Controlled helical orientation of carbazole in amino acid derived poly(N‐propargylamide)s |
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Authors: | Haichao Zhao Fumio Sanda Toshio Masuda |
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Institution: | 1. Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615‐8510, Japan;2. Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615‐8510, JapanDepartment of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615‐8510, Japan |
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Abstract: | Novel L ‐alanine and L ‐glutamic acid derivatized, carbazole‐containing N‐propargylamides N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐alanine N′‐propargylamide and N‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] were synthesized and polymerized with (nbd)Rh+η6‐C6H5B?(C6H5)3] (nbd = norbornadiene) as a catalyst to obtain the corresponding polymers with moderate molecular weights in high yields. Polarimetry, circular dichroism, and ultraviolet–visible spectroscopy studies revealed that both polyN‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐alanine N′‐propargylamide] and polyN‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] took a helical structure with a predominantly one‐handed screw sense in tetrahydrofuran, CHCl3, and CH2Cl2. The helix content of polyN‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐alanine N′‐propargylamide] could be tuned by heat or the addition of a protic solvent, and the helical sense of polyN‐(9‐carbazolyl) ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] was inverted by heat in CHCl3 or in mixtures of tetrahydrofuran and CH2Cl2. PolyN‐(9‐carbazolyl) ethyloxycarbonyl‐L ‐alanine N′‐propargylamide] and polyN‐(9‐carbazolyl)ethyloxycarbonyl‐L ‐glutamic acid‐γ‐benzyl ester N′‐propargylamide] also took a helical structure in film states. They showed small fluorescence in comparison with the monomers and redox activity based on carbazole. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 253–261, 2007 |
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Keywords: | amino acids biomimetic carbazole helix polyacetylenes stimuli‐sensitive polymers |
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