Structures of Gold(I) and Silver(I) Thiolate Complexes of Medicinal Interest: A Review and Recent Results

We review the crystal structures, electrospray ionization mass spectra (ESI-MS) data and chiral HPLC data for the racemic and optically pure mononuclear AuL2 complexes, and for racemic [AuLI]n and optically pure [AgLII]n polymers (LI = thiomalate, LII = D-penicillamine). We postulate an equilibrium between polymeric, mononuclear and free ligand species for [AuLII]n (gold sodium thiomalate or GST). The ESI-MS results clearly show a tetrameric principal species in the 1:1 gold polymers, [AuLI]n. For the 1:1 silver: D-penicillamine complex, [AgLII]n, a non-molecular crystal of double helical structure, the ESI-MS results show multi-ligand-silver species, including tetramers, pentamers and hexamers. Other, relevant gold, silver and copper complexes are compared.