Chemical and Photochemical Functionality of the First Molecular Bismuth Vanadium Oxide

Anionic metal oxide clusters, so-called polyoxometalates, can be developed as molecular model compounds to mimic the chemical and photochemical reactivity of solid-state metal oxides on the molecular level. Inspired by the well-known visible-light photocatalyst BiVO4, the first molecular bismuth vanadium oxide has been synthesized to investigate the chemical and photochemical similarities between the solid-state and molecular compounds. The cluster H3[(Bi(dmso)3)4V13O40]center dot ca. 4DMSO was obtained from simple precursors in almost quantitative yield. Structural analysis showed that the cluster shell is based on the unusual all-vanadium e-Keggin framework [epsilon-V12O40]15-, which is stabilized by coordination of four BiIII centers. The acidic character of the three cluster protons was demonstrated by titration studies. The cluster shows promising photocatalytic properties in visible-light photooxidation reactions and has high activity (turnover number >1200), high quantum yield (phi=7.6%), and good recyclability, which make it a promising first example of a new class of heterometallic polyoxometalates.