Tuning the redox profiles of polyoxovanadate-alkoxide clusters via heterometal installation: toward designer redox Reagents

Abstract

Herein, we describe a rational synthetic approach for tuning the electrochemical profiles of a series of Lindqvist polyoxovanadate-alkoxide clusters through heterometal functionalization. Synthetic procedures for group(IV) functionalization of the mixed-valent POV-alkoxide cluster, [V₆O₇(OCH₃)₁₂], are established, resulting in the heterometallic species, [NBu₄][V₅O₆(OCH₃)₁₂MOCH₃] (M = Ti, Zr, Hf). We demonstrate that these d⁰, heterometallic dopants anodically shift the potential of the electrochemical processes associated with the cluster, making the molecule more resistant to oxidation. Conversely, incorporation of electron rich heterometals yields a more readily oxidized molecule, with redox processes shifted cathodically. The predictable tuning and remarkable electrochemical profiles of this family of heterometal-functionalized polyoxometalates highlights their potential use as designer redox agents.