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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inorganic and organometallic polymers and materials 5 (1995), S. 163-168 
    ISSN: 1572-8870
    Keywords: Polysilanes ; cyclopolysilanes ; solvated electron ; crown ether
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Permethylcyclopolysilanes are most often prepared by Würtz-type coupling of Me2SiCl2 with Na K alloy in THI: When nonpolar solvents like benzene were used, only linear polysilanes (Me2Si)n were produced, but the addition of a catalytic amount of crown ether 18-crown-6 was found to increase significantly the amount of cyclic oligomers. The ratio of (Me2Si)6 to (Me2Si)5 decreased from 18:1 to 6:1 in the presence of crown ether in a typical synthesis in THF. An explanation based on solvated electron theory has been proposed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0044-2313
    Keywords: Gold ; thiolate complex ; synthesis ; structure ; X-ray ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 65. Darstellung, Kristall- und Molekülstruktur von cyclo-Tetrakis[tri-tert-butoxysilanthiolatogold(I)], [(t-C4H9O)3SiSAu]4, dem ersten Komplex mit einem Au4S4-Ring-SystemDie Darstellung des ersten Silanthiolato-Goldkomplexes - cyclo-Tetrakis[tri-tert-butoxysilanthiolatogold(I)] - ist beschrieben. Die Kristallstruktur wurde bei 200 K an einem farblosen, orthorhombischen Prisma bestimmt. Bei 187 K wurde eine reversible Phasenumwandlung beobachtet. Das Zentrum des Moleküls ist ein gefalteter Au4S4-Achtring mit alternierender Abfolge aus dreifach koordinierten Schwefel- und zweifach koordinierten Goldatomen. Charakteristische Abstände und Winkel: Au—S 228,4 und 229,6 pm, Si—S 216,9 pm, S—Au—S 178,8° und 178,3°, Au—S—Au 90,3°, Si—S—Au 103,7° und 101,9°. Der kürzeste Abstand zwischen zwei Goldatomen beträgt 324,8 pm.
    Notes: The preparation of the first silanethiolate complex of gold, cyclo-tetrakis[tri-tert-butoxysilanethiolatogold(I)] from tri-tert-butoxysilanethiol and tetrachloroauric acid is described. The compound forms colorless orthorhombic crystals, and the molecular structure was determined at 200 K by single crystal X-ray diffraction. At 187 K, a possible, reversible phase transition is observed. The center of the molecule is a distinctly folded eight-membered Au4S4 ring of alternating three-fold coordinated sulfur and two-fold coordinated gold atoms. The relevant bond lengths and angles are: Au—S 228.4 and 229.6 pm, Si—S 216.9 pm, S—Au—S 178.8° and 178.3°, Au—S—Au 90.3°, Si—S—Au 103.7° and 101.9°. The gold atoms are separated by 324.8 pm.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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