Computational characterization of the internal bonding and solvation structure for [Nb10O28]aq6−

Abstract

The chemistry of polyoxometalate ions is richly explored, but mostly via synthesis and experimental studies. Less emphasis has been placed on developing a robust computational understanding of their aqueous dynamics. In this work, we utilize both a previously created force-field model and ab initio molecular dynamics to explore the solvation structure of [Nb10O28]aq(6-). We examine characteristic behaviors of both cluster-water interactions and intra-cluster bond strengths. We show that cluster-water interactions are dictated by electrostatic interactions, which in turn are dictated by the shape of the cluster; ultimately reflecting a quantitatification of the steric shielding to the cluster's oxygen sites. We also show that bond strengths within the cluster do not correlate with oxygen reactivities, lending credence to previous suggestions that oxygen exchange for decaniobate clusters occurs via intermediates that form by significant structural reorganizations.