The structural chemistry of gold(I) quinoline-2-thiolate and iodide complexes of polytertiary phosphines

Treatment of (chloro)gold(I) complexes of di- and tetra-tertiary phosphines with equivalent quantities of sodium quinoline-2-thiolates in methanol / d ichloromethane affords the corresponding (phosphine)gold(I) quinoline-2-thi olates in high yields. The di- and tetranuclear complexes, respectively, of alpha,omega-bis(diphenylphosphino)-propane (1), -butane (2) and -pentane ( 3) and of tris(2-diphenylpbosphino-ethyl)phosphine (4) have been obtained a s crystalline solids, and the structures of 2 and 4 have been determined by single crystal X-ray diffraction studies. Unexpectedly, the molecules of 2 are loosely aggregated into strings via weak intermolecular gold-sulfur, n ot via Au ... Au interactions. Compound 4 is a monomeric tetranuclear clust er in the solid state with two intramolecular Sold-gold bonds. Bis(2-diphen ylphosphino-ethyl)phenylphosphine (PPP) forms trinuclear complexes with gol d(I) chloride, bromide and iodide (5a - c). The iodide complex features a c hain structure through intermolecular Au ... Au contacts between the two te rminal P-Au-I units. The closest contacts between the chains are determined by Au ... I and I ... I interactions of the central P-Au-I unit.