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1.
1 INTRODUCTION During the past decade, a series of organic-inor- ganic hybrid compounds based on metal halide units have been prepared and studied[1]. The combination of organic and inorganic components at the mole- cular level affords us the opportunity to design new hybrid materials and modulate the properties of components[2]. As a result, some interesting proper- ties, such as non-linear optical[3], interesting magne- tic[4], efficient luminescence[2], ideal thermal and mechanical sta…  相似文献   

2.
1 INTRODUCTION Recently, the researches on inorganic-organic hy-brid compounds represent an advanced field in mate-rial science[1]. At the molecular level, the combina-tion of two extremely different components providesan avenue to design new hybrid materials as well asthe ability to modulate properties of one or more ofthe components[2~6]. Some attractive properties, suchas efficient luminescence[2~4], ideal thermal and me-chanical stability, interesting magnetic[5], non-linearoptical[…  相似文献   

3.
用DFT B3LYP方法及6-311G(d,p),6-311+G(d,p)和LanL2dz基组,对C6F5X+(X=Cl,Br,I,CH3)阳离子做了理论研究,优化了它们的电子基态的构型,计算了对应分子的垂直电离势(VIP)和绝热电离势(AIP).结果表明四种离子的构型的对称点群和对应分子相同,但构型参数有明显差别.B...  相似文献   

4.
Cis-dioxo-metal complex ( NH3CH2CH2NH2 ) 2.5 [ Mo0.5^(V)W0.5^(VI)O2 ( OC6H4O ) 2] 1 was obtained by the reaction of tetra-butyl ammonium hexamolybdotungstate with 1, 2-dihydroxybenzene in the mixed solvent of CH3OH, CH3CN and ethylenediamine,and characterized by X-ray diffraction, UV-vis and EPR analysis. Compared with its analogous complexes (NH3CH2CH2NH2)3[Mo^(V)O2(OC6H40)2] 2 and (NH3CH2CH2NH2)2[W^(VI)O2(OC6H4O)2] 3, the results show that tungsten(VI) is less active in redox than molybdenum (VI) and that the change of the valence induced by substitution of W(VI) for Mo(V) in EMO2(OC6H40)2]n- does not influence the coordination geometry of the complex anion in which the metal center exhibits distorted octahedral coordination with cis-dioxo catechol. The responses to EPR of complexes 1 and 2 are active but complex 3 is silent,and the UV-vis spectra exhibited by the three complexes are obvious different because of the different electronic configuration between the central Mo(V) and W(VI) ions in the complexes.It is noteworthy that complexes 1 and 2 have the similar EPR signal to flavoenzyme, suggesting that the three complexes have the same coordination geometry feature with the co-factor of flavoenzyme.  相似文献   

5.
马春林  李凤 《中国化学》2003,21(2):146-152
Three distannoxane dimers[(PhCH2)2(Cl)SnOSn(X)(CH2Ph)2]2(X=Cl,OMe,OEt)were prepared by the hydrolytic reaction of (PhCH2)2SnCl2 with sodium alkoxides.The compounds are assigned tetranuclear distannoxane structures in solid state.which contain the so-called ladder arrangement with a central planar Sn2O2 four-membered ring.The endo-and exo-cyclic Sn atoms are both five-coordinate,and have distorted trigonal bipyramidal geometries.A variety of hydrolyses of(PhCH2)2SnCl2 were performed and these dimers were characterized by IR,^1H NMR spectroscopy and X-ray diffraction analysis.  相似文献   

6.
王洪涛  韩奎  李艳 《物理化学学报》2007,23(9):1468-1472
在MP2理论水平上采用6-311G基组系列计算了一价阴离子van der Waals复合物[Li…X]e-[1](X=FH, OH2, NH3)的偶极矩(μ)、平均极化率(α)以及平均一阶超极化率(β), 讨论了基组效应和电子相关效应对计算结果的影响, 比较了价电子对复合物一阶超极化率的贡献. 在MP4(SDQ)/6-311++G(2df, 2pd)水平上计算得到[Li…FH]e-[1]的μ=2.5633 a.u., α=1.0476×103 a.u., β=1.0948×105 a.u.;[Li…OH2]e-[1] 的μ=2.3204 a.u., α=1.2201×103 a.u., β=2.1410×105 a.u.;[Li…NH3]e-[1]的μ=2.4687 a.u., α=1.4817×103 a.u., β=3.4040×105 a.u.. 计算结果表明, 三种一价阴离子复合物分子均具有非常大的一阶超极化率, 而一个价电子对复合物的一阶超极化率的贡献超过1.0×105 a.u..  相似文献   

7.
采用DFT B3LYP和QCISD方法研究了不饱和类锗烯H2C=GeLiCl与RH(R=F, OH, NH2)的插入反应. 在B3LYP/6-311+G(d,p)水平上优化了反应势能面上的驻点构型. 结果表明, H2C=GeLiCl与HF、H2O 或NH3发生插入反应的机理相同. QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p)计算的三个反应的势垒分别为173.53、194.48和209.05 kJ·mol-1, 反应热分别为60.18、72.93和75.34 kJ·mol-1. 相同条件下发生插入反应时, 反应活性顺序都是H—F>H—OH>H—NH2.  相似文献   

8.
Studies on the Electronic Structures and Spectra of C78(CH2)3   总被引:1,自引:0,他引:1  
The structures and spectra of 20 possible isomers of C78(CH2)3 have been studied by using AM1,INDO/CIS and DFT methods. The results show that the most stable isomer is 1,2,3,4,5,6-C78(CH2)3 (A) with annulene structures,where three -CH2 groups are added to the 6/6 bonds located at the same hexagon passed by the shortest axis of C78 (C2v). Compared with that of C78 (C2v),the first absorption in the electronic spectrum of C78(CH2)3 (A) is blue-shifted because of its wider LUMO-HOMO energy gap. While the IR frequencies of the C–C bonds on the carbon cage are red-shifted owing to the formation of annulene structures and the extension of the conjugated system. The chemical shifts of the carbon atoms in 13C NMR spectra are moved upfield upon the addition.  相似文献   

9.
10.
The synthesis and crystal structure of oxo-centered carboxylate-bridge trinuclear ruthenium complex,Ru3O(CH3OO)6(py)2Cl(py=pyridine)(1),are reported herein.The complex 1 has been characterized by IR,cyclic voltammetry (CV),UV-Vis and X-ray crystal analysis.The complex 1 in 0.1 mol/L (n-C4H9)4HPF6-CH2Cl2 solution at room temperature shows four oneelectron redox processes at E1/2=-1.38,1.20,-0.17 and 1.07V vs. Ag/AgCl.  相似文献   

11.
众所周知,电子相关能问题是量子化学的瓶颈问题‘’‘.为了更深人地了解和认识电子相关能的轨道本质,建立P。St-HF理论校正模型,JS等”-”应用电子对内对间电子相关模式,指出国际著名量子  相似文献   

12.
IntroductionAsawell knownfact ,thecalculationofelectroncor relationenergyisabottleneckprobleminthecalculationsofmolecularpropertiesandchemicalreactionsinquantumchemistry .1Ithasattractedgreatattentionoftheoreticalchemists.NumerousdifferentmethodshavebeenusedtocalculatethecorrelationenergysinceL wdin2 givethedef initionofelectroncorrelationin 195 9.In 196 0s ,Sinanoˇglu3,4 definedtheexactelectronpaircorrelationen ergyanddevelopedmany electrontheoryofatomsandmoleculesinwhichthetotalcorrelation…  相似文献   

13.
The reaction mechanism of model compounds H2S and CH3SH for cysteine proteases with NH2CH2COCH2X (X = F and Cl) molecules has been investigated using DFT methods with B3LYP and B3PW91 hybrid density functionals at 6‐31+G* basis sets. The single point energy has been calculated for the above reactions with B3LYP and B3PW91 functionals using aug‐cc‐PVDZ infinite basis set in both gas and solution phases. The intrinsic reaction coordinates calculations have been performed to confirm that each transition state is linked by the desired reactants and products. The geometries and relative energies for various stationary points have been determined and discussed. The zero point vibrational energy corrections have been made to predict the reliable energy. The negative value of reaction energy indicates that the overall reaction profile is found to be exothermic. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008  相似文献   

14.
The energetics of the stationary points of the gas-phase reactions CH(3)X+F(-)-->CH(3)F+X(-) (X=F, Cl, CN, OH, SH, NH(2) and PH(2)) have been definitively computed using focal point analyses. These analyses entailed extrapolation to the one-particle limit for the Hartree-Fock and MP2 energies using basis sets of up to aug-cc-pV5Z quality, inclusion of higher-order electron correlation [CCSD and CCSD(T)] with basis sets of aug-cc-pVTZ quality, and addition of auxiliary terms for core correlation and scalar relativistic effects. The final net activation barriers for the forward reactions are: E (b/F,F)=-0.8, E (b/F, Cl)=-12.2, E (b/F,OH)=+13.6, E b/F,OH=+16.1, E b/F,SH=+2.8, Eb/F, NH=+32.8, and E b/F,PH =+19.7 kcal x mol(-1). For the reverse reactions E b/F,F= -0.8, Eb/Cl,F =+18.3, E b/CN,F=+12.2, E b/OH,F =-1.8, E b/SH,F =+13.2, E b/NH(2),=-1.5, and E b/PH(2) =+9.6 kcal x mol(-1). The change in energetics between the CCSD(T)/aug-cc-pVTZ reference prediction and the final extrapolated focal point value is generally 0.5-1.0 kcal mol(-1). The inclusion of a tight d function in the basis sets for second-row atoms, that is, utilizing the aug-cc-pV(X+d)Z series, appears to change the relative energies by only 0.2 kcal x mol(-1). Additionally, several decomposition schemes have been utilized to partition the ion-molecule complexation energies, namely the Morokuma-Kitaura (MK), reduced variational space (RVS), and symmetry adapted perturbation theory (SAPT) techniques. The reactant complexes fall into two groups, mostly electrostatic complexes (FCH(3).F(-) and ClCH(3).F(-)), and those with substantial covalent character (NCCH(3).F(-), CH(3)OH.F(-), CH(3)SH.F(-), CH(3)NH(2).F(-) and CH(3)PH(2).F(-)). All of the product complexes are of the form FCH(3).X(-) and are primarily electrostatic.  相似文献   

15.
In this article, the transferable property of pair correlation energies of OH components is discussed for a series of OH containing compounds MOH (M=H, Li, Na). In this series of compounds, from OH free radicals through HOH, LiOH, NaOH to OH?, both the intra‐ and interpair correlation energies and intra‐ and intershell correlation energies of the inner orbital electrons change little. The 1s$_{\mathrm{O}}^{2}$ is very much alike in all the above OH containing systems and such a pair correlation is transferable. But the interpair correlation and intrashell correlation energies of the valence electrons are large and change a lot in all systems. In MOH molecules, the OH correlation energy contribution increases with the increase of the ionic bond strength of the compound and this contribution is always between the correlation energy values of OH free radicals and OH? atomic groups. For strong ionic compounds, we present a very simple method to estimate the correlation energy by adding the correlation energies of its component ions within the chemical accuracy (2 kcal/mol). © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 311–317, 2001  相似文献   

16.
In contrast to the abundant data on the neutral-neutral reactions, little is known about the ion-molecule reactions involving silicon ions. A detailed mechanistic study at the B3LYP/6-311G(d,p) and CCSD(T)/6-311+G(2df,p) (single-point) computational levels was reported for the reactions of SiCN+/SiNC+ with a series of -bonded molecules HX (X = H, CH3, F, NH2). Together with the recently studied SiCN+/SiNC+ + H2O reactions, all of these reactions have nucleophilic substitution as their major pathway. Insertion is a much slower reaction. By contrast, the known atomic Si+ and C2N+ ion-molecule reactions go by insertion. Generally, the initial gas-phase condensation between SiCN+/SiNC+ and HX (except the nonionic H2) effectively forms the adduct HX...SiCN+/HX...SiNC+. The stability of the adduct increases with the electron-donating ability of X. Even at low temperatures, reactions with the electron donors NH3, H2O, and HF proceed rapidly to generate the fragments SiX+ + HCN (dominant) and SiX+ + HNC (minor). This suggests that such reactions may be useful in the synthesis of novel Si-X bonded species. However, the reactions of SiCN+ with completely saturated CH4 and H2 produce fragments only at high temperatures, and SiNC+ may even be unreactive. The calculated results may be helpful for understanding the chemistry of SiCN-based microelectric and photoelectric processes in addition to astrophysical processes in which the [Si,C,N]+ ion is involved. The results can also provide useful mechanistic information for the analogous ion-molecule reactions of the monovalent silicon-bearing ions.  相似文献   

17.
The ability of B atoms on two different molecules to engage with one another in a noncovalent diboron bond is studied by ab initio calculations. Due to electron donation from its substituents, the trivalent B atom of BYZ2 (Z=CO, N2, and CNH; Y=H and F) has the ability to in turn donate charge to the B of a BX3 molecule (X=H, F, and CH3), thus forming a B⋅⋅⋅B diboron bond. These bonds are of two different strengths and character. BH(CO)2 and BH(CNH)2, and their fluorosubstituted analogues BF(CO)2 and BF(CNH)2, engage in a typical noncovalent bond with B(CH3)3 and BF3, with interaction energies in the 3–8 kcal/mol range. Certain other combinations result in a much stronger diboron bond, in the 26–44 kcal/mol range, and with a high degree of covalent character. Bonds of this type occur when BH3 is added to BH(CO)2, BH(CNH)2, BH(N2)2, and BF(CO)2, or in the complexes of BH(N2)2 with B(CH3)3 and BF3. The weaker noncovalent bonds are held together by roughly equal electrostatic and dispersion components, complemented by smaller polarization energy, while polarization is primarily responsible for the stronger ones.  相似文献   

18.
First, the intrapair and interpair correlation energies of the Rg atom, X atom, and the optimized RgX (Rg = Ar, Kr, X = F, Cl, Br) complexes are calculated by the MELD program at the 6‐311++g(d), 6‐311++g(3df, 3pd), and cc‐pvqz basis sets (denoted by basis sets a, b, and c, respectively). It is found that the relationship Ecorr(RgX) ≈ Ecorr(Rg) + Ecorr(X) is correct for all the above systems but introducing an unsound absolute error for some RgX systems. Second, the same calculations are selectively carried out for ArF (the smallest system) and KrBr (the largest system) at their increasing interatomic distance. It was found that both the correlation energies of ArF and those of KrBr will decrease whenever the interatomic distance of them become larger. On the basis of our results, we provided an approach to quickly estimate the correlation energies of RgX complexes by which not only the absolute error becomes smaller but more computation work is saved than the direct calculation. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004  相似文献   

19.
The structures of seven gas phase identity S(N)2 reactions of the form CH(3)X + X(-) have been characterized with seven distinct theoretical methods: RHF, B3LYP, BLYP, BP86, MP2, CCSD, and CCSD(T), in conjunction with basis sets of double and triple zeta quality. Additionally, the energetics of said reactions have been definitively computed using focal point analyses utilizing extrapolation to the one-particle limit for the Hartree-Fock and MP2 energies using basis sets of up to aug-cc-pV5Z quality, inclusion of higher order correlation effects [CCSD and CCSD(T)] with basis sets of aug-cc-pVTZ quality, and additional auxiliary terms for core correlation and scalar relativistic effects. Final net activation barriers for the reactions are E(b)(F,F)= -0.8, E(b)(Cl,Cl)= 1.6, E(b)(CN,CN)= 28.7, E(b)(OH,OH)= 14.3, E(b)(SH,SH)= 13.8, E(b)(NH2,NH2)= 28.6, and E(b)(PH2,PH2)= 25.7 kcal mol(-1). General trends in the energetics, specifically the performance of the density functionals, and the component energies of the focal point analyses are discussed. The utility of classic Marcus theory as a technique for barrier predictions has been carefully analyzed. The standard Marcus theory results show disparities of up to 9 kcal mol(-1) with respect to explicitly computed results. However, when alternative approaches to Marcus theory, independent of the well-depths, are considered, excellent performance is achieved, with the largest deviations being under 3 kcal mol(-1).  相似文献   

20.
采用键表酉群方法对C6H5F、C6H5OH和C6H5NH2中的电子离域现象进行了计算和分析,讨论了取代苯的价键描述特性,并计算了取代基的π电子离域能.结果表明离子结构成分与离域能有直接关系,即离子成分越多,电子离域能越大./6-31G基组及“分子中的原子”方法将电荷密度分区积分得到各原子上的电荷集居数,并将此结果与取代苯的反应性能进行了比较。为在价键意义上分析和理解取代基对苯环电子结构及其反应性能的影响,本文对3个典型的取代苯Ph-X(X=F,OH,NH2)进行了初步的价键计算和讨论.1计算方法及构型在键表酉群方法中[5],体系的一个共振结构可用一个价键结构函数即键表ψ(k)来描述,相应的体系总波函数Ψ可表示为M个正则键表的线性组合:式(1)便构成了键表相互作用(BTI)计算方法[6]的基础.键表对体系的结构贡献定义为:原子轨道q上的电荷集居数定义为:式中mq(k)可取0、1或2,分别对应于键表ψ(k)中原子轨道q出现0、1或2次.为简比计算,我们将取代苯的σ骨架用HF分子轨道固定[7],这样仅需考虑π电子及轨道.原子轨道积分及HF-SCF计算采用Gaussian80程序.联系人及第一作者:莫亦荣,男,29  相似文献   

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