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The new carbazole‐containing acetylene monomers, 2‐ethynyl‐9‐tert‐butoxycarbonylcarbazole (1) and 3‐ethynyl‐9‐tert‐butoxycarbonylcarbazole (2) were synthesized and polymerized with Rh+(nbd)[η6–C6H5B−(C6H5)3], [(nbd)RhCl]2–Et3N, [(nbd)RhCl]2–KN(SiMe3)2, and WCl6–Ph4Sn catalysts. The corresponding polyacetylenes with number‐average molecular weights ranging from 23 000 to 185 000 were obtained in 80%‐quantitative yields, except for the polymerization of 1 with W catalyst. Rh‐based poly(1) showed UV‐Vis absorption in the longer wavelength region than Rh‐based poly(2). W‐based poly(2) showed an absorption band edge at a wavelength longer than the Rh‐based polymer. W‐based poly(2) emitted fluorescence at 375 nm upon excitation at 291 nm, while the Rh‐based compound emitted almost no fluorescence. The polymers exhibited new absorption around 360–600 nm based on electrochemically doped species by application of an external voltage.magnified image

Novel chiral acetylene monomers containing carbazole, 2‐ethynyl‐9‐[(S)‐2‐methylbutoxycarbonyl]carbazole (1), 3‐ethynyl‐9‐[(S)‐2‐methylbutoxycarbonyl]carbazole (2), 2‐ethynyl‐9‐[(S)‐2‐methylbutyl]carbazole (3), and 2‐ethynyl‐9‐[(S)‐4‐methylhexyl]carbazole (4) were synthesized and polymerized with [(nbd)RhCl]2Et3N. The corresponding polyacetylenes with number‐average molecular weights ranging from 68,700 to 310,000 were obtained in good yields. Poly(1) exhibited a large specific rotation and an intense Cotton effect in toluene, indicating that it formed a helix with predominantly one‐handed screw sense, while the other three polymers showed no evidence for taking a helical structure. Poly(1) largely decreased the CD intensity upon heating from −10 to 60 °C. Poly(1) showed a Cotton effect in film state in a manner similar to solution state. No chiral amplification was observed in the copolymerization of 1 with achiral 2‐ethynyl‐9‐tert‐butoxycarbonylcarbazole (5). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4450–4458, 2007

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