New Schiff Bases with Pyridine Core: Spectral, Thermal and Optical Characterizations
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Copyright: © 2020 Sie-Tiong Ha, Lay-Khoon Ong, Yip-Foo Win, Guan-Yeow Yeap, Nilesh L. Bonde and Peng-Lim Boey. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Problem statement: Numerous studies have been conducted on the Schiff base's alkyl and alkyloxy possessing aromatic core. However, the thermo tropic properties of Schiff base's ester (or alkanoyloxy) with pyridine core was rare studied. Approach: To study spectral, thermal and optical behaviors of Schiff base ester possessing heterocyclic (pyridine) terminal core. A series of 4-[(pyridin-3-ylmethylene) amino] phenylalkanoates were prepared and all the members are differed by the length of alkanoyloxy chain, Cn-1H2n-1COO, where n = 12, 14, 16 and 18. The thermal and optical characteristics were studied using differential scanning calorimetry and polarizing optical microscopy. Results: DSC studies showed that all of the title compounds exhibited direct isotropization and recrystallization during heating and cooling cycles, respectively. Under polarizing optical microscope, crystal phase texture was observed to change to dark region isotropic without displaying any liquid crystal phase. Conclusion: The presence of terminal pyridine core suppressed the formation of mesosphere in the compounds studied.
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- thermo tropic
- phase transition