Ethylene-polymerization by surface supported Cr(IV) species: possible reaction mechanisms revisited by theoretical calculations

Abstract

Possible reaction mechanisms of olefin polymerization catalyzed by surface supported Cr(IV) species have been investigated by first principles density functional theory (DFT). Pathways starting from neutral alkylidene or bisalkyl complexes were found to suffer from high ethylene insertion barriers, whereas a cationic system formed by protonation of the alkylidene show a low barrier for chain propagation.Key words: density functional theory, alkylidene, olefin polymerization, Cr(IV) species.