Transition Metal Carbonyl Catalysts for Polymerizations of Substituted Acetylenes

Most of the existing metal carbonyl catalysts for acetylene polymerizations need to be preactivated by chlorine-containing additives or by UV irradiation in halogenated solvents. In this work, we developed a series of “simple” metal carbonyl catalysts of general structure M(CO)xLy (M = Mo, W), none of which require additives or pre-photoirradiation, most of which are air- and moisture-stable, and some of which work well in nonhalogenated solvents. The acetonitrile complexes M(CO)3(NCCH3)3 initiated polymerizations of a variety of mono- and disubstituted acetylenes at room temperature. The arene and diene complexes W(CO)3(mes) and Mo(CO)3(nbd) (mes = mesitylene, nbd = 2,5-norbornadiene) are tolerant of polar groups and effected polymerizations of functional acetylenes containing ester, ether, and cyano groups. The halogenated complexes MI2(CO)3(NCCH3)2 catalyzed polymerizations of phenylacetylene in toluene. The chlorine-containing acetylene monomers ClC⋮CC6H5 and ClC⋮CC6H13 were readily polymerized by the Mo complexes in nonhalogenated solvents such as toluene and dioxane, giving polymers with high molecular weights (Mw up to 883 × 103) in high yields (up to 100%).