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Asadollah Farhadi Mohammad Ali Takassi Hamid Reza Memarian Mousa Soleymani 《Frontiers of Chemistry in China》2011,6(2):91-97
Density functional theory (DFT) calculations were carried out on some cyclohexane derivatives to investigate the deviation
atoms on the 1- and 4-positions of chair plane. The deviations of chair plane of two position in the cyclohexane derivatives
were calculated at the B3LYP/6-31 ++ G(d,p) level. Furthermore, we investigated the correlation between deviations of two
positions from chair plane on the chemical shift hydrogen atoms on the 4-position. 相似文献
63.
R. Hekmatshoar Y. Sh. Beheshtiha M. M. Heravi K. Asadollah 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):703-707
Protonation of the reactive 1:1 intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by substituted phenols lead to vinyl triphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with the phenolate conjugated base to produce coumarin derivatives. 相似文献
64.
Nano-CaO was prepared by calcination of ball-milled chicken eggshell waste. This novel, bioactive, heterogeneous catalyst, which had high catalytic activity and reusability, was used in the green synthesis of pyrano[4,3-b]pyrans via condensation of various aromatic aldehydes, malononitrile, and 4-hydroxy-6-methyl-2H-pyran-2-one at 120℃ under solvent-free conditions. The reaction proceeded to completion within 5-45 min in 93%-98% yield. The nano-CaO was fully characterized by scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, X-ray fluorescence spectroscopy, and thermal gravimetric, surface area, and elemental analyses. 相似文献
65.
Phosphorus pentoxide supported on silica gel or alumina (P2O5/SiO2, P2O5/Al2O3) has been used in many organic transformations as versatile solid catalysts. These catalysts have received considerable attention as an inexpensive, eco-friendly, highly reactive, easy to handle and non-toxic acid catalyst for various organic transformations, affording the corresponding products in excellent yields and high selectivity. In this review, some applications of these catalysts in organic reactions are discussed. 相似文献
66.
AbstractIn this paper, by the sub-super solution method we provide explicit lower bounds for the principal eigenvalue of the p-Laplacian on the unit ball. We compare our results with those of earlier studies and also demonstrate that they are in good agreement with numerical results. 相似文献
67.
Cu(II) Schiff base complex supported on Fe3O4 nanoparticles as an efficient nanocatalyst for the selective aerobic oxidation of alcohols 下载免费PDF全文
Herein, we have prepared a new Cu(II) Schiff base complex supported onto the surface of modified Fe3O4 nanoparticles as highly stable, heterogeneous and magnetically recyclable nanocatalyst for the selective aerobic oxidation of different alcohols. The structure, morphology, chemical composition and magnetic property of the nanocatalyst and its precursors were characterized using FT‐IR, TGA, AAS, ICP‐AES, XRD, SEM, EDS, VSM and N2 adsorption–desorption analyses. Characterization results exhibited the uniform spherical morphology for nanocatalyst and its precursors. A promising eco‐friendly method with short reaction time and high conversion and selectivity for oxidation of various primary and secondary alcohols under O2 atmosphere condition was achieved. The synthesized nanocatalyst could be recovered easily by applying an external magnetic field and reused for least eight subsequent reaction cycles with only negligible deterioration in catalytic performance. 相似文献
68.
Goudarz Mohseni Rouzbehani Asadollah Boshra Ahmad Seif 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):255-263
Abstract Density functional theory (DFT) calculations were performed to determine boron-11 and nitrogen-14 nuclear magnetic resonance
(NMR) and nuclear quadrupole resonance (NQR) spectroscopy parameters in the three most stable B24N24 fullerenes for the first time. The considered samples were first allowed to relax entirely, and then the NMR and NQR calculations
were performed on the geometrically optimized models. The calculations of the 11B and 14N nuclear magnetic shielding tensors and electric field gradient tensors employed the Gaussian 98 software implementation
of the gauge-including atomic orbital (GIAO) method using the Becke3, Lee-Yang-Parr (B3LYP) DFT level and 6-311G** and 6-311++G**
standard basis sets in each of the three optimized forms, and converted the results to experimentally measurable NMR parameters.The
calculated NMR chemical shieldings of the three cages show significant differences, providing a way to identify these clusters.
The evaluated NQR parameters of the 11B and 14N nuclei in the clusters are also reported and discussed.
Graphical abstract
相似文献
69.
Goudarz Mohseni Rouzbehani Asadollah Boshra Ahmad Seif 《Monatshefte für Chemie / Chemical Monthly》2009,83(13):255-263
Abstract
Density functional theory (DFT) calculations were performed to determine boron-11 and nitrogen-14 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) spectroscopy parameters in the three most stable B24N24 fullerenes for the first time. The considered samples were first allowed to relax entirely, and then the NMR and NQR calculations were performed on the geometrically optimized models. The calculations of the 11B and 14N nuclear magnetic shielding tensors and electric field gradient tensors employed the Gaussian 98 software implementation of the gauge-including atomic orbital (GIAO) method using the Becke3, Lee-Yang-Parr (B3LYP) DFT level and 6-311G** and 6-311++G** standard basis sets in each of the three optimized forms, and converted the results to experimentally measurable NMR parameters.The calculated NMR chemical shieldings of the three cages show significant differences, providing a way to identify these clusters. The evaluated NQR parameters of the 11B and 14N nuclei in the clusters are also reported and discussed. 相似文献70.