Zn(ii), Cd(ii) and Cu(ii) complexes of 2,5-bis(N-(2,6-diisopropylphenyl)iminomethyl)pyrrole: Synthesis, structures and their high catalytic activity for efficient cyclic carbonate synthesis

Abstract

The syntheses of Zn(ii), Cd(ii) and Cu(ii) complexes of 2,5-bis(N-(2,6-diisopropylphenyl)iminomethyl)pyrrole (DIP2pyr)H 1 and their catalytic activities in CO2 fixation are reported. The structures of these complexes were characterized by IR, 1H, 13C NMR and single crystal X-ray diffraction techniques. The catalytic activities of these complexes for the cycloaddition of CO2 to an epoxide under one atmosphere of pressure and mild temperature conditions to yield cyclic carbonate have been studied. Among the four complexes synthesized, the Zn(ii) and Cu(ii) complexes were found to be versatile whereas the Cu(ii) complex was more selective in the conversion. They were highly effective for the conversion of monosubstituted terminal epoxides, disubstituted terminal and internal epoxides to their corresponding cyclic carbonates with good to high yields. © 2012 The Royal Society of Chemistry.