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Krishnakumar V.,Periyar University | Sangeetha R.,Nehru Memorial College | Mathammal R.,Salem College | Barathi D.,Nkr Government Arts College W
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

This work deals with the vibrational spectra of 2-fluoro 5-nitrotoluene and 2-bromo 5-nitrotoluene by quantum chemical calculations. The solid phase FTIR and FT-Raman spectra of the title compounds were recorded in the regions 4000-400 cm-1 and 4000-50 cm-1 respectively. The spectra were interpreted with the aid of normal co-ordinate analysis based on density functional theory (DFT) using standard B3LYP/6-31G* basis set for the most optimized geometry. The vibrational frequencies are calculated and scaled values are compared with experimental FTIR and FT-Raman spectra. The scaled theoretical wave numbers showed very good agreement with the experimental ones. The complete vibrational assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. 13C and 1H NMR chemical shifts results are compared with the experimental values. © 2012 Elsevier B.V. All rights reserved. Source


Krishna Kumar V.,Periyar University | Suganya S.,Nkr Government Arts College W | Mathammal R.,Salem College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

This work deals with the vibrational spectra of 2,3,4,5,6-Penta Bromo Toluene (PBT) and Bromo Durene (BD) by quantum chemical calculations. The solid phase FTIR and FT-Raman spectra of the title compounds were recorded in the regions 4000-400 cm-1 and 4000-50 cm- 1, respectively. The spectra were interpreted with the aid of normal coordinate analysis based on density functional theory (DFT) using B3LYP/6-31Gâ̂ - level and basis set combinations and was scaled using various scale factors yielding a good agreement between observed and calculated frequencies. The infrared and Raman spectra were also predicted from the calculated intensities. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes. The HOMO and LUMO energies were calculated within the molecule. 13C and 1H NMR chemical shifts results were also calculated and compared with the experimental values. Thermodynamical properties like entropy heat capacity, zero point energy have been calculated for the title molecules. © 2013 Elsevier B.V. All rights reserved. Source


Valarmathi M.,Nkr Government Arts College W | Gomathi A.,Sri Kgs Arts College | Manisankar P.,Alagappa University
Advanced Materials Research | Year: 2013

Two reactive azo dyes Reactive yellow 84 (RY84) and Reactive Red 120 (RR120) were investigated voltammetrically using plain glassy carbon electrode (GCE) and multiwalled carbon nanotube modified GCE (MWCNT/GCE). Influence of pH, scan rate and concentration on voltammograms were studied. The irreversible oxidation process observed for both dyes was adsorption controlled. The surface characterization of the modified electrode in the absence and presence of dyes was done using scanning electron microscopy (SEM). A systematic study of the experimental parameters that affects differential pulse stripping voltammetry (DPSV) was carried out and the optimized experimental conditions were arrived. Under optimized conditions, stripping voltammetry procedure was developed for the determination of reactive dyes. MWCNT/GCE seems to present better responses than plain GCE and the limit of detection (LOD) was 0.6 μg mL-1 for RY84 and 0.3μg mL-1 for RR120 on this modified system. Suitability of the differential pulse stripping voltammetric method using the developed Multiwalled carbon nanotube based sensor, for the trace determination of these textile dyes in real samples was also realized. © (2013) Trans Tech Publications, Switzerland. Source


Krishnakumar V.,Periyar University | Barathi D.,Nkr Government Arts College W | Mathammal R.,Salem College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

The vibrational spectra of 1,2-dichloro-4-nitrobenzene (DCNB) and 2,3,5,6-tetrachloro-1-nitrobenzene (TCNB) were computed using B3LYP methodology with 6-31G* basis set. The solid phase FTIR and FT-Raman spectra were recorded in the region 4000-400 cm -1 and 4000-50 cm -1, respectively. A similarity was achieved between the observed and calculated frequencies by refinement of the scale factors. The HOMO and LUMO energies were calculated. 13C and 1H NMR chemical shifts results were also compared with the experimental values. © 2011 Elsevier B.V. All rights reserved. Source


Glorybai L.,Nkr Government Arts College W | Kannan K B.,Loyola College | Arasu M.V.,King Saud University | Al-Dhabi N.A.,King Saud University | Agastian P.,Loyola College
Annals of Clinical Microbiology and Antimicrobials | Year: 2015

Background: Novel chemical molecules recovered from endangered medicinal plants have wide applications and have the potential to cure different diseases caused by microorganisms. The aim of this study was to investigate In vitro antimicrobial, α-glucosidase inhibition and antioxidant activity of different solvent extracts of Epaltes divaricata L. Methods: Antimicrobial activity of hexane, ethyl acetate and methanol extract of Epaltes divaricata was determined against bacteria and fungi using disc diffusion and microdilution method respectively. α-glucosidase inhibition, Total phenolic content (TPC), Reducing power activity, DPPH radical scavenging assay, hydroxyl radical scavenging activity, nitric oxide scavenging activity, superoxide scavenging activity and lipid peroxidation assay of plant extracts were performed according to standard protocol. Compound detection from the potential solvent extract was done through GC-MS analysis. Results: Epaltes divaricata ethyl acetate extracts (EDEa) (1.25 mg/disc) showed significant inhibition for E. lentum (23 mm), E. aerogenes (18 mm), P. fluorescence (15 mm) and A. baumanii (15 mm). Minimum inhibitory concentration (MIC) of EDEa was found to be 31.25 μg/ml, 62.5 μg/ml and 62.5 μg/ml against A. flavus, A. niger and T. rubrum respectively. EDEa showed more α-glucosidase inhibition and antioxidant activity compared to hexane and methanol. EDEa showed 50% α-glucosidase inhibition at the concentration of 525.20 ± 2.37 μg/ml. The TPC of EDEa was 412.0 ± 2.21 mg of catechol equivalents/g extract. EDEa showed great scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC50 560 ± 2.02 μg/ml), hydroxyl (IC50 314.75 ± 2.56 μg/ml), nitric oxide (IC50 648.20 ± 2.09 μg/ml) and superoxide (IC50 361.14 ± 1.45 μg/ml) radicals, as well as high reducing power. EDEa also showed a more suppressive effect on lipid peroxidation. Using Antioxidant β-carotene linoleate method, the scavenging values of EDEa was significantly lower than BHT. GC-MS analysis of EDEa showed maximum amount of 2-butenamide, N-(4-fluorophenyl)-3-methyl trans-cinnamyl tiglate silane and trichlorocyclohexyl silane (36.86%). Conclusion: The results obtained in this study clearly indicate that EDEa can be used as a natural antimicrobial, α-glucosidase inhibition and antioxidant agent. © Glorybai et al.; licensee BioMed Central. Source

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