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91.
A multireference configurational interaction method based on the separated electron pair (SEP) wave functions, SEP‐CI approach, has been developed as an approximation to the traditional CASSCF method. It differs from the CASSCF method in that active orbitals are obtained from the SEP wave function without further optimization in the subsequent CI calculations, and the active space is automatically constructed according to the occupation coefficients of SEP natural orbitals. These features make the present SEP‐CI method computationally much less demanding than the CASSCF method. The applicability of the SEP‐CI method is illustrated with sample calculations on the insertion reaction of BeH2 and dissociation energies of LiH, BH, FH, H2O, and N2. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 39–47, 2006 相似文献
92.
Karsten Schubert Theodor Alpermann Tobias Niksch Helmar Grls Wolfgang Weigand 《无机化学与普通化学杂志》2006,632(6):1033-1042
Synthesis and Analytical Characterization of Functionalized β‐Hydroxydithiocinnamic Acids and their Esters. Complex Chemistry towards Nickel(II), Palladium(II), and Platin(II) Starting from silyl‐protected 4‐hydroxy acetophenone ( 1 ) the 1,1‐ethenedihiolato complexes 3 – 5 were synthesised using carbon disulfide and potassium‐tert‐butylate as a base. After being deprotected, the resulting 4‐hydroxy‐substituted complexes 6 – 8 were esterified with DL‐α‐lipoic acid to obtain the compounds 9 – 11 . The resulting complexes were characterized using NMR spectroscopy, mass spectrometry and IR spectroscopy. 3‐substituted β‐hydroxydithiocinnamic acid methyl ester ( 12 ) was obtained via an analogous path of reaction using silyl‐protected 3‐hydroxy acetophenone ( 2 ), carbon disulfide and methyl iodide. After removing of the silyl group the resulting hydroxy group was esterified with DL‐α‐lipoic acid. Using the dithioacid ester 14 as a ligand the NiII ( 15 ), PdII ( 16 ) and PtII ( 17 ) [O,S] complexes were obtained. 相似文献
93.
用密度泛函方法(DFT)和全活化空间自洽场方法(CASSCF)以及耦合簇理论(CCSD)优化了反式和顺式HOOOH的平衡几何构型, 用DFT计算了HOOOH顺反异构化反应的势能曲线和谐振动频率. 用含时密度泛函理论(TD-DFT)和二阶全活化空间微扰理论(CASPT2)计算了反式和顺式HOOOH垂直激发能. 计算结果表明: (1)反式异构体比顺式异构体稳定; (2)两种稳定构型的异构化反应有两种路径; (3)对于垂直跃迁能最低的单态和叁态, 反式的垂直跃迁能比顺式的低; (4)在单激发态中, CASPT2方法预测的顺式HOOOH寿命最长的激发态为21A′′, 其跃迁能是167.43 nm, 寿命为 1.44×10−5 s; 反式HOOOH寿命最长的激发态为21A, 其跃迁能是165.52 nm, 寿命为 2.07×10−5 s. 相似文献
94.
建立了处理双原子分子-表面相互作用的推广的LEPS势.借助推广的LEPS势,系统研究了一氧化碳分子在铂低指数表面吸附的动力学特性,重现了低指数表面的分子吸附热、吸附几何及本征振动等实验数据;鉴定了某些不合理的文献信息,预测了实验尚未探测到的重要信息:预测到Pt(100)表面四重洞位的C-O伸缩振动频率为1 962.60 cm-1;预测到Pt(110)表面吸附态的C-O及C-Pt键长分别为115.1、147 pm. 相似文献
95.
96.
V. R. Kartashov T. N. Sokolova O. A. Leksina A. B. Radbil N. V. Malisova Yu. K. Grishin 《Russian Chemical Bulletin》1995,44(3):527-531
The reaction of Hg(OAc)2 with bornylene in THF-H2O and CH3CN-H2O mixed solvents (75 25, v/v) was studied. The effects of the addition of NaOAc on the reaction rate and the composition of products were investigated. In the CH3CN-H2O mixture, the addition of NaOAc decreases the amount of the rearranged product, fundamentally changes the ratio between the regioisomeric solvoadducts, and promotes the formation of products of Hg(OAc)2 addition. The reaction proceedsvia an ion pair and free mercurinium ion; the cation of the ion pair and the free mercurinium ion have dissimilar structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 544–548, March, 1995. 相似文献
97.
N. I. Golovina R. F. Trofimova L. O. Atovmyan A. G. Korepin P. V. Galkin G. V. Lagodzinskaya M. V. Loginova L. T. Eremenko 《Russian Chemical Bulletin》1994,43(3):398-401
The reaction of -fluorosubstituted polynitroalkylaldimines with HCl results in replacement of the fluorine atom by a chlorine atom. The hitherto unknown -chlorosubstituted polynitroalkylaldimines have been obtained, and their X-ray structural investigation has been performed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 440–443, March, 1994. 相似文献
98.
No modern theory of polymer excluded volume adequately describes the crossover from poor solvent to good solvent conditions; a fundamental difficulty is a singularity in the binary cluster integral. Mayer expansion techniques are applied to a model with a pair interaction between monomers to clarify the distinction between geometric and solvent contributions to excluded volume. Detailed calculations are undertaken for a hard-core potential and a mimic Lennard-Jones potential. The significance of the singularity in the binary cluster integral for calculations in the crossover regime is discussed. 相似文献
99.
V. R. Kartashov T. N. Sokolova I. V. Timofeev E. V. Skorobogatova N. S. Zefirov 《Russian Chemical Bulletin》1994,43(5):760-768
The kinetics of mercuration of bornylene and cyclohexene in different solvents in the presence of NaOAc and LiClO4 has been investigated. Addition of NaOAc sharply decreases the rate of addition reactions of mercuric acetate to bornylene and cyclohexene in alcohols; the main direction of the mercuration of bornylene is the formation of acetoxy-adducts, and the yield of solvo-adducts decreases from 76 % in the absence of NaOAc, to 19 % in the presence of the salt (4·10–3 mol L–1). A reaction scheme involving the participation of intermediate ion pairs and a solvated mercurinium ion is suggested and confirmed by a steady-state concentration method. The influence of NaOAc on the rate of the reaction and on product formation is realized through the common ion effect.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 819–826, May, 1994. 相似文献
100.
Adi Wolfson Ivo F.J. Vankelecom Pierre A. Jacobs 《Journal of organometallic chemistry》2005,690(15):3558-3566
When ionic liquids (ILs) are employed as solvents for transition metal complex (TMC) catalyzed reductions, a second solvent can be added to increase the efficiency of the catalytic cycle and the solubility of the reactant in the IL phase. Two industrially relevant asymmetric hydrogenations, the enantioselective reductions of methyl 2-acetamidoacrylate with Rh-EtDuPHOS and methyl acetoacetate with Ru-BINAP, were performed in different catalytic systems including 1-butyl-3-methylimidazolium hexafluorophosphate/ tetrafluoroborate as ILs. Product separation and TMC recycling was performed by extracting the product from the reaction mixture. This can be accomplished by cooling the system, by adding an excess of the second solvent or by adding a third solvent. A high solubility of the second solvent in the IL catalytic phase favors the reaction activity, but can induce leaching of the IL and TMC. 相似文献