Metal, from thiolates

Reduction of sulfur compounds. Formation of the metal(III) thiolates from ytterbium and disulfides is catalyzed by benzophenone. The thiolates are useful in conjugate addition to enones. 

The fdr studies reveal that the alkyl chains in SAMs of thiolates on Au(lll) usually are tilted 26-28° from the surface normal, and display 52-55° rotation about the molecular axis. This tilt is a result of the chains reestabUshing VDW contact in an assembly with - 0.5 nm S—S distance, larger than the distance of - 0.46 nm, usually quoted for perpendicular alkyl chains in a close-packed layer. On the other hand, thiolate monolayers on Ag(lll) are more densely packed owing to the shorter S—S distance. There were a number of different reports on chain tilt in SAMs on Ag(lll), probably owing to different amounts of oxide, formed on the clean metallic surface (229,230,296,297). In carefully prepared SAMs of alkanethiolates on a clean Ag(lll) surface, the alkyl chains are practically perpendicular to the surface. 

We found recently that the viscosity (//vac) of the colloidal thiolate precursor is a key parameter in controlling the shape of the nanoproducts in the solventless method [8]. Uniform nanowires, rods, or spheres could be made from the corresponding precursors that came from the solutions with different viscosities. The viscosity is a measure of the polymerization of the metal-thiolate complexes. Accordingly, the precursor with the highest viscosity produces nanowires (Fig. 20.5 a), and with decreases in the viscosity, the product morphology changes to rods (Fig. 20.5b) and then spheres (Fig. 20.5c). 

B. Krebs and G. Henkel, Transition metal thiolates — from molecular fragments of sulfidic solids to models of active centers in biomolecules. Angew. Chem. Int. Ed. 30 (1991) 769. 

Protection from any poisonous metal ions liberated from their sulfides by oxidation by 02 was secured by the use of strong chelating agents in the cytoplasm, most of which are proteins, or small molecules, thiolates, which were connected to exit pumps or to chemical metabolic tricks for metal ion neutralisation (sequestration). The genes that code for these proteins are usually to be found on plasmids in the cytoplasm of the bacterial cells (Section 5.15). Bacteria adapt very quickly to... 

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