A new phoshotungstate-supported rhenium carbonyl derivative: synthesis, characterization and catalytic selective oxidation of thiophenes

A monomeric phoshotungstate-supported rhenium carbonyl derivative: [N(CH3)4]6H4[P2W17O62{Re(CO)3}2]·25H2O (1) has been synthesized in the conventional solution system and structurally characterized by single crystal X-ray diffraction crystallography, IR spectroscopy, thermogravimetric (TG) analyses, X-ray power diffraction (XPRD), and electrospray ionization mass spectromety (ESI-MS). To our knowledge, the {Re2} fragment existed in the polyoxoanion is first observed in polyoxometalate-supported metal carbonyl derivatives. Moreover, UV-Vis spectroscopy has been employed to elucidate the stability of polyoxoanion, and its electrochemical property was also investigated. In particular, complex 1 could act as an efficient homogeneous catalyst for selective oxidation of thiophenes. For example, dibenzothiophene (DBT) undergoes up to 99% conversion and 99% sulfone selectivity in acetonitrile with 30% H2O2 as an oxidant.