Ethynylene-disilanylene copolymers |
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Authors: | Robert West Shuzi Hayase and Takahisa Iwahara |
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Affiliation: | (1) Department of Chemistry, University of Wisconsin, 53706 Madison, Wisconsin |
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Abstract: | Polymers of structure (SiR2SiR2-C C-SiR2 SiR2 -C C)
n
, in which ethynylene units alternate with disilylene units, have been prepared by two routes: (a) condensation of dichlorodisilanes with dilithium derivatives of 1,2-diethynyldisilanes and (b) ring-opening polymerization of strained cyclic disilanylene-acetylnes, (SiR2SiR2C C)2. The polymers display UV absorption near 240 nm indicative of – conjugation between the Si2 and the C C moieties. Polymers with R=R =n-Bu or R=n-Bu, R =Ph, undergo solid-state transitions to form liquid crystalline mesophases resembling those observed for many poly(silylenes). Single crystals were obtained for the polymer with R=R =CH3, by precipitation from dilute cyclohexane solution. The solid-state properties and structures of this family of polymers are discussed.This paper was presented at the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.![rdquo](/content/t30806j769h41222/xxlarge8221.gif) |
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Keywords: | Polysilanes sigma-pi conjugation mesophases polymer crystals |
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