Water-soluble titanium-polyoxomolybdate with external μ3 bridging oxygen coordination on a lacunary Keggin structure

A titanium-polyoxomolybdate K6(H3O)8[{PMo9O34TiO}2]·32H2O (1) was successfully synthesized and structurally characterized. It is an unprecedented instance that the titanium-containing polyoxomolybdate is water-soluble and was synthesized by using a conventional aqueous solution method. The Ti4+ ions exist in an unusual coordination mode. Besides, compound 1 as a wide band gap semiconductor showed evident photocatalytic activity for the oxidation of benzaldehyde into benzoic acid.