Gold-silver mercaptides

Fitch expanded on his work on gold(I) mercaptides in combination with silver(I) mercaptides to include the synthesis of novel gold-silver mercaptide precursor compounds [53], These were prepared by simply reacting the gold(I) mercaptide compounds with an eqnimolar amonnt of silver(I) mercaptide or silver(I) carboxylate at elevated temperatures in a suitable solvent (for example, toluene) (Equation 15.5). 

Joo, S.-W. and Kim, Y.-S. (2004) Surface-enhanced Raman scattering study of benzyl mercaptide and benzyl isocyanide on gold and silver nanocolloid surfaces. Colloids Surf. A, 234, 117-22. 

Most mercaptides are not available as commercial products, since large-scale applications of these chemical compounds are quite limited (only mercaptides of tin and antimony are used industrially as thermal stabilizers for poly(vinyl chloride) [de Sousa et al., 2000 Qu L. et al., 2002]). However, these compounds can be synthesized in a very simple way. Owing to their low water solubility, mercaptides can precipitate by reacting thiols (or thiophenols) with aqueous solutions of the corresponding metal salts. In addition to the well-known mercaptides of mercury, lead, zinc, and copper, many others, such as mercaptides of silver, gold, platinum, palladium, iridium, nickel, iron, cobalt, antimony, bismuth, and cadmium, have been prepared. 

Many silver(I) mercaptide compounds, Ag(S/ ) , are known, and Akerstrom [38] reported a systematic study of primary, secondary, and tertiary silver(I) mercaptides highlighting the relationship between substituent R, polymeric nature, and the solubility of the silver(I) mercaptides. As observed for the analogous gold compounds, the solubility of many silver(I) mercaptide compounds is very limited. However, some sterically hindered compounds, such as silver tert-alkylmercaptides have been shown to be soluble enough to be used within liquid gold formulations in combination with the equivalent gold compounds [52]. 

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