Ab initio and DFT study of the exchange coupling in the highly reduced polyoxoanion [PMo12O40(VO)2]5−

Density functional theory and post Hartree–Fock computations are carried out to revisit the electronic structure and the exchange coupling in the bicapped 8-electron reduced [PMo12O40(VO)2]5− polyoxoanion. Our results confirm the 6/2 electronic distribution at Mo/V centers calculated some years ago at BP86 level. The six electrons on Mo pair up in molecular orbitals delocalized over all twelve Mo-centers. The coupling between the two unpaired electrons localized at the two V-centers is predicted to be negligible as expected from simple, qualitative models. The results validate the performance of DFT methods in reduced polyoxoanions when the delocalized d electrons are paired in the lowest-energy multiplet states.