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  • General Chemistry  (2)
  • Wiley-Blackwell  (2)
  • 1
    ISSN: 1434-1948
    Keywords: Dimethyltin salicylaldoximates ; Chiral ligands ; Proton-tin HMQC NMR ; X-ray structure ; Trinuclear microclusters ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complex {[(CH3)2Sn]2[(CH3)2SnO](OCH3)(HONZO)(ONZO)} (3) [ONZOH is the oximate residue, o-(-ON=CH-C6H4-OH), HONZO the corresponding phenolate residue, o-(HON=CH-C6H4-O-), and ONZO the dibasic species o-(-ON=CH-C6H4-O-), all derived from salicylaldoxime, o-(HON=CH-C6H4-OH)] reacts with an excess of racemic (d,l)-2-methyl-1-butanol to afford the μ2-substitution product 5a {[(CH3)2Sn]2[(CH3)2SnO][OCH2CH(CH3)CH2CH3](HONZO)(ONZO)]}. Crystallographic characterisation of the trinuclear microcluster 5a shows the presence of the monobasic HONZO ligand in a tridentate μ2-O,N mode and of the dibasic ONZO ligand in a tridentate O,N,O mode. This coordination mode leads to one seven-coordinate and two five-coordinate tin centers that are linked by a μ3-oxo function. The coordination geometries are distorted pentagonal bipyramidal and trigonal bipyramidal, respectively. The two low-coordinate tin atoms are linked by the alkoxide ion. The corresponding chiral (S)-2-methyl-1-butanol reacts analogously to yield 5b. By contrast, reaction of 3 with chiral secondary alcohols (2-butanol or 1-phenyl-1-ethanol), in various molar ratios, failed to provide the corresponding μ2-alkoxy complex. Instead, pure crystals of {[(CH3)2Sn]2[(CH3)2SnO](OH)(HONZO)(ONZO)} (2a) were isolated.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-1948
    Keywords: Tin ; Nucleotides ; NMR spectrometry ; Mass spectroscopy ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interactions between diethyltin dichloride and 5′-CMP, 5′-dCMP, and 5′-UMP in aqueous solution were investigated by multinuclear 1D and 2D NMR techniques including 119Sn, 15N and 31P nuclei. These studies were combined with electrospray mass spectrometry, infrared spectroscopy, solid state 13C, 31P and 117Sn CP-MAS NMR, and elemental analysis. As demonstrated by 31P-1H HOESY spectroscopy, the diethyltin moiety interacts with the phosphate group of the pyrimidic mononucleotides in the pH range 0.5-3.5. Compound 8 (X = Cl), the solid isolated in this pH range from 5′-CMP, contains two tin atoms bridged by one oxygen and one chlorine atom, each tin atom being linked to the phosphate group of a nucleotide moiety. For 5′-UMP the solid isolated (12) has a dimeric structure with two different tin atoms; it can be formed by dimerization of compound 11 with the elimination of two water molecules. As demonstrated by 1H-119Sn HMQC correlation NMR data and the 2J(119Sn-O-117Sn) coupling constant of 156 Hz, the diethyltin moiety reacts with the O(2′) and O(3′) oxygen atoms of the nucleotides to form a dimeric diethyldioxastannolane at pH 〉 9.0. Between pH 5.0 and 9.0, no evidence for any interaction between the diethyltin moiety and the nucleotides was found.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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