Syntheses, crystal structures, and third-order nonlinear optical properties of two novel Mo/Cu/S clusters: [MoS4Cu4(α-MePy)5Br2] · 2(α-MePy)0.5 and {[MoS4Cu4(α-MePy)3Br](μ-Br) · (α-MePy)}n (α-MePy = α-methylpyridine)

Two new clusters [MoS4Cu4(α-MePy)5Br2] · 2(α-MePy)0.5 and {[MoS4Cu4(α-MePy)3Br](μ-Br) · (α-MePy)}n were prepared from (NH4)2MoS4/CuBr/AgBr or (NH4)2MoS4/CuBr in excess α-methylpyridine. The structures of both compounds were characterized by X-ray crystallography and their third-order NLO properties in solution were studied.