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271.
Kamlesh Kumari Prashant Singh Monica Dubey Narendra D. Pandey Ramesh Chandra Gopal K. Mehrotra 《Comptes Rendus Chimie》2012,15(4):267-272
Herein, we report a simple, convenient and catalyst free one-pot synthesis of chromenothiazolone analogues via multicomponent reaction between thiazolidine-2,4-dione, aromatic aldehyde and phenol. This reaction proceeded smoothly in good to excellent yields and offered several other advantages including short reaction time, simple experimental workup procedure and no byproduct. 相似文献
272.
Gadolinium (Gd) complexes of benzene (C(6)H(6)) and (1,3,5,7-cyclooctatetraene) (C(8)H(8)) were produced in a laser-vaporization supersonic molecular beam source and studied by single-photon pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy. Adiabatic ionization energies and metal-ligand stretching frequencies were measured for the first time from the ZEKE spectra. Metal-ligand bonding and electronic states of the neutral and cationic complexes were analyzed by combining the spectroscopic measurements with ab initio calculations. The ground states of Gd(C(6)H(6)) and [Gd(C(6)H(6))](+) were determined as (11)A(2) and (10)A(2), respectively, with C(6v) molecular symmetry. The ground states of Gd(C(8)H(8)) and [Gd(C(8)H(8))](+) were identified as (9)A(2) and (8)A(2), respectively, with C(8v) molecular symmetry. Although the metal-ligand bonding in Gd(C(6)H(6)) is dominated by the covalent interaction, the bonding in Gd(C(8)H(8)) is largely electrostatic. The bonding in the benzene complex is much weaker than that in the cyclooctatetraene species. The strong bonding in Gd(C(8)H(8)) arises from two-electron transfer from Gd to C(8)H(8), which creates a strong charge-charge interaction and converts the tub-shaped ligand into a planar form. In both systems, Gd 4f orbitals are localized and play little role in the bonding, but they contribute to the high electron spin multiplicities. 相似文献
273.
Ganai AK Kumari S Sharma KP Panda C Kumaraswamy G Gupta SS 《Chemical communications (Cambridge, England)》2012,48(43):5292-5294
We report a facile one-pot synthesis of hierarchically porous scaffolds, with independent control over nanoparticle mesoporosity and scaffold macroporosity. Our technique combines the chemistry of mesoporous silica nanoparticles with the control afforded by dynamic templating of surfactant mesophases. These materials are readily functionalizable and allow controllable spatial variation in macroporosity. 相似文献
274.
V. U. M. Rao M. Vijaya Santhi T. Vinutha G. Sree?Devi?Kumari 《International Journal of Theoretical Physics》2012,51(10):3303-3310
Bianchi type-I dark energy model with variable equation of state (EoS) parameter is presented in a scalar-tensor theory of gravitation proposed by Brans and Dicke (Phys. Rev. 124:925, 1961). To get a determinate solution of the field equations we will take the help of special law of variation for Hubble’s parameter presented by Bermann (Nuovo Cimento B. 74:182, 1983) which yields a dark energy cosmological model with negative constant deceleration parameter. It is observed that this dark energy cosmological model always represents an accelerated and expanding universe and also consistent with the recent observations of type-Ia supernovae. Some physical and geometrical properties of the model are also discussed. 相似文献
275.
S. Kumari L. K. Jha 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(4):87
Theoretical studies of electron impact double ionisation cross sections of Mg+ ions have been performed in the binary encounter approximation (BEA). Direct double ionisation has been investigated in the
modified double binary encounter model. Ionization cross sections of different shells have been also calculated in order to
analyse the contributions to double ionisation from ionisation-autoionization. The effect of the Coulombic field of the target
ion on the incident electron has been considered in the present work. Accurate expression of σ
ΔE
(cross-section for energy transfer ΔE) and Hartree-Fock velocity distributions for the target electrons have been used throughout the calculations. The theoretical
results show satisfactory agreement with the experimental observations. 相似文献
276.
277.
Photogalvanic effects were studied in photogalvanic cells containing sodium lauryl sulphate as surfactant, EDTA as reductant
and azur-B as photosensitizer. The photopotential and photocurrent generated were 814#x00B7;0 mV and 255·0 μA respectively.
The observed conversion efficiency was 1·2% and the maximum power of cell was 207·57 μW. The storage capacity of the cell
was 26#x00B7;0 min in dark. The effect of different parameters on electrical output of the cell was observed. A mechanism
has been proposed here for the generation of photocurrent in photogalvanic cells 相似文献
278.
Kumari Binita Sanjay Kumar Vinay Kumar Sharma Veena Sharma Savita Yadav 《Applied biochemistry and biotechnology》2014,172(4):2091-2105
Syzygium cumini is traditionally used medicinal plant. The different part of the plant such as bark, leaves, seed and fruits are widely used as an alternative medicine in various diseases. Although the scientific community has a strong interest on S. cumini seed biochemistry focusing on metabolite composition, proteins have not yet been investigated. In the present study, we have applied a proteomic approach to study the proteome of the S. cumini seed using phenol extraction method for protein isolation, which were never analysed before. Fifteen brightly silver stained protein spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry after resolving on two-dimensional gel electrophoresis. These proteins have been found to involve in various functions such as antifungal, sulphur metabolism, carbohydrate metabolism, fruit ripening and softening, dormancy breaking and seed germination, hormone signalling, secondary metabolite transport, defence and stress response, nitrogen metabolism, synthesis and stabilization. Amongst the identified protein, lactoferrin was a mammalian origin protein with high nutritious and pharmaceutical value, which was purified by different types of chromatographic techniques and confirmed by western blotting. The antibacterial activity of lactoferrin was assessed by disc diffusion assay. We suggest that the protein constituents of S. cumini may have role in various functions required for plant physiology and its dietary values. 相似文献
279.
Poonam Kumari Sumit Sood Anil Kumar Karan Singh 《Journal of heterocyclic chemistry》2020,57(2):796-804
The synthesis of 4-formylpyrazoles using Vilsmeier-Haack reagent is a common protocol in pyrazole chemistry. An efficient microwave-assisted synthesis of 4-formylpyrazoles by employing Vilsmeier-Haack reagent (OPC-VH) derived from phthaloyl dichloride/dimethylformamide has been described. This method offers the advantages of operational simplicity, avoiding the use of POCl3 as toxic reagents and reuse of the by-product in the preparation of phthaloyl dichloride. 相似文献
280.
Thermal Expansion,Anharmonicity and Temperature‐Dependent Raman Spectra of Single‐ and Few‐Layer MoSe2 and WSe2
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Dr. Dattatray J. Late Sharmila N. Shirodkar Prof. Umesh V. Waghmare Prof. Vinayak P. Dravid Prof. C. N. R. Rao 《Chemphyschem》2014,15(8):1592-1598
We report the temperature‐dependent Raman spectra of single‐ and few‐layer MoSe2 and WSe2 in the range 77–700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high‐resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A22u mode is larger than that of the A1g mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single‐layer MoS2 and of the G band of graphene. The temperature coefficients of the two modes in single‐layer MoSe2 are larger than those of the same modes in single‐layer WSe2. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS2 and MoSe2 within a quasi‐harmonic approximation, with inputs from first‐principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman‐active mode A1g in MoS2 and MoSe2 arises essentially from the difference in their strain–phonon coupling. 相似文献