Structural diversity in gold(I) complexes of 4-sulfanylbenzoic acid

Treatment of the gold(I) halide species AuLCl (where L=PMe3, PEt3, PPh3, PPh2(C5H4N-2) or SPPh3) and (AuCl)(2)(P-P) (where P-P=1,4-bis(diphenylphosphino)butane or 1,1'-bis(diphenylphosphino)ferrocene) with 4-sulfanylbenzoic acid (1 or 2 equivalents as required) in the presence of sodium methoxide provided the corresponding phosphine gold(I) thiolate complexes AuL(4-SC6H4CO2H) and [Au(4-SC6H4CO2H)](2)(P-P), respectively. Addition of two equivalents of the acid (in the presence of NaOMe) to [N(PPh3)(2)][AuCl2] yielded the dithiolate species [N(PPh3)(2)][Au(4-SC6H4CO2H)(2)]. A polyaurated product [(Ph3PAu)(2)(4-SC6H4CO2H)]BF4 was obtained on treating the acid with the oxonium complex [(Ph3PAu)(3)O]BF4. The species AuL(4-SC6H4CO2H) (L=PEt3, PPh3 or PPh2(C5H4N-2)) have been investigated crystallographically and reveal diverse structures incorporating aurophilic contacts, Au . . .S interactions and hydrogen bonding.