Catalytic properties of the polyoxometalate [Ti2(OH)2As2W19O67(H2O)]8− in selective oxidations with hydrogen peroxide

The catalytic properties of the sandwich polyoxometalate [Ti 2 (OH) 2 As 2 W 19 O 67 (H 2 O)] 8− , which contains two ( B -α-As III W 9 O 33 ) fragments linked together by a “belt” consisting of one octahedral WO(H 2 O) 4+ and two square-pyramidal Ti(OH) 3+ groups, have been investigated in the selective liquid-phase oxidation of organic compounds by aqueous hydrogen peroxide. The polyoxometalate shows high catalytic activity and selectivity in the oxidation of alkenes, alcohols, diols, and thioethers. The composition of the reaction products indicates that hydrogen peroxide is activated via a heterolytic mechanism.