遷移金属触媒による置換アセチレンのリビング重合

抄録

Catalysts composed of MoOCl₄ (or MoCl₅), nBu₄Sn, and ethanol effect living polymerization of 1-chloro-1- octyne; i, e., this polymerization provides a polymer with narrow molecular weight distribution (MWD) (M_w/ M_n 1.1-1.3), whose molecular weight increases in direct proportion to conversion. These Mo-based three-component catalysts polymerize also o-Me₃Si-, o-CF₃-, and p- nBu- o, o, m, m-F₄-phenylacetylenes in a living fashion irrespective of the electronic effect of ortho-substituent (M_w/M_n 1.05-1.2). In the presence of MoOCl₄-nBu₄Sn-EtOH, tert-butylacetylene yields a stereoregular living polymer (cis 97%, M_w/ M_n1. 1). Reaction of MoOCl₄ (or MoCl₅) with nBu₄Sn affords a metal carbene, and ethanol stabilizes it by replacing chlorine ligand with ethoxy group, which will eventually lead to living polymerization. Living polymerization of substituted acetylenes by other catalysts is also mentioned.