Synthesis, structural analysis, and visualization of poly(2ethynyl-9-substituted carbazole)s and poly (3-ethynyl-9-substituted carbazole)s containing chiral and achiral minidendritic substituents

The synthesis of 2-ethynyl-9-substituted carbazole and 3-ethynyl-9-substituted carbazole monomers containing first-generation chiral and achiral dendritic (i.e., minidendritic) substituents, 2-ethynyl-9-[3,4,5-tris(dodecan-1-yloxy)benzyl]carbazole (2ECz), 3-ethynyl-9-[3,4,5-tris(dodecan-1-yloxy)benzyllcarbazole (3ECz), 2-ethynyl-913,4,5-tris[(S)-2-methylbutan-1-yloxylbenzyl)carbazole (2ECz*), and 3-ethyny1-9-{3,4,5-tris[(S)-2-methylbutan-1-yloxylbenzyl)carbazole (3ECz*), is presented. All monomers were polymerized and copolymerized by stereospecific polymerization to produce cis-transoidal soluble stereoisomers, A structural analysis of poly(2ECz), poly(2ECz*), poly(3ECz), poly(3ECz*), poly(2ECz*-co-2ECz), and poly(3ECz*-co-3ECz) by a combination of techniques, including H-1 NAIR, ultraviolet-visible, and circular dichroism spectroscopy, thermal optical polarized microscopy, and X-ray diffraction experiments, demonstrated that these polymers had a helical conformation that produced cylindrical macromolecules exhibiting chiral and achiral nematic phases. Individual chains of these cylindrical macromolecules were visualized by atomic force microscopy. (C) 2002 Wiley Periodicals, Inc.