Entity

Time filter

Source Type

Dharwad, India

Tonannavar J.,Karnatak University | Prasannakumar S.,Kittel Science College | Savanur J.,Karnatak University | Yenagi J.,Karnatak University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

Vibrational spectra of 2-methyl-3-nitrophenyl isocyanate and 4-methyl-2-nitrophenyl isocyanate, in the spectral region 4000-100 cm -1, have been measured and assigned. Conformational and harmonic frequency analyses have been performed at B3LYP/6-311G level of calculations. The two stable conformers, cis and trans, have been computed for each of the molecules. It has been determined that the trans conformer has lower energy than the cis by 3.954 kJ/mol for 2-methyl-3-nitrophenyl isocyanate; whereas the cis conformer has lower energy than the trans by 10.230 kJ/mol for 4-methyl-2-nitrophenyl isocyanate. The vibration structure of 2-methyl-3-nitrophenyl isocyanate conforms to the combined behavior of its both conformers from which the deviation is shown by the structure of 4-methyl-2-nitrophenyl isocyanate which follows only the trans conformer. The occurrence of symmetric mode of the methyl group at higher frequency near 2944-20 cm -1 is attributed to the phenyl ring strain caused by the substituents. As for the other stretching and bending modes, mutually exclusive pattern appears to work for the molecules: The nitro group's non-coplanarity with the phenyl ring is more evident in 4-methyl-2-nitrophenyl isocyanate where the asymmetric mode was assigned to the band at 1569 cm -1, whereas the symmetric mode at lower frequency 1339 cm -1. Occasional doublet appearance of the strong asymmetric absorption near 2282 cm -1 due to isocyanate moiety has been observed in the present study and is assumed to arise from the torsional vibration motion of the moiety rendered by the small energy gap between the conformers of 2-methyl-3-nitrophenyl isocyanate. © 2012 Elsevier B.V. All rights reserved. Source


Yenagi J.,Karnatak University | Arlikatti N.V.,Kittel Science College | Tonannavar J.,Karnatak University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

Ab initio conformers and dimers have been computed at RHF and B3LYP/6-31G* levels for isomers 2-chloro-3-hydroxybenzaldehyde and 3-chloro-4-hydroxybenzaldehyde to explain the observed infrared absorption and Raman vibrational spectral features in the region 3500-50 cm-1. The position of the chlorine in ortho position with respect to aldehyde group in 2-chloro-3-hydroxybenzaldehyde yields four distinct conformers; whereas the chlorine in meta position in 3-chloro-4-hydroxybenzaldehyde yields effectively only three conformers. Major spectral features as strong absorptions near 3160-80 cm-1, down-shifting of the aldehydic carbonyl stretching mode and up-shifting of hydroxyl group's in-plane bending mode are explained using ab initio evidence of O-H⋯O bond-aided dimerization between the most stable conformers of each molecule. Absorption width of about 700 cm -1 (∼8.28 kJ/mol) of O-H stretching modes suggests a strong hydrogen bonding with the ab initio bond lengths, O-H⋯O in the range of 2.873-2.832 . A strong Raman mode near 110-85 cm-1 in each molecule is interpreted to be coupled vibrations of pseudo-dimeric trans and cis structures. © 2010 Elsevier B.V. All rights reserved. Source


Sandigawad A.M.,Kittel Science College
International Journal of Pharma and Bio Sciences | Year: 2015

Lonicera japonica (Honeysuckle) is one of the oldest medicinal herbs in known history. Lonicera japonica is an ingredient of herbal tea and has been known thousands of years for its cooling and detoxification effects. According to the Natural Medicines Comprehensive Database, Lonicera japonica is taken orally for digestive disorders, enteritis, dysentery, urinary disorders, diabetes, rheumatoid arthritis, malignant tumours etc. In the present study ethanolic extract was obtained from leaves and flowers of Lonicera japonica and phytochemical analysis was done to screen alkaloids, phenols terpenoids and flavonoids. Antibacterial activity was carried out by using bacterial strains Staphylococcus aureus MTCC 3160, Bacillus subtilis MTCC 736, Vibrio cholerae MTCC 3906, and Salmonella typhi MTCC 3220.Extracts of leaf and flower in various dilutions were found to have antibacterial activity against tested organisms. Chloroform and Ethanol leaf extracts of Lonicera japonica has shown high degree of inhibition (DIZ-22mm and 22 mm) against test organisms. It is found that there was no antibacterial activity exhibited by some concentration. Ethanol and Methanol flower extracts of Lonicera japonica has shown high degree of inhibition (DIZ 21mm-23mm) against the test organisms and our results supported the usage of Lonicera japonica in traditional medicine. Source


Harihar A.L.,Kittel Science College | Dodamani G.R.,Kittel Science College
Oxidation Communications | Year: 2013

The reaction between periodate and guanidine hydrochloride in alkaline medium has a stoichiometry of 2:1 with first order dependence each on [periodate] and [osmium(VIII)] and fractional order in [OH-], while zero order dependence on [guanidine hydrochloride]. No effect of added products, ionic strength and dielectric constant has been observed. Investigation at different temperatures allowed the determination of the activation parameters with respect to slow step of the proposed mechanism. The observed kinetic data were compared with uncatalysed reaction. Entirely different observation obtained is discussed with respect to kinetic result and activation parameters. Source

Discover hidden collaborations