Chromium(iii) amine-bis(phenolate) complexes as catalysts for copolymerization of cyclohexene oxide and CO2

Abstract

Chromium complexes of tri- and tetradentate amine-bis(phenolate) ligands in combination with chloride, azide or DMAP nucleophiles are effective catalysts for the copolymerization of CO ₂ with cyclohexene oxide to give polycarbonates.

Abstract

Amine-bis(phenolate) chromium( iii) complexes catalyze the copolymerization of cyclohexene oxide with carbon dioxide. These catalysts incorporate tetra- or tridentate amine-bis(phenolate) ligands and when combined with dimethylaminopyridine (DMAP) or bis(triphenylphosphoranylidene)ammonium chloride or azide, (PPNCl or PPNN ₃), yield low molecular weight polymers with moderately narrow polydispersities. The tetradentate ligand containing catalysts show higher conversions and yields of polycyclohexene carbonate, but with a wide variety of polymer end groups as shown by MALDI-TOF mass spectrometry.