Oxoperoxo-molybdenum and -tungsten (VI) complexes: their synthesis, structure and catalytic uses in the peroxidic oxidation of alcohols to aldehydes and ketones

MO3 · nH2O when dissolved in H2O2 reacts with QOH (8-quinolinol) affording MO(O2)2 · 2QOH wherefrom [MO(O2)(QO)2] [M=Mo (1) and W (2)] is obtained during crystallization and the synthesis and structure of 2 is reported here for the first time. Using both 1and 2 as catalyst precursor and H2O2, O2 or H2O2 + O2 as oxidant, benzyl and cinnamoyl alcohol, cyclohexanol and isopropanol are selectively oxidized to their corresponding aldehydes and ketones, but this selectivity is not strictly exhibited when substrates are aliphatic alcohols.