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  • 1
    ISSN: 0044-2313
    Keywords: Tin complexes ; thiolated ligands ; 119Sn Mössbauer spectra ; molecular dynamics ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zinn(IV)-, Monomethylzinn(IV)- und Dimethylzinn(IV)-Komplexe mit Thiolschwefel- und heterocyclischen Stickstoff-Donatoren: Moleküldynamik und Struktur bei 119Sn-Mössbauer-SpektrenDie Moleküldynamik der Komplexe Sn(SPyN)4 (1), SnCl2(SPyN)2 (2), MeSn(SPy)3 (3), MeSnCl(SPyN)2 (4), Me2Sn(TCy)2 (5), Me2SnCl(TOx) (6) und Me2Sn(TUr) (7) (HSPy = 2-Mercaptopyridin; HSPyN = 2-Mercaptopyrimidin; HTCy = 2-Thiocytosin; HTOx = 8-Thiochinolin; H2TUr = 2-Thiouracil) wurde mit 119Sn-Mössbauer-Spektroskopie bei verschiedenen Temperaturen untersucht. Die Flächen unter den Resonanzlinien wurden als Funktion der Temperatur bestimmt und daraus die Debye-Temperaturen, die cut-off-Frequenzen wie auch die rückstoßfreien Anteile (Lamb-Mössbauer-Faktor) und die mittleren quadratischen Auslenkungen der 119Sn-Atome berechnet. Durch Fingerprintvergleiche auf Grund von Literaturdaten wurden monomere Strukturen den Komplexen (1) bis (4) und (6) zugeordnet, während (5) und (7) an der Grenze monomer eindimensionaler Polymerer liegen. Die Ergebnisse werden auf der Basis bekannter Kristall- und Molekülstrukturen diskutiert. Die Umgebung der Zinnatome wird durch Punktladungsmodell-Berechnungen von Kernquadrupolaufspaltungs-Parametern simuliert; Molekülstrukturen für die Komplexe (5) bis (7), von denen keine Röntgendaten verfügbar sind, werden vorgeschlagen.
    Notes: The molecular dynamics of the complexes Sn(SPyN)4 (1), SnCl2(SPyN)2 (2), MeSn(SPy)3 (3), MeSnCl(SPyN)2 (4), Me2Sn(TCy)2 (5), Me2SnCl(TOx) (6), and Me2Sn(TUr) (7) [HSPy = 2-mercaptopyridine; HSPyN = 2-mercaptopyrimidine; HTCy = 2-thiocytosine; HTOx = 8-thioquinoline; H2TUr = 2-thiouracil] has been investigated by variable temperature 119Sn Mössbauer spectroscopy. The area under the resonant peaks has been determined as function of temperature, from which Debye temperatures and cut-off frequencies, as well as recoil-free fractions (Lamb Mössbauer factor) and mean square displacements of 119Sn, have been calculated. By fingerprint procedures on the basis of literature data, monomeric structures are attributed to complexes (1)-(4) and (6), while (5) and (7) lie in the borderline monomersmonodimensional polymers. The results are discussed on the basis of known crystal and molecular structures. The nature of the environment of tin atoms has been simulated by point-charge model calculations of nuclear quadrupole splitting parameters; molecular structures are proposed for complexes (5)-(7), where no X-ray diffractometric data are available.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 71 (1911), S. 347-355 
    ISSN: 0863-1778
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 170 (1928), S. 109-110 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 887-890 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The recent development of specific and sensitive surface techniques has prompted new studies of electrode properties, in particular of their catalytic activity. Many papers have reported the use of X-ray photoelectron spectrometry, Rutherford backscattering spectrometry, secondary ion mass spectrometry etc. in the analysis of mixed-oxide films, and interesting results concerning electrochromic and catalytic properties have been shown. The influence of the method of preparation has also been confirmed, together with the important role of microstructural composition. In previous studies, our group performed composition analyses and depth profiles of RuO2/TiO2 and IrO2/TiO2 mixed-oxide coatings by secondary ion mass spectrometry (SIMS). Many positive-and negative-ion species are of particular interest in characterizing electrodes synthesized by different methods. This paper presents the results obtained by SIMS analysis of IrO2/RuO2/TiO2 films before and after their use in CI2 anodic production. Mass spectra obtained under different experimental conditions are reported and the aspects related to surface compositon modifications induced by Cl2 evolution on electrode films are discussed.
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  • 5
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Mixed-oxide coatings are extensively used in the electrochemical industry. Secondary-ion mass spectrometric data confirm that technological research can indeed find a new way of controlling precursors, synthesis conditions, purity of coatings and electrodic activity. Results obtained by argon and oxygen primary-ion bombardment of RuO2/TiO2, IrO2/TiO2, RuO2/IrO2/TiO2 films are reported. The presence of metal, metal oxide and cluster ions suggests a more systematic use of secondary-ion mass spectrometry in the elucidation of catalytic aspects. In-depth profiles of some ionic species and their correlation with parameters that induce significant modifications can help in the understanding of the solid state physics and inorganic chemistry involved.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 6 (1992), S. 537-542 
    ISSN: 0268-2605
    Keywords: Organotin ; DNA ; Mössbauer ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The compounds R2SnCl2 and R3SnCl (R=Me, Et, nBu, nOct, Ph, in ethanol solution) as well as the aqueous species [Me2Sn(OH2)n]2+ and [Me3Sn(OH2)2]+, react with aqueous native DNA, yielding solid phases. According to the pointcharge model treatment of the 119Sn Mössbauer parameter nuclear quadrupole splitting, trans-octahedral R2Sn(O2PXY)2, and trigonalbipyramidal R3Sn(O2PXY), (R=Me, Et, nBu), would occur in the pellets, the tin atoms being coordinated by phosphodiester groups of the nucleic acid. The precipitates from Ph2SnIV would consist of the DNA complex as well as of the Ph2SnIV distannoxane obtained by hydrolysis of the reactant, whilst nOct2SnCl2, nOct3SnCl and Ph3SnCl would mainly yield stannoxanes and hydroxides. The water-soluble hydrolyzed species [Me2Sn(OH)(OH2)n]+, Me2Sn(OH)2 and Me3Sn(OH)(OH2) do not show any interaction with native DNA, although they are possibly coordinated by phosphate oxygen atoms in model aqueous systems, in the presence of excess ligand.These trends have been rationalized by QSAR approach (Quantitative Structure-Activity Relationships) in terms of electronic factors related to tin-oxygen (phosphate) Coulomb interactions, as well as the lipophilicity of R in the RnSnIV moieties.
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  • 7
    ISSN: 0268-2605
    Keywords: organotin ; amino-acid ; cysteine ; penicillamine ; Mössbauer ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bonding and the configuration of the tin environment in the title compounds {R2Sn[SCH2CH(NH3+)COO-]2 and R2Sn[SC(CH3)2CH(NH3+)COO-]2, indicated in the following as R2Sn(cysH)2 and R2Sn(penH)2 respectively} has been investigated through the determination of the Mössbauer-Zeeman spectra of Ph2Sn(cysH)2 and Ph2Sn(penH)2 in the solid state, and through conventional Mössbauer spectroscopy of Me2Sn(penH)2 in the solid state as well as of Me2Sn(cysH)2 and Me2Sn(penH)2 in aqueous solution (frozen). The treatment of the data by the pointcharge model approach suggested the general occurrence of a tetrahedral C2SnS2 core. In aqueous Hepes buffer, a tertiary amino nitrogen atom has been observed to coordinate tin in Me2Sn(cysH)2 and Me2Sn(penH)2, with formation of trigonal bipyramidal tin environments. The latter solutions undergo slow decomposition reactions at room temperature. From (Me2SnS)3 occurs, as well as formation of soluble complex species in the presence of glycylglycine; Me2Sn(penH)2 appears to undergo a slow desulfuration reaction.
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  • 8
    ISSN: 0268-2605
    Keywords: triorganotin(IV) ; L-homocysteic acid ; infrared ; Mössbauer ; NMR ; sea urchin ; Paracentrotus lividus (Echinodermata) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several new triorganotin(IV) derivatives of L-homocysteic acid (L-HCAH) with formula R3Sn(L-HCA) (R=Me, nBu, Ph) have been synthesized. Their solid-state configurations were determined by IR and Mössbauer spectroscopy. The tin(IV) atom is five-coordinated in all the complexes, with the L-homocysteic acid behaving as a monoanionic bidentate ligand coordinating the tin(IV) atom through a chelating or bridging carboxylate group. The sulfonate (SO3-) and NH3+ groups of L-homocysteic acid maintain their free acid configuration and hence do not participate to the coordination of the tin(IV) atom. Coordination hypotheses have been checked through the correlation between the Mössbauer parameter isomer shift, δ, and partial atomic charge on the tin atoms, QSn, performed, for all the new organotin(IV) compounds, on the basis of an equalization procedure applied to idealized trigonal-bipyramidal structures for R3Sn(L-HCA).1H and 13C NMR spectra of the complexes show that pentacoordination of the tin atom, with R groups in the equatorial plane of a trigonal bipyramid, is retained in DMSO solution. The NMR data confirm also that the uncoordinated NH3+ group of the ligand is still present in solution.Results gathered after exposure of two- to four-cell embryos of the sea urchin Paracentrotus lividus (Echinodermata) to the triorganotin(IV) L-homocysteate derivatives as well as to the parent triorganotin(IV) chlorides document cytotoxicity of the complexes, while free L-homocysteic acid exerts no significant toxic activity. The trimethyltin(IV) L-homocysteate derivative seems to exert a lower cytotoxicity than the tributyl- and triphenyl-tin(IV) ones. Different structural lesions have been identified by comparative analysis of mitotic chromosomes from untreated embryos (negative controls) and embryos treated with triorganotin(IV) L-homocysteate derivatives, such as (1) suppression of the stretch among sister chromatids at the beginning of anaphase stage; (2) deeply stained zones mainly located at the telomeric regions of chromosomes; (3) arm breakages; and (4) chromosome bridges among daughter chromosomes at anaphase stage. A colchicine-like effect of triorganotin(IV) L-homocysteate derivatives was observed. © 1997 John Wiley & Sons, Ltd.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 861-871 
    ISSN: 0268-2605
    Keywords: diorganotin ; Pyrimidine ; complex ; Mössbauer ; IR ; NMR ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes formed between the diorganotin(IV) moieties, R2Sn(IV), and the ligand 2-mercaptopyrimidine, (H)SPym, were investigated. Complexes R2SnHal(SPym) and R2Sn(SPym)2 [R = Me, iPr, nBu, iBu, tBu, cyclohexyl(Cy), Ph] were synthesized, and characterized by elemental analysis. In the solid state, chelation of SPym through S and N donors was established by IR spectroscopy, and the nature of the environment of tin centers was investigated by 119Sn Mössbauer spectroscopy. From the dynamics of 119Sn nuclei determined by variable-temperature measurements on representative compounds [Me2SnCl(SPym) and Cy2SnBr(SPym)], as well as by point-charge model treatment of nuclear quadrupole splitting parameters, it was inferred that Me2SnCl-­(SPym) may assume a trans-Me2 octahedral coordination geometry around tin in a monodimensional polymer, or a monomeric trigonal-bipyramidal structure (distorted). The latter type of structure was assigned to the other R2SnHal(SPym) species, while R2Sn(SPym)2 complexes assume a trans-octahedral, or skew trapezoidal, tin environment. In CHCl3-CDCl3 solutions, monomeric species occur (according to vapor-pressure osmometry), where 1H and 13C NMR spectroscopic parameters of SPym indicate the persistence of Sn chelation by S and N donor atoms. The Me2SnCl(SPym) species assume trigonal-bipyramidal structures with a chelating SPym ligand, in CDCl3 and C2H5OH solutions, according to the coupling constants 1J(119Sn,13C), as well as IR and 119Sn Mössbauer spectroscopic data. 119Sn NMR parameters fully correspond with data for the homologous complexes with 2-mercaptopyridine. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 10
    ISSN: 0268-2605
    Keywords: organotin ; pyridine-2-thiolate complexes ; pyrimidine-2-thiolate complexes ; crystal structure ; Mössbauer ; IR ; NMR ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mono-organotin(IV) and tin(IV) derivatives of 2-mercaptopyridine (HSPy) and 2-mercaptopyrimidine (HSPym), RSnL3 (R=Me, n-Bu, Ph; L=SPy, SPym; R=Bz=benzyl, o-ClBz, o-ClC6H4, p-ClC6H4, o-tolyl, p-tolyl; L=SPy), RSnClL2 (R=Me, n-Bu, Ph; L=SPy, SPym), RSnCl2L (R=Me, n-Bu; L=SPy, SPym) and SnCl4-nLn (L=SPy, SPym; n=2, 4) were obtained from RSnCl3 or SnCl4 and NaL or by neutralization (R=Ph, p-tolyl; L=SPy, SPym). RSnClL2 and RSnCl2L were better prepared by comproportionation of RSnCl3 and RSnL3.MeSn(SPy)3 and PhSn(SPy)3·1.5CHCl3 crystals, as determined by single-crystal X-ray diffraction, are monoclinic. In the discrete monomeric RSn(SPy)3 units, three bidentate SPy ligands together with R form a distorted pentagonal bipyramid around tin. One S and the C(R) atom are in the axial positions. Two S atoms and three N atoms form the pentagonal plane.From 119Sn Mössbauer and IR data, analogous structures are inferred for the other solid RSnL3 compounds, except for R=Bz, o-ClBz, o-ClC6H4 and o-tolyl, in which tin would be hexacoordinated. In the compounds RSnClL2 and RSnCl2L, tin is at the center of an octahedron or a trigonal bipyramid, respectively. For Sn(SPym)4 and SnCl2(SPym)2, the same type of octahedral structure as was previously found for Sn(SPy)4·HSPy and SnCl2(SPy)2 is proposed.According to IR and 1H, 13C and 119Sn NMR data, the solid-state molecular structures are retained in chloroform and dimethyl sulfoxide solution. © 1997 John Wiley & Sons, Ltd.
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