Inorganic Chemistry, Vol.36, No.25, 5735-5739, 1997
Complexes with S-donor ligands .6. Synthesis of the first family of (trithiocarbonato)gold complexes. Crystal structure of [(PPh3)(2)N][AuCl2(CS3)]
[(PPh3)(2)N][Au(SH)(2)] reacts with CS2 in acetone to give [(PPh3)(2)N](2)[AU(2)(CS3)(2)] (1) which reacts with iodine (1:1) or PhICl2 (1:1) to give 2 or 2', which is an equimolar mixture of the gold(III) complex [(PPh3)(2)N][Au(CS3)(2)] (3) and [(PPh3)(2)N][AuX2] (X = I, Cl). These mixtures decompose in dichloromethane or acetone solutions giving an insoluble dark-red solid analysing as the mixed-valence complex [(PPh3)(2)N][Au-n(I){Au-III(CS3)(2)}(n+1)]1 (4) with an average n value of 6. The best method to prepare 3 is by reacting 2 with PTo(3) (To = C6H4Me-4). The reaction of 4 with [Et2NC(S)S](2) gives [Au(S2CCNEt2)(2)][Au(CS3)(2)] (5), which can also be obtained by reacting 3 with [Au(S2CNEt2)(2)]ClO4. The complex [(PPh3)(2)N][AuCl2(CS3)] (6) can be obtained by reacting 3 with PhICl2 (1:1) or 1 with PhICl2 (1:2). By reaction of 6 with an excess of NaBr, the complex [(PPh3)(2)N][AuBr2(CS3)] (7) can be isolated. Iodine reacts with 3 (1:1) to give [(PPh3)(2)N][AuI2(CS3)] (8). Cationic complexes [Au(CS3)(LL)]CF3SO3 [LL = 1,10-phenanthroline (phen) (9), 2,2'-bipyridyl (bipy) (10)] can be obtained by reacting 6 with TlO3SCF3 and the corresponding bidentate ligand (1:2:1). Complex 6 crystallizes in the triclinic system, space group P (1) over bar, with a = 9.482(2) Angstrom, b = 11.888(2) Angstrom, c = 17.303(2) Angstrom, alpha = 108.236(6)degrees, beta = 93.340(10)degrees, gamma = 95.605(10)degrees, V = 1835.5 Angstrom 3, and Z = 2. The structure was refined to values of R1 = 0.0393 [I > 2 sigma(I)] and wR2 = 0.0970 (all data). The planar coordination at the gold atom is distorted by the bite of the CS3 ligand [the S(2)-Au-S(1) angle is only 74.49(7)degrees]. The CSAu bond distances are 1.743(7) and 1.748(7) Angstrom, whereas the CSexo bond is much shorter at 1.608(7) Angstrom.