Synthesis, Structure, and Spectroscopic Study of Redox-Active Heterometallic Cluster-Based Complexes [Re(5)MoSe(8)(CN)(6)](n)

The heterometallic cluster-based compound K[ReMoSe(CN)] was obtained by high-temperature reaction from a mixture of ReSe and MoSe in molten potassium cyanide. The redox behavior of the [ReMoSe(CN)] cluster anion was studied by cyclic voltammetry in aqueous and organic media showing two reversible one-electron-redox transitions with of -0.462 and 0.357 V versus Ag/AgCl in CHCN. Aqueous media potentials were found to be noticeably shifted to higher values because of solvation. Chemically accessible potentials allowed us to structurally isolate and characterize the [ReMoSe(CN)] ( = 3-, 4-, and 5-) cluster complex in several charge states with corresponding cluster skeletal electron (CSE) numbers ranging from 24 to 22. The electronic absorption of the [ReMoSe(CN)] cluster complex varies significantly upon a change of the CSE number, especially in the visible and near-IR regions. The local cluster core distortion upon electron removal was confirmed by density functional theory calculation, while the overall geometry of the cluster anion remained practically unaltered.