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This work reports simple, highly efficient protocol for the oxidation of arylboronic acids. Various arylboronic acids were selectively and completely converted into their corresponding oxidized phenols using H2O2 as an oxidant in presence of catalytic amount of silica chloride. The results show that silica chloride is a suitable and efficient promoter for the oxidation of arylboronic acids. Heterogeneous catalyst, mild reaction conditions, easy availability of the reagent, easy work-up, excellent yield of corresponding phenols, short reaction time and broad substrate scope makes this protocol attractive and a practical alternative to the existing methods. 相似文献
43.
Shriwas S. Ashtaputre Aparna Deshpande Sonali Marathe M. E. Wankhede Jayashree Chimanpure Renu Pasricha J. Urban S. K. Haram S. W. Gosavi S. K. Kulkarni 《Pramana》2005,65(4):615-620
Zinc oxide and cadmium selenide particles in the nanometer size regime have been synthesized using chemical routes. The particles
were capped using thioglycerol in case of ZnO and 2-mercaptoethanol in case of CdSe to achieve the stability and avoid the
coalescence. Zinc oxide nanoparticles were doped with europium to study their optical properties. A variety of techniques
like UV-Vis absorption spectroscopy, X-ray diffraction (XRD), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS),
Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) were used to carry out structural
and spectroscopic characterizations of the nanoparticles. 相似文献
44.
Identification of effective substrates for the direct analysis of lipids from cell lines using desorption electrospray ionization mass spectrometry 下载免费PDF全文
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S. Samundeeswari M.V. Kulkarni Jayashree Yenagi J. Tonannavar 《Journal of fluorescence》2017,27(4):1247-1255
Electronic absorption and emission spectra of 3-acetyl coumarin, 3-(bromoacetyl) coumarin and 3-(di bromoacetyl) coumarin have been recorded at room temperature in thirteen solvents with different polarities. Both ground and excited state dipole moments have been calculated for both locally excited and charge transfer transitions by using the solvatochromic method. Excited state dipole moments of all the three compounds are higher than their ground state values. DFT calculations have been profound to estimate their ground and excited state dipole moments. The estimated change in dipole moment by the application of microscopic solvent polarity parameter and bulk solvent polarity methods are in close agreement. Concentration dependent dual fluorescence has been observed in the emission spectra of all the three compounds. 相似文献
46.
Hiremath CS Yenagi J Tonannavar J 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(3):710-717
Fourier-transform laser Raman (3500-50 cm(-1)) and infrared (4000-400 cm(-1)) spectral measurements have been made for the solid 3-chloro-4-methoxybenzaldehyde. The electronic structure calculations -ab initio (RHF) and hybrid density functional methods (B3LYP and B3PW91) -- have been performed with 6-31G* and 6-311G* basis sets. Molecular electronic energies, equilibrium geometries, IR and Raman spectra have been computed. Potential energy distribution (PEDs) and normal mode analysis have also been performed. A complete assignment of the observed spectra has been proposed. Investigation of the relative orientation of the aldehydic oxygen and chlorine atom with respect to the methoxy group has shown that two forms, O-cis and O-trans exist, with O-trans form being more stable. The energy difference between O-cis and O-trans forms is 0.057 kcal/mol (21 cm(-1)) with B3LYP/6-31G*, which is less than the calculated torsional vibrational frequencies of the aldehyde and methoxy group. In the CH (O) aldehydic stretching region five observed bands are probably due to multiplet Fermi resonance. An infrared doublet near 1700 cm(-1) with nearly equal intensities has been ascribed to the Fermi resonance: the two bands at 1696 and 1679 cm(-1) arise due to the interaction between the CO stretching fundamental and a combination of O-CH(3) and CC stretching vibrations. 相似文献
47.
A. Jayashree B. Narayana Gauthama B. Uppine Vivek M. Ghate Shaila A. Lewis Bharathi Prakash Sarojini B. Kunhanna Madan S. Kumar 《Journal of heterocyclic chemistry》2019,56(9):2398-2410
A new series of novel highly substituted imidazole and imidazole bi‐heterocycles have been synthesized via atom economic, one‐pot condensation reaction using benzil, substituted benzaldehydes, various amine scaffolds, and ammonium acetate using ZnO nanoparticles as effective catalyst. Simple operation, cheap catalyst, good to excellent yield, etc, are some of the advantages of this protocol. The characterization of the synthesized imidazole analogues was performed by Fourier transform infrared, nuclear magnetic resonance (1H and 13C), mass analysis, and elemental analysis. The structures were unequivocally confirmed by single‐crystal X‐ray diffraction analysis. Synthesized compounds were tested for antibacterial activities by resazurin reduction assay. All compounds tested showed significant activity against bacteria. Among the 24 compounds tested, compounds 1c , 1i , 2c , 2g , and 3a proved to be more active against the bacterial strain tested. 相似文献
48.
Hiremath CS Yenagi J Tonannavar J Sundius T 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,77(5):918-926
FT-IR (4000-400 cm(-1)) and FT-Raman (3500-50 cm(-1)) spectral measurements of solid sample of 2-chloro-5-bromopyridine have been done. Ab initio and DFT calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies, depolarization ratios, IR intensities, Raman activities and atomic displacements. Furthermore, force field calculations have been performed by normal coordinate analysis. A complete assignment of the observed spectra, based on spectral correlations, electronic structure calculations and normal coordinate analysis, has been proposed. The results of the calculations have been used to simulate IR and Raman spectra for the molecule that showed good agreement with the observed spectra. The SQM method, which implies multiple scaling of the DFT force fields, has been shown superior to the uniform scaling approach. The energy and oscillator strength calculated by Time-dependent DFT results are in good agreement with the experimental results. 相似文献
49.
Jayashree Biswal S.P. Ramnani R. Tewari G.K. Dey S. Sabharwal 《Radiation Physics and Chemistry》2010,79(4):441-445
The synthesis of short aspect ratio gold nanorods using gamma radiation method by incorporating cetyltrimethyl ammonium bromide (CTAB) as a directing agent is reported in this communication. The radiolysis of Au+, in the presence of 2.5 nm Au seeds and 0.1 mol dm?3 isopropanol, results in the formation of Au spheres as evident from surface plasmon resonance band at 527 nm. However, by carrying out radiolysis at lower radiation dose rate, short aspect gold nanorods having surface plasmon bands at 513 and 670 nm have been prepared. The formation of rods at low radiation dose rate was observed to be governed by the kinetics of particle growth. The TEM of as-synthesized nanoparticles confirmed the formation of uniform sized nanorods having an aspect of 2.4. 相似文献
50.
R. H. Fitri Faradilla George Lee Aditya Rawal Try Hutomo Martina H. Stenzel Jayashree Arcot 《Cellulose (London, England)》2016,23(5):3023-3037
Many tonnes of agricultural wastes are generated annually, which contains a relatively high amount of cellulose; banana pseudo-stem is one waste type that is a promising material for nanocellulose production. This research characterised nanocellulose from inner and outer layers of banana pseudo-stem as a preliminary research strategy for designing biodegradable packaging material from banana pseudo-stem nanocellulose. Nanocellulose was successfully prepared through TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl)-mediated oxidation. The extracted nanocellulose from both the inner and outer layers had observed widths of approximately 7–35 nm and long fibrillated fibre. They had high negative zeta potential (lower than ?33.6) that provided good colloidal stability. The purity of the nanocellulose was high as demonstrated by 13C solid-state NMR and Fourier transform infrared spectroscopy. Nanocellulose from both layers was significantly more crystalline than the raw materials. Thermal stability of nanocellulose sourced from inner and outer layers was relatively similar, with degradation temperature of approximately 220 °C, which was slightly lower than the degradation temperature of its native form (232 °C for inner layer and 261 °C for outer layer). 相似文献