Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Author: search.filters.author.Trivedi, D.Subject: search.filters.subject.Hydrogen bonds

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Substituent effect on colorimetric detection of biologically and environmentally relevant anions: Insight in real-life applications
    (Elsevier B.V., 2019) Singh, A.; Girish Gowda, R.; Trivedi, D.
    A new set of chromogenic anion receptors R1-R4 have been synthesized with a different substituent, including electron withdrawing (nitro moiety in R1), conjugated group (naphthyl in R2), and electron donating (methyl in R3), respectively. The receptors R1-R4 exhibited very good sensitivity towards the F ? and AcO ? anions in the DMSO. In addition, R1 showed selectivity towards H 2 PO 4 ? ions over other tested anions. R1 especially acted as an effective sensor for sodium salts of F ? , AcO ? , AsO 2 ? , and AsO 4 2? ions in an aqueous medium due to the presence of two electron-withdrawing nitro substituents, which showed hydrogen bond donor tendency and acidity of the OH proton. This result indicates that R1 is highly capable of competing with an aqueous medium to detect anions without counter Na + ion interference. Interestingly, R1 displays solvatochromic property in the presence of AcO ? ions in different aprotic solvents. Additionally, the receptor R1 shows high binding affinity towards AcO ? ions in the buffer medium (DMSO: HEPES, 9:1 v/v), which displayed remarkable colour change from pale yellow to blue with a large ?? red shift of 170 nm. The CV studies reveal the deprotonation of the -NH proton upon interaction with the AcO ? ions. The receptor R1 is subjected to practical application to sense F ? and AsO 2 ? ions using the test strip. In addition, the receptor R1 proves itself as a potential applicant for the detection of F ? ions quantitatively in commercially available mouthwash. © 2019 Elsevier B.V.
  • No Thumbnail Available
    Item
    Exploring the possibilities of double proton transfer in hydrazides: A theoretical approach
    (John Wiley and Sons Ltd vgorayska@wiley.com Southern Gate Chichester, West Sussex PO19 8SQ, 2019) Mohan, M.; Satyanarayan, M.N.; Trivedi, D.
    Hydrazides are known to exhibit keto-enol tautomerism upon photoexcitation. Theoretical aspects uncovering excited state intramolecular proton transfer (ESIPT) of N-acylsubstituted hydrazides with bithiophene core have been investigated. Geometrical aspects of the system are expected to undergo double proton translocation at its excited state. However, potential energy surface study for all the molecules reveals an impossible concurrent double proton translocation and to a greater extent dubious step-wise double proton translocation in the system. Potential energy scans reveal molecules possessing a lower forward barrier at its excited state in comparison with their ground state suggestive of possible excited state single proton transfer. Geometrical attributes and spectral analysis suggest the strengthening of intramolecular hydrogen bond (N?H???O) at its excited state, favoring single proton translocation. Theoretical estimation of electronic energy transition for all the conformers yields good correlation with the experimental figures with an energy overestimation <0.17 eV. © 2019 John Wiley & Sons, Ltd.