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  • DNA  (2)
  • Industrial Chemistry and Chemical Engineering  (2)
  • 119Sn NMR  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Hyperfine interactions 126 (2000), S. 43-46 
    ISSN: 1572-9540
    Keywords: organotin ; DNA ; bonding and structure ; molecular dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Ethanol solutions of Alk n SnCl4−n (Alk = Me, Et; n = 1–3) added to aqueous calf thymus DNA provoke DNA condensation (even in the presence of added cysteine) possibly through charge neutralization of DNA phosphodiesters by organotin(IV) cations. The structures of tin bonding environments in binary and ternary condensed systems organotin(IV)-DNA and ligand-organotin(IV)-DNA are determined through point-charge model treatment of the 119Sn Mössbauer parameter Δ, while the possible interchain interaction DNA-tin is inferred from the dynamics of 119Sn nuclei through vtMs.
    Type of Medium: Electronic Resource
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  • 2
    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.
    Additional Material: 5 Ill.
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  • 3
    ISSN: 0268-2605
    Keywords: Diorganotin dipeptides ; X-ray structure determination ; 13C ; 119Sn NMR ; IR ; Mössbauer ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dipeptide complexes of the diethyltin(IV) moiety, Et2SnL, have been synthesized, H2L being glycylglycine (H2GlyGly), glycylalanine (H2GlyAla), alanylalanine (H2AlaAla), glycylvaline (H2GlyVal), valylvaline (H2ValVal), glycylmethionine (H2GlyMet), glycyltyrosine (H2GlyTyr). The crystal and molecular structure of the complex Et2SnGlyTyr has been determined by singlecrystal X-ray diffraction. It consists of monomeric units, with the tin atom having a considerably distorted trigonal bipyramidal environment. The dipeptide acts as a tridentate ligand bonding the tin of the C2Sn fragment (equatorial carbon atoms) with the peptide nitrogen atom (equatorial) and axial (monodentate) carboxyl oxygen and amino nitrogen atoms, into a monomeric unit. Bond lengths and angles are reported. Infrared spectroscopic data show the occurrence of monodentate carboxyl in all solid compounds, as well as in methanol solutions of some representative complexes. 119Sn Mössbauer spectroscopic data, and their rationalization through point-charge model (literal version) calculations of the parameter nuclear quadrupole splitting (ΔE) confirm the general occurrence of trigonal bipyramidal structures of the Et2SnGlyTyr type, in the solid state, and give evidence of variations of the C—Sn—C angle in the individual Et2SnL species. Monomers occur in CH3OH solution as suggested by osmometric measurements. 13C and 119Sn NMR spectroscopic data in CD3OD show the persistence of the solid-state structures also in the solution phase, where the order of magnitude of the C—Sn—C angles, as estimated from the coupling constants |1J(119Sn,13C)|, corresponds to that shown by Et2SnGlyTyr in the solid state. 119Sn Mössbauer parameters of Et2SnGlyGly in frozen CH3OH solution are consistent with the assumptions from the NMR studies.
    Additional Material: 2 Ill.
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  • 4
    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.
    Additional Material: 3 Ill.
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  • 5
    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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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