{SeO₂(OH)} Bridging Lanthanide-Containing Antimono-Seleno-Tungstates

A series of new trigonal pyramidal {SeO₂(OH)} bridging lanthanide-containing antimono-seleno-tungstates [H₂N(CH₃)₂]₈Na₈Cs₄H₉[Ln₂SeW₄O₁₁(OH)(H₂O)₄(SbW₉O₃₃)(SeW₉O₃₃)(Se_1/2Sb_1/2W₉O₃₃)]₂·32H₂O [Ln = Tb (1), Dy (2), Ho (3), Er (4)] have been prepared by the synthetic strategy of simultaneously using the antimonotungstate precursor and simple material in an acidic aqueous solution and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectrometry, and thermogravimetric analysis. Their molecular structures contain an unprecedented hexameric polyoxoanion [Ln₂SeW₄O₁₁(OH)(H₂O)₄(SbW₉O₃₃)(SeW₉O₃₃)(Se_1/2Sb_1/2W₉O₃₃)]₂^29- constituted by two equivalent trimeric subunits Ln₂W₄O₉(H₂O)₄(SbW₉O₃₃)(SeW₉O₃₃)(Se_1/2Sb_1/2W₉O₃₃) bridged via two μ₂-{SeO₂(OH)} linkers. Furthermore, the catalytic oxidation of various aromatic sulfides and sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) by compound 3 as the heterogeneous catalyst has been investigated, exhibiting high conversion and selectivity as well as good stability and recyclability.