AMixed-valentHexanuclearCuⅡ-CuⅠComplexwithUnusualTridentatepbiLigand(pbi=2-（2-Pyridyl）-benzimidazole)

A mixed-valent hexanuclear complex [CuIICuI2(pbi)2Br2]2 (pbi = (2-(2-pyridyl)-ben- zimidazole) exhibiting a dimeric unit bridged by two Br atoms was synthesized by hydrothermal reaction. Interestingly, there exist intramolecular and intermolecular π-π stacking interactions as well as metal- aromatic ring interactions in the title complex. The crystal belongs to the monoclinic system, space group P1, with a = 7.1061(9), b = 12.1008(13), c = 14.0711(17)A, α = 91.742(8), β = 100.155(9), γ = 90.486(7)o, V = 1190.3(2) ·3, Z = 2, C48H32Br4Cu6N12, Mr = 1477.74, Dc = 2.061 g/cm3, F(000) = 718, μ(MoKα) = 6.039 mm-1, the final R = 0.0481 and wR = 0.0974 for 3426 observed reflections (I > 2σ(I)).