C-13-H-1 dipolar couplings for probing rod-like hydrogen bonded mesogens

Reddy, Kesava M and Reddy, Subramanyam K and Narasimhaswamy, T and Das, Bibhuti B and Lobo, Nitin P and Ramanathan, KV (2013) C-13-H-1 dipolar couplings for probing rod-like hydrogen bonded mesogens. In: NEW JOURNAL OF CHEMISTRY, 37 (10). pp. 3195-3206.

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Abstract

Hydrogen bonding is the most important non-covalent interaction utilised in building supramolecular assemblies and is preferred often as a means of construction of molecular, oligomeric as well as polymeric materials that show liquid crystalline properties. In this work, a pyridine based nematogenic acceptor has been synthesized and mixed with non-mesogenic 4-methoxy benzoic acid to get a hydrogen bonded mesogen. The existence of hydrogen bonding between the pyridyl unit and the carboxylic acid was established using FT-IR spectroscopy from the observation of characteristic stretching vibrations of unionized type at 2425 and 1927 cm(-1). The mesogenic acceptor and the complex have been investigated using C-13 NMR in solution, solid and liquid crystalline states. Together with the 2D separated local field NMR experiments, the studies confirm the molecular structure in the mesophase and yield the local orientational order parameters. It is observed that the insertion of 4-methoxy benzoic acid not only enhances the mesophase stability but also induces a smectic phase due to an increase in the core length of the hydrogen bonded mesogen.

Item Type:	Journal Article
Publication:	NEW JOURNAL OF CHEMISTRY
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	copyright for this article belongs to RSC
Department/Centre:	Division of Chemical Sciences > NMR Research Centre (Formerly Sophisticated Instruments Facility) Division of Physical & Mathematical Sciences > Physics
Date Deposited:	30 Oct 2013 11:22
Last Modified:	30 Oct 2013 11:22
URI:	http://eprints.iisc.ac.in/id/eprint/47624

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