The {Re4} Tetrahedral Cyanometalate Cluster Anion [{Re4(μ3-CCN)4}(CN)12]8- with Inner (μ3-CCN)3- Ligands and Its Features in Coordination of Cu2+ Cations.

A reaction between ReI3 and KCN at elevated temperature led to the formation of the new cyanometalate cluster anion [{Re4(μ3-CCN)4}(CN)12]8- (1). The anion contains μ3-CCN3- ligands, which are stabilized by the coordination to the triangular faces of the tetrahedral {Re4} metallocluster in a μ3 mode. The compound crystallized as a potassium salt, and its crystal structure was determined by single-crystal X-ray diffraction analysis. It was shown that μ3-CCN3- ligands are ambidentate and can interact with transition-metal cations similarly to terminal CN groups, resulting in the polymer framework formation.