Browsing by Author "Trivedi, D.R."

Now showing 1 - 20 of 67

4-Nitrobenzoic acid-sulfathiazole (1/1)
(2014) Oruganti, M.; Trivedi, D.R.
In the crystal structure of the title compound, C7H 5NO4·C9H9N3O 2S2, the sulfathiazole and 4-nitrobenzoic acid molecules are held together by short ?-? contacts between the thiazole and nitrobenzene rings, with a centroid-centroid distance of 3.8226(7)Å. The sulfathiazole molecules form dimers via N-H.N hydrogen bonds involving the thiazole and sulfonamide moieties, owing to the fact that sulfathizole exhibits amide-imide tautomerism. The N-H (amine) groups of two sulfathiazole molecules are linked to the two S=O groups of a sulfathiazole via N-H.O hydrogen bonds. Two molecules of coformer are held together by O-H.O hydrogen bonds. These units self-assemble, forming a three-dimensional network stabilized by (acid)C-H.?(sulfathiazole benzene ring) interactions.
A catalyst- and solvent-free three-component reaction for the regioselective one-pot access to polyfunctionalized pyrroles
(2013) Bhat, S.I.; Trivedi, D.R.
A facile method for the regioselective synthesis of tetrasubstituted pyrroles, from readily accessible 1,3-dicarbonyls, benzoin derivatives and ammonium acetate, has been developed. The one-pot three-component reactions were performed to afford tetrasubstituted pyrroles under solvent- and catalyst-free conditions. © 2013 Elsevier Ltd. All rights reserved.
A highly efficient and green cascade synthesis of 3-methyl-substituted-4- hydroxy-1-methyl-quinolin-2(1H)-ones under solvent- and catalyst-free conditions
(2014) Bhat, S.I.; Trivedi, D.R.
An expeditious and green protocol for the synthesis of 3,3?- methanediylbis(4-hydroxy-1-methylquinolin-2(1H)-one) (MDBHQ) derivatives and 3-((2-amino-6-oxocyclohex-1-enyl)methyl)-4-hydroxy-1-methylquinolin-2(1H)-one (AOCHQ) derivatives has been developed via a cascade Knoevenagel-Michael reaction. The products were obtained in high yield under neat reaction conditions without any work-up or chromatographic purification. The generality and functional tolerance of this environmentally benign protocol is demonstrated. © 2014 The Royal Society of Chemistry.
A new colorimetric chemosensors for Cu2+ and Cd2+ ions detection: Application in environmental water samples and analytical method validation
(Elsevier B.V., 2017) Tekuri, V.; Trivedi, D.R.
A new heterocyclic thiophene-2-caboxylic acid hydrazide based chemosensor R1 to R4 were designed, synthesized and characterized by various spectroscopic techniques like FT-IR, UV-Vis, 1H NMR, 13C NMR, Mass and SC-XRD. The chemosensor R3 showed a significant color change from colorless to yellow in the presence of Cu2+ ions and chemosensor R4 showed a significant color change from colorless to yellow in the presence of Cd2+ ions over the other tested cations such as Cr3+, Mn2+, Fe2+, Fe3+, Co2+, Ni2+, Zn2+, Ag2+, Al3+, Pb2+, Hg2+, K+, Ca2+ and Mg2+. The high selective and sensitivity of R3 towards Cu2+ and R4 towards Cd2+ ions was confirmed by UV-Vis spectroscopic study. The R3 showed a red shift in the presence of Cu2+ ions by ??max 67 nm and R4 showed a red shift in the presence of Cd2+ ions by ??max 105 nm in the absorption spectrum. The binding stoichiometric ratio of the complex between R3 - Cu2+ and R4 - Cd2+ ions have been found to be 1:1 using the B-H plot. Under optimized experimental conditions, the R3 and R4 exhibits a dynamic linear absorption response range, from 0 to 50 ?M for Cu2+ ions and 0 to 30 ?M for Cd2+ ions, with the detection limit of 2.8 × 10?6 M for Cu2+ and 2.0 × 10?7 M for Cd2+ ions. The proposed analytical method for the quantitative determination of Cu2+ and Cd2+ ions was validated and successfully applied for the environmental samples with good precision and accuracy. © 2017 Elsevier B.V.
A new colorimetric receptor for selective detection of maleate vs. fumarate and ratiometric detection of F- ions
(Royal Society of Chemistry, 2014) Kigga, M.; Trivedi, D.R.
Two new receptors, R1 and R2, were designed and synthesized for the isomeric discrimination of maleate ions over fumarate ions. Receptor R1 showed high selectivity with a significant color change from colorless to orange red with ??max of 104 nm. This was owing to the hydrogen bonded electrostatic interactions of maleate ions with receptor R1. The formation of hydrogen bond between receptor R1 and maleate ions was confirmed by 1H NMR titrations, where the signal at ? 12.25 corresponding to the benzohydrazide -NH proton showed a downfield shift upon binding with the anion. Receptor R3 did not show any binding with maleate ions or fumarate ions due to steric hindrance. Receptors R1 and R2 detected F- ions with color changes from colorless to orange and colorless to pale yellow, respectively. Upon incremental addition of F- ions, the color was further transformed from orange to blood red in receptor R1 and pale yellow to dark yellow in receptor R2. This result was due to the formation of initial hydrogen bonds followed by the deprotonation of receptors at higher concentrations of F- ions. © the Partner Organisations 2014.
Aminophenol based colorimetric chemosensor for naked-eye detection of biologically important fluoride and acetate ions in organo-aqueous medium: Effective and simple anion sensors
(Elsevier B.V., 2018) Singh, A.; Tom, S.; Trivedi, D.R.
Three new novel colorimetric receptors (R1-R3) based on aminophenol have been designed and synthesized by simple Schiff base reaction and their anion sensing properties were examined, characterized by common spectroscopic techniques such as FT-IR, UV–visible, 1HNMR,13CNMR, ESI–MS and fluorescence. Receptors R1 and R2 bearing ?OH group at ortho and para position acting as anion binding sites with –NO2 moiety as an optical signaling unit. Receptors R1 and R2 elevated selective and sensitive ability towards F? and AcO? ions over the other competing anions in DMSO as well as in CH3CN. Receptors R1 and R2 showed high capability of sensing acetate and fluoride ions present in the form of sodium salts such as NaAcO and NaF in an aqueous medium. The color of both the receptors R1 and R2 solution changes from pale green to blue and pale yellow to peach color with the addition of sodium salts of acetate (NaAcO) and fluoride (NaF) with a bathochromic shift of 168 nm and 165 nm in the UV–vis absorption spectra of receptor R1 and 103 nm and 100 nm in case of receptor R2 due to ICT transition between the electron rich ?OH and electron deficient –NO2 moiety. Moreover, receptors R1-R2 showed noteworthy fluorescence enhancement, response towards F? and AcO? ion in DMSO. Compared to receptor R2, R1 shows a huge red shift towards F? and AcO? ions in organo-aqueous medium due to the presence of ?OH proton at ortho position which effectively bind with both the anions. The binding constant and stoichiometry of the receptors-anions complex was calculated by using Benesi-Hildebrand (B–H) plot. The anion binding properties of receptor R1 via ICT mechanism was enlightened by UV–vis titration, 1HNMR studies. © 2017 Elsevier B.V.
An Efficient Three-component, One-pot Synthesis of Quinazolines under Solvent-free and Catalyst-free Condition
(HeteroCorporation support@jhetchem.com, 2015) Bhat, S.I.; Das, U.K.; Trivedi, D.R.
An efficient green protocol for the synthesis of quinazolines in the absence of solvent and catalyst has been developed. 2,4-Disubstituted quinazolines have been synthesized from three-component one-pot reactions of 2-aminoaryl ketones, orthoesters, and ammonium acetate. The present method has advantages of operational simplicity, substrate generality, clean reaction, high yields (76-94%), and moderate reaction time. The plausible mechanism of the reaction has been proposed based on the spectral characterization and single crystal X-ray analysis of isolated intermediate. © 2014 HeteroCorporation.
Benzidine-based chemosensors for the selective detection of phosphate, carbonate and copper ions: Applications in water and food sample analysis and on-field detection kit
(Elsevier Inc., 2024) Chowdhary, A.; Dhawale, A.; Trivedi, D.R.
In this work, benzidine-based chemosensors were synthesized. A5R1 had a cage-like structure along with 2-OH binding sites for encapsulation of Cu2+, A5R2 was found to bind with PO43¯ and CO32¯ ion; whereas A5R3 was innocent towards any cations or anions. The LOD for A5R1 with Cu2+ was found to be 2.63 ppm. A5R2 detected PO43¯ and CO32¯ with limit of detections 4.13 ppm and 5.40 ppm respectively. The interference studies indicated that there was no other ion which could restrain the analysis. Job's Plots showcased the 1:2 binding of the receptors with the analyte ion(s). The practical applicability of the probes was demonstrated by on-field detection kit and test-strip fabrication with colour change chart. Logic gate formulation with active simulation governed by the reversibility studies envisaged the reversibility and reusability of the probe and its solicitation in making electric devices. Furthermore, spiking studies proved the application of the receptors for convenient analyte detection in real-life food and water samples. © 2024 Elsevier B.V.
Bithiophene based red light emitting material - Photophysical and DFT studies
(2019) Mohan, M.; Satyanarayan, M.N.; Trivedi, D.R.
Bithiophene based red fluorescent light emitting material BTCN has been synthesized by Schiff base condensation reaction and characterized by standard spectroscopic techniques. The effect of -CN substituted amino pyrazole unit covalently linked to bithiophene moiety enhances the emission intensity in the system. In solid state BTCN exhibits an emission wavelength of 651nm with 170nm FWHM. Cyclic voltammogram shows the HOMO energy level of the BTCN to be -5.59 eV with LUMO around -3.24 eV. DFT optimized geometry of BTCN possesses a high amount of planarity in their structure and TD-DFT estimates the nature of electronic transitions occurring in the system. Overall, BTCN can act as good red light emitting material for organic light emitting applications. � 2019 Author(s).
Bovine serum albumin catalyzed one-pot, three-component synthesis of dihydropyrano[2,3-c]pyrazole derivatives in aqueous ethanol
(Royal Society of Chemistry, 2016) Dalal, K.S.; Tayade, Y.A.; Wagh, Y.B.; Trivedi, D.R.; Dalal, D.S.; Chaudhari, B.L.
Bovine serum albumin (BSA) catalyzed synthesis of dihydropyrano[2,3-c]pyrazole derivatives via a one pot, three component reaction of an aldehyde/ketone/isatin, malononitrile and 3-methyl-1H-pyrazol-5-(4H)-one in H2O-EtOH (7: 3) at ambient temperature was developed in this work. The catalyst was found to work efficiently for aldehydes, ketones and isatins to give the corresponding dihydropyrano[2,3-c]pyrazole and spiro[indoline-3,4?-pyrano[2,3-c]pyrazole] derivatives in high yields. BSA showed a broad range of catalytic promiscuity towards various aldehydes, aromatic/aliphatic ketones and substituted isatins. The use of an environmentally benign protocol, reusability of the catalyst, avoidance of hazardous solvents, excellent yields, easy work up and no byproduct formation make BSA an attractive candidate for further applications as a biocatalyst. © The Royal Society of Chemistry.
Chromogenic Chemosensor for Simultaneous Detection of PO43? and CO32? Anions in Organo-Aqueous Solutions: Application in Arduino Based Electronic Color Sensor Device and Logic Gate
(John Wiley and Sons Inc, 2024) Dhawale, A.; Trivedi, D.R.
Three new chromogenic receptors have been synthesized with the primary objective of facilitating the selective recognition of PO43?and CO32? ions in an organo-aqueous medium. R1 and R2 exhibit an extraordinary detection limit aligning with both EPA and WHO guidelines. R1 shows LOD of 0.135 ppm for PO43? and 0.175 ppm for CO32?, while R2 sets forth a LOD of 0.427 ppm for PO43? and 0.729 ppm for CO32?. The binding mechanism involves intramolecular charge transfer (ICT) band are substantiated by comprehensive studies that include UV-Vis titration, 1H-NMR titration, DFT studies and electrochemical studies. Chemosensors were employed in the formulation of logic gate, the fabrication of a paper strip test kit and its application in RGB color sensor device. © 2024 Wiley-VCH GmbH.
Chromogenic detection of fluoride, dihydrogen phosphate, and arsenite anions based on 2,4-dinitrophenyl hydrazine receptors: spectral and electrochemical study
(Taylor and Francis Ltd., 2021) K, N.; Singh, A.; Nityananda Shetty, A.N.; Trivedi, D.R.
The colorimetric recognition of biologically relevant fluoride (F?), acetate (AcO?), and dihydrogen phosphate (H2PO4?) ions, and poisonous arsenite (AsO2?) ions, was devised and new receptors for these anions synthesised via the Schiff base condensation procedure. UV–visible titration, fluorescence titration, 1H-NMR titration, and cyclic voltammetry were used to explore the interactions of receptors R1–R3 with anions and possible detection mechanisms. The synthesised probes could sense inorganic fluoride, acetate, dihydrogen phosphate, and arsenite in the organo–aqueous medium (H2O/ Dimethylsulphoxide, 1:?9, v/v) and displayed a change in colour detectable to the naked eye. Out of the three synthesised receptors, receptor R1 showed better sensing ability of fluoride, acetate, dihydrogen phosphate, and arsenite ions in the organo–aqueous medium with a lower detection limit of 0.1 ppm, 0.171 ppm, 0.194 ppm, and 0.144 ppm, respectively. All three receptors formed complexes with the anions through H-bonding interaction followed by deprotonation of the NH proton. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
Cocrystal of nutraceutical sinapic acid with Active Pharmaceutical Ingredients ethenzamide and 2-chloro-4-Nitrobenzoic acid: Equilibrium solubility and stability study
(Elsevier B.V., 2018) Nechipadappu, S.K.; Trivedi, D.R.
Sinapic acid (SNP) is a nutraceutical compound of hydroxybenzoic acid derivative which possesses anti-oxidant, anti-microbial, anti-inflammatory, anti-cancer, and anti-anxiety activity properties. In the present work, two cocrystals of SNP with two active drug ingredients such as Ethenzamide (ETZ) and 2-chloro-4-nitrobenzoic acid (CNB) are reported. Both the cocrystals were synthesized via simple solvent evaporation method and the crystal structures were characterized by Single Crystal X-ray Diffraction (SC-XRD) techniques. The cocrystals were formed via robust acid-amide heterosynthon and acid-acid homosynthon between SNP and drug molecules. Both the cocrystals were crystallized in monoclinic crystal system with P 21/c space group. The synthesized cocrystals were further characterized by DSC, PXRD, FT-IR, and 1H NMR techniques. The solubility study in purified distilled water and in 0.1 N HCl solution demonstrate that there was no increment in the solubility of drug molecules in the cocrystals in both purified water and in 0.1 N HCl solution. The synthesized cocrystal exhibited six months stability at ambient conditions (?25 °C, 60–65% RH). © 2018 Elsevier B.V.
Cocrystals of Ethenzamide: Study of Structural and Physicochemical Properties
(American Chemical Society service@acs.org, 2016) Hariprasad, V.M.; Nechipadappu, S.K.; Trivedi, D.R.
Pharmaceutical cocrystals of an analgesic drug ethenzamide (ETZ) with various coformers, namely, gallic acid (GA), 2-nitrobenzoic acid (2NB), 3-nitrobenzoic acid (3NB), 2,4-dinitrobenzoic acid (DNB), and 3-toluic acid (3TA) were synthesized by the solvent evaporation method. All the cocrystals were characterized by various analytical techniques, and the crystal structures were determined by the single-crystal X-ray diffraction method (SCXRD). SCXRD analysis revealed that all the synthesized cocrystals were formed through a robust supramolecular acid-amide heterosynthon except the ethenzamide/gallic acid cocrystal, where molecules interacted through O-H···O hydrogen bond involving -OH of gallic acid and oxygen of amide group of the ETZ molecule. The physicochemical properties such as stability, hygroscopicity, and solubility studies of the ETZ-GA cocrystal were evaluated. It was found that the ETZ-GA cocrystal has a higher solubility (2-fold) than that of the pure ETZ drug molecule. Hygroscopic study of the ETZ-GA cocrystal revealed that synthesized cocrystal was non-hygroscopic at ?75% RH conditions. The ETZ-GA cocrystal found to be stable for a time period of four months at ambient temperature. © 2016 American Chemical Society.
Colorimetric and fluorometric turn-on sensor for selective detection of fluoride ions: Sol-gel transition studies and theoretical insights
(Royal Society of Chemistry, 2018) Pangannaya, S.; Mohan, M.; Trivedi, D.R.
A new organic receptor R1 based on a naphthyl unit covalently linked to a long alkyl chain has been designed, synthesized and characterized by standard spectroscopic techniques. The colorimetric response of receptor R1 from colorless to a pale yellow color and blue fluorescence emission in the presence of F- ions revealed its selective sensing ability in the solution phase. UV-Vis titration, fluorescence titration and 1H NMR titration studies confirmed the formation of the R1-F- complex. Receptor R1 formed a stable gel in DMSO and was confirmed through the standard heating-and-cooling method. Addition of F- ions resulted in disruption of the gel forming a solution that exhibited blue fluorescence emission. The binding constant of the R1-F- complex was found to be of the order of 5.9 × 105 M-1. DFT studies revealed the formation of the receptor-anion complex agreeing well with the experimental results. The detection limit was calculated and found to be 0.8 ppm, implying the potential for application of receptor R1 in environmental applications. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Colorimetric anion sensors based on positional effect of nitro group for recognition of biologically relevant anions in organic and aqueous medium, insight real-life application and DFT studies
(Elsevier B.V., 2018) Singh, A.; Sahoo, S.K.; Trivedi, D.R.
A new six colorimetric receptors A1-A6 were designed and synthesized, characterized by typical common spectroscopic techniques like FT-IR, UV–Visible, 1H NMR, 13C NMR and ESI-MS. The receptor A1 and A2 exhibit a significant naked-eye response towards F? and AcO? ions in DMSO. Due to presences of the NO2 group at para and ortho position with extended ?-conjugation of naphthyl group carrying –OH as a binding site. Compared to receptor A2, A1 is extremely capable of detecting F? and AcO? ions present in the form of sodium salts in an aqueous medium. This is owed to the occurrence of –NO2 group at para position induced in increasing the acidity of –OH proton. Consequently, it easily gets deprotonated in aqueous media. The detection limit of receptor A1 was turned out to be 0.40 and 0.35 ppm for F? and AcO? ions which is beneath WHO permission level (1.0 ppm). Receptor A1 shows a solitary property of solvatochromism in different aprotic solvents in presence of AcO? ion. Receptor A1 depicts high selectivity towards AcO? ion in DMSO: HEPES buffer (9:1, v/v). Receptor A1 proved itself for real life application by detecting anion in solution and solid state. The binding mechanism of receptor A1 with AcO? and F? ions was monitored from 1HNMR titration and DFT study. © 2017 Elsevier B.V.
Colorimetric chemosensors for the detection of environment-polluting arsenite and cyanide
(wiley, 2023) K, K.; Nityananda Shetty, A.N.; Trivedi, D.R.
Due to the biotic and ecological implications of extremely deadly cyanide and arsenite ions, the design, manufacturing, and development of cyanide and arsenite chemosensors has been a particularly active study subject in recent decades. The main works on colorimetric/fluorimetric chemosensor sensing mechanisms and their application in cyanide and arsenite detection are summarized and highlighted. This book chapter categorizes cyanide sensors based on their structure, while arsenite sensors are segregated based on their detecting mechanism strategies. This chapter provides a detailed summary of current research in this field and will be valuable in creating and synthesizing novel cyanide and arsenite chemosensors. © 2024 WILEY-VCH GmbH. Published 2024 by WILEY-VCH GmbH. All rights reserved.
Colorimetric chemosensors for the selective detection of arsenite over arsenate anions in aqueous medium: Application in environmental water samples and DFT studies
(Elsevier B.V., 2023) K, K.; Nityananda Shetty, A.N.; Trivedi, D.R.
Novel organic receptors N3R1- N3R3 were developed for the selective colorimetric recognition of arsenite ions in the organo-aqueous media. In the 50% aq. acetonitrile media and 70% aq. DMSO media, receptors N3R2 and N3R3 showed specific sensitivity and selectivity towards arsenite anions over arsenate anions. Receptor N3R1 showed discriminating recognition of arsenite in the 40% aq. DMSO medium. All three receptors formed a 1:1 complex with arsenite and stable for a pH range of 6–12. The receptors N3R2 and N3R3 achieved a detection limit of 0.008 ppm (8 ppb) and 0.0246 ppm, respectively, for arsenite. Initial hydrogen bonding on binding with the arsenite followed by the deprotonation mechanism was well supported by the UV–Vis titration, 1H- NMR titration, electrochemical studies, and the DFT studies. Colorimetric test strips were fabricated using N3R1- N3R3 for the on-site detection of arsenite anion. The receptors are also employed for sensing arsenite ions in various environmental water samples with high accuracy. © 2023 Elsevier B.V.
Colorimetric differentiation of arsenite and arsenate anions using a bithiophene sensor with two binding sites: DFT studies and application in food and water samples
(Royal Society of Chemistry, 2024) K, K.; Nityananda Shetty, A.N.; Trivedi, D.R.
Chemosensor N7R1 with two acidic binding sites was synthesized, and the ability of the sensor to differentiate arsenite and arsenate in the organo-aqueous medium was evaluated using colorimetric sensing methods. N7R1 distinguished arsenite with a peacock blue color and arsenate with a pale green color in a DMSO/H2O (9 : 1, v/v) solvent mixture. The specific selectivity for arsenite was achieved in DMSO/H2O (7 : 3, v/v). The sensor demonstrated stability over a pH range of 5 to 12. The computed high binding constant of 9.3176 × 1011 M−2 and a lower detection limit of 11.48 ppb for arsenite exposed the chemosensor's higher potential for arsenite detection. The binding mechanism with a 1 : 2 binding process is confirmed using UV-Vis and 1H NMR titrations, electrochemical studies, mass spectral analysis and DFT calculations. Practical applications were demonstrated by utilizing test strips and molecular logic gates. Chemosensor N7R1 successfully detected arsenite in real water samples, as well as honey and milk samples. © 2024 The Royal Society of Chemistry.
Colorimetric receptors for naked eye detection of inorganic fluoride ion in aqueous media using ICT mechanism
(Royal Society of Chemistry, 2012) Kigga, M.; Nityananda Shetty, A.N.; Trivedi, D.R.
A new series of receptors were designed and synthesized based on benzohydrazide for the colorimetric detection of fluoride ion. The receptors L1 and L2 are highly selective towards fluoride ion over other anions. These receptors are able to detect inorganic fluoride such as NaF in aqueous solutions. The presence of two carbonyl groups in the receptor molecule makes the -NH proton highly acidic and hence these receptors are capable of competing with water molecules to bind fluoride ion. The receptors L1 and L2 showed a significant colour change from colourless to yellow in aqueous solutions of NaF with a ??max of 149 nm and 147 nm respectively. The mechanism involved in the colour change was deprotonation, formation of imidic acid intermediate followed by stabilization of complex through Intramolecular Charge Transfer (ICT). This was further confirmed by 1H NMR titrations where the formation of imidic acid was observed. The receptor L1 proved itself to be potentially useful for real-life applications by detecting fluoride ion quantitatively in sea water and commercially available mouth wash. © 2012 The Royal Society of Chemistry.