Immobilization of Keggin polyoxovanadoniobate in crystalline solids to produce effective heterogeneous catalysts towards selective oxidation of benzyl-alkanes.

Two ionic organic-inorganic hybrid compounds, [Cu(CNH)][Cu(CNH)(HO)][PNbOVVO]·(OH)·11HO (1) and [Co(CNH)][Co(CNH)(HO)][HPNbO VVO]·20HO (2), based on P-centered dicapped polyoxoniobates and organometallic cations were isolated and structurally characterized by routine techniques. The trivalent cobalt complex-containing compound exhibits a looser arrangement compared with its divalent copper complex-containing counterpart, with a space volume of 34.9% for the former and 17.0% for the latter. The two compounds were proved to be effective in facilitating the oxidation of benzyl-alkanes to ketone products in a heterogeneous manner, evidencing the feasiblity of the strategy of self-immobilization of catalytically active, readily soluble PNbO(VO) species in crystalline solids.