Columnar phases from semi-discoid molecules. Phase induction via hydrogen bonding and charge transfer interactions |
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| Authors: | W Paulus H Ringsdorf S Diele G Pelzl |
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| Institution: | 1. Institut für Organische Chemie, Johannes-Gutenberg Universit?t , 6500, Mainz, Germany;2. Sektion Chemie, WB Physikalische Chemie , Martin-Luther-Universit?l , 4010, Halle-Wittenberg, Germany |
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| Abstract: | Abstract To investigate the non-linear optical properties of nitrophenylhydrazones, a series of 4-nitro- and 2,4-dinitrophenylhydrazones of substituted aromatic aldehydes were synthesized. It was found that many of the dinitrophenythydrazone derivatives are liquid-crystalline and X-ray investigations show that the mesophase corresponds to a hexagonal columnar structure. To explain this unusual behaviour it is necessary to assume that a mesogenic structure is formed by intramolecular hydrogen bonding of the dinitrophenylhydrazones. Charge transfer induced antiparallel alignment of these moleculer dipoles leads to discoid structures, forming the columnar phases. |
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