Gold(I) thiosulfonate complexes

A series of seven gold(I) p-tolylthiosulfonate complexes of the general type (L)A-SS(O)₂C₆H₄-4-Me have been prepared from the reaction of silver p-tolylthiosulfonate with the corresponding precursor complexes (L)AuCl in dichloromethane. Yields in excess of 90% were obtained throughout for tertiary phosphine and isocyanide ligands L=PMe₃, PPh₃, Ph₂(2-Py)P, (4-Me₂NC₆H₄)Ph₂P, ⁱPrNC, and ^tBuNC. The complexes are surprisingly stable and undergo controlled decomposition well above 100°C. The crystal and molecular structures have been determined for three representative examples. The Me₃P and Ph₃P complexes form dimers with short aurophilic bonding [Au-Au 2.9955(3) and 3.0509(2) Å] in a crossed-swords conformation, while for the ^tBuNC complex the monomers with their linear five-atom axes appear as only loosely aggregated dimers with a parallel head-to-tail arrangement [Au-Au 3.5423(3) Å]. In all cases the p-tolylthiosulfonate ligand is S-bonded to the metal center.