Synthetic, Structural, and Spectroscopic Studies of Sterically Crowded Tin–Chalcogen Acenaphthenes

Tuning the Electronic Structure of Atomically Precise Sn/Co/Se Nanoclusters via Redox Matching of Tin(IV) Surface Sites

A new strategy is reported to tailor the electronic properties of a superatomic metal chalcogenide cluster by redox matching the cluster core with surface tin(IV) sites. Two ternary clusters (SnR₂)₃Co₆Se₈L₆ (R = Me, ⁿBu) are synthesized by salt metathesis from the hexalithiated salt [Li₂(py)₂]₃Co₆Se₈L₆ and R₂SnCl₂. Cyclic and differential-pulse voltammetry studies reveal that the tristannylated clusters feature two new, near-degenerate, electronic states within the highest occupied molecular orbital-lowest unoccupied molecular orbital gap of the Co₆Se₈ core, which are attributed to the reduction of a surface tin site. Single-crystal X-ray diffraction analysis reveals that no Sn···Se coordination is present in the solid state. The single-crystal X-ray structure of the hexalithiated salt starting material is reported for the tetrahydrofuran (THF) adduct variant [Li₂(THF)₂]₆Co₆Se₈L₆.