Electron-Sponge Behavior and Electronic Structures in Cobalt-Centered Pentagonal Prismatic Co11Te7(CO)10 and Co11Te5(CO)15 Cluster Anions

The novel cluster anion [Co11Te5(CO)15]- ([3]-) has been isolated and structurally characterized as part of the salt [Cp*2Nb(CO)2][3] (Cp* = C5Me5). The cobalt-centered Co10 pentagonal prism is surrounded by a shell of two μ5-Te, three μ4-Te ligands, and 15 CO groups in terminal, symmetrical, and σ-semibridging bonding modes. The hybrid carbonyl-telluride character of the ligand shell is reflected in the solid state by a one-dimensional assembly of polyhedral prisms along a backbone of [Cp*2Nb(CO)2]+ cations. Electrochemical studies reveal the presence of four redox couples of [3]n (n = −1 to −5). The electronic structures of various metal-centered and empty pentagonal-prismatic (PP) M10 cl…