Synthesis and Helical Structure of Poly(1‐methylpropargyl ester)s with Various Side Chains |
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| Authors: | Yuji Suzuki Masashi Shiotsuki Dr Fumio Sanda Prof Dr Toshio Masuda Prof Dr |
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| Institution: | Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615‐8510 (Japan), Fax: (+81)?75‐383‐2592 |
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| Abstract: | Optically active 1‐methylpropargyl esters bearing various substituents were polymerized with (nbd)Rh]+η6‐C6H5B(C6H5)3]? (nbd=norbornadiene) as a catalyst to afford the corresponding poly(1‐methylpropargyl ester)s with moderate molecular weights in good yields. The polymers have a cis‐stereoregular structure, which was determined by 1H NMR spectroscopy. Large optical rotations and clear CD signals demonstrated that all these polymers take on a helical structure with a predominantly one‐handed screw sense. The polymers exhibited large viscosity indices in the range 1.14–1.75. Chiral amplification was observed in R/S copolymerization. Conformational analysis revealed that the polymers form a tightly twisted helical structure with a dihedral angle of 70° at the single bond of the main chain. |
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| Keywords: | chirality helical structures polyacetylenes polymers rhodium |
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