Alkyl-substituted shape-persistent macrocycles: The first discotic liquid crystal composed of a rigid periphery and a flexible core

Angewandte Chemie - International Edition

Volumn 39, Issue 13, 2000, Pages 2267-2270

  Höger, Sigurd ^a   Enkelmann, Volker ^a   Bonrad, Klaus ^a   Tschierske, Carsten ^b  

^a MAX PLANCK INSTITUTE FOR POLYMER RESEARCH   (Germany)

^b MARTIN LUTHER UNIVERSITY HALLE WITTENBERG   (Germany)

Author keywords

Liquid crystals; Macrocycles; Supramolecular chemistry

Indexed keywords

MACROCYCLIC COMPOUND;

ALKYLATION; ARTICLE; CATALYSIS; COMPLEX FORMATION; CRYSTAL STRUCTURE; CRYSTALLIZATION; DERIVATIZATION; LIQUID CRYSTAL; MOLECULAR INTERACTION;

EID: 2242423889     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/1521-3773(20000703)39:13<2267::aid-anie2267>3.0.co;2-7     Document Type: Article

References (22)

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10. b) S. Höger, J. Polym. Sci. Part A 1999, 37, 2685.
11. One of the basic conditions for the formation of columnar liquid crystalline phases is an optimal coverage of the periphery of the central core by lateral chains (B. Kohnke, K. Praefke, Chem. Z. 1985, 109, 121). Owing to the size of our rigid structure and the attachment of only four octadecyloxy groups, the appearance of such a mesophase is improbable.
12. When 2 is heated for a longer period above 220°C, a temperature well above the clearing point of 4, we cannot eliminate the possibility of partial decomposition.
13. The exact type of the nematic phase (e.g.. nematic discotic, nematic-columnar, etc.) could not be determined yet.
14. w = 0.0571. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-139443. Copies of the data can be obtained free of charge on application to CCDC. 12 Union Road, Cambridge CB21EZ, UK (fax: (+ 44)1223-336-033; e-mail: deposit@ccdc.cam.ac.uk).
15. Nematic and smectic phases can be also observed for some other alkylated shape-persistent macrocycles, for example, a) C. C. Ling, R. Darcy, W. Risse, J. Chem. Soc. Chem. Commun. 1993, 438; b) N. Usol'tseva. K. Praefcke, D. Singer, B. Gündogan, Liq. Cryst. 1994, 16, 601. However, in all those cases, the interior of the rings is much smaller, such that a complete intraannular arrangement of the side chains can be excluded.
16. Nematic and smectic phases can be also observed for some other alkylated shape-persistent macrocycles, for example, a) C. C. Ling, R. Darcy, W. Risse, J. Chem. Soc. Chem. Commun. 1993, 438; b) N. Usol'tseva. K. Praefcke, D. Singer, B. Gündogan, Liq. Cryst. 1994, 16, 601. However, in all those cases, the interior of the rings is much smaller, such that a complete intraannular arrangement of the side chains can be excluded.
17. V. Enkelmann in Electronic Materials: The Oligomeric Approach (Eds.: K. Müllen, G. Wegner), Wiley-VCH, Weinheim. 1998, p. 295.
18. B. Wunderlich, Macromolecular Physics, Vol. 1, Academic Press, New York, 1973, p. 91.
19. a) S. Höger, V. Enkelmann, Angew. Chem. 1995, 107, 2917; Angew. Chem. Int. Ed. Engl. 1995, 34, 2713;
20. a) S. Höger, V. Enkelmann, Angew. Chem. 1995, 107, 2917; Angew. Chem. Int. Ed. Engl. 1995, 34, 2713;
21. b) D. L. Morrison, S. Höger, Chem. Commun. 1996, 2313.
22. The investigation of the conformation of 4 in the melt as well as the extension of this concept to macrocycles with a fixed intraannular arrangement of the flexible side groups is part of our current studies.