Supramolecular non-symmetric dimers derived from cholesterol: synthesis and phase transitional properties |
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Authors: | Uma S Hiremath Geetha G Nair D S Shankar Rao |
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Institution: | 1. Centre for Nano and Soft Matter Sciences, Bengaluru, Indiahiremath@cens.res.in;3. Centre for Nano and Soft Matter Sciences, Bengaluru, India |
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Abstract: | Three series of novel dimeric supramolecules, possessing both inter- as well as intramolecular H-bonding, have been prepared and investigated for their thermal properties. They were obtained in excellent yields by condensing cholesteryl ω-(3-hydroxy-4-formylphen-oxy)alkanoates with 4-(n-alkoxy)benzohydrazides, 3,4-bis(n-decyl-oxy)benzohydrazide and 3,4,5-tris(n-decyloxy)benzohydrazide. The influence of increase in the number of terminal n-alkoxy tails from one to three and the length and parity of the flexible spacer on phase transitional behaviour have been thoroughly investigated with the aid of microscopic, calorimetric and X-ray diffraction (XRD) techniques. The results of these complementary studies clearly illustrate the dependence of thermal behaviour of the dimers on these structural factors. The rigid intermolecular association via H-bonds through complementary benzohydrazide component enforce their self-assembly into frustrated and polar smectic phases; H-bond force coupled with the bulkiness of steroid moiety affects the electrical switching property of this fluid polar structure. |
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Keywords: | H-Bonds supramolecular dimers ferroelectric behaviour frustrated phases |
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