Mutual conversion between stretched and contracted helices accompanied by a drastic change in color and spatial structure of poly(phenylacetylene) prepared with a [Rh(nbd)Cl]2‐amine catalyst |
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| Authors: | Ranko Motoshige Yasuteru Mawatari Asahi Motoshige Yoshiaki Yoshida Takahiro Sasaki Hiroaki Yoshimizu Tomoyuki Suzuki Yoshiharu Tsujita Masayoshi Tabata |
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| Institution: | 1. Department of Applied Chemistry, Graduate School of Engineering, Muroran Institute of Technology, , Muroran, Hokkaido, 050‐8585 Japan;2. Research Center for Environmentally Friendly Materials Engineering, Muroran Institute of Technology, , Muroran, Hokkaido, 050‐8585 Japan;3. Graduate School of Engineering, Nagoya Institute of Technology, , Gokiso‐cho, Showa‐ku, Nagoya, 466‐8555 Japan |
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| Abstract: | The yellow‐colored poly(phenylacetylene), Poly( Y ), is obtained from phenylacetylene using a Rh(nbd)Cl]2‐NEt3 catalyst in ethanol at 25 °C. The color of Poly( Y ) drastically changes into red Poly( R ) or reddish‐black Poly( B ) by immersion in acetylacetone or exposure to chloroform vapor, respectively. Poly( R ) is also created from Poly( B ) by contact with acetylacetone. Poly( Y ) is regenerated from both Poly( R ) and Poly( B ) by reprecipitation from their chloroform solution into methanol. Wide‐angle X‐ray scattering (WAXS) patterns of Poly( Y ) and Poly( R ) correspond to a pseudohexagonal crystal called a columnar as stretched cis‐transoid and contracted cis‐cisoid helices, respectively. These helical diameters and pitch widths obtained from the WAXS measurements are agreed with those of MMFF94 calculation models. The smallest helical pitch width is 3.3 Å for Poly( R ) and Poly( B ). Moreover, information regarding the size and ordering of the vacant space within each polymer is estimated by using 129Xe NMR technique. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 752–759 |
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| Keywords: | conjugated polymers crystal structures polyacetylenes self‐assembly transitions |
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