Highly efficient oxidation of diphenylmethane to benzophenone employing a novel ruthenium catalyst with tert-butylhydroperoxide under mild conditions

• Ru(bpbp)(pydic) was used as catalyst in the oxidation of diphenylmethane.
• Excellent turnover number of catalyst (94,000) was achieved in the catalytic oxidation.
• Redox ruthenium species was confirmed by in situ UV–vis spectrum in the oxidation.

The ruthenium complex Ru(bpbp)(pydic) (bpbp = 2,6-bis(1-phenylbenzimidazol-2-yl), pydic = pyridine-2,6-dicarboxy acid) has been synthesized and tested in the selective oxidation of diphenylmethane to benzophenone utilizing tert-butylhydroperoxide as the terminal oxidant. The influence of various reaction parameters such as temperature, catalyst amount and nature of solvent on the activity and selectivity was evaluated. Diphenylmethane was converted with 94% conversion and 100% selectivity to benzophenone under the optimized reaction conditions, in which the turnover number (TON) of catalyst reached 94,000. Moreover, a plausible reaction mechanism through redox ruthenium species was proposed.

The ruthenium complex-catalyzed oxidation of diphenylmethane to benzophenone using tert-butylhydroperoxide as oxidant under mild conditions has been developed.Figure optionsDownload as PowerPoint slide