Assembly of a Hexameric Cluster of Polyoxomolybdotriphosphonate Builts from [Zn(H₂O){TeMo₆O₂₁}{N(CH₂PO₃)₃}]^6– Subunits and Its Optical and Catalytic Properties

The crown-shaped organotriphosphonate-modified 36-molybdenum cluster (NH₄)₁₈­Na₇H₁₁­[Zn­(H₂O)­TeMo₆O₂₁­{N­(CH₂PO₃)₃}]₆·23H₂O (1) has been synthesized, which is the largest zinc-containing organophosphonate-based polyoxometalate to date. Compound 1 was prepared in buffer solution (pH 5.5) with heptamolybdate and amino trimethylene phosphonic acid (ATMP) as the organic ligand. The polyanion constructed from a hexmeric assembly of [Zn­(H₂O)­{TeMo₆O₂₁}­{N­(CH₂PO₃)₃}]^6– subunits has been fully investigated by a few characterization methods. In this work, we discovered that 1 exhibited reversible photochromism and it changed from white to reddish brown upon UV irradiation. In addition, compound 1, as a catalyst, can oxidize sulfides to sulfoxides, showing a high yield/conversion and a good selectivity.