Mössbauer and nuclear magnetic resonance spectroscopic studies on ‘Myocrisin’, ‘Solganol’, ‘Auranofin’, and related gold(I) thiolates

Abstract

A large number of gold(I) thiolates, [Au(SR)], have been prepared in which the R group is an alkyl, aryl, carboxylic acid, amino acid, or heterocycle. Most are highly insoluble in all common solvents, but [Au(SC₆H₄R′-p)](R′= Et, Prⁱ, Bu^s, or Bu^t) dissolve in organic solvents. The ¹H and ¹³C n.m.r. spectra of the soluble compounds show several sets of signals, which coalesce to single sets at high temperature, consistent with the presence of fluxional, possibly pentameric, polymeric rings. The ¹⁹⁷Au Mössbauer spectra are consistent with linear co-ordination of the gold by two sulphur ligands and, in agreement with the n.m.r. data, show broadening indicative of the presence of non-equivalent gold atoms. The therapeutic compounds appear to be structurally similar to the other gold(I) thiolates.