Nucleation Roadmap of Reduced Polyoxovanadate-Alkoxide Clusters

Abstract

Polyoxovanadate-alkoxides are a growing family of earth-abundant first-row transition metal polynuclear species highly promising for their tunable redox properties. The speciation and nucleation chemical space of these species is divided into two groups: 1) fully oxidized V(V) monomeric precursors that aggregate into Lindqvist-type clusters and 2) reduced V(IV) precursors forming cyclic structures. The nucleation of cyclic polyoxovanadate-alkoxides with varying alkyl chain lengths, the impact of the presence of templating anions, and their subsequent evolution to the Lindqvist-type congener were studied by using density functional theory. The evolution of cyclic polyoxovanadate-alkoxides to oxygen-vacant cluster structures was found to be endergonic, in agreement with previous experimental work. Moreover, the reactivity with traces of water in alcohol solvents was confirmed to be the main thermodynamic driving force toward the formation of the mixed-valent Lindqvist-type polyoxovanadate species.