Mono and Tetranuclear Gold(I) Complexes of Tris(1-benzylimidazole-2-yl)phosphine

The reaction of tris(1-benzylimidazole-2-yl)phosphine, (Bzim)3P, 1, with Ph3AsAuCl in 1:1 stoichiometric ratio produced (Bzim)3PAuCl, 2. The reaction of (Bzim)3PAuCl with NaAuCl4 in 1:1 stoichiometry in dichloromethane gives an orange-yellow crystalline tetranuclear gold(I) cluster [{μ-N,N′-(Bzim)3PAuCl}2Au2][AuCl2][AuCl4], 3. Complex 4, [{μ-N,N′-(Bzim)3PAuCl}2Au2][AuCl2]2 is formed when the reaction stoichiometry of (Bzim)3PAuCl and AuCl4 − is 2:1. The crystal structure of 3 shows the formation of a 12-membered macrocycle with Au···Au distances of ∼3.0 Å. The structures of (Bzim)3PAuCl and 3 show Au···H−C interactions ranging from 2.57 to 2.95 Å. Complex 2 crystallizes in the monoclinic space group P21/n (Z = 4), a = 9.1927(5), b = 13.528(2), c = 22.995(2) Ǻ, and β = 94.537(5)o. Complex 3 crystallizes in the monoclinic space group P21/c (Z = 4), a = 13.785(4), b = 21.426(6), c = 25.203(8) Ǻ, and β = 96.51(6)o.