Influence of polar substituents and flexible chain length on mesomorphism in non-mesogenic linear hydrogen bonded complexes

Bhagavath, Poornima and Mahabaleshwara, S and Bhat, Sangeetha G and Potukuchi, D M and Shetty, Prakash and Maddasani, Srinivasulu (2021) Influence of polar substituents and flexible chain length on mesomorphism in non-mesogenic linear hydrogen bonded complexes. Journal of Molecular Liquids, 336. ISSN 0167-7322

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Abstract

Liquid Crystalline (LC) behavior is observed in the mixtures of low molecular weight dihalobenzoic acids viz., 2,4-dichlorobenzoic acid and 4-chloro-2-fluorobenzoic acid and the Schiff’s base pyridyl units, viz., (4-pyridyl)-benzylidene-4ʹ-n-alkyl anilines (heptyl, decyl, dodecyl, tetradecyl and hexadecyl homologues, PyBnA) in 1:1 M ratio. The dihalobenzoic acids and the pyridyl moieties are non-mesogenic, but their equimolar (1:1) mixtures exhibit liquid crystalline behavior through intermolecular hydrogen bonding (HB), which is characterized by the infrared spectroscopy. The dihalobenzoic acids are the proton donors, while the pyridyl units are proton acceptors and are found to undergo self-assembly. The dihalobenzoic acid HB complexes are found to exhibit higher liquid crystallinity than the corresponding mono halo sub�stituted benzoic acid HB complexes with the same pyridyl units. The 4-chloro-2-fluorobenzoic acid HB complexes exhibit large mesomorphic state than the 2,4-dichlorobenzoic acid HB complexes with the same pyridyl moieties. The thermal range of the HB complexes are found to exhibit an increasing trend initially, followed by a decreasing tendency with the increase of chain length of the proton acceptors. The HB complexes of the decyl homologue of the proton acceptor (PyB10A) is found to show high liquid crys�tallinity in both the series. The influence of the moieties on melting and clearing temperatures is dis�cussed in the wake of results in other liquid crystalline ser

Item Type: Article
Uncontrolled Keywords: Hydrogen bonding Induced mesomorphism Linear HB complexes Pyridyl units Smectic phases Dihalobenzoic acids Polar substituents
Subjects: Engineering > MIT Manipal > Chemistry
Depositing User: MIT Library
Date Deposited: 23 Dec 2021 09:45
Last Modified: 23 Dec 2021 09:45
URI: http://eprints.manipal.edu/id/eprint/157875

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