Synthesis of block copolymers from 1‐chloro‐1‐octyne and other acetylenes through their sequential living polymerization by MoOCl₄<i>n</i>‐Bu₄SnEtOH

Abstract

Abstract Block copolymerizations of 1‐chloro‐1‐octyne (1‐ClO) with several substituted acetylenes were examined by means of living polymerization. o ‐(Trifluoromethyl)phenylacetylene ( o ‐CF 3 PA), o ‐(trimethylsilyl)phenylacetylene ( o ‐Me 3 SiPA), 1‐chloro‐2‐phenylacetylene (1‐ClPA), p ‐butyl‐ o , o , m , m ‐tetrafluorophenylacetylene ( p ‐BuF 4 PA), and tert ‐butylacetylene ( t ‐BuA) were used as comonomers, and the MoOCl 4 ‐ n ‐Bu 4 Sn‐EtOH (mole ratio 1:1:1) catalyst, which is known to effect living polymerization of substituted acetylenes, was employed. When o ‐CF 3 PA and 1‐CIPA were the comonomers in combination with 1‐CIO, block copolymers were exclusively obtained in both orders of monomer addition. In the cases of o ‐Me 3 SiPA and p ‐BuF 4 PA as comonomers, the copolymerizations initiated from 1‐CIO produced block copolymers selectively, whereas the homopolymers of o ‐Me 3 SiPA and p ‐BuF 4 PA also formed if the order of monomer addition was reversed. The pair of 1‐CIO and t ‐BuA did not selectively yield block copolymers irrespective of the order of monomer addition. Thus, block copolymerization occurred between 1‐CIO and monomers that show high “livingness” and close reactivities.