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The standard enthalpy of formation, δfHo, of2 II CH has been determined at converged levels of ab initio electronic structure theory, including high order coupled cluster and full configuration interaction benchmarks. The atomic Gaussian basis sets employed include the (aug)-cc-p(C)VXZ family with X = 3, 4, 5 and 6. Extrapolations to the complete one-particle basis set and the full configuration interaction limits, where appropriate, have been performed to reduce remaining computational errors. Additional improvements in the enthalpy of formation of 2II CH were achieved by appending the valence-only treatment with core-valence correlation, relativistic effects including spin-orbit correlation, and the diagonal Born-Oppenheimer correction. The recommended values for δfHo 0 and δAf H o 298 of 2II CH are 592.48+0.47 ?0.56 kJ mol?1 and 595.93 +0.47 ?0.56 kJ mol?1, respectively. 相似文献
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Ramesh Balaboina Narasimha Swamy Thirukovela Ravinder Vadde Chandra Sekhar Vasam 《Tetrahedron letters》2019,60(12):847-851
We present a base free method for amide bond construction via oxidative coupling of alcohols with amines catalyzed by Silver(I) N-heterocyclic carbenes (Ag(I)-NHCs) and mediated by tert-butyl hydroperoxide (TBHP) in ethanol. The results of controlled experiments suggest that the oxidative coupling proceeds through the formation of aldehyde, then subsequent attack by amine to give hemiaminal, which can then be oxidized to amide. 相似文献
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Lin JC Tang SS Vasam CS You WC Ho TW Huang CH Sun BJ Huang CY Lee CS Hwang WS Chang AH Lin IJ 《Inorganic chemistry》2008,47(7):2543-2551
Ionic gold(I) complexes with general formula of [Au(Py)2][AuCl2] and [Au(Py)2][PF6] (Py = 4-substituted pyridines) have been synthesized. Structures of five Au(I) complexes and a Ag(I) complex were determined by single crystal X-ray diffraction. Evidence for cationic aggregation of [Au(py)2][PF6] complexes in solution was obtained by conductivity measurements and by the isosbestic point observed from variable temperature UV-visible absorption spectra. All compounds were luminous in the solid state. Calculations employing density functional theory were performed to shed light on the nature of the electronic transitions. While the [Au(4-dmapy)2][AuCl2] (4-dmapy = 4-dimethylaminopyridine) and [Au(4-pic)2][AuCl2] (4-pic = 4-picoline) emissions were found to be mainly ligand in nature, their [PF6](-) counterparts involved a Au...Au-interaction imbedded in the highest occupied molecular orbital. [Au(4-dmapy)2][AuCl2] was found to be an efficient catalyst for Suzuki cross-coupling of aryl bromide and phenylboronic acid. 相似文献
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Chandra S. Vasam Sarangapani Modem Shravankumar Kankala Shanker Kanne Geeta Budige Ravinder Vadde 《Central European Journal of Chemistry》2010,8(1):77-86
A first effort employing a range of polar-group functionalized phosphines (L
1
–L
7
) to design mononuclear Rh(I) compounds of [Rh(quin-8-O)(CO)(L)] (quin-8-O = 8-hydroxy quinolate) is described. The reaction
of a Rh(I) precursor [Rh(μ-Cl)(CO)2]2 with 8-hydroxyquinoline in the presence of a base followed by phosphines (L
1
–L
7
) produced only a single isomer of [Rh(quin-8-O)(CO)(L)] compounds (1–7) with pendant, i.e. non-bonded, polar-groups (includes carboxyl, hydroxyl and formyl). A relationship between Δgd31P chemical shifts and the ν(C≡O) was derived to evaluate and explain the σ-donor properties of these phosphines with respect
to the electronic properties of the polar groups and the extent of π-back-bonding to the CO group. These mononuclear Rh(I)-Phosphines
were investigated as catalysts in the hydroformylation of 1-hexene and cyclohexene in aqueous two-phase and single-phase solvent
systems. The Rh(I) catalysts with strong σ-donor and hydrophilic phosphines provided better yields and selectivities for the
hydroformylation products, which is a reverse trend compared to literature reports. When the Rh(I) compounds contained strong
σ-donor phosphines, the π-acceptor properties of the pyridine ring of 8-hydroxyquinolate were found to be beneficial for the
facile cleavage of the CO group during hydroformylation, and additionally, to improve the kinetic stability of catalysts. 相似文献
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Narasimha Swamy Thirukovela Ramesh Balaboina Ravinder Vadde Chandra Sekhar Vasam 《Tetrahedron letters》2018,59(42):3749-3752
An effective green synthesis of α-ketoamides was developed for the first time in water via gold nanoparticles (AuNPs) catalyzed aerobic oxidative cross-dehydrogenative coupling of secondary amines with phenylglyoxals with a broad substrate scope. 相似文献
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Mishra A. Jahan CS A. Kesarwani S. Raval H. Kumar S. Meena J. 《The European Physical Journal A - Hadrons and Nuclei》2019,55(6):1-8
The European Physical Journal A - In this paper, we investigated the spectroscopy of heavy tetraquarks through a relativistic diquark-antidiquark model. To this aim, the two-bosonic Klein-Gordon... 相似文献
20.
GYÖRGY TARCZAY ATTILA G. CSÁSZÁR WIM KLOPPER HARRY M. QUINEY 《Molecular physics》2013,111(21):1769-1794
Relativistic energy corrections which arise from the use of the Dirac-Coulomb Hamiltonian, and the Gaunt and Breit interaction operators, plus Lamb-shift effects have been determined for the global minima of the ground electronic states of C2H6, NH3, H2O, [H,C,N], HNCO, HCOOH, SiC2, SiH? 3, and H2S, and for barrier characteristics for these molecular systems (inversion barrier of NH3 and SiH? 3, barrier to linearity of H2O, H2S, and HNCO, rotational barrier of C2H6, difference between conformations of HCOOH (Z/E) and SiC2 (linear/T-shaped), and isomerization barrier of HCN/HNC). The relativistic calculations performed at the Hartree-Fock and the highly correlated CCSD(T) levels employed a wide variety of basis sets. Comparison of the perturbational and the four-component fully variational results indicate that the Coulomb-Pauli Hamiltonian and the lowest order Hamiltonian of direct perturbation theory (DPT(2)) are highly successful for treating the relativistic energy effects in light molecular systems both at a single point on the potential energy hypersurface and along the surface. Electron correlation contributions to the relativistic corrections are relatively small for the systems studied, and are comparable with the 2-electron Darwin correction. Corrections beyond the Dirac-Coulomb treatment are usually rather small, but may become important for high accuracy ab initio calculations. 相似文献