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91.
Goryunov E. I. Petrovskii P. V. Shcherbina T. M. Zakharov L. S. 《Russian Chemical Bulletin》2001,50(6):1085-1087
Catalytic phosphorylation of -trifluoromethylbenzyl alcohols with POCl3 taken in a ratio of 3 : 1 under particular temperature conditions afforded predominantly symmetrical tris(-trifluoromethylbenzyl) phosphates. The latter were obtained as mixtures of two diastereomers with a statistical ratio of the components. 相似文献
92.
A family of layered bismuth oxyhalides, LI0.5Bi1.5O2X and LIIBiO2X has been reinvestigated. Formation of X1-type Sillén compounds has been established for LI=Li, Na, LII=Ca, Sr, Ba, and X=Cl, Br, I, but the details of their crystal structures are different. While all LI0.5Bi1.5O2X, CaBiO2Br, and CaBiO2I adopt the disordered tetragonal Nd2O2Te structure, all compounds of LII=Sr and Ba are orthorhombic and isostructural to PbSbO2Cl, due to L/Bi cation ordering. Crystal structures have been determined for CaBiO2I, SrBiO2Br, SrBiO2I, and BaBiO2I. We discuss the factors which determine the occurrence and type of cation ordering in the quaternary bismuth and antimony X1-type oxyhalides. We also predict that more isostructural compounds can be prepared with antimony. 相似文献
93.
应用INDO/S半经验量子化学方法,对簇合物离子Mo3S和Mo3S4Mn+(M=Fe、Ni,n=4;M=Cu,n=5)分别进行分子轨道计算。根据计算得到的簇离子中的原子表观电荷和成键指标,说明Fe、Ni、Cu+与Mo3S成键作用的相对强度依次是Fe-Mo>Ni-Mo>Cu+-Mo。比较了用含组态作用的INDO/S方法计算得到的电子跃迁能与实验得到的电子吸收光谱值,并讨论了吸收峰归属情况。对于M为Fe、Ni的簇离子Mo3S4M4+,最低能量的电子跃迁吸收峰起源于异金属间电荷转移跃迁(MM’CT);而Mo3S4Cu(5+)簇离子观察到的吸收峰主要是Mo3S芯的局域内电荷转移跃迁。根据理论计算结果,由Cu+离子到Mo3S的电荷转移跃迁谱线,大约在46000cm-1以上才能观察到吸收峰。从Mo3S4Fe4+次低能量吸收峰的实验值16600cm-1和理论值16500cm-1与Mo3S的最低能量吸收峰的实验值16600cm-1和理论值16900cm-1比较,表明无论从理论上或实验上都能证实簇离子Mo3S4Fe4+在能量为16600cm-1处的吸收峰是起因于Mo3S芯的局域内电荷转移跃迁。 相似文献
94.
95.
V. E. Schneider E. E. Tornau A. A. Vlasova A. A. Gurskas 《Journal of inclusion phenomena and macrocyclic chemistry》1985,3(3):235-242
Clathrate thermodynamic stability conditions and the phase transitions associated with either the orientational ordering of the guest molecules or with the condensation of the guest molecules in the host lattice are investigated by means of the common microscopic model. The theory proposed describes the thermodynamic properties of -hydroquinone (Q
) clathrates. The dielectric constant (T) was measured experimentally inQ
·CH3OH andQ
·SO2 in the temperature range from 4.2 to 300 K and the phase transitions were found. It is shown that the theory qualitatively explains the experimental data obtained.Dedicated to Professor H. M. Powell. 相似文献
96.
Nonisothermal kinetics of the solid‐solid phase transition in (n‐C10H21NH3)2ZnCl4(C10Zn), (n‐C16H33NH3)2ZnCl4(C16Zn) and their binary system were determined by Kissinger and Ozawa methods from DSC measurements. The activation energy Ea of the binary system shows a waving dependence on WC10Zn%, which is caused by not only an intermediate (C10H21NH3)(n‐C16H33NH3)ZnCl4 but also three solid solution ranges (α, β, γ) in the phase diagram of C10Zn‐C16Zn. The variations of the layer d‐spacing are also convenient for the above result. 相似文献
97.
Winfried Mientus Hans-Georg Bartel Werner Haberditzl Hans-Joachim Spitzer 《Monatshefte für Chemie / Chemical Monthly》1980,111(3):597-606
A normalization of the wave functions by means of the theoretical exact Multiple-Scattering-(MS)-formalism is discussed within the framework of the SCF-X-SW-method. For the atomic and extramolecular regions the integrals of normalization can be easily determined and the results can be described by the corresponding electronic charges. The calculation of the integral of the interatomic region is problematic. The needful volume integration is only necessary to theGreen's functions of the wave functions and can be solved by means of the residual theory. The further analytical calculation of the surface integrals leads to a complicated formalism which can be numerically evaluated. 相似文献
98.
氢化物发生石墨炉原位富集直接测定高温镍基合金中碲 总被引:5,自引:0,他引:5
通过选择碲的氢化物发生条件,克服了高含量镍对碲的干扰,把氢化物富集在涂钯石墨管里,然后再原子化,成功地测定了高温镍基合金中碲。 相似文献
99.
100.
The initial formation of organotin derivatives with Sn-S-N bonds in heterolytic reactions of hexamethylditin or trimethyltin sulfide withN-(chlorothio)phthalimide is suggested. Subsequent interaction of these compounds with sulfenyl chloride affordsN, N-thioorN, N-dithiobisphthalimide. Homolytic reaction of hexamethylditin withN, N-dithiobisphthalimide also occursvia an organotin intermediate, which, in the absence of a nucleophilic reagent, eliminates sulfur and converts intoN-trimethylstannylphthalimide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2111–2114, December, 1993. 相似文献