Heterobimetallic and Heterotrimetallic Clusters Containing a Redox-Active Metalloligand

A new multimetallic construct has been developed utilizing a redox-active metalloligand. The molybdenum complex, Mo[SNS](2) {1; [SNS]H-3 = bis(2-mercapto-p-tolyl)amine}, has been shown to coordinate to Ni(dppe) {dppe = 1,2-bis(diphenylphosphanyl)ethane} through two cis thiolate donors to generate heterobimetallic Mo[SNS](2)Ni(dppe) (2) and heterotrimetallic Mo[SNS](2){Ni(dppe)}(2) (3). X-ray diffraction studies confirm the presence of formal metal-metal bonds between the molybdenum and nickel centers in the solid state; however, NMR spectroscopic studies show that intracluster interactions are dynamic in solution. The Mo[SNS](2) metalloligand engenders rich redox chemistry in 2 and 3, and in the latter case, electrochemical and spectroscopic data suggest that 3(+) is a localized mixed-valence complex, despite the metal-metal bonding network.