Polymerization of acetylenes catalyzed by rhenium carbonyl halides

Abstract

Abstract The homogeneous catalyst Re(CO) 5 X (X = Cl, Br) was found to promote the homopolymerization of terminal alkynes at elevated temperatures. Detection and structure characterization of low‐molecular‐weight products provided evidence of the formation of a metal–acetylide species as the initiator of polymerization, and propagation occurs by a series of insertion reactions of coordinated alkynes into metal–carbon bonds of the growing chain. Evidence of the active forms of the catalyst comes from studies on gas evolution, catalyst derivatization, and copolymerization reactions. The final polymers have a linear, polyconjugated macrostructure, and the formation of aromatic species was not detected in these reactions.