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389 results on '"Karvembu, R."'

51. Electrochemical sensing of doxepin using acylthiourea-modified glassy carbon electrode.

Author

Kalaiyarasi, A., Bhuvanesh, N. S. P., Karvembu, R., and Biju, V. M.

Subjects
CARBON electrodes, DOXEPIN, BENZOIC acid, BLOOD plasma, MOLECULAR structure, MOLECULES, BENZOYL compounds
Abstract

Acylthiourea (ATU) compounds 4-(3-(furan-2-carbonyl)thioureido)benzoic acid (1), 4-(3-(thiophene-2-carbonyl)thioureido)benzoic acid (2), and 4-(3-(benzoyl)thioureido)benzoic acid (3) were synthesized and characterized by NMR (1H and 13C), FT-IR, UV–Vis and mass spectrometry. The molecular structures of compounds 1 and 2 were confirmed by single crystal X-ray diffraction studies. An electrochemical method employing Nafion (Nf)–ATU (1–3)–multi-walled carbon nanotubes (MWCNTs)-modified glassy carbon (GC) electrode (Nf/ATU/MWCNTs/GC) has been developed for the determination of DHCl. Electrochemical studies were carried out in phosphate buffer by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). DHCl was detected at 1.1 V vs Ag/AgCl (3 M KCl). The proposed sensor for the determination of DHCl was investigated with three acylthiourea derivatives (1, 2, and 3) under optimized experimental conditions using blood plasma samples. The lowest detection limit toward DHCl was 0.09 mM. [ABSTRACT FROM AUTHOR]

Published
2022
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78. Hydrothermal synthesis and characterization of ruthenium oxide nanosheets using polymer additive for supercapacitor applications.

Author

Vijayabala, V., Senthilkumar, N., Nehru, K., and Karvembu, R.

Subjects
RUTHENIUM oxides, X-ray diffraction, POLYMERS, TRANSITION metal oxides, MACROMOLECULES
Abstract

In the present work, Ruthenium oxide (RuO) nanosheets were prepared by simple hydrothermal synthesis route in the presence and absence of PEG as surfactant. The synthesized RuO nanosheets act as electrode material and it was subjected to various physico-chemical properties to analyze the material suitability for the supercapacitor applications. The cubic structure, crystalline nature and purity of the material were confirmed by powder X-ray diffraction studies. The FTIR analysis confirms the presence of various functional groups in the RuO nanosheets. The optical absorbance wavelength was observed at 411 and 416 nm in the absence and presence of PEG surfactant. The shifting of wavelength reduces the energy band gap from bulk state of 2.45-2.26 eV due to the quantum confinement effect. The shape and surface morphology of the RuO nanosheets were determined by using FE-SEM analysis. The zeta potential analysis reveals the stability of the synthesized RuO nanosheets. The electrochemical properties of modified electrode RuO were investigated using various process such as cyclic voltammetry, specific capacitance, galvanostatic charge-discharge and electrochemical impedance spectroscopy in electrochemical workstation. Based on the electrochemical properties, the electrode material reveals the ideal capacitance behavior with high capacitance of 600 F/g at the sweep rate of 5 mV/s in 3 M KCL aqueous electrolyte solution. The remarkable electrochemical performance proves RuO as the promising material for storage applications. [ABSTRACT FROM AUTHOR]

Published
2018
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81. Antibacterial Activities of 4-Substituted-2-[(E)-{(1S,2R)/(1R,2S)-1-Hydroxy-1-Phenylpropan-2-Ylimino}Methyl]Phenol

Author

Tamizh, M.M., Kesavan, D., Sivakumar, P.M., Mereiter, K., Deepa, M., Kirchner, K., Doble, M., and Karvembu, R.

Subjects
Staphylococcus aureus, Phenylpropanolamine, Molecular Conformation, Microbial Sensitivity Tests, Crystallography, X-Ray, Schiff base, antibacterial activity, Phenols, Escherichia coli, Proteus vulgaris, controlled study, infrared spectroscopy, Schiff Bases, hydrogen bond, nonhuman, norephedrine, Bacteria, Hydrogen Bonding, Stereoisomerism, X ray crystallography, dilution, Anti-Bacterial Agents, antiinfective agent, priority journal, chemical structure, Bacillus subtilis
Abstract

A series of norephedrine-based Schiff bases (1a-6a and 1b-6b) were synthesized by reacting substituted salicylaldehydes with d-norephedrine or l-norephedrine. The structure of these compounds was confirmed by elemental analyses and spectroscopic techniques. The molecular structures of 5a and 6a have been determined by X-ray crystallography, which revealed that the compounds are in the oxoamino form, with bent intramolecular N-H���O (N���O?2.58�) hydrogen bonds and that they are associated in dimers bridged by linear intermolecular O-H���O (O���O?2.69�) hydrogen bonds. The density functional theory calculations on 5a confirmed that the oxoamino form is more stable than the phenolimino form by 12.2kcal/mol. All the compounds were evaluated for their antibacterial activity using resazurin dye as indicator by twofold dilution method against four bacteria namely, Bacillus subtilis (NCIM2718), Staphylococcus aureus (NCIM5021), Escherichia coli (NCIM2931), and Proteus vulgaris (NCIM2813). � 2011 John Wiley & Sons A/S.

Published
2012
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