Cycloaddition of CO2 to epoxides using di-nuclear transition metal complexes as catalysts

Studies on the reaction and conversion of CO2 to valuable products have made much progress in recent years, and the search for efficient catalysts is also expanding. Cycloaddition of CO2 to epoxides was carried out selectively using di-nuclear Cu-II, Co-II and Ni-II complexes (C1, C2 and C3, respectively) as catalysts. The complexes were synthesized in good yield and characterized by various physical and spectroscopic methods. In all complexes the ligand L acted as a bidentate NO donor favouring distorted octahedral, tetrahedral or square planar geometry for C1, C2 and C3, respectively. Complex C2 in the presence of n-Bu4NI as a cocatalyst showed the highest activity among the reported complexes in the cycloaddition reaction.