Solvent-driven association and dissociation of the hydrogen-bonded protonated decavanadates.

Hydrogen-bond-assisted molecular aggregation of decavanadate anions, [H(n)V(10)O(28)]((6-n)-), in non-aqueous solutions was probed by systematic small-angle X-ray scattering and (1)H and (51)V NMR spectroscopic measurements in mixtures of acetone and 1,4-dioxane. Under acetone-rich conditions, the decavanadate anion prefers a self-associated hydrogen-bonded dimer of {[H(3)V(10)O(28)](2)}(6-), which dissociates into monomeric species as the proportion of 1,4-dioxane increases. The association/dissociation behaviors of the decavanadate anions were proven to be reversible and driven by the protophobic/protophilic nature of the solvent.