1 January 1998 Synthesis and mesophase studies of crown ether derivatives
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Novel mesogenic para-substituted dibenzo-18-crown-6 (I a-c) and dibenzo-24-crown-8 (II d, e) are studied. Synthesis and the structural investigations of 4,4'(5')-bis(4''- alkoxybenzylidenamino)-dibenzo-18-crown-6 (I-a), 4,5'-bis (3''-(4''-alkoxyphenyl-)-3''-oxo-1''-propenyl-amino)- dibenzo-18-crown-6(I-c), 4,5'-bis(4''-(4'''- alkoxybenzoyloxy)-benzylidenamino)-(II-e) are presented. The high temperature nematic phase is observed for the trans- isomers of materials I-b,c and II-d,e. The aroylvinylamine- derivatives (I-c, II-e) have higher phase transition temperatures than relevant azomethine derivatives (I-b, II- d). Among studied compounds the material II-d is the most stable. Materials I and II have also rather complex solid state polymorphism. The structure of Cr-8 (II-d and II-e) was investigated by the x-ray scattering method. In crystal phases of II-d and II-e the monoclinic lattices have been found with a equals 5.48 angstrom, b equals 8.34 angstrom, c equals 47.3 angstrom (beta) equals 124 degrees and a equals 45.0 angstrom, b equals 8.8 angstrom, c equals 13.8 angstrom, (gamma) equals 111 degrees parameters, respectively. The conformation of a central crown-ether fragment in the crystal as well as in nematic phase is suggested.
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Olga Akopova, Olga Akopova, Anatoly Alexandrov, Anatoly Alexandrov, Tamara Pashkova, Tamara Pashkova, Lubov Kotovicz, Lubov Kotovicz, Alexandr Kurnosov, Alexandr Kurnosov, Adam Krowczynski, Adam Krowczynski, "Synthesis and mesophase studies of crown ether derivatives", Proc. SPIE 3319, Liquid Crystals: Chemistry and Structure, (1 January 1998); doi: 10.1117/12.301252; https://doi.org/10.1117/12.301252


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