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  • 1
    Electronic Resource
    Electronic Resource
    Population genetics of unequal crossing over (1975)
    Springer
    Journal of molecular evolution 4 (1975), S. 201-247 
    Details
    ISSN: 1432-1432
    Keywords: Crossing over ; Unequal Crossing over ; Gene Duplication ; Selection Relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The population genetics of unequal crossing over was examined for an infinite population with random mating. The following cases were considered: 1. There is an initial portion of duplicated genes which offer the opportunity for unequal crossing over, but the primary event leading to the duplication does not occur any more (model 1a). 2. This primary event occurs with a certain (small) probability (model 1b). For both possibilities the long-term consequences for the distribution of “alleles” (i.e. the single gene, the duplicated gene, the triplicated gene etc.) were considered with the following additional assumptions: 1. No selection. 2. Selection with maximum fitness for an optimum “allele length” (i.e. number of gene repeats). 3. For model 1a, selection with general advantage of longer alleles over shorter ones was also examined. The results are briefly the following: In model 1a under assumption 1 the distribution of allele length tends with increasing generation number to a stationary state which depends on the initial allele distribution (i.e. on the initial frequency of the duplicated gene) but not on the frequency, P, of unequal crossing over; the stationary frequencies of the alleles decrease with increasing allele length. Under assumption 2 there is likewise a stationary allele distribution, but this depends on P as on the strength of selection and not on the initial allele distribution; it is concentrated more or less tightly around the optimal allele length. Under assumption 3 no stationary state seems to be reached: the mean and the standard deviation of the allele distribution increase steadily with the generation number. In model 1b under assumption 1, with certainty no stationary distribution exists. Under assumption 2 the situation is the same as that in model 1a; the stationary distribution of allele length is identical with that in model 1a for the same P and same selection strength, quite independent of the probability of the primary event. The results were discussed with respect to empirical examples in which unequal crossing over is expected to be important, for example human haptoglobins, immune globulin determining cistrons, and nucleolus organizer regions. The consequences of selection relaxation were considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732983
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  • 2
    Electronic Resource
    Electronic Resource
    Strain-induced crystallization, Part IV: Induction time analysis (1979)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 401-405 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The empirical equation, 1/ti = AeEi/RT, which expresses the exponential dependence of the reciprocal of crystallization induction time, ti, has been analyzed and shown to be equivalent to the nucleation rate equations derived earlier in Part III (1). Consequently we have used the ti measurements obtained earlier by Krueger and Yeh to calculate not only the nucleation rate enhancements but also the melting point elevations, the relative crystal thickness changes and molecular coil extension ratios of shear-crystallization polyethylene. It is shown that polyethylene when crystallized between 129 and 131°C at shear rates between 1.56 and 9.70 sec-1 can have melting point increases of 4.2 to 7.2°C and crystal thickness decreases of 20 to 25 percent, when compared to those crystallized at 130°C in the quiescent state. The predicted “coil” extension in the melt just prior to shear-induced crystallization ranges between 21 and 36 percent. The results of these analyses as well as those on nucleation rates of polyethylene oxide are discussed in detail.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760190606
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  • 3
    Electronic Resource
    Electronic Resource
    N-(morpholinothio)imides as curing agents in semiefficient vulcanization systems (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 1731-1742 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Semiefficient vulcanization systems (semi-EV) are often used when a stock requires good aging properties as well as good fatigue resistance. A partial replacement of sulfur in a conventional cure system with 4,4′-dithiobismorpholine or 2-mercaptabenzothiazyl 4-morpholino disulfide (BMD) is an example of semi-EV system. However, with BMD the scorch time is not always long enough for multisteps involved in the manufacturing of tires. Such new cure retarders as N-(cyclohexylthio)phalimide or N, N′-bis(cyclohexylthio)oxanilide showed very little efficiency in BMD cure systems. This paper describes the usage of new curing agents, (N-morpholinothio)imides, which can overcome the disadvantage of scorchness in BMD cure system and provide excellent aging properties. This is rationalized by the formation of BMD during vulcanization. The facile formation of BMD from N-(4-morpholinothio)phthalimide (MTP) and 2-mercaptobenzothiazole (MBT) serves to illustrate the feasibility of in situ formation of BMD during cure and to explain long scorch time observed with N-(4-morpholinothio)imides.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210701
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  • 4
    Electronic Resource
    Electronic Resource
    Die Reaktion von 2,4-Pentandion mit C6H5PCI2-Komplexen:Acetylaceton als Dien-Diol-Ligand (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3637-3643 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of 2,4-Pentanedione with C6H5PCI2 complexes: Acetylacetone as Diene Diol LigandReaction of dichlorophenylphosphane complexes with acetylacetone results in substitution of the chlorine functions by the oxygen of the enolized dione. One or both chlorine substituents may be replaced by an acetylacetonate group (4-5). In addition, under appropriate conditions, 1,3,2- dioxaphosphorine systems (2-6) are formed in which both chlorine functions are substituted by the oxygen atoms of one acetylacetone moiety bonded in its diene diol form. Examples of the new reactions are given for (CO)5Cr- and (CO)5W-dichlorophenylphosphane complexes. For 2,4 the constitution is exemplified by x-ray analyses.
    Notes: Dichlorphenylphosphan-Komplexe reagieren mit Acetylaceton unter Subsititution der Halogenfunktionen durch den Sauerstoff des enolisierten Dions. Dabei Können zwei Chlorsubstituenten durch je einen Acetylacetonat-Rest ersetzt werden (4,5). Unter geeigneten Bedingungen entstehen darüber hinaus 1,3,2-Dioxaphosphorin-Systems (2,6), in welchen beide Chlorfunktionen durch die Sauerstoffatome eines in der Dien-Diol-Form gebundenen Acetylacetonrestes substituiert sind. Diese neuen Reaktionen werden am Beispiel von (CO)5Cr - und (CO)5W-Derivaten des C6H5PCI2 vorgestellt. An 2 und 4 wird die Konstitution durch Röntgenstrukturanalysen examplarisch belegt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791121113
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  • 5
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie der Alkylverbindungen der übergangsmetalle. XXV [1]. Darstellung und Eigenschaften des [Ti(CH2CN)4 · 2 THF]n (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 437 (1977), S. 210-212 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXV. Preparation and Properties of [Ti(CH2CN)4 · 2 THF]nTetracyanomethyl titanium, [Ti(CH2CN)4 · 2 THF]n, can be prepared by reaction of TiCl4 with LiCH2CN in form of a tetrahydrofuran complex. The brown, stable compound, which seems to be a coordination polymer, was characterized by i.r. and 1H-n.m.r. spectra.
    Notes: Tetracyanmethyltitan läßt sich durch Reaktion von Titan(IV)-chlorid mit Cyanmethyllithium als braune, thermisch recht beständige, offensichtlich koordinationspolymere Verbindung der Formel [Ti(CH2CN)4 · 2 THF]n gewinnen. Eine nähere Charakterisierung erfolgte mittels des IR- und des 1H-NMR-Spektrums.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19774370130
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  • 6
    Electronic Resource
    Electronic Resource
    Dijodo- und Dibromometallazide X2MN3 von Aluminium und Gallium (1978)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 444 (1978), S. 71-76 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diiodo- and Dibromometal Azides X2MN3 of Aluminium and GalliumAluminium and gallium triiodide react in benzene with iodine azide yielding the diiodometal azides I2MN3 (M = Al, Ga). With liquid bromine the dibromometal azides can be obtained. Boron triiodide reacts similar with iodine azide, however, the resulting I2BN3 can not be obtained in a pure condition. Some properties and the i.r. spectra of the azides were recorded and assigned.
    Notes: Aluminium- und Galliumtrijodid reagieren in Benzol mit Jodazid unter Bildung der Dijodometallazide J2MN3 (M = Al, Ga). Mit flüssigem Brom lassen sie sich in die Dibromometallazide Br2MN3 umwandeln. Bortrijodid reagiert ähnlich mit Jodazid, jedoch läßt sich das entstehende J2BN3 wegen seiner Zersetzlichkeit nicht in reiner Form erhalten. Einige Eigenschaften und die IR-Spektren der Azide werden mitgeteilt und zugeordnet.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19784440107
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  • 7
    Electronic Resource
    Electronic Resource
    Darstellung, Kristall- und Molekülstruktur von Triphenylphosphinoxidhydrochlorid (C6H5)3PO · HCl (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 436 (1977), S. 229-236 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation, Crystal and Molecular Structure of Triphenylphosphineoxide Hydrochloride (C6H5)3PO · HCl(C6H5)3PO · HCl was prepared from HCl and (C6H5)3PO in benzene. It crystallizes in the monoclinic space group P21/n with a = 9.788(1), b = 16.477(6), c = 10.568(6) Å, β = 112.11(6)° and Z = 4; d(calc./obs.) 1,32/1,29 g · cm-3. The structure was determined by direct methods from 2 164 independent reflections and has been refined by full matrix least squares methods to R = 0.036. In the compound (C6H5)3PO and HCl are linked by a short, unsymmetrical, largely linear H-bond (distances O—Cl 2.747(2), O—H 1.116(40), H—Cl 1.633(40) Å, ∡ O—H—Cl 176.6(3.2)°). The P—O-distance measures 1.517(2) Å. From the position of the bridging H-Atom the compound can be conceived according to the contributing formula \documentclass{article}\pagestyle{empty}\begin{document}$ \left({{\rm C}_{\rm 6} {\rm H}_{\rm 5} } \right)_3 \mathop {\rm P}\limits^ + {\rm OH} \cdot \cdot \cdot \mathop {{\rm Cl}}\limits^ - $\end{document} as hydroxotriphenylphosphonium chloride.
    Notes: (C6H5)3PO · HCl wurde aus HCl und (C6H5)3PO in Benzol gewonnen. Es kristallisiert monoklin in der Raumgruppe P21/n mit a = 9,788(1), b = 16,477(6), c = 10,568(6) Å, β = 112,11(6)° und Z = 4; d(ber./gef.) = 1,32/1,29 g · cm-3. Die Struktur wurde anhand von 2 164 unabhängigen Reflexen direkt bestimmt und nach der Kleinste-Quadrate-Methode (volle Matrix) bis zu einem R-Wert von 0,036 verfeinert. In der Verbindung sind (C6H5)3PO und HCl über eine kurze unsymmetrische, weitgehend lineare H-Brücke (Abstände O—Cl 2,747(2), O—H 1,116(40), H—Cl 1,633(40) Å, ∡ O—H—Cl 176,6(3,2)°) verknüpft. Der P—O-Abstand beträgt 1,517(2) Å. Die Verbindung ist auf Grund der Lage des Brücken-H-Atoms entsprechend der Grenzstruktur \documentclass{article}\pagestyle{empty}\begin{document}$ \left({{\rm C}_{\rm 6} {\rm H}_{\rm 5} } \right)_3 \mathop {\rm P}\limits^ + {\rm OH} \cdot \cdot \cdot \mathop {{\rm Cl}}\limits^ - $\end{document} als Hydroxotriphenylphosphoniumchlorid aufzufassen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19774360130
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  • 8
    Electronic Resource
    Electronic Resource
    Difluorophosphate von Zinn(IV) und Antimon(V) (1978)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 438 (1978), S. 169-175 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Difluorophosphates of Tin (IV) and Antimony(V)Preparation and properties of SnCl2(PO2F2)2 (l), Cl4Sb(O2PF2) (2) and F4Sb(O2PF2) (3) are described. According to their vibrational spectra the structures are assumed. 31P-nmr spectra of 2 and 3 are given. 1 is characterised additional by its 119Sn-Mössbauer spectrum.
    Notes: Darstellung und Eigenschaften von SnCl2(PO2F2)2 (1), SbCl4(PO2F2) (2) und F4Sb(O2PF2) (3) werden beschrieben. Aus den Schwingungsspektren werden Strukturvorschläge abgeleitet. 31P-KMR-Spektren werden für 2 und 3 mitgeteilt, 1 wird zusätzlich durch das 119Sn-Mößbauer-Spektrum charakterisiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19784380118
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  • 9
    Electronic Resource
    Electronic Resource
    [(S)-tert-Butylmethylphenylphosphin][(+)-(1R,5R-3-2-10-η-pinenyl]nickelbromid, C10H14NiBrP(CH3)3(C6H5) Molekülstruktur und absolute Konfiguration (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 3574-3580 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [(S)-tert-Butylmethylphenylphosphine][(+)-(1R,5R-3-2-10-η-pinenyl]nickel Bromide, C10H14NiBrP(CH3)3(C6H5) Molecular Structure and Absolute ConfigurationThe X-Ray structural analysis of the compound 2 show a square planar arrangement of the ligands around the nickel atom. The pinene part of the molecule is linked to the metal in exoposition via a non-symmetric π-allyl-group. The more positions at the nickel atom are occupied by bromine and phosphorus. The arrangement of the substituents at the phosphorus atom is essentially tetrahedral with identical C-P-C angles (104.6°), but different C-P-Ni angles (106-122°). The absolute configuration has been determined with more than 99.9% probability.
    Notes: Die Röntgenstrukturanalyse der Titelverbindung 2 ergab eine quadratisch planare Anordnung der Liganden am Nickel-Zentralatom, wobei der Pinen-Rest über eine unsymmetrische π-Allyl-Gruppierung in exo-Stellung am Nickel fixiert ist. Zwei weitere Koordinationsstellen des Nickels werden durch Brom und Phosphor besetzt. Die Anordnung der Substituenten am Phosphor ist verzerrt tetraedrisch mit nahezu identischen C-P-C-winkeln (104.6°), jedoch stark unterschiedlichen C-P-Ni-Winkeln (106-122°). Die absolute Konfiguration der Verbindung wurde mit über 99.9 proz. Wahrscheinlichkeit aus den Beugungsdaten abgeleitet.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761091110
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Reaktivität von Metall-π-Komplexen, XXII. Sandwichartig gebaute (Pd-Pd)-Zweikernkomplexe mit brückenbildenden Cyclopentadienyl- und Allyl-Liganden (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1763-1775 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Reactivity of Metal π-Complexes, XXII. Sandwich-like Dinuclear (Pd-Pd)-Complexes with Bridging Cyclopentadienyl and Allyl LigandsThe reaction of C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-allyl) with tertiary phosphines or phosphites in the molar ratio of 1:1 produces in practically quantitative yields the dinuclear complexes (C5H5)(2-RC3H4)Pd2L2 (4-20) in which palladium has the oxidation state +1. The crystal structure analysis of 5 (R = CH3, L = P(C6H5)3) and 12 (R = CH3, L = P(OC6H4-o-CH3)3) shows that the cyclopentadienyl as well as the allyl ligand is bonded in a sandwich manner to the Pd-Pd unit. The Pd-Pd distance of 267.9 (in 5) or 268.9 pm (in 12) is suggestive of a metal-metal bond. It is not possible to determine whether the cyclopentadienyl ring in 4-20 exists as a pentahapto- or trihapto-bonded ligand on the basis of the 1H- and 13C n. m. r. data. The reactivity of the dinuclear complexes is in agreement with square planar coordination of the metal atoms.
    Notes: Bei den Reaktionen von C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-Allyl) mit tertiären Phosphinen oder Phosphiten im Molverhältnis 1:1 entstehen in praktisch quantitativer Ausbeute die Zweikernkomplexe (C5H5)(2-RC3H4)Pd2L2 (4-20), in denen Palladium in der Oxidationszahl +1 vorliegt. Wie die Kristallstrukturanalysen von 5 (R = CH3, L = P(C6H5)3) und 12 (R = CH3, L = P(OC6H4-o-CH3)3) zeigen, sind sowohl der Cyclopentadienyl- als auch der Allyl-Ligand sandwichartig an die Pd2-Einheit gebunden. Der Pd-Pd-Abstand von 267.9 (in 5) bzw. 268.9 pm (in 12) weist auf das Vorliegen einer Metall-Metall-Bindung hin. Aufgrund der 1H- und 13C-NMR-Daten ist nicht zu entscheiden, ob in 4-20 der Cyclopentadienylring als pentahapto-oder trihapto-gebundener Ligand vorliegt. Die Reaktivität der Zweikernkomplexe steht mit einer quadratisch-planaren Koordination der Metallatome in Einklang.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100522
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