Design and Synthesis of New Substituted Polyacetylenes

Abstract

The present paper deals with recent studies on the metathesis polymerization of substituted acetylenes: (a) the living polymerization by MoOCl₄-based catalysts; and (b) the synthesis and properties of poly(diphenylacetylenes). Several acetylenes (ClC≡C-n-C₆H₁₃, HC≡C-t-Bu, etc.) undergo living polymerization with MoOCl₄-n-Bu₄Sn-EtOH (1:1:1). It is noteworthy that tert-butylacetylene provides a ster eor egular living polymer. Whereas phenylacetylene does not polymerize in a living fashion, its derivatives with bulky or tho groups (e.g., CF₃) undergo virtually ideal living polymerization. The MoOCl₄-Et₃Al-EtOH catalyst also effects living polymerization. Diphenylacetylenes with various groups (e.g., p-Me₃Si, p-t-Bu, p-PhO, and p-carbazyl) polymerize in high yields with TaCl₅-n-Bu₄Sn. The formed polymers are yellow solids totally soluble in toluene and thermally very stable (Mw 1x10⁶-3x10⁶). Some of them are more permeable to gases than is poly(dimethylsiloxane).