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Geometrical structures of poly(haloalkyl propiolate)s prepared with a [Rh(norbornadiene)Cl]2 catalyst |
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| Authors: | Eriko Sato Yasuteru Mawatari Yoshikazu Sadahiro Bunichiro Yamada Yoshiaki Kashiwaya |
| Affiliation: | a Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan b Formerly Department of Applied and Bioapplied Chemistry, Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan c Division of Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan |
| Abstract: | The polymerization of ω-haloalkyl propiolates initiated by [Rh(norbornadiene)Cl]2 in methanol has been investigated in detail together with the geometrical forms of the resulting polymers. The polymer yield and molecular weight of poly(2-haloethyl propiolate)s (P(2XEPA)s) were markedly reduced in the order of X = Cl, Br, and I. 1H NMR, electron spin resonance, and diffuse reflective UV-vis spectroscopic studies of P(2XEPA)s revealed that the content of cis form regarding the C C was markedly decreased from 60% for P(2ClEPA) to 15% for P(2IEPA). The decrease in the cis content also resulted in notable reduction of the crystallinity of the polymer from 30% for P(2ClEPA) to less than 10% for P(2IEPA). Compression of P(2XEPA)s at room temperature induced the so-called cis-to-trans isomerization accompanied with decomposition of the polymers. |
| Keywords: | Conjugated polymers Isomerization Substituted acetylenes |
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