Synthesis and Characterization of Mixed-Metal Sulfido Clusters with the Cubane-Type PtMo3S4 Core

The reaction of the incomplete cubane-type cluster [Mo3(μ3-S)(μ-S)3(H2O)9]Cl4 (1) and [Pt(dba)2] (dba = 1,5-diphenyl-1,4-pentadien-3-one) in MeOH gave a brown precipitate (4) that contains platinum and molybdenum in the atomic ratio of 1 : 3. Further treatment of 4 with 3 equiv of dppe (dppe = 1,2-bis(diphenylphosphino)ethane) gave the cubane-type cluster [PtMo3(μ3-S)4Cl4(dppe)3] (5) in 37% yield, whose molecular structure was unambiguously characterized by X-ray diffraction study of 5·2CH2ClCH2Cl·2H2O. A similar reaction of 4 with 4 equiv of dppe afforded the cationic cluster [PtMo3(μ3-S)4Cl3(dppe)4]Cl (6) in 29% yield, which was characterized spectroscopically. The Pd-Mo and Ni-Mo analogues of the above Pt-Mo clusters, [PdMo3(μ3-S)4Cl3(dppe)4]Cl·CH2Cl2 (7) and [NiMo3(μ3-S)4Cl4(dppe)3] (8), were also synthesized by the reactions of the corresponding aqua clusters with dppe.