Tailoring Heterometallic Cluster Functional Building Blocks: Synthesis, Separation, Structural and DFT Studies of [Re6−xMoxSe8(CN)6]n

Influence of the metal core composition and geometry on the structure, spectroscopic properties and redox potentials was investigated for the first time for heterometallic (Re/Mo)6 octahedral clusters. The discrete anionic clusters [Re6‐xMoxSe8(CN)6]n− (x=2, 3; n=4, 5) were obtained as individual salts. Their isomeric composition and bond‐length distribution were inspected using a combination of single‐crystal X‐ray structure analysis, NMR, EXAFS, and DFT calculations. Excision reaction of polymeric phase K6[Re3.6Mo2.4Se8(m‐CN)(CN)4] and selective oxidation afford the individual heterometallic redox‐active [Re4Mo2Se8(CN)6]n− and [Re3Mo3Se8(CN)6]n− cyanoclusters. Electron deficient anions demonstrate significant metal core distortion determined by EXAFS and DFT calculations.