Faculty Publications

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    Dual colorimetric receptor with logic gate operations: Anion induced solvatochromism
    (Royal Society of Chemistry, 2014) Kigga, M.; Swathi, N.; Manjunatha, J.R.; Das, U.K.; Nityananda Shetty, A.N.; Trivedi, D.R.
    A receptor R1 was designed and synthesised for colorimetric detection of F- ions as well as Cu2+ ions via intramolecular charge transfer mechanism. Upon addition of F- ions in dry DMSO, the color of the receptor R1 changed from pale yellow to blue. The receptor showed a unique property of solvatochromism by displaying different coloration with different solvents only in the presence of F- ions, which were applied to determine the percentage composition of binary solvent mixtures. The receptor R1 was able to detect Cu2+ ions colorimetrically where it exhibited a color change from pale yellow to orange-red. In addition, the receptor was subjected to molecular logic gate applications, wherein it showed 'ON-OFF' switching operations. © 2014 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
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    Pharmaceutical Co-Crystal of Flufenamic Acid: Synthesis and Characterization of Two Novel Drug-Drug Co-Crystal
    (Elsevier B.V., 2017) Nechipadappu, S.K.; Tekuri, V.; Trivedi, D.R.
    Two novel pharmaceutical co-crystals of anti-inflammatory drug flufenamic acid (FFA) with 2-chloro-4-nitrobenzoic acid (CNB) and ethenzamide (ETZ) have been synthesized by solvent evaporation method as well as by solvent drop-assisted grinding method. The synthesized co-crystals were characterized thoroughly by various spectroscopic methods and crystal structures were determined by single-crystal x-ray diffraction technique. In FFA-CNB co-crystal, robust supramolecular acid-acid homosynthon was observed. FFA-ETZ co-crystal is formed via robust supramolecular acid-amide heterosynthon. In FTIR spectra, a significant shift in the carbonyl stretching frequency was observed for the co-crystals due to the presence of intermolecular hydrogen bond. 1H nuclear magnetic resonance study suggests the presence of hydrogen bond in the solution state of FFA-ETZ co-crystal; however, it was absent for FFA-CNB co-crystal. Solubility study in Millipore water revealed that the solubility of FFA is increased by 2-fold when it is in the form of FFA-CNB co-crystal and no increment in the solubility of FFA was observed in FFA-ETZ co-crystal. About 5-fold increment in the solubility of FFA was observed in both the co-crystals in 0.1 N HCl (pH 1) solution. The synthesized co-crystals were found to be non-hygroscopic at ?75% relative humidity and stable for a period of 6 months at ambient temperature (?25°C). © 2017 American Pharmacists Association®