GOLD COORDINATION BY TERTIARY PHOSPHANE SULFIDES

Treatment of the ditertiary phosphane sulfides (CH2)(n)[PPh2S](2), 1a- 1d, n = 1-4, with equivalent amounts of (dimethylsulfide) gold(I) chlo ride (Me2S)AuCl affords the dinuclear complexes 2a-2d with an AuCl uni t attached to each sulfur atom. The chlorides can be converted into th e bromides 3a-3e by metathesis using KBr, or by reacting 1d with (tetr ahydrothiophene)gold bromide. With [(Ph3P)Au](+) O3SCF3- as the aurati ng agent for the diphosphane disulfides, the corresponding dicationic products are obtained: {(CH2)(n)[SPPh2AuPPh3](2)}(2+). 2 O3SCF3- (4b-4 d, n = 2-4). An excess of the reagents does not lead to polygold clust ering at the sulfur atoms, and P-S cleavage occurs instead to give sul fonium salts {S[Au(PPh3)](3)}(+) X-. The reaction of Ph3PS with equimo lar quantities of [(Ph3P)Au]O3SCF3 leads to the cationic 1:1 complex 5 , and with an excess of the agent the P-S bond is ruptured. The struct ures of compounds 4b and 4d were determined by single-crystal X-ray di ffraction. The dications have crystallographic centers of inversion, t he coordination at the gold atoms is linear [4b: 179.03(3)degrees; 4d: 175.29(2)degrees] and the angles at the sulfur atoms are acute [4b: 9 7.76(4)degrees; 4d: 96.37(3)degrees], but there are no short Au-Au con tacts.