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2.
Complete geometry optimizations were carried out by HF and DFT methods to study the molecular structure of binuclear transition-metal compounds (Cp(CO)3W(μ-PPh2)W(CO)5) (I) and (Cp(CO)2W(μ-PPh2)W(CO)5) (II). A comparison of the experimental data and calculated structural parameters demonstrates that the most accurate geometry parameters are predicted by the MPW1PW91/LANL2DZ among the three DFT methods. Topological properties of molecular charge distributions were analyzed with the theory of atoms in molecules. (3, −1) critical points, namely bond critical point, were found between the two tungsten atoms, and between W1 and C10 in complex II, which confirms the existence of the metal–metal bond and a semi-bridging CO between the two tungsten atoms. The result provided a theoretical guidance of detailed study on the binuclear phosphido-bridged complex containing transition metal–metal bond, which could be useful in the further study of the heterobimetallic phosphido-bridged complexes. 相似文献
3.
Equilibrium geometries, interaction energies, and charge transfer for the intermolecular interactions between BrF and HnX (HF, H2O, and NH3) were studied at the MP2/6-311++G(3d,3p) level. The halogen-bonded geometry and hydrogen-bonded geometry are observed in these interactions. The calculated interaction energies show that the halogen-bonded structures are more stable than the corresponding hydrogen-bonded structures. To study the nature of the intermolecular interactions, symmetry-adapted perturbation theory (SAPT) calculations were carried out and the results indicate that the halogen bonding interactions are dominantly inductive energy in nature, while electrostatic energy governs the hydrogen bonding interactions. 相似文献
4.
The dependent relation between temperature and pressure of supercritical CO2+ ethanol binary system under the pressure range from 5 to 10 MPa with the variety of densities and mole fractions of ethanol
that range from 0 to 2% was investigated by the static visual method in a constant volume. The critical temperature and pressure
were experimentally determined simultaneously. The PTρ figures at different ethanol contents were described based on the determined pressure and temperature data, from which pressure
of supercritical CO2 + ethanol binary system was found to increase linearly with the increasing temperature. P-T lines show certain convergent feature in a specific concentration of ethanol and the convergent points shift to the region
of higher temperature and pressure with the increasing ethanol compositions. Furthermore, the effect of density and ethanol
concentration on the critical point of CO2 + ethanol binary system was discussed in details. Critical points increase linearly with the increasing mole fraction of
ethanol in specific density and critical points change at different densities. The critical compressibility factors Zc of supercritical CO2 + ethanol binary systems at different compositions of ethanol were calculated and Z
c
-ρ figure was obtained accordingly. It was found from Z
c
-ρ figure that critical compressibility factors of supercritical CO2 unitary or binary systems decline linearly with the increasing density, by which the critical point can be predicted precisely. 相似文献
5.
Particular solutions to the Einstein equations with cosmological constant are presented and discussed for an isotropic, spatially homogeneous, and spatially flat space-time in the case that the matter fields are
4,
6, and sine-Gordon fields. 相似文献
6.
Lv Y Zhang J Cao W Juan JC Zhang F Xu Z 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(2):382-386
Rare-earth ternary complexes Eu(X)Y(1-X)(TTA)3Dipy {X=0, 0.1, 0.25, 0.5, 0.75, 0.9, 1.0, using thenoyltrifluoroacetone (TTA) as ligand and 2,2'-dipyridyl (Dipy) as synergic agent} were synthesized. Characterization with X-ray diffraction (XRD), IR and elemental analysis had also been carried out. The photophysical properties of these complexes were studied in detail with ultraviolet absorption spectra and fluorescent spectra. It is found that the enhanced luminescence of Eu(3+) ions by Y(3+) ions occurs in ternary complexes. And we monitored the spectra of Eu(X)Y(1-X)(TTA)3Dipy (PVK:Eu/BCP/AlQ/Al) at the different rate (rpm). The results showed that the Y(3+) ion acts as an energy transfer bridge that helps energy transfer from PVK to Eu(3+). 相似文献
7.
Pan Shiwei Li Puhui Xu Guihua Guo Jingchang Ke Libin Xie Canquan Zhang Zhoucai Hui Yonghai 《Research on Chemical Intermediates》2020,46(2):1353-1371
Research on Chemical Intermediates - Heterogeneous ordered mesoporous silica materials catalyst, MCM-41@Schiff base-Co(AcO)2, reveals high catalytic performance within the synthesis of pyran... 相似文献
8.
合成了一种新的含有3个配体的稀土配合物Eu(TTA)2(N-HPA)Phen(TTA-噻吩甲酰基三氟丙酮,N—HPA=N-苯基邻氨基苯甲酸,phen=邻菲咯啉)。将稀土配合物作为掺杂物与基质PVK按照不同质量比混合共溶,旋涂成膜。通过荧光光谱,分析了薄膜的发光特性,并将其应用于有机电致发光。研究了PVK和Eu(TTA)2(N—HPA)Phen之间的能量传递,并且制备了发光层为PVK:Eu(TTA)2(N—HPA)Phen,结构为ITO/PVK:Eu(TrA)2(N—HPA)Phen/BCP/Alq3/Al的多层器件,发现改变PVK和稀土配合物的掺杂比,可以不同程度地抑制PVK的发光,最终得到纯的Eu^3+的红色发光。实验结果证明,在PVK:Eu(TTA)2(N—HPA)Phen=5:1的质量比下,从PVK到稀土配合物之间存在充分的能量传递。 相似文献
9.
10.
Jingchang Sun Hongwei Liang Jianze Zhao Ziwen Zhao Guotong Du 《Applied Surface Science》2007,253(11):5161-5165
ZnO films were deposited on c-plane Al2O3 substrates by pulsed laser deposition. The etching treatments for as-grown ZnO films were performed in NH4Cl aqueous solution as a function of NH4Cl concentration and etching time. It was found that NH4Cl solution is an appropriate candidate for ZnO wet etching because of its controllable and moderate etching rate. The influence of etching treatment on the morphology, optical and electrical properties of the ZnO films has been investigated systematically by means of X-ray diffraction, atomic force microscope, photoluminescence and Hall effect. The results indicated that the surface morphology and optical properties of the films were highly influenced by etching treatment. 相似文献