A series of bifunctional rare-earth metal complexes bearing zwitterionic amino-bis(phenolato) ligands were synthesized and structurally characterized. These complexes were applied as catalysts for the synthesis of cyclic carbonates from epoxides and CO 2 . Lanthanum complex 1 La was most active, converting terminal epoxides into the cyclic carbonates in moderate to excellent yields at 40 °C in the presence of 1 bar CO 2 . The catalyst was also recycled five runs without loss of catalytic activity. The kinetics of the cycloaddition of CO 2 and epichlorohydrin (ECH) catalyzed by complex 1 La were investigated. According to the Arrhenius equation, the activation barrier for cyclic carbonate formation is determined to be 8.29 � 0.68 kcal/mol.
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