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.

三(1-苄基咪唑-2-基)膦(tris(1-benzylimidazole-2-yl)phosphine, (Bzim)₃P，记为化合物1)与三苯基砷合氯化金(Ph₃AsAuCl)按1:1化学计量比反应，得到(Bzim)₃PAuCl（记为化合物2）。将(Bzim)₃PAuCl与四氯合金酸钠(NaAuCl₄)在二氯甲烷中以1:1化学计量比反应，可得到橙黄色结晶态四核金(I)团簇[{μ-N,N′-(Bzim)₃PAuCl}₂Au₂][AuCl₂][AuCl₄]，记为化合物3。当(Bzim)₃PAuCl与四氯合金酸根(AuCl₄⁻)的反应计量比为2:1时，会生成化合物4：[{μ-N,N′-(Bzim)₃PAuCl}₂Au₂][AuCl₂]₂。化合物3的晶体结构表明其形成了一个12元大环，金-金间距约为3.0埃(Å)。(Bzim)₃PAuCl与化合物3的晶体结构中均存在Au···H-C相互作用，作用距离介于2.57至2.95埃之间。化合物2以单斜晶系空间群P2₁/n结晶（Z=4），晶胞参数为a=9.1927(5)、b=13.528(2)、c=22.995(2)埃，晶胞角β=94.537(5)°。化合物3则以单斜晶系空间群P2₁/c结晶（Z=4），晶胞参数为a=13.785(4)、b=21.426(6)、c=25.203(8)埃，晶胞角β=96.51(6)°。