Mono and tetranuclear gold(I) complexes of tris(1-benzylimidazole-2-yl)phosphine

The reaction of tris(1-benzylimidazole-2-yl)phosphine, (Bzim)(3)P, 1, with Ph(3)AsAuCl in 1:1 stoichiometric ratio produced (Bzim)(3)PAuCl, 2. The reaction of (Bzim)(3)PAuCl with NaAuCl(4) in 1:1 stoichiometry in dichloromethane gives an orange-yellow crystalline tetranuclear gold(I) cluster [{mu-N,N'-(Bzim)(3)PAuCl}(2)Au(2)][AuCl(2)][AuCl(4)], 3. Complex 4, [{mu-N,N'-(Bzim)(3)PAuCl}(2)Au(2)][AuCl(2)](2) is formed when the reaction stoichiometry of (Bzim)(3)PAuCl and AuCl(4)(-) is 2:1. The crystal structure of 3 shows the formation of a 12-membered macrocycle with Au...Au distances of approximately 3.0 A. The structures of (Bzim)(3)PAuCl and 3 show Au...H-C interactions ranging from 2.57 to 2.95 A. Complex 2 crystallizes in the monoclinic space group P2(1)/n (Z = 4), a = 9.1927(5), b = 13.528(2), c = 22.995(2) A, and beta = 94.537(5)(o). Complex 3 crystallizes in the monoclinic space group P2(1)/c (Z = 4), a = 13.785(4), b = 21.426(6), c = 25.203(8) A, and beta = 96.51(6)degrees.