Polymerization of substituted acetylenes by (mesitylene)M(CO)3 (M=W, Mo)

Abstract

Phenylacetylene could be polymerized by (mesitylene)W(CO)3 in CCl4 to give a polymer with \(\overline M _{\text{n}} \) 12,000 in ca. 80% yield. UV irradiation was unnecessary unlike the W(CO)6−CCl4-hν catalyst. The present polymerization did not proceed in toluene. The (mesitylene)W(CO)3 catalyst afforded high molecular weight polymers \(\left( {\overline M _{\text{n}} 3x10^5 - {\text{4}}x10^5 } \right)\) from phenylacetylenes bearing bulky substituents (e.g., Me3Si and CF3) at the ortho position. The Mo counterpart, (mesitylene)Mo(CO)3, catalyzed the polymerization of 1-chloro-2-phenylacetylene and 1-chloro-1-octyne to provide high molecular weight polymers \(\left( {\overline M _{\text{n}} ca. {\text{4}}x10^5 } \right)\). Catalytic amounts of Lewis acids accelerated the polymerization of phenylacetylene by (mesitylene)W(CO)3, but decreased the polymer molecular weight; this polymerization proceeded not only in CCl4 but also in toluene.