New aqua rhenium oxocomplex; synthesis, characterization, thermal studies, DFT calculations and catalytic oxidations

The aqua rhenium oxocomplex [ReO(OH)(H2O)4]2− (1) has been prepared and characterized by spectroscopy, thermogravimetry, and elemental analysis and its reactivity towards triphenylphosphine has been evaluated. Complex (1) acts as a catalyst precursor in the presence of molecular oxygen for the oxidation of PPh3 to OPPh3. This proceeds through complex intermediates like [Re(PPh3)n]3+ (2), and [ReO(PPh3)n]3+ (3). The newly prepared complex (1) was also employed as catalyst for catalytic oxidation of cyclohexane. The geometry of [ReO(OH)(H2O)4]2− has also been optimized in the singlet state by the DFT method with B3LYP level of theory.