Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
3 results
Search Results
Item Electrooptical characteristics and anion binding behaviour of organic receptors: Effect of substitution on colorimetric response(Elsevier B.V., 2017) Pangannaya, S.; Trivedi, D.R.A series of four organic receptors, R1, R2, R3 and R4 possessing [sbnd]NH unit as binding site with varied positional substitution of [sbnd]OH and [sbnd]NO2functionalities have been synthesized and studied for their anion binding ability. Significant changes were observed in the UV–vis spectra of receptors with the addition of AcO?ion justifying the observed color changes visible to naked eye. Receptors R1, R2 and R3 showed mild color changes in the presence of F?and H2PO4 ?ions whereas R4 exhibited selective response towards AcO?ion. UV–vis titration and cyclic voltammetric studies performed with the incremental addition of AcO?ion to the receptors confirmed the anion binding process. The band gap value derived from the experimental results of UV–vis spectroscopic and cyclic voltammetric studies support the formation of AcO?ion-receptor complex. 1H NMR titration studies performed with the addition of AcO?ion to receptor R3 confirms the deprotonation of the [sbnd]NH proton involved in the binding mechanism. © 2017 Elsevier B.V.Item Design and synthesis of a new organic receptor and evaluation of colorimetric anion sensing ability in organo-aqueous medium(Elsevier B.V., 2017) Pangannaya, S.; Tarafder, K.; Trivedi, D.R.A new organic receptor has been designed and synthesized by the combination of aromatic dialdehyde with nitro-substituted aminophenol resulting in a Schiff base compound. The receptor exhibited a colorimetric response for F? and AcO? ion with a distinct color change from pale yellow to red and pink respectively in dry DMSO solvent and yellow to pale greenish yellow in DMSO:H2O (9:1, v/v). UV–Vis titration studies displayed a significant shift in absorption maxima in comparison with the free receptor. The shift could be attributed to the hydrogen bonding interactions between the active anions and the hydroxyl functionality aided by the electron withdrawing nitro substituent on the receptor. 1H NMR titration and density functionality studies have been performed to understand the nature of interaction of receptor and anions. The lower detection limit of 1.12 ppm was obtained in organic media for F? ion confirming the real time application of the receptor. © 2016Item Hydrazinylpyridine based highly selective optical sensor for aqueous source of carbonate ions: Electrochemical and DFT studies(Elsevier B.V., 2018) Thimaradka, V.; Pangannaya, S.; Mohan, M.; Trivedi, D.R.A series of new receptors PDZ1–3 based on 2-(arylidenehydrazinyl)pyridines have been designed and synthesized for the detection of biologically and environmentally important ions. The colorimetric detection of CO32 ? using neutral organic receptor PDZ-1 has been achieved with characteristic visual colour change from yellow to green accompanied by a large redshift of 215 nm in absorption maxima. UV–Vis spectroscopic and cyclic voltammetric studies reveal the stoichiometry of binding and electrochemistry of host-guest complex formation. The binding constant was found to be 0.77 × 104 M? 2. In addition, electrochemical studies provide an insight into the stability of the complex. DFT studies performed on the PDZ-1 and PDZ-1 ? CO32 ? complex reveal the binding mechanism involved in the anion detection process. PDZ-1 is highly selective for carbonate and does not show any colorimetric response towards any other anions or cations, while PDZ-2 and PDZ-3 remain inactive in the ion detection process. The limit of detection (LOD) and limit of quantification (LOQ) of PDZ-1 for carbonate was found to be 0.11 mM and 0.36 mM respectively. Considerable binding constant and limit of detection make PDZ-1 to be used as a real time sensor for the detection of carbonate in environmental and biological samples. © 2017 Elsevier B.V.