Browsing by Author "Trivedi D.R."

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Design, Synthesis and Characterization of N-Substituted Heteroaromatics: DFT-Studies and Organic Light Emitting Device Application
(2020) Mohan M.; John R.; Nagarajan S.M.; Trivedi D.R.
Schiff's base condensation of 4,5-Dimethyl-1,2-phenylenediamine with various aldehydes namely fluorene-2-carboxaldehyde (MBF), N-ethyl-3-carboxaldehyde (MBE), 8-hydroxyjulolidine-9-carboxaldehyde (MBJ) and N-(4-formylphenyl) carbazole (MBB) functioning as light emitters have been synthesized. Solid-state emission reveals the exhibition of variant fluorescent color achieved by mere variation in the peripheral group attached to the core. Amongst the designed system, MBB showed a solid-state blue light emission with its emission peak centered at 453 nm. The fluorescence quantum yield of MBB displayed value of 44.82% in the solution state. Electrochemical studies on MBB estimated a HOMO energy level at −5.7 eV and LUMO at −3.2 eV. OLED realized with MBB as an active emitter material was successful in the generation of bluish-green emission with a maximum brightness of 280 cd/m2. Current efficiency of 2 cd/A and a power efficiency of 0.18 lm/W was observed for the fabricated device. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Smart Colorimetric Chemosensors for Multi-Analyte Signaling: Recognition of Heavy Metal Ions in an Aqueous Medium and DFT Studies
(2020) Tekuri V.; Mohan M.; Trivedi D.R.
A Schiff's base colorimetric chemosensors R1–R3 consist of carbohydrazide, and heterocyclic aldehydes have been designed and synthesized for sensing of heavy metal ions. Synthesized receptors were well characterized by various standard spectroscopic techniques. The receptor R1 exhibited multi-ion selectivity for Cd2+, Hg2+, Pb2+, Cu2+ ions and showed lowest detection limit of 1.9 ppb, for Cd2+ & Hg2+ ions. The receptors R2 and R3 displayed dual ion selectivity (R2 for Hg2+, Cu2+, and R3 for Cu2+, AsO2 – ions) in an aqueous medium at ppb levels. The UV–Vis and colorimetric studies confirmed the selectivity and sensitivity of chemosensors R1–R3 in the presence of other interfering metal ions. Further, using the B–H plot, FT-IR, and mass analysis data, the binding modes, stoichiometric ratios of receptors R1–R3 with the metal ions were investigated. The estimated association constant values were found to be 104 to 105 M–1/M–2. The experimental results are well concordant with that of calculated theoretical DFT results. The receptors R1–R3 exhibited good sensitivity and selectivity compared to literature reports and successfully demonstrated for test strip applications. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Spectroscopic studies of colorimetric receptors for detection of biologically important inorganic F−, AcO− and H2PO4 − anions in organo-aqueous medium: Real-life application
(2020) Singh A.; Nishith U.; Trivedi D.R.
Two new 4-nitrobenzylidene based receptors 2-((E)-(((E)-4-nitrobenzylidene) hydrazono) methyl)-1H-indole (R1) and 2-((E)-(((E)-4-nitrobenzylidene)hydrazono)methyl)-1H-pyrrole (R2) have been designed and synthesized by the simple condensation reaction and characterized by using spectroscopic techniques. The receptors exhibited high sensitivity and selectivity towards biologically important anions such as F−, AcO− and H2PO4 − in DMSO and sodium salts F−, AcO− and H2PO4 − in aqueous medium (9:1 v/v, DMSO: H2O). The receptors R1 and R2 dispensed high sensitivity towards sodium arsenite and detection limit were found to be 0.143 ppm and 0.32 ppm in (9:1 v/v, DMSO: H2O) reflect the stable complex formation of the receptor with AsO2 − ion in aqueous medium. 1H NMR titration carried out to understand the nature of interaction between receptor R1 and F− ion. Cyclic voltammetric studies performed for receptors R1 and R2 in DMSO exhibited shift in oxidation and reduction peak with addition of basic F− ion signifying strong interaction between receptors and anions. Interesting, receptor R1 exhibited high selectivity for AcO− ion in the different range of pH from (6–11). Furthermore, receptor R1 and R2 showed colorimetric sensing of F− and AcO− ion present in commercially available toothpaste and vinegar in the form of Na+F− and Na+AcO− in aqueous medium. © 2020 Elsevier B.V.