A Precious Catalyst: Rhodium-Catalyzed Formic Acid Dehydrogenation in Water

The performance of rhodium complex [Cp*Rh(bis(pyrazol-1-yl)methane)Cl]Cl was evaluated for formic acid dehydrogenation in aqueous solution. Solid-state X-ray diffraction helped to confirm the catalyst structure. Multinuclear NMR spectroscopy was employed to follow the dehydrogenation of formic acid. The reactions have been carried out in high-pressure NMR sapphire tubes. An activation energy of +77.19 +/- 4 kJ/mol was determined via an Arrhenius plot, which is in good agreement with literature findings. The catalyst afforded a TOF of 1086 h(-1) and exhibited good stability. Based on our observations and literature, we propose a catalytic cycle.