KCS

Activation or utilization of carbon dioxide (CO₂) is widely studied, owing to their environmental concerns and high abundant and CO₂ has the most attractive applications as C1 source in organic synthesis due to their non-toxic and non-corrosive nature. However, the inertness of CO₂ makes it very difficult to activate. Several methods have been developed, and among them, one of the very interesting methods is atom-economical synthesis of five membered cyclic carbonates from CO₂ and propylene oxides (Scheme 1). Due to the various applications of the cyclic carbonates such as aprotic polar solvents, electrolyte, starting material of poly carbonates and polyurethane, and raw material for the chemical reactions, conversion of CO₂ to cyclic carbonatehas gained much attention. Previously, Co(III), Al(III) and Cr(III) complexes with salen ligand derivatives were studied elaborately with different cocatalysts. Similarly, ionic liquids were used to successfully convert the CO₂ to cyclic carbonate with propylene oxides. However synthesis ofcyclic carbonate from CO₂ and propylene oxide using the metal complexes and the ionic liquids was conducted at high CO₂ pressure and temperatures. Additionally some of the catalysts afford the mixture of polycarbonate and cyclic carbonate, and most of the metal catalysts were highly sensitive to water molecule which deactivates the catalyst. Herein, we report the Cp^*-Rh(III) complex, where Cp^* is pentamethylcyclopentadiene, catalyzed formation of cyclic carbonate from CO₂ and propylene oxide, under mild conditions without the influence of moisture.