercury ; Dichloromethylmercuryalkyles ; synthesis ; NMR, vibrational spectra ; X-ray structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Spectroscopic and X-Ray Structural Investigations on Dichloromethyl Mercury CompoundsBis(dichloromethyl)mercury, Hg(CHCl2)2, and mixed alkyl compounds RHgCHCl2 (with R = CH3, C2H5) have been synthesized by known methods from CH2Cl2, lithium butanide and HgCl2, CH3HgCl or C2H5HgCl, respectively. The 1H-, 13C-NMR as well as the IR and Raman spectra of the liquid alkyls RHgCHCl2 and the high melting Hg(CHCl2)2 have been measured and assigned. According to the X-ray structure determination Hg(CHCl2)2 crystallizes in the monoclinic space group P21/c with 4 non-symmetric molecules per unit cell (R = 0.046).
    Notes: Bis(dichlormethyl)quecksilber, Hg(CHCl2)2, und die gemischten Alkylverbindungen RHgCHCl2 (mit R = CH3, C2H5) werden nach bekannten Vorschriften aus CH2Cl2, Lithiumbutanid und HgCl2 bzw. CH3HgCl oder C2H5HgCl synthetisiert. Die 1H- und 13C-NMR- sowie die IR- und Ramanspektren der flüssigen Alkyle RHgCHCl2 und des hochschmelzenden Hg(CHCl2)2 werden registriert und ausgewertet. Nach der Röntgenstrukturanalyse kristallisiert Hg(CHCl2)2 in der monoklinen Raumgruppe P21/c mit 4 azentrischen Molekülen in der Elementarzelle (R = 0,046).
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    Darstellung von μ-Schwefeldisulfoniumsalzen [(CH3)2S—Sx—S(CH3)2]2+2A- (x = 1-3, A- = AsF6-, SbF6-, SbCl6-). Über die Analogie im Reaktionsverhalten zwischen Sulfanen und SulfoniumsalzenProfessor Wolfgang Sawodny zum 60. Geburtstag gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 632-637 
    Details
    ISSN: 0044-2313
    Keywords: μ-Sulfurdisulfonium salts ; preparation ; single crystal X-ray structure ; Raman, NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of μ-Sulfurdisulfonium Salts [(CH3)2S—Sx—S(CH3)2]2+2A- (x = 1-3, A- = AsF6-, SbF6-, SbCl6-). On the Analogy of the Reactivity of Sulfanes and Sulfonium SaltsThe preparation of the μ-sulfurdisulfonium salts [(CH3)2S—Sx—S(CH3)2]2+(A-)2 with x = 1-3 and A- = AsF6-, SbF6-, SbCl6- is reported. The salts are formed by reaction of (CH3)2SH+A- and (CH3)2SSH+A- with SCl2 and S2Cl2, resp. They are characterized by vibrational spectroscopic measurements. [(CH3)2S—S2—S(CH3)2]2+(SbF6-)2 crystallizes in the space group C2/c with a = 1 884.5(7) pm, b = 1 302.8(5) pm, c = 1 477.2(5) pm, β = 98.62(3)° und Z = 8.
    Notes: Es wird über die Darstellung der μ-Schwefeldisulfoniumsalze [(CH3)2S—Sx—S(CH3)2]2+ (A-)2 mit x = 1-3 und A- = AsF6-, SbF6-, SbCl6- berichtet. Die Salze werden durch Kondensationsreaktionen von (CH3)2SH+A- und (CH3)2SSH+A- mit SCl2 bzw. S2Cl2 gebildet. Ihre Charakterisierung erfolgt schwingungsspektroskopisch. Das [(CH3)2S—S2—S(CH3)2]2+(SbF6-)2 kristallisiert in der Raumgruppe C2/c mit a = 1 884,5(7) pm, b = 1 302,8(5) pm, c = 1 477,2(5) pm, β = 98,62(3)° und Z = 8.
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    Über die Reaktion von HCl im System HF/SbF5 und die Kristallstruktur von SbCl3F2 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 638-641 
    Details
    ISSN: 0044-2313
    Keywords: Stibiumtrichlorodifluoride ; Crystal Structure ; Raman Spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of HCl with HF/SbF5 and the Crystal Structure of SbCl3F2The reaction of HCl in HF/SbF5 solution at -78°C yields H2F+SbClF5-. At -40°C formation of SbCl3F2 was observed, which crystallizes in the tetragonal space group I-4 with a = 1 281.6(5) pm, c = 758.1(6) pm with 8 formula units per unit cell. The structure contains cis-fluorine-bridged tetramers, in which Sb has a distorted octahedral coordination.
    Notes: Die Reaktion von HCl mit einer HF/SbF5 Lösung ergibt bei -78°C H2F+SbClF5-. Bei -40°C wird die Bildung von SbCl3F2 beobachtet. Es kristallisiert in der tetragonalen Raumgruppe I-4 mit a = 1 281,6(5) pm, c = 758,1(6) pm und Z = 8. Die Struktur enthält cis-Fluor-verbrückte Tetramere, in denen Antimon eine verzerrt oktaedrische Koordinationssphäre hat.
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    URL: http://dx.doi.org/10.1002/zaac.19946200409
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    Zur Kristallchemie der Kupfer-Lanthanoid-Oxowolframate: (I) triklin-α-CuTbW2O8, (II) monoklin-CuInW2O8 und (III) monoklin-CuYW2O8 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 642-646 
    Details
    ISSN: 0044-2313
    Keywords: Copper, rare earth, tungsten, oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Chemistry of Copper Rare-Earth Oxotungstates: (I): triclinic-α-CuTbW2O8, (II): monoclinic-CuInW2O8 and (III): monoclinic-CuYW2O8Single crystals of (I), (II) and (III) were prepared by recrystallisation in closed systems and examined by X-ray technique. (I): space group Cil—P1, a = 7.3080, b = 7.8945, c = 7.1476 Å, α = 115.23, β = 116.21, γ = 56.98°, Z = 2; (II): space group C2h6—C2/c, a = 9.6576, b = 11.6496, c = 4.9863 Å, β = 91.17°, Z = 4; (III): space group C2h4—P2/n, a = 10.0504, b = 5.8214, c = 5.0224 Å, β = 94.23°, Z = 2. The crystal structures are discussed with respect to calculations of the coulombterms of lattice energy and possible valence states of Cu2+ and Mo5+.
    Notes: Einkristalle von (I), (II) und (III) wurden durch Rekristallisation in geschlossenen Systemen dargestellt und röntgenographisch untersucht. Die kristallographischen Daten lauten: (I): Raumgruppe Cil—P1, a = 7,3080, b = 7,8945, c = 7,1476 Å, α = 115,23, β = 116,21, γ = 56,98°, Z = 2; (II): Raumgruppe C2h6—C2/c, a = 9,6576, b = 11,6496, c = 4,9863 Å, β = 91,17°, Z = 4; (III): Raumgruppe C2h4—P2/n, a = 10,0504, b = 5,8214, c = 5,0224 Å, β = 94,23°, Z = 2. Die Kristallstrukturen werden mit Blick auf Berechnungen der Coulombterme der Gitterenergie und mögliche Ladungen von Cu2+ und Mo5+ diskutiert.
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    Zur Kenntnis eines Barium-Kupfer-Orthoarsenats: BaCu2(AsO4)2 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 651-654 
    Details
    ISSN: 0044-2313
    Keywords: Barium, copper, arsenic, oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Structure of Barium-Copper-Orthoarsenate BaCu2(AsO4)2Single crystals of BaCu2(AsO4)2 were prepared above 1 000°C by CO2-LASER technique and investigated by X-ray structure determination. The light blue crystals show monoclinic symmetry, space group C2h5—P21/n, a = 4.752; b = 8.506; c = 8.945 Å; β = 93.49°, Z = 2. BaCu2(AsO4)2 represents a hitherto unknown structure type with Cu2+ in trigonal bipyramidal coordination. Ba2+ shows an 8 + 2 surrounding by O2- and As5+ is tetrahedrally coordinated. The crystal structure is discussed with respect to related orthophosphates and vanadates.
    Notes: Mit CO2-LASER-Technik wurden bei ca. 1 000°C Einkristalle der Verbindung BaCu2(AsO4)2 dargestellt und röntgenographisch untersucht. Die blaßblauen Kristalle haben monokline Symmetrie, Raumgruppe C2h5—P21/n, mit a = 4,752; b = 8,506; c = 8,945 Å; β = 93,49°, Z = 2. BaCu2(AsO4)2 repräsentiert einen neuen Strukturtyp, der Cu2+ in trigonal bipyramidaler Koordination zeigt. Ba2+ ist 8 + 2-fach und As5+ tetraedrisch von Sauerstoff umgeben. Die Kristallstruktur wird unter Bezug auf verwandte Orthophosphate und -vanadate diskutiert.
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    Darstellung, Schwingungsspektren und Normalkoordinatenanalyse der Decahalogenoditechnetate(IV), [Tc2X10]2-, X = Cl, Br (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 655-658 
    Details
    ISSN: 0044-2313
    Keywords: Decachloroditechnetate(IV) ; Decabromoditechnetate(IV) ; Synthesis ; Raman, IR Spectra ; Normal Coordinate Analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation, Vibrational Spectra and Normal Coordinate Analysis of Decahalogenoditechnetates(IV), [Tc2X10]2-, X = Cl, BrThe reaction of [TcX6]2-, X = Cl, Br, with trifluoroacetic acid yield at room temperature the edge-sharing bioctahedral anions [Tc2X10]2-, which IR and Raman spectra are assigned according to point group D2h. Using the crystal data of isostructural osmium complexes a normal coordinate analysis based on a general valence force field has been performed for [Tc2X10]2-, revealing a good agreement of the calculated frequencies with the bands observed in the IR and Raman spectra. The stronger bonding of the terminal as compared to the bridging ligands is shown by the valence force constants, fd(TcXt) 〉 Fd(TcXb).
    Notes: [TcX6]2-, X = Cl,Br, reagiert bei Raumtemperatur mit Trifluoressigsäure unter Bildung der kantenverknüpften Dioktaederanionen [Tc2X10]2-, deren IR- und Raman-Spektren entsprechend der Punktgruppe D2h zugeordnet werden. Basierend auf den kristallographischen Daten isostruktureller Osmiumkomplexe und unter Verwendung des allgemeinen Valenzkraftfeldes, werden für Decachloro- und Decabromodi-technetat(IV) Normalkoordinatenanalysen durchgeführt, die eine gute Übereinstimmung der berechneten Frequenzen mit den beobachteten Banden aus den IR- und Raman-Spektren ergeben. Die festere Bindung terminaler im Vergleich zu verbrückenden Liganden spiegelt sich in den Valenzkraftkonstanten wider: fd(TcXt) 〉 fd(TcXb).
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    Zur Kenntnis ‘Kationen-reicher’ Tantalate Über Li7[TaO6] (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 659-664 
    Details
    ISSN: 0044-2313
    Keywords: Tantalate Li7[TaO6] ; Single Crystals ; Crystal Structure ; MAPLE ; Charge Distribution ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Tantalates ‘rich in Cations’ On Li7[TaO6]For the first time, colourless single crystals of Li7[TaO6] were grown by annealing intimate mixtures of Li2O and Ta2O5 (Li:Ta = 7,7:1) in closed Ni-cylinders (1 000°C, 156 d). [Trigonal-rhomboedral with a = 535.8(1) pm, c = 1 507.3(3) pm, c/a = 2.81/Guinier-Simon-powder data; Z = 3. Space group R3 for the part Li(1)6TaO6 and presumably P3 for Li7TaO6, including Li(2)].The crystal structure was solved by four-cycle-diffractometer data [Mo—Kα, 331 from 331 Io(hkl), R = 1.99%, Rw = 1.96%], parameters see text.The positions of anions correspond to the motif of a hexagonal closest packing of spheres, obviously deformed (with MEFIR of O2- space filling corresponds to 69.8% instead of expected 73.2%. 1/3 of the octahedron holes are ordered occupied by Ta and Li(2), 1/2 of the tetrahedral holes likewise ordered by Li(1). All polyhedra of coordination of the anions are trigonal prisms.The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, as well as charge distribution ‘CHARDI’ are calculated and discussed.
    Notes: Erstmals wurden farblose Einkristalle von Li7[TaO6] durch Tempern inniger Gemenge von Li2O und Ta2O5 (Li:Ta = 7,7:1) in einem verschlossenen Ni-Zylinder (1 000°C, 156 d) dargestellt trigonal-rhomboedrisch; a = 535,8(1) pm, c = 1 507,3(3) pm, c/a = 2,81/Guinier-Simon-Pulverdaten; Z = 3. Raumgruppe R3 für den Li(1)6TaO6-Teil; vermutlich P3 für Li(1)6Li(2)1[TaO6].Die Kristallstruktur wurde mittels Vierkreisdiffraktometerdaten [Mo—Kα, 331 von 331 Io(hkl), R = 1,99%, Rw = 1,96%] bestimmt, Parameter siehe Text.Es liegt bezüglich der Anionen im Prinzip das Motiv einer hexagonal-dichtesten Kugelpackung vor; die Verzerrung ist deutlich mit MEFIR(O2-) = 154,3 pm beträgt die Raumerfüllung 69,8% statt ideal 73,2%). Es sind 2 der 6 Oktaeder- (mit Ta bzw. Li(2)) und 6 der 12 Tetrederlücken mit Li(1) besetzt. Alle Koordinationspolyeder um O sind trigonale Prismen.Der Madelunganteil der Gitterenergie, MAPLE, und Effektive Koordinationszahlen, ECoN, diese über Mittlere Fiktive Ionenradien, MEFIR, sowie die Ladungsverteilung ‘CHARDI’ wurden berechnet und diskutiert.
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    Hydrate des Cer(III)-chlorids (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 665-671 
    Details
    ISSN: 0044-2313
    Keywords: Cerium(III) chloride hydrates ; Synthesis ; Solution enthalpies ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrates of Cerium(III) ChlorideThe thermal dehydration of CeCl3 · 7 H2O to CeCl3 gives four definite intermediates: CeCl3 · 6 H2O, CeCl3 · 3 H2O, CeCl3 · 2 H2O, CeCl3 · H2O. In the hexahydrate monomeric [CeCl2(H2O)6]+ units exist. A structure analysis of CeCl3 · 3 H2O gave an orthorhombic unit cell (S.G. Pnma; Z = 4) with a = 1 242.7(4) pm; b = 881.8(8) pm, c = 693.4(5) pm. The structure consists of [CeCl4/2Cl(H2O)3] chains, where two Ce3+ ions are connected via two chloride ions, forming bent chains in the [010] direction. The trihydrates LnCl3 · 3 H2O (Ln = Pr—Tb) are isotypic, also one modification of LaCl3 · 3 H2O. The structures of the di- and mono-hydrate are not yet known. Molar volumina and solution enthalpies in water vary linearly with the number of H2O molecules per formula unit.
    Notes: Der thermische Abbau von CeCl3 · 7 H2O zu CeCl3 verläuft über die präparativ faßbaren Hydrate CeCl3 · 6 H2O, CeCl3 · 3 H2O, CeCl3 · 2 H2O und CeCl3 · H2O. CeCl3 · 6 H2O kristallisiert isotyp zu PrCl3 · 6 H2O mit monomeren [CeCl2(H2O)6]+-Einheiten. Eine Strukturbestimmung von CeCl3 · 3 H2O Pnma; Z = 4; a = 1 242,7(4) pm; b = 881,8(8) pm, c = 693,4(5) pm ergab das Vorliegen von [CeCl4/2Cl(H2O)3]-Einheiten, die über je zwei Chlorid-Doppelbrücken zu gewinkelten Ketten in [010]-Richtung verknüpft sind. Die Trihydrate LnCl3 · 3 H2O (Ln = Pr—Tb) sind isotyp, ebenfalls eine Modifikation von LaCl3 · 3 H2O. Die Strukturen des Di- und Monohydrats sind noch unbekannt. Die Molvolumina und Lösungsenthalpien in Wasser ändern sich linear mit dem Hydratationsgrad.
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    Beiträge zum thermischen Verhalten von Sulfaten. XII. Zum chemischen Transport von In2(SO4)3 mit Cl2 und mit HCl. Experimente und ModellrechnungenProfessor Heinz Dieter Lutz zum 60. Geburtstage gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 672-681 
    Details
    ISSN: 0044-2313
    Keywords: Chemical transport ; In2(SO4)3 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions on the Thermal Behaviour of Sulfates XII. The Chemical Vapour Transport of In2(SO4)3 with Cl2 and HCl. Experimental Results and CalculationsBy means of CVT (T1 between 500°C and 825°C; ΔT = 50°C), well shaped crystals of anhydrous In2(SO4)3 can be grown in the less hot region of a closed silica ampoule. We investigated the dependence of the deposition rate on the variation of the concentration of the transport agent (system In2(SO4)3/Cl2) and on the variation of the transport temperature (In2(SO4)3/Cl2 as well as In2(SO4)3/HCl).A comparison of the experimental results with thermodynamical calculations shows a satisfying agreement. The influence of the variation of some additional parameters (H2O from the wall of the ampoule; ΔBH2980(In2(SO4)3)) on the deposition rate is discussed.
    Notes: Chemische Transportexperimente im Temperaturgradienten (500°C ≤ T1 ≤ 825°C; T2 〉 T1; ΔT = 50°C) ermöglichten es, gut ausgebildete Kristalle von wasserfreiem In2(SO4)3 in der weniger heißen Zone einer geschlossenen Quarzampulle phasenrein abzuscheiden. Der Einfluß einer Variation der Transportmittelkonzentration (C(Cl2)) (Cl2 eingesetzt als PtCl2)) sowie der mittleren Transporttemperatur (T̄ = 0,5 · (T2 + T1)) auf die Transportrate wurde untersucht. Weiterhin wurden Experimente mit dem Transportmittel HCl bei unterschiedlichem T̄ durchgeführt.Die Beobachtungen lassen sich durch thermodynamische Modellrechnungen befriedigend wiedergeben. Der Einfluß einer Variation weiterer Parameter (H2O aus der Ampullenwand; ΔBH2980(In2(SO4)3) auf die berechneten Transportraten wird diskutiert.
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    Synthese, Eigenschaften und Kristallstrukturen von Magnesium-Diazadien-Komplexen (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 691-696 
    Details
    ISSN: 0044-2313
    Keywords: Magnesium complexes ; diazadiene ligands ; radical anions ; endiamides ; X-ray structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Properties and Crystal Structures of Magnesium Diazadiene ComplexesReactions of phenyl-substituted 1,4-diaza-1,3-butadienes (DAD) RN=CPh—CPh=NR (R = C6H5) 1a, C6H4-4-CH3 1b, C6H4-4-OCH3 (1c) with magnesium in dimethoxyethan lead to complexes of the type [Mg(DAD)2(DME)] 2a-c, with DAD ligands in form of radical anions. Furthermore, highly reactiv complexes of the composition [Mg(DAD)(DME)2] 3a-c could be obtained. The crystal structures of 2a, 3a and 3c were determined.
    Notes: Die Reaktion phenylsubstituierter 1,4-Diaza-1,3-butadiene (DAD) RN=CPh—CPh=NR (R = C6H5 1a, C6H4-4-CH3 1b, C6H4-4-OCH3 1c) mit Magnesium in Dimethoxyethan (DME) führt zu Verbindungen des Typs [Mg(DAD)2(DME)] 2a-c, in denen die DAD-Liganden als Radikalanionen gebunden sind. Außerdem enstehen äußerst reaktive Komplexe der Zusammensetzung [Mg(DAD)(DME)2] 3a-c. Die Kristallstrukturen von 2a, 3a und 3c wurden aufgeklärt.
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    High-spin Mangan(II)-Phthalocyanine: Darstellung und spektroskopische Eigenschaften von Acidophthalocyaninatomanganat(II) (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 682-690 
    Details
    ISSN: 0044-2313
    Keywords: Phthalocyanines ; MnII complex ; Uv-vis-n.i.r., m.i.r., f.i.r., resonance Raman, ESR spectra ; magnetism ; cyclovoltammetry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: High Spin Manganese(II) Phthalocyanines: Preparation and Spectroscopical Properties of Acidophthalocyaninatomanganate(II)Acidophthalocyaninatomanaganese(III) is reduced by boranate, thioacetate or hydrogensulfide to yield acidophthalo-cyaninatomanganate(II) ([Mn(X)Pc2-]-; X = Cl, Br, NCO, NCS) being isolated as tetra(n-butyl)ammonium salt. In the cyclovoltammogram of [Mn(NCO)Pc2-]- the halv-wave potential for the redoxcouple MnII/MnIII is at -0.13 V, that of the first ring reduction at -0.99 V. The magnetic moments are indicative of high-spin 6A1 ground states: μMn = 5.84 (NCO), 5.78(Cl), 5.65 (Br), 5.68 μB (NCS). A Curie-like temperature dependence of μMn is observed in the region 300-30 K. Below 30 K an increase in μMn occurs due to weak intermolecular ferromagnetic coupling. The ESR spectra confirm the S = 5/2 ground state with a strong g = 6 resonance observed (AMn = 80 G) as expected for an axially distorted ligand-field. Besides the typical π-π* transitions of the Pc2--ligand several weak bands are observed in the Uv-vis-n.i.r. spectra at ca. 7.5, 9.1, 14.0 and 19.0 kK that are assigned to trip-multiplet transitions. In resonance with the band at 19.0 kK the Mn—X stretching vibration (v(MnX)) is resonance Raman enhanced: X = NCO: 319, Cl: 286, SCN: 238, Br: 202 cm-1. These vibrational frequencies are confirmed by the f.i.r. spectra. In the case of the thiocyanato-complex probably both forms of bonding of the ambident NCS-ligand are present (v(Mn—NCS): 274 cm-1). The frequencies of the vibrations of the inner (CN)8 ring are reduced by up to 20 cm-1 as compared with those of low spin MnII phthalocyanines.
    Notes: Acidophthalocyaninatomanagan(III) wird mittels Boranat, Thioacetat oder Hydrogensulfid zum Acidophthalocyaninatomanganat(II) ([Mn(X)Pc2]; X = Cl, Br, NCO, NCS) reduziert und als Tetra(n-butyl)ammoniumsalz isoliert. Im Cyclovoltammogramm von [Mn(NCO)Pc2-]- liegt das Halbstufenpotential für das Redoxpaar MnII/MnIII bei -0,13 V, das der ersten Ringreduktion bei -0,99 V. Die magnetischen Momente der Komplexe weisen auf einen high-spin 6A1-Grundzustand hin: μMn = 5,84 (NCO), 5,78 (Cl), 5,65 (Br), 5,68 μB (NCS). Die Temperaturabhängigkeit der magnetischen Suszeptibilität μMn zeigt zwischen 300 und 30 K Curie-Verhalten. Unterhalb von 30 K steigt μMn wegen schwacher intermolekularer ferromagnetischer Kopplungen an. Die ESR-Spektren bestätigen den S = 5/2-Grundzustand mit einem starken g = 6 Resonanzsignal (AMn = 80 G), wie es für ein axial verzerrtes Ligandenfeld erwartet wird. In den UV-VIS-NIR-Spektren treten neben den typischen π-π*-Übergängen des Pc2--Liganden weitere schwache Banden bei ca. 7,5, 9,1, 14,0 und 19,0 kK auf, die Trip-Multiplett-Übergängen zugeordnet werden. In den Resonanz-Raman-Spektren werden in Resonanz mit der Bande bei 19,0 kK bevorzugt die Mn—X-Valenzschwingungen (v(MnX)) angeregt: X = NCO: 319, Cl: 286, SCN: 238, Br: 202 cm-1. Die Schwingungsfrequenzen stimmen mit entsprechenden FIR-Absorptionen gut überein. Im Falle des Thiocyanato-Komplexes sind eventuell beide Bindungsformen des ambidenten NCS-Liganden präsent (v(Mn—NCS): 274 cm-1). Die Schwingungsfrequenzen des inneren (CN)8-Ringes liegen um bis zu 20 cm-1 tiefer als die von low-spin MnII-Phthalocyaninen.
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    Li2H3IO6, eine neue Variante der Molybdänitstruktur (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 53-57 
    Details
    ISSN: 0044-2313
    Keywords: Dilithium trihydrogen orthoperiodate ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Li2H3IO6, a New Variant of the Molybdenite StructureLi2H3IO6 crystallizes in P61 (a = 529.70(8), c = 2 759.6(5) pm; Z = 6). The crystals are twinned by merohedry, described by m ‖ [001] and 2 ⊥ [001]. According to the results of an X-ray structure determination (2 778 diffractometer data, Rw = 0.047), Li2H3IO6 exhibits a layer structure, with oxygen forming a distorted variant of the sulfur partial structure in molybdenite (MoS2), however, with iodine and lithium in the more (Li) or less (I) distorted octahedral holes. The Li2IO6 packages are connected via strong hydrogen bonds along the edges of distorted trigonal prisms.
    Notes: Li2H3IO6 kristallisiert in der Raumgruppe P61 (a = 529,70(8), c = 2 759,6(5) pm; Z = 6). Die Kristalle sind merohedrisch verviellingt, beschrieben durch m ‖ [001] und 2 ⊥ [001]. Nach der Röntgenstrukturanalyse (2 778 unabhängige Reflexe, Rw = 0,047) liegt eine Schichtstruktur vor, in der die Sauerstoffatome eine verzerrte Variante der Schwefelteilstruktur von Molybdänit (MoS2) ausbilden, die Kationen besetzen die mehr (Li) oder weniger (I) verzerrten Oktaederlücken. Die Li2IO6-Schichtpakete werden entlang der Kanten der verzerrten trigonalen Prismen durch Wasserstoffbrückenbindungen miteinander verknüpft.
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    Zur Reaktion von 2,2′-Dilithiumbiphenyl mit SmBr3 Die Struktur von [(C24H16)SmBr(thf)2]2 · [C24H14] (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 703-706 
    Details
    ISSN: 0044-2313
    Keywords: SmIII dimeric complex ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of Dilithiumbiphenyl with SmBr3. The Crystal Structure of [(C24H16)SmBr(thf)2]2 · [C24H14]In THF SmBr3 forms with [(biph)Li2] the dimeric complex [(quaph)SmBr(thf)2]2 · [C24H14]. The structure was characterized by X-ray single crystal structure analysis (space group P1 (No. 2), Z = 1, a = 943.3(6) pm, b = 1 350.3(1) pm, c = 1 599.9(9) pm, α = 64.99(5)°, β = 89.02(5)°, γ = 73.02(6)°). The Sm iones are bridged by two Br iones. Coordination by one quaph and THF ligands leads to distorded octahedra coordination of the Sm iones. Additionally crystallizes one molecule dibenzonaphthacene.
    Notes: SmBr3 reagiert mit [(biph)Li2] in THF zu dem zweikernigen Komplex [(quaph)SmBr(thf)2]2 · [C24H14]. Der Aufbau konnte durch eine Kristallstrukturanalyse geklärt werden (Raumgruppe P1 (Nr. 2), Z = 1, a = 943,3(6) pm, b = 1 350,3(1) pm, c = 1 599,9(9) pm, α = 64,99(5)°, β = 89,02(5)°, γ = 73,02(6)°). Die Sm-Ionen werden durch zwei Br-Ionen verbrückt. Durch zusätzliche Koordination eines quaph- und zweier THF-Liganden ist jedes Sm-Ion verzerrt oktaedrisch koordiniert. Zusätzlich kristallisiert ein Molekül Dibenzonaphthacen mit aus.
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    Synthesen und Strukturen funktionell substituierter Ferrocene (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 716-722 
    Details
    ISSN: 0044-2313
    Keywords: N,O-Bis(trimethylsilyl)ferrocenylimidate ; E,Z-(Ferrocenyl-trimethylsiloxymethyliden)trimethylsilylphosphane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Structures of functional substituted FerrocenesSubstituted ferrocenes have been prepared using carbonic acid chloride of ferrocene. New pathways have been found reacting the acid chloride with sodium hexamethyldisilazane and tris(trimethylsilyl)phosphane, respectively. The compounds FecC(OSiMe3)N(SiMe3) (Fec = C5H5FeC5H4) 1 and FecC(OSiMe3)P(SiMe3) 2 have been obtained and characterized by X-ray single crystal structure analysis. Experiments for the preparation of FecCP 3 are reported.
    Notes: Zur Synthese funktionell substituierter Ferrocene wurde Ferrocencarbonsäurechlorid mit Natriumhexamethyldisilazan und Tris(trimethylsilyl)phosphan umgesetzt und das Imidat FecC(OSiMe3)N(SiMe3) (Fec = C5H5FeC5H4) 1 und das Phosphaalken FecC(OSiMe3)P(SiMe3) 2 erhalten. Versuche zur Darstellung von FecCP 3 werden mitgeteilt. Von den Verbindungen 1 und 2 konnten Einkristall-Röntgenstrukturanalysen angefertigt werden.
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    Über Chalkogenolate. 203. Derivate der Selendithioallophansäure 2. Darstellung und Eigenschaften von Alkylestern (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 730-732 
    Details
    ISSN: 0044-2313
    Keywords: Alkyl esters of selenodithioallophanic acid ; synthesis ; electron absorption spectra ; infrared spectra ; nuclear magnetic resonance spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 203. Derivatives of Selenodithioallophanic Acid. 2. Preparation and Properties of Alkyl EstersSynthesis and properties of selenodithioallophanic acid esters H2N—CSe—NH—CS—SR where R = CH3, C2H5 as well as their characterization by means of electron absorption, infrared, and nuclear magnetic resonance spectra are described.
    Notes: Synthese und Eigenschaften von Alkylestern der Selendithioallophansäure H2N—CSe—NH—CS—SR mit R = CH3, C2H5 sowie deren Charakterisierung durch Elektronenabsorptions-, Infrarot- und kernmagnetische Resonanzspektren werden beschrieben.
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    Dimethylzinndithioquadratat: Die Kristallstruktur des Benzol-Solvats und des Dimethylsulfoxid-Addukts (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 723-729 
    Details
    ISSN: 0044-2313
    Keywords: Dimethyltin dithiosquarate benzene solvate ; Dimethyltin dithiosquarate-dimethylsulfoxide adduct ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimethyltin Dithiosquarate: The Crystal Structure of the Benzene Solvate and of the Dimethylsulfoxide Adduct(CH3)2SnS2C4O2 · 1/3 C6H6 (I) crystallizes in the orthorhombic space group Pnma. a = 14.393(2), b = 21.668(3), c = 10.424(1) Å, Z = 12.(CH3)2SnS2C4O2 · (CH3)2SO (II) is monoclinic, space group P21/n, a = 9.918(5), b = 12.028(6), c = 12.223(6) Å, β = 108.82(3)°, Z = 4.In I there are two independent dimethyltin dithiosquarate molecules. But in both molecules the Sn atoms display weak coordinative bonds to two O atoms of adjacent dithiosquarate groups. The distances amount 2.873 Å (2×), resp. 2.678 and 2.831 Å. The coordination number of tin becomes 6 and the structure gets connected in three dimensions.In II dimethylsulfoxide is bound with the O atom to Sn (2.345 Å) and the result is a distorted trigonal bipyramid. There a more distant O atom (2.944 Å) leads to a connection of the molecules to a ribbon. The changes of the geometrical parameters are described, which result from the progressive approach of the one O atom.
    Notes: (CH3)2SnS2C4O2 · 1/3 C6H6 (I) kristallisiert in der orthorhombischen Raumgruppe Pnma; a = 14,393(2); b = 21,668(3); c = 10,424(1) Å; Z = 12.(CH3)2SnS2C4O2 · (CH3)2SO (II) ist monoklin, Raumgruppe P21/n; a = 9,918(5); b = 12,028(6); c = 12,223(6) Å; β = 108,82(3)°; Z = 4.In I liegen zwei kristallographisch unabhängige Dimethyl-zinndithioquadratat-Moleküle vor. Bei beiden weisen jedoch die Sn-Atome schwache koordinative Bindungen zu zwei O-Atomen benachbarter Dithioquadratat-Gruppen auf. Die Abstände betragen 2,873 Å (2×) bzw. 2,678 und 2,831 Å. Dadurch erhält Zinn die Koordinationszahl 6, und es ergibt sich eine dreidimensional vernetzte Struktur.In II ist Dimethylsulfoxid über das O-Atom an Sn gebunden (2,345 Å), und es liegt eine verzerrte trigonale Bipyramide vor. Ein weiter entferntes O-Atom (2,944 Å) bewirkt hier die Vernetzung der Moleküle zu einem Band. Die Veränderungen der geometrischen Parameter als Folge der fortschreitenden Annäherung des einen O-Atoms werden beschrieben.
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    Chemischer Transport und Sublimationsverhalten von CrBr3  -  Experimente und Modellrechnungen (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 73-80 
    Details
    ISSN: 0044-2313
    Keywords: Chromium bromide ; chemical vapor transport ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Chemical Transport and Sublimation of CrBr3  -  Experiments and Model CalculationsThe migration of CrBr3 in the presence of high concentrations of bromine (for example D(Br2) = 0,05 mmol/ml; closed silica ampoules) in the investigated temperature range (T̄ = 625°C to 875°C; T̄ = 50°C) is a result from the endothermic reaction \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}{(1)} & {{\rm CrBr}_{{\rm 3,s}} + 1/2{\rm Br}_{{\rm 2,g}} = {\rm CrBr}_{4,{\rm g}}}\end{array} $$\end{document} The chemical transport of CrBr3 is superimposed with the sublimation. With low concentrations of D(Br2) and high temperatures T̄ is the sublimation decisive participated. This is a result of the homogenous equilibrium between CrBr3,g and CrBr4,g (2a) \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}{(2)} & {{\rm CrX}_{{\rm 4,g}} = {\rm CrX}_{{\rm 3,g}} + 1/2\,{\rm X}_{{\rm 2,g}},} & {({\rm a)\,X} = {\rm Br,}} & {{\rm (b)\,X} = {\rm Cl}}\end{array} $$\end{document} The reaction (2a) in comparison with the chemical transport of CrCl3 with Cl2 (Gl. (2b)) is more shifted to CrBr3,g.
    Notes: CrBr3 wandert in einer geschlossenen Ampulle bei hohen Transportmitteldichten (z. B. D(Br2)  -  0,05 mmol/ml) im untersuchten Temperaturbereich (T̄ = 625°C bis 875°C; T̄ = 50°C) von der heißeren (T2) in die weniger heiße Zone (T1) über das endotherme Transportgleichgewicht \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}{(1)} & {{\rm CrBr}_{{\rm 3,s}} + 1/2{\rm Br}_{{\rm 2,g}} = {\rm CrBr}_{4,{\rm g}}}\end{array} $$\end{document} Der chemische Transport von CrBr3 wird von einer Sublimation überlagert, die bei niedrigeren Transportmitteldichten D(Br2) und höherer Temperatur T̄ maßgeblich beteiligt ist, wie die Lage des homogenen Gasphasengleichgewichts (2a) zwischen CrBr3,g und CrBr4,g zeigt. \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}{(2)} & {{\rm CrX}_{{\rm 4,g}} = {\rm CrX}_{{\rm 3,g}} + 1/2\,{\rm X}_{{\rm 2,g}},} & {({\rm a)\,X} = {\rm Br,}} & {{\rm (b)\,X} = {\rm Cl}}\end{array} $$\end{document} Gleichgewicht (2a) liegt im Vergleich zum chemischen Transport von CrCl3 mit Cl2 (Gl. (2b)) mehr auf der Seite von CrBr3,g.
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    Die Elektronische Struktur von Nb3Br8 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 81-84 
    Details
    ISSN: 0044-2313
    Keywords: Nb3Br8 ; electronic structure ; molecular orbitals ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Electronic Structure of Nb3Br8The bonding in Nb3Br8 was investigated with the aid of extended Hückel and molecular orbital calculations to gain some understanding concerning stability and possible chemical altering. Seven electrons occupy metal - metal bonding states of a Nb3Br8 unit. Six of them are responsible for strong σ bonds within the Nb3 cluster. One to two additional electrons may be incorporated to occupy a1 orbitals, which slightly increase the bonding in a Nb3 cluster, rather than between adjacent clusters.
    Notes: Die Bindungsverhältnisse in Nb3Br8 werden mittels Extended-Hückel- und Molekülorbital-Rechnungen untersucht, um hieraus Hinweise auf die Stabilität und mögliche chemische Modifizierbarkeit zu erhalten. Sieben Elektronen sind den Metall - Metall-bindenden Zuständen einer Nb3Br8-Einheit zuzurechnen. Sechs davon sind für starke σ-Bindungen in den Nb3-Clustern verantwortlich. Ein bis zwei zusätzliche Elektronen können in den a1-Orbitalen untergebracht werden, die sich innerhalb eines Nb3-Clusters schwach bindungsverstärkend auswirken, nicht aber zwischen benachbarten Clustern.
    Additional Material: 4 Ill.
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    Synthese und Eigenschaften von molekularen Leitern auf der Basis von dmit-isologen Chelaten Kristall- und Molekülstruktur des Tetramethylammonium-bis-[bis-(1,3-dithiol-2-selon-4,5-diselenolato)nickelat]; [(CH3)4N][Ni(dsise)2]2 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 90-100 
    Details
    ISSN: 0044-2313
    Keywords: Dichalcogenolenchelates ; conducting materials ; x-ray ; EPR ; dmit isologues ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Properties of Molecular Conductors based on dmit isologous Chelates. Crystal and Molecular Structure of Tetramethylammonium-bis-[bis(1,3-dithiole-2-selone-4,5-diselenolato)nickelate]; [(CH3)4N] [Ni(dsise)2]2Syntheses and properties of dichalcogenolate chelates of the general type [(CH3)4N]n[ML2] (n ≤ 2; M = Ni, Pd, Pt); L = dmit (1,3-dithiole-2-thione-4,5-dithiolate), dmise (1, 3-dithiole-2-selone-4,5-dithiolate), dsit (1, 3-dithiole-2-thione-4,5-diselenolate), dsise (1, 3-dithiole-2-selone-4,5-diselenolate), dsis (1, 3-diselenole-2-selone-4,5-diselenolate) are reported. The effects of the chalcogen atom variation in these chelates are discussed by using UV/VIS, IR, EPR, cyclovoltammetric and conductivity data. The x-ray structure of [(CH3)4N][Ni(dsise)2]2 (space group Pccn, a = 7.427(1), b = 39.144(5), c = 11.836(1) Å) and the conductivity of the crystal (12 S cm-1 at room temperature) are given.
    Notes: Synthese und Eigenschaften von Dichalkogenolat-Chelaten vom Typ [(CH3)4N]n[ML2] mit n ≤ 2; M = Ni, Pd, Pt und L = dmit (1, 3-Dithiol-2-thion-4,5-dithiolat), dmise (1,3-Dithiol-2-selon-4,5-dithiolat), dsit (1,3-Dithiol-2-thion-4,5-diselenolat), dsise (1,3-Dithiol-2-selon-4,5-diselenolat) und dsis (1, 3-Diselenol-2-selon-4, 5-diselenolat) werden beschrieben. Anhand von UV/VIS-, IR-, EPR-, cyclovoltammetrischen und Leitfähigkeitsuntersuchungen werden die Auswirkungen der Chalkogenvariation in den Chelaten diskutiert. Die röntgenkristallographischen Daten von [(CH3)4N] [Ni(dsise)2]2 (Raumgruppe Pccn, a = 7,427(1), b = 39,144(5), c = 11,836(1) Å) und die Kristalleitfähigkeit (12 S cm-1, Raum-temperatur) werden vorgestellt.
    Additional Material: 5 Ill.
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  • 89
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    Na2[Pr4O2]Cl9 und K2[Pr4O2]Cl9, die ersten reduzierten quaternären Praseodymchloride mit anti-SiS2-analogen [Pr4/2O]-Ketten (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 85-89 
    Details
    ISSN: 0044-2313
    Keywords: Praseodymium ; Reduced Chlorides ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Na2[Pr4O2]Cl9 and K2[Pr4O2]Cl9, the First Reduced Quaternary Praseodymium Chlorides with Anti-SiS2 Analogous [Pr4/2O] ChainsThe compounds A2[Pr4O2]Cl9 (A = Na, K) are the first reduced quaternary praseodymium chlorides with anti-SiS2 analogous [Pr4/2O] chains. Synthesis took place in the temperature range from 900 to 600°C in silica-jacketed niobium containers from Pr metal, PrCl3, PrOCl and NaCl (KCl) as starting materials. The X-ray structure analysis of a single crystal of Na2[Pr4O2]Cl9 (monoclinic, P21/m (No. 11), Z = 2, a = 812.2(2) pm, b = 1 134.1(2) pm, c = 937.6(2) pm, β = 106.51(2)°, R = 0.048, Rw = 0.037) exhibits trans-edge connected chains of [Pr4/2O] tetrahedra running along [001] which are connected by surrounding common chloride ions forming layers parallel to (001). These layers are connected by further chloride ions to a three-dimensional network. The sodium ions surrounded by a heavily distorted octahedron of chloride ions are placed between the layers. The X-ray structure analysis of a single crystal of the otherwise isotypic K2[Pr4O2]Cl9 (monoclinic, P21/m (No. 11), Z = 2, a = 820.6(2) pm, b = 1 133.2(4) pm, c = 949.2(3) pm, β = 103.94(2)°, R = 0.073, Rw = 0.054) shows that potassium is coordinated by nine chloride ions.
    Notes: Erstmals erhalten wurden reduzierte quaternäre Praseodymchloride mit anti-SiS2-analogen [Pr4/2O]-Ketten vom Typ A2[Pr4O2]Cl9 (A = Na, K). Die Synthese erfolgt im Temperaturbereich von 900 bis 600°C in quarzglasummantelten Niobampullen aus Pr-Metall, PrCl3, PrOCl und NaCl bzw. KCl. Die Röntgenstrukturanalyse an einem Einkristall von Na2[Pr4O2]Cl9 (monoklin, P21/m, Z = 2, a = 812,2(2) pm, b = 1 134,1(2)pm, c = 937,6(2)pm, β = 106,51(2)°, R = 0,048, Rw = 0,037) zeigt, daß die entlang [010] verlaufenden, über gemeinsame transständige Pr—Pr-Kanten zu Ketten verknüpften [Pr4/2O]-Tetraeder in der (001)-Ebene über umgebende, gemeinsame Chloratome zu Schichten verknüpft sind, die ihrerseits über Chloratome zu einer dreidimensionalen Struktur verbunden sind. Zwischen den Schichten befindet sich Na+, stark verzerrt oktaedrisch von Cl- umgeben. Die Röntgenstrukturanalyse an einem Einkristall des ansonsten isotypen K2[Pr4O2]Cl9 (monoklin, P21/m (Nr. 11), Z = 2, a = 820,6(2)pm, b = 1 133,2(4)pm, c = 949,2(3)pm, β = 103,94(2)°, R = 0,073, Rw = 0,054) zeigt, daß K+ dort von 9 Cl- umgeben ist.
    Additional Material: 2 Ill.
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  • 90
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    CO2-Transfer durch Metallphenolate: N-Methyl-ε-carolactam/Natriumphenolat als selektives Reagenz für Carboxylierungsreaktionen (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 101-106 
    Details
    ISSN: 0044-2313
    Keywords: Sodium phenoxide ; CO2 transfer ; carboxylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: CO2 Transfer by Metal Phenoxides: N-Methyl-ε-caprolactam/Sodium Phenoxide as a Selective Reagent for Carboxylation ReactionsCarboxylation reaction of aceton and other substrates with active C—H bonds can be carried out selectively by complexes of sodium phenoxide with N-methyl-ε-caprolactam („NMC“) and CO2. With aceton 3-keto-glutaric acid is formed in 85% yield upon hydrolysis. X-Ray structural analysis of the tetrameric [(NMC)Na(OPh)]4 shows that sodium- and oxygen ions of the phenoxide occupy the positions of a cubus. NMC acts as monodendate ligand, the oxygen atoms of the phenoxide are tridendate bridging ligands. The lithium compound has a similar structure. The complex solved in NMC takes up 0.5 mol CO2 per mol Natrium which at room temperature and normal pressure is transformed to aceton.
    Notes: Carboxylierungsreaktionen von Aceton und anderen Substraten mit aktiven C—H-Bindungen können selektiv mit Komplexen des Natriumphenolats mit N-Methyl-ε-caprolactam („NMC“) und CO2 durchgeführt werden. Mit Aceton entsteht in 85% Ausbeute nach Hydrolyse 3-Ketoglutarsäure. Die Röntgenstrukturanalyse des tetrameren Komplexes [(NMC)Na(OPh)]4 zeigt, daß Natrium- und Phenolatsauerstoffionen die Ecken eines Würfels besetzen.Na1 hat die Koordinationszahl 4. NMC fungiert als einzähliger Ligand, die Sauerstoffatome des Phenolats sind dreizählige Liganden. Die Lithiumverbindung hat eine vergleichbare Struktur. Der Komplex nimmt pro Mol Natriumion in NMC 0,5 Mol CO2 auf, das bei Raumtemperatur und Normaldruck auf Aceton übertragen wird.
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    Synthese und Kristallstruktur von Cu4[PhN3C6H4N3(H)Ph]4(μ2-O)2, einem vierkernigen Kupfer(II)-Komplex mit 1-Phenyltriazenido-2-phenyltriazenobenzol als Ligand (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 107-111 
    Details
    ISSN: 0044-2313
    Keywords: Tetrameric copper(II) complex ; μ2-oxo ligand ; 1-phenyltriazenido-2-phenyltriazeno benzene ligand ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of Cu4[PhN3C6H4N3(H)Ph]4(μ2-O)2, a Tetranuclear Copper(II) Complex with 1-Phenyltriazenido-2-phenyltriazeno-benzene as LigandCu4[PhN3C6H4N3(H)Ph]4(μ-O)2 (1) results from the reaction of an aqueous solution of [Cu(NH3)4]2+ with 1,2-bis(phenyltriazeno)benzene in ether. 1 crystallizes in the orthorhombic space group Pba2 with the lattice parameters a = 1661.5(5), b = 1914.7(7), c = 1269.2(5) pm; Z = 2. In the tetrameric complex with the symmetry C2 the Cu2+ cations form a tetrahedron (Cu—Cu: 298.3(1)-337.1(1) pm). The μ2-oxo ligands occupy the twofold axis and bridge two opposite edges of the Cu4 tetrahedron (Cu—O: 190.0(3) and 192.5(4) pm). The 1-phenyltriazenido-2-phenyltriazeno benzene anions bridge two Cu2+ ions chelating one metal ion and coordinating monodentate the neighbouring one (Cu—N: 191.0(5)-204.1(4) pm).
    Notes: Cu4[PhN3C6H4N3(H)Ph]4(μ-O)2 (1) entsteht bei der Umsetzung einer wäßrigen Lösung von [Cu(NH3)4]2+ mit 1,2-Bis(phenyltriazeno)benzol in Ether. 1 kristallisiert orthorhombisch in der Raumgruppe Pba2 mit den Gitterkonstanten a = 1661,5(5); b = 1914,7(7); c = 1269,2(5) pm; Z = 2. Im tetrameren Komplex mit der Symmetrie C2 bilden die Cu2+-Ionen ein Tetraeder (Cu—Cu: 298,3(1)-337,1(1) pm). Die μ2-Oxoliganden liegen auf der C2-Achse und überbrücken zwei gegenüberliegende Tetraederkanten (Cu—O: 190,0(3) und 192,5(4) pm). Die 1-Phenyltriazenido-2-phenyltriazeno-benzol-Anionen verbrücken benachbarte Cu2+-Ionen, die sie einerseits chelatisierend und andererseits einzähnig koordinieren (Cu—N: 191,0(5)-204,1(4) pm).
    Additional Material: 1 Ill.
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  • 92
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    Crystal and molecular structure of Dicyanotetrasulfane S4(CN)2 (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 117-120 
    Details
    ISSN: 0044-2313
    Keywords: X-ray crystallography ; sulfur-sulfur bonds ; tetra-sulfides ; dicyanosulfanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Kristall- und Molekülstruktur von Dicyanotetrasulfan S4(CN)2S4(CN)2 kristallisiert in der monoklinen Raumgruppe P21/c mit den im Abstract angegebenen Parametern. Die Moleküle besetzen allgemeine Lagen, sind aber ungefähr von C2-Symmetrie. Die Konformation ist all-trans mit den Torsionswinkeln CSSS = 74,6° und 81,7° sowie SSSS = 84,8°. Die mittlere SS-Bindung (201,7 pm) ist viel kürzer als die äußeren (Mittelwert 206,8 pm). Die intermolekularen Wechselwirkungen sind vom van-der-Waals-Typ.
    Notes: S4(CN)2 crystallizes in the monoclinic space group P21/c with a = 885.7 pm, b = 794.2 pm, c = 1032.6 pm, β = 109.0° (at 173 K). The molecules occupy general sites but are of approximate C2 symmetry. The conformation of the molecules is all-trans with torsional angles CSSS = 74.6° and 81.7° and SSSS = 84.8°. The central SS bond (201.7 pm) is much shorter than the terminal SS bonds (av. 206.8 pm). There are no stronger than van-der-Waals type intermolecular interactions.
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    URL: http://dx.doi.org/10.1002/zaac.19946200119
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  • 93
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    Substitutionsreaktionen der Bis(trimethylelement)carbodiimide des Siliciums und Germaniums mit Metallchloriden und Dimethylmetallchloriden des Sb, Al, Ga und In (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 112-116 
    Details
    ISSN: 0044-2313
    Keywords: Bis(trimethylsilyl)-, bis(trimethylgermyl)carbodiimide ; substitution compounds ; chloro- and dimethylmetal(III) derivatives ; syntheses ; vibrational spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substitution Reactions of Bis(trimethylelement)carbodiimides of Silicon and Germanium with Metal Chlorides and Dimethylmetalchlorides of Sb, Al, Ga, and InThe reaction of Me3Ge—N=C=N—GeMe3 (Me=CH3) with SbCl5 in a 1 : 1 molar ratio forms dimeric Cl4SbNCNGeMe3 in high yields. The corresponding compounds (X2MNCNSiMe3)2-3 (with X=Cl, Me and M = Al, Ga), formed by reactions of X2MCl and Me3SiNCNSiMe3, are less stable and tend to condensations, eliminating Me3SiX. The carbodiimide derivates (Me2MNCNEMe3)2-3 (with E = Si, Ge) are also available in aprotic solvents from polymeric LiNCNEMe3 and Me2MCl (M = Al, Ga, In). According to the IR and Raman spectra the low associated substitution products consists of cyclic ring skeletons and asymmetric 〉 N—C≡N—EMe3 units with cyanamide conformation.
    Notes: Bei der Reaktion von Me3Ge—N=C=N—GeMe3 (Me=CH3) mit SbCl5 im Molverhältnis 1 : 1 entsteht in hoher Ausbeute dimeres Cl4SbNCNGeMe3. Die entsprechend aus X2MCl und Me3SiNCNSiMe3 dargestellten Verbindungen (X2MNCNSiMe3)2-3 (mit X = Cl, Me und M = Al, Ga) sind weniger beständig und neigen zu Kondensationen unter Abspaltung von Me3SiX. Carbodiimidderivate der Form (Me2MNCNEMe3)2-3 (mit E = Si, Ge) sind auch aus polymerem LiNCNEMe3 und Me2MCl (M = Al, Ga, In) in aprotischen Lösungsmitteln zugänglich. Die IR- und Ramanspektren der Verbindungen werden aufgenommen und diskutiert, danach weisen die niedrig assoziierten Produkte ein cyclisches Ringgerüst und unsymmetrische 〉N—C≡N—EMe3 Einheiten mit Cyanamidkonformation auf.
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    The Decomposition of Aqueous Dithionite and its reactions with polythionates SnO2-6 (n = 3-5) studied by ion-pair chromatography (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 121-126 
    Details
    ISSN: 0044-2313
    Keywords: Dithionite decomposition ; polythionate reduction ; thiosulfate decomposition ; ion-pair chromatography ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Zersetzung von Dithionit in Wasser und seine Reaktionen mit Polythionaten SnO2-6 (n = 3-5)  -  eine Untersuchung mittels IonenpaarchromatographieDithionit hydrolysiert in Wasser bei 20°C und pH-Werten nicht weit von 7,0 zu Thiosulfat und Sulfit, aus denen dann Trithionat entstehen kann. Zugabe von Thiosulfat beschleunigt die Hydrolysereaktion nur bei pH 〈 6. Diese pH-Abhängigkeit wird durch die Bildung des Ions HS2O3- erklärt, das durch Dithionit zu Sulfid und Sulfit reduziert wird. Sulfidionen zerstören Dithionit durch nucleophile Spaltung, wobei wahrscheinlich primär Sulfoxylat und Thiosulfit entstehen. Die Polythionate SnO62- (n = 3-5) werden von Dithionit bei 20°C und pH = 7,0 reduziert (Gleichung siehe Abstract), wobei die Reaktionsgeschwindigkeit mit der Kettenlänge n rasch ansteigt. In Sekundärreaktionen baut Sulfit die Polythionationen unter Bildung von Thiosulfat ab.
    Notes: Aqueous dithionite decomposes at 20°C and pH values not far from 7.0 to give thiosulfate and sulfite from which trithionate may form. Addition of thiosulfate accelerates this reaction only at pH 〈 6. The pH dependence is explained by formation of HS2O3- ions which are reduced by dithionite to HS- and SO2-3. Sulfide destroys dithionite by nucleophilic cleavage, probably with formation of sulfoxylate and thiosulfite ions. The polythionates SnO2-6 (n = 3-5) are reduced by dithionite at pH = 7.0 and 20°C according to SnO2-6 + S2O2-4 + 2 H2O→S2O32- + Sn-3SO32- + 4H1 + 2SO32- The reaction rate rapidly increases with the number n of sulfur atoms. In secondary reactions sulfite attacks SnO62- ions with thiosulfate formation.
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    Zur Kenntnis des Natrium-tetrahydroxoaluminat-chlorids Na2[Al(OH)4]Cl (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 771-776 
    Details
    ISSN: 0044-2313
    Keywords: Tetrahydroxoaluminate chloride, Na2[Al(OH)4]Cl ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Sodium Tetrahydroxoaluminate Chloride Na2[Al(OH)4]ClThe hitherto unknown compound Na2[Al(OH)4]Cl was prepared by crystallisation from a NaCl containing sodium aluminate solution. According to the X-ray single crystal investigation (tetragonal, space group P4/nmm, a = 7.541 Å, c = 5.059 Å, Z = 2) the compound represents the first example of a crystalline hydroxoaluminate with monomeric [Al(OH)4]- anions. Cl- shows a quadratic anti prismatic coordination to 4 Na+ and over hydrogen bonds to 4 O2- while Na+ is octahedrally coordinated by 4 O2- and 2 Cl- (axial). The results of the crystal structure analysis are confirmed by 27Al and 23Na MAS NMR investigations. Na2[Al(OH)4]Cl decomposes at about 200°C without intermediates under formation of β-NaAlO2 and NaCl.
    Notes: Die bisher unbekannte Verbindung Na2[Al(OH)4]Cl wurde durch Kristallisation aus mit NaCl versetzter Natriumaluminatlösung erhalten. Entsprechend der Röntgenstrukturanalyse an einem Einkristall (tetragonal, Raumgruppe P4/nmm, a = 7,541 Å, c = 5,059 Å, Z = 2) liegt mit dieser Verbindung erstmals ein Beispiel für ein kristallines Hydroxoaluminat mit monomeren [Al(OH)4]--Anionen vor. Cl- ist quadratisch antiprismatisch mit 4 Na+ sowie über Wasserstoffbrückenbindungen mit 4 O2- koordiniert, während Na+ oktaedrisch von 4 O2- und 2 Cl- (axial) umgeben ist. Die Ergebnisse der Kristallstrukturanalyse werden durch 27Al- und 23Na-MAS-NMR-Messungen bestätigt. Na2[Al(OH)4]Cl zersetzt sich ohne Zwischenprodukte bei 200°C zu β-NaAlO2 und NaCl.
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    Template-Reaktion von Bis(acetylacetonato)-dioxo-molybdän(VI) mit Benzoylhydrazin und Triphenylphosphan (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 955-958 
    Details
    ISSN: 0044-2313
    Keywords: Template Reactions ; Benzoylhydrazine ; Hydrazide Ligands ; Molybdenum Complexes ; Crystal Structure ; Triphenylphosphane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Template Reactions of Bis(acetylacetonato)-dioxo-molybdenum(VI) with Benzoylhydrazine and TriphenylphosphaneBy reaction of MoO2(acac)2 with C6H5—CO—NH—NH2 in the presence of P(C6H5)3 Mo(NNCOC6H5)((CH3)2CNNCOC6H5)(P(C6H5)) was obtained besides MoO(acac-NNHCOC6H5)(NNHCOC6H5). The earlier compound was characterized by X-ray structural analysis. Crystallographic data see „Inhaltsübersicht“.
    Notes: Bei der Umsetzung von MoO2(acac)2 mit C6H5—CONH—NH2 in Gegenwart von P(C6H5)3 wurde neben MoO(acac-NNHCOC6H5)(NNHCOC6H5) als weitere Substanz Mo(NNCOC6H5)(NNHCOC6H5)((CH3)2CNNCOC6H5) · (P(C6H5)3) erhalten, welche Benzoylhydrazidoliganden in verschiedenen Bindungsformen aufweist. Die Verbindung wurde durch Röntgenkristallstrukturanalyse charakterisiert.Raumgruppe P 21/c, Z = 4, 2 632 beobachtete unabhängige Reflexe, R = 5,9%, Gitterabmessungen bei 19°C: a = 1 583,6(2) pm, b = 1 485,0(2) pm, c = 1 656,1(2) pm, β = 100,79(1)°C.
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    Masthead (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200601
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    Synthesis and Metal Complex Formation of Nitrogen-Oxygen Donor Macrocyclic Ligands (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 959-964 
    Details
    ISSN: 0044-2313
    Keywords: Macrocyclic N,O-Donor Ligands ; Metal Complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese und Metallkomplexbildung von makrozyklischen Stickstoff-Sauerstoff-DonorligandenDie Reduktion von 2,3:9,10-Dibenzo-5,12-diaza-1,8-dioxacyclotetradecan-5,11-dien(1) mit Natriumborhydrid in Ethanol ergibt 2,3:9,10-Dibenzo-5,12-diaza-1,8-dioxacyclotetradecan(2) in guter Ausbeute. Der makrozyklische Ligand 2,3:9,10-Dibenzo-5,12-diaza-1,8-dioxacyclotetradecan-N,N′-diessigsäure(3) wurde synthetisiert und analysiert.Die Reaktion von 2 mit einem Überschuß von Acrylnitril ergibt 2,3:9,10-Dibenzo-5,12-diaza-1,8-dioxacyclotetradecan-N,N′-di(2-cyanethyl) (4). Verschiedene Komplexe von diesen Liganden mit NiII, CuII und CoII wurden dargestellt und untersucht. Die Strukturen dieser Komplexe werden auf Grund von elementaranalytischen Daten, 1H, 13C-NMR, IR-, UV-VIS, magnetischen- und Leitfähigkeitsdaten vorgeschlagen.
    Notes: Reduction of 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacylotetradecane-5,11-diene(1) with sodium borohydride in ethanol generates 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane(2) in high yield. The macrocyclic ligand 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane-N,N′-diacetic acid (3) has been synthesized and characterized. In addition, reaction of (2) with an excess of acrylonitrile gives 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane-N,N′-di(2-cyanoethyl) (4). Several new complexes of these ligands with nickel(II), copper(II) and cobalt(II) have been prepared and identified. The structures of these complexes are proposed on the basis of elemental analysis, 1H, 13C-NMR, IR, UV-VIS spectra, magnetic susceptibility and conductivity data.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19946200536
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    Kristallstruktur von Hexamincyclotriphosphazen, P3N3(NH2)6Professor Friedo Huber zum 65. Geburtstage gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 965-968 
    Details
    ISSN: 0044-2313
    Keywords: Hexamine cyclotriposphazene ; crystal growth ; crystal structure ; hydrogen-bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of Hexamine Cyclotriphosphazene, P3N3(NH2)6In the presence of KNH2 hexamine cyclotriphosphazene semi ammoniate (molar ratio 12:1) in NH3 gives crystals of solvent free P3N3(NH2)6 within 5 d at 130°C and p(NH3) = 110 bar. The structure was solved by X-rax methods: P3N3(NH2)6: P21/c, Z = 4, a = 10.889(6) Å, b = 5.9531(6) Å, c = 13.744(8) Å, β = 97.83(3)°, Z(Fo) = 1 721 with (Fo)2 ≥ 3σ(Fo)2, Z(var.) = 157, R/Rw = 0,036/0,041The structure contains columns of molecules P3N3(NH2)6 all in the same orientation. The six-membered rings within one molecule have boat conformation. The columns are stacked together in a way that one is surrounded by four others shifted by half a lattice constant in direction [010]. Strong hydrogen bridge-bonds N—H…N connect molecules within the columns and between them.
    Notes: Bei Umsetzungen von Hexamincyclotriphosphazensemiammoniakat mit KNH2 (Molverhältnis 1:12, 5 d, T = 130°C, P(NH3) = 110 bar) in NH3 wurden Kristalle von ammoniakfreiem P3N3(NH2)6 als Nebenprodukt erhalten. Die Struktur dieser Verbindung wurde röntgenographisch bestimmt: P3N3(NH2)6: P21/c, Z = 4, a = 10,889(6) Å, b = 5,9531(6) Å, c = 13,744(8) Å, β = 97,83(3)°, Z(Fo) = 1 721 für (Fo)2 ≥ 3σ(Fo)2, Z(Parameter) = 157, R/Rw = 0,036/0,041In der Struktur liegen Säulen deckungsgleich gestapelter Moleküle P3N3(NH2)6 mit wannenförmiger Konformation vor. In nächster Umgebung befinden sich vier weitere Säulen, die um eine halbe Gitterkonstante in Richtung [010] entlang der Staperlrichtung gegenüber einer Bezugssäule versetzt sind. Starke Wasserstoffbrückenbidungen N—H⋅⋅⋅N verknüpfen die Moleküle sowohl zwischen den Säulen als auch in Säulenrichtung.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200602
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  • 100
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    HgPb2O2Cl2, ein „perforiertes“ Blei(II)-oxidProfessor Friedo Huber zum 65. Geburtstage gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 977-980 
    Details
    ISSN: 0044-2313
    Keywords: Mercury(II) lead(II) oxide chloride ; synthesis ; crystal structure ; structural comparison ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: HgPb2O2Cl2, a “Perforated” Lead(II) OxideSingle crystals of HgPb2O2Cl2 were grown in a HgCl2 flux by reaction of PbO with HgCl2. Crystal structure analysis by single crystal X-ray methods were carried out. HgPb2O2Cl2 crystallizes monoclinic with a = 11.788(2) Å, b = 3.910(1) Å, c = 7.749(2) Å, β = 122.64(3)°, space group C2/m (No. 12) and Z = 2. HgPb2O2Cl2 is the first member of a new structure type, closely related to the structure of PbO.
    Notes: Einkristalle von HgPb2O2Cl2 wurden durch Umsetzung von PbO und HgCl2 in HgCl2-Schmelzen gezüchtet. An ihnen wurde der Aufbau mittels Einkristallröntgenstrukturanalyse bestimmt. HgPb2O2Cl2 kristallisiert monoklin mit a = 11,788(2) Å, b = 3,910(1) Å, c = 7,749(2) Å, β = 122,64(3)°, Raumgruppe C2/m (Nr. 12) und Z = 2. HgPb2O2Cl2 ist der erste Vertreter eines neuen Strukturtyps, der kristallchemisch von der Struktur von PbO ableitbar ist.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200604
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