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Study of EPR, optical properties and electrical conductivity of vanadyl doped Bi2O3.PbO.B2O3 glasses
Gahlot PS Agarwal A Seth VP Sanghi S Gupta SK Arora M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(6):1189-1194
Heavy metal based oxide glasses having composition xBi(2)O(3).(0.30 - x)PbO.0.70B(2)O(3) have been prepared (0.00 < or = x < or = 0.15, mol%) containing 2.0mol% of V(2)O(5) by normal melt-quenching technique. Electron paramagnetic resonance (EPR), optical spectra and dc conductivity of these glasses have been studied. Spin Hamiltonian parameters (SHP) of VO(2+) ions, dipolar hyperfine parameter, P and Fermi contact interaction parameter, K, molecular orbital coefficients (alpha(2) and gamma(2)) and optical band gap have been calculated. It is observed that in these glasses, the tetragonal nature of V(4+)O(6) complex increases with Bi(2)O(3) content. Increase in Bi(2)O(3):PbO ratio results in the contraction of 3d(xy) orbit of the unpaired electron in the vanadium ion, and the SHP are dependent on the theoretical optical basicity, Lambda(th). In present glasses, the conductivity (activation energy) first decreases (increases) with increase in mol% of Bi(2)O(3) content upto x = 0.08 and then shows a maxima (minima) at x = 0.10 and then starts decreasing (increasing) upto x < or = 0.15 with mol% of Bi(2)O(3) content. 相似文献
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Sweta Sharma 《光谱学快报》2013,46(8):520-528
ABSTRACTThe present paper deals with the investigation of the changes in chemical contents of the leaf of wheat seedling stressed by excess manganese using attenuated total reflectance Fourier transform infrared spectroscopy (FTIR) technique. The infrared spectra of the leaves of control and manganese-treated wheat plants have been recorded in the spectral region 485–4000?cm?1 at a resolution of 4?cm?1. The recorded spectrum has been analyzed with the help of curve-fitting method for the quantitative estimation of chemical contents and conformational changes. The study indicated changes arising in the polysaccharide, lignin, amino acid, secondary structure of protein, and lipid in the leaves of control and manganese-treated wheat plants. Manganese treatment increased the amount of cellulose, lignin, and amide II till 200?μM concentration, while a decrease was observed at 1000?µM concentration. Manganese induced conformational changes in the secondary structure of protein which was indicated by shifting of the bands to the higher wavenumber and change in the β sheet/α helix ratio. In addition, manganese stress decreased lipid content in the leaves of the wheat seedlings. The study demonstrates the potential of attenuated total reflectance FTIR for the non-invasive and rapid monitoring of the plants stressed with heavy metals. 相似文献
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Kumar VG Gokavarapu SD Rajeswari A Dhas TS Karthick V Kapadia Z Shrestha T Barathy IA Roy A Sinha S 《Colloids and surfaces. B, Biointerfaces》2011,87(1):159-163
A simple biological method for the synthesis of gold nanoparticles (AuNPs) using Cassia auriculata aqueous leaf extract has been carried out in the present study. The reduction of auric chloride led to the formation of AuNPs within 10 min at room temperature (28°C), suggesting a higher reaction rate than chemical methods involved in the synthesis. The size, shape and elemental analysis were carried out using X-ray diffraction, TEM, SEM-EDAX, FT-IR and visible absorption spectroscopy. Stable, triangular and spherical crystalline AuNPs with well-defined dimensions of average size of 15-25 nm were synthesized using C. auriculata. Effect of pH was also studied to check the stability of AuNPs. The main aim of the investigation is to synthesize AuNPs using antidiabetic potent medicinal plant. The stabilizing and reducing molecules of nanoparticles may promote anti-hyperglycemic if tested further. 相似文献
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Glasses with composition xGeO2.(0.30−x)M2O.0.70B2O3 (M=Li, K) containing 2.0 mol% of V2O5 have been prepared in the range 0.00≤x≤0.15 by normal melt quenching method. Electron paramagnetic resonance (EPR), optical transmission and absorption spectra and dc conductivity of these glasses have been studied. Spin Hamiltonian parameters (SHPs) of VO2+ ions, dipolar hyperfine coupling parameter, P, Fermi contact interaction parameter, K and molecular orbital coefficients (α2 and γ2) have been calculated. In GeO2·Li2O·B2O3 glasses there is no change in the tetragonality of the V4+O6 complex and the size of 3dxy orbit also remains unchanged with increase in GeO2 content. In GeO2·K2O·B2O3 glasses, there is an increase in the tetragonality of the V4+O6 complex and the 3dxy orbit expands with increase in GeO2 content. Values of the theoretical optical basicity, Λth, have also been reported. Optical band gap decreases with increase in GeO2 content. The dc conductivity of these glasses decreases and the activation energy increases with increase in GeO2:M2O ratio. 相似文献
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Sweta Misra Shailja Misra-Bhattacharya Ray J. Butcher Diksha Katiyar 《Tetrahedron: Asymmetry》2017,28(5):734-743
The resolution of racemic coumarinyl amino alcohols 5–10 was achieved by using the inexpensive and readily accessible chiral resolving agent N-carbethoxy-l-proline (S)-11. Direct esterification of rac-5–10 with (S)-11 furnished diastereomeric esters, which were easily separated by column chromatography. The obtained diastereomers yielded the desired enantiopure coumarinyl amino alcohols (S)-(+)-5–10 and (R)-(?)-5–10 in good yields with high enantiomeric excess on saponification. The absolute configurations were determined by X-ray crystal analysis and/or by comparison of the specific rotations. Furthermore, in in vitro antifilarial motility inhibition assays, enantiopure coumarins (S)-(+)-9, (R)-(?)-9 and (S)-(+)-10, (R)-(?)-10 were found to be less efficient in affecting the viability of macrofilariae of Brugia malayi than their racemic forms 9 and 10, respectively, indicating the synergistic effect of the enantiomers in evoking antifilarial action. 相似文献
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Mehta VP Sharma Ak Modha SG Sharma S Meganathan T Parmar VS Van der Eycken E 《The Journal of organic chemistry》2011,76(8):2920-2925
The N-heterocyclic carbene catalyzed chemoselective C3-aroylation of 3,5-dichloro-2(1H)-pyrazinones with various aldehydes is reported. We herein describe results of this remarkable mild and efficient procedure. 相似文献
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Graphite oxide and graphene oxides have been used as solid catalysts for the synthesis of 5,5-dialkyldipyrromethanes and calix[4]pyrroles in organic and aqueous solutions at room temperature. 相似文献
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Glasses with composition xBi2O3 ·(0.30 - x)BaO · 0.70B2O3 have been prepared in the range (0.00 ≤ x ≤ 0.15) containing 2.0 mol% of V2O5. Electron paramagnetic resonance (EPR), optical transmission and absorption spectra and DC conductivity of these glasses have been studied. The spin Hamiltonian parameters (SHP) of VO2+ ions, dipolar hyperfine coupling parameter P, Fermi contact interaction parameter K, and molecular orbital coefficients (α2 and γ2) have been calculated. The SHP arc related with the theoretical optical basicity. Ath. The position of the absorption edge and the values of the optical band gap have also been reported. The effect of addition of Bi2O3 on the DC conductivity has also been studied. 相似文献