Orbital Engineering: Photoactivation of an Organofunctionalized Polyoxotungstate

Tungsten‐based polyoxometalates (POMs) have been employed as UV‐driven photo‐catalysts for a range of organic transformations. Their photoactivity is dependent on electronic transitions between frontier orbitals and thus manipulation of orbital energy levels provides a promising means of extending their utility into the visible regime. Herein, an organic–inorganic hybrid polyoxometalate, K6[P2W17O57(PO5H5C7)2]⋅6 C4H9NO, was found to exhibit enhanced redox behaviour and photochemistry compared to its purely inorganic counterparts. Hybridization with electron‐withdrawing moieties was shown to tune the frontier orbital energy levels and reduce the HOMO–LUMO gap, leading to direct visible‐light photoactivation of the hybrid and establishing a simple, cheap and effective approach to the generation of visible‐light‐activated hybrid nanomaterials. A new strategy was introduced for the visible‐light photoactivation of polyoxotungstates through simple organofunctionalization. The new hybrid system exhibited enhanced redox and photoreduction behaviour, assigned to the effect of the electron‐withdrawing organic group on the electronic structure of the molecule (see figure).