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Ordering of a lateral crown ether and terminal short POE chains in some symmetrical nematogens by $^{13}C\hspace{2mm}NMR$

Sinha, Neeraj and Ramanathan, KV and Leblanc, K and Judeinstein, P and Bayle, JP (2002) Ordering of a lateral crown ether and terminal short POE chains in some symmetrical nematogens by $^{13}C\hspace{2mm}NMR$. In: Liquid Crystals, 29 (3). pp. 449-457.

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Abstract

A lateral crown ether fragment can be introduced on symmetrical mesogens containing only three aromatic rings. The replacement of the terminal alkoxy chains by chains containing oxyethylene units decreases the melting and clearing temperatures allowing one to obtain nematic compounds near room temperature. These compounds dissolve LiBF4 salt only to a small extent, but the nematic arrangement, is thereby destroyed. The carbon chemical shift anisotropy and the local C-H bond order parameters were obtained for the nematic phase for the crown ether fragment and the terminal chains. This study indicates that the crown ether average conformation changes insignificantly on decreasing the temperature. The lateral crown ether protrudes markedly from the core with the consequence that the molecular shape is far from rod-like in geometry.

Item Type: Journal Article Copyright of this article belongs to Taylor & Francis Group. Division of Chemical Sciences > Sophisticated Instruments Facility (Continued as NMR Research Centre) Sahana R Sahini 03 Jun 2006 27 Aug 2008 12:09 http://eprints.iisc.ac.in/id/eprint/7447