C—H键核自旋耦合常数和伸缩频率的自然杂化轨道研究

利用PM3级别上的最大重迭对称性分子轨道法和自然杂化轨道方法,计算了系列碳氢化合物的杂化轨道,拟合出了计算C—H键核自旋耦合常数和伸缩频率的简单关系式.研究了系列碳氢化合物中不同的C—H键核自旋耦合常数和伸缩频率.结果表明,碳氢化合物中的C—H核自旋耦合常数和伸缩频率主要取决于C原子的轨道杂化作用,为从简单价键理论角度解释和计算1JCH和νCH提供了一种简便直观的方法.     

用数值遗传算法同时求解配合物稳定常数和各型体的纯光谱

用数值遗传算法同时求解配合物稳定常数和各型体的纯光谱张众杰，李通化，朱仲良，丛培盛，孙云平（同济大学化学系，上海，２０００９２）关键词数值遗传算法，二维数据，稳定常数利用滴定或光度法的测定数据，求解酸的离解常数和配合物的稳定常数是化学工作者十分熟悉并...     

反式-PtHL2X配合物中Pt-H核自旋偶合常数的量子化学计算

在计算两个核之间的自旋偶合常数时, 一般只考虑两个核与各自的s价电子的Fermi接触相互作用.这种近似处理不能解释反式-PtHL2X配合物的Pt-H偶合常数.本文考察到铂原子的6s价轨道在氢核处有较大的数值, 除考虑核与各自的s价电子的Fermi接触互作用之外, 引入铂的6s价电子与氢核的Fermi接触相互作用, 称为Fermi交换接触相互作用. 在有限微扰理论和EHMO近似下, 计算了上述配合物的铂氢偶合常数, 得到与实验值一致的结果.     

铌团簇和配合物的多面体分子轨道理论研究

应用多面体理论方法研究铌纯金属团簇和配合物的电子结构成键性质,并将理论预测结果用密度泛函方法验证.证实多面体理论是简便预测过渡金属簇,尤其是簇骨架电子结构的有效方法.铌的小团簇总是以低自旋密堆积结构为稳定构型,当体系的价电子数满足轨道成键数时,用该方法可较准确地推断成键性质(如Nb₄和[Nb₆Cl₁₂]⁺⁴);而对于不满足成键数的体系(如Nb₅和Nb₆),则可利用该理论分析畸变趋势.     

质子化丙酮分子团簇的结构和振动光谱

The stable structures and vibrational spectra of protonated acetone molecule clusters with different sizes （CH3COCH3）nH +（n=1-7）are calculated at the 6-31G（d）level by means of density functional theory （B3LYP）quantum chemical calculations. The corresponding energies are analyzed at the level B3LYP/6-311+G（3df,2p）in order to obtain more accurate results. The proton affinity of neutral cyclic acetone molecule clusters increases with the increasing of cluster size. The calculated results show that the protonated acetone clusters have certain growth regularity with forming a solvation shell at the beginning and then new added acetone molecule attacking different active sites including the middle carbon atoms and the different methyl in solvation shell. The IR spectra of the protonated clusters are more complicate than that of neutral ones. The strongest peaks result from the movement of the proton between the two oxygen atoms in solvant shell apart from the case of n=1. Carbonyl stretching vibraional peaks split into the more and more and in general the corresponding intensities are weakened due to the protonation with the increasing of cluster size.     

两态反应Ni2+与c-C6H12的机理及自旋-轨道耦合研究

在密度泛函理论的B3LYP方法下, 对两态反应Ni₂⁺与环己烷体系进行了较为系统的研究. 结果表明, 反应分别在第一个氢迁移(⁴IM1→⁴TS1/2), 第三个氢迁移(⁴TS15/16→⁴IM15)以及 翻转过程(⁴IM5→⁴TS5/6, ²TS11/12→²IM12)发生了二、四重态势能面的交叉, 本文运用内禀反应坐标单点垂直激发计算的方法得到势能面大致的交叉点(CP), 进一步利用Crossing2004程序获得精确的最低能量交叉点(MECP). 对MECP附近的自旋轨道耦合(SOC)常数进行了计算. MECP1～MECP4处的SOC值分别为318.01, 396.89, 268.74和306.67 cm^-1. 较大的SOC值说明不同势能面间发生了有效地跃迁并使反应沿着最低反应通道进行. 对反应通道的研究发现, 反应中同面脱氢是主要反应通道. 异面脱氢由于翻转过程中决速步骤势垒为33 kcal/mol(吸热3 kcal/mol), 只生成少量的异面脱氢产物. 计算结果解释了实验现象.     

含2,4—二硫代乙丙酰脲分子片卡宾铁羰基簇合物的合成和结构

Ｆｅ３（ＣＯ）１２与５个２，４－二硫代乙内酰脲ＳＣＮＨＣ（Ｒ１）（Ｒ２）Ｃ（Ｓ）ＮＨ应制得通式为Ｆｅ３（ＣＯ）８（μ３－Ｓ）２（Ｌ）含卡宾配体的５个新铁羰基簇合物（１～５）对其进行了元素分析，ＩＲ、ＨＮＭＲ和ＭＳ表征，并用Ｘ射线衍射法测定了簇合物３的晶体和分子结构，表明２，４－二硫代乙内酰脲分子片配位基：ＣＮＨＣ（ＣＨ３）２Ｃ（Ｓ）ＮＨ的卡宾碳具有ｓｐ＾２成键特征，其Ｃ－Ｆｅ键长０．１８９８ｎｍ，     

含2，4－二硫代乙内酰脲分子片卡宾铁羰基簇合物的合成和结构

Ｆｅ_３（ＣＯ）_（１２）与５个２，４－二硫代乙内酰脲ＳＣＮＨＣ（Ｒ_１）（Ｒ_２）Ｃ（Ｓ）ＮＨ反应制得通式为Ｆｅ_３（ＣＯ）_８（ｕ３－Ｓ）_２（Ｌ）含卡宾配体的５个新铁羰基联合物（１～５），对其进行了元素分析、ＩＲ、~１ＨＮＭＲ和ＭＳ表征，并用Ｘ射线衍射法测定了簇合物３的晶体和分子结构，表明２，４－二硫代乙内酰脲分子片配位基：ＣＮＨＣ（ＣＨ_３）_２Ｃ（Ｓ）ＮＨ的卡宾碳具有ｓｐ~２成键特征，其Ｃ卡宾－Ｆｅ键长０．１８９８ｎｍ，３的分子几何构型维持母体物Ｆｅ_３（ＣＯ）_９（ｕ_３－Ｓ）_２的形状，其中卡宾取代了四方锥分子骨架基底平面Ｆｅ（１）Ｓ（１）Ｆｅ（３）Ｓ（２）的Ｆｅ（１）原子上轴向位置的一个端羰ＣＯ。     

簇合物Mo2X4(X＝S,O)电子结构和光谱性质的Ab Initio研究

在abinitio水平上对含cis/trans-MO₂S₄核和含Mo₂O₄核簇合物的电子结构进行了研究.对钼原子选取和构造了一组适合于含Mo-Mo金属键的双核钼簇合物从头算的(4s4p2d)基组,利用该基组并结合自然键轨道(NBO)方法,对含上述簇胳的3个簇合物的电子结构进行了研究,并与相应的钨簇合物进行了比较.     

两个含dmit配体的二核钨簇合物的合成,结构表征和电学性质

通过配体取代反应, 以W2S4(dtp)2 (dtp = S2P(OC2H5)2-)为起始物, 将它和(PhCO)2dmit(dmit = )及R4NBr (R = Et, Bu)反应, 首次获得两个二核钨化合物(Bu4N)2W2S4(dmit)2 (I)和(Et4N)2W2S4(dmit)2 (II). 并对这两个化合物进行了红外光谱表征, 测定了化合物(I)的13C NMR谱和晶体结构. 结构分析表明, 在化合物(I)的晶胞堆积中存在S(((S超分子相互作用. 对化合物(II)的变温电导率测定证实化合物(II)具有半导体导电性. 化合物(I)的结晶学参数为: 正交晶系, 空间群Pbcn, 晶胞参数a = 18.048 (5), b = 15.937 (5), c = 19.191 (6) ?, V = 5520 (5) ?3, Z = 4, R = 0.084, Rw = 0.090     

NO双分子和二聚体与Cu2作用的理论计算

采用密度泛函理论(DFT)中的B3LYP方法，在Lanl2DZ基组下，对NO双分子和二聚体与铜原子簇相互作用的结构进行了研究. 结果表明，NO可以在铜表面相邻的两个铜原子上形成稳定的双分子吸附和二聚体吸附，而在双分子吸附形式中NO以氮原子吸附在铜上的构型最稳定，且顶点吸附的稳定性不如非顶点吸附形式.在二聚体吸附形式中， N－N键被加强，而N－O键被削弱的程度大于双分子吸附形式，说明二聚体的形成有利于NO在金属铜表面的直接分解.同时电荷布居分析表明，单重态的二聚体与铜作用时，铜原子上的平均电荷达到0.66 e,说明在这种吸附形式中铜被离子化的倾向较大，而且这种吸附形式最有利于NO的分解.这些结果说明NO经二聚体形式在铜表面直接催化分解是可行的.     

Valence Bond Study of Dissociation Behavior and Spectroscopic Constants for the Ground States of LiF and NaF

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｌｋａｌｉｈａｌｉｄｅｄｉａｔｏｍｉｃｍｏｌｅｃｕｌｅｓｐｒｏｖｉｄｅａｔｙｐｉｃａｌｃｕｒｖｅｃｒｏｓｉｎｇｐｒｏｂｌｅｍ［１］．Ｔｈｅｏｕｔｓｔａｎｄｉｎｇｎｏｎａｄｉａｂａｔｉｃｂｅｈａｖｉｏｒｏｆｔｈｅｃｈｅｍ...     

四配位铂磷光发射体结构与光物理性质关系的理论研究

定量理解光物理过程对于开发新型高效发射极至关重要. 优化提升二价铂配合物磷光量子效率是提升基于金属铂有机发光二极管发光效率的关键. 本文借助密度泛函理论计算, 探讨了一类平面四齿配位二价铂配合物磷光辐射的微观机制, 包括自旋轨道耦合积分、 辐射寿命、 速率常数、 跃迁偶极矩和隙间蹿跃通道. 综合研究发现, 沿着N→Pt方向推电子, 可有效屏蔽非辐射跃迁过程, 从而提升磷光发射效率. 本文将为高效发射器的分子工程学设计提供必要的指导.     

Theoretical Investigation on Hyperfine Structures of Perfluoropolyether Radicals

The geometries of CF3OCF2·, CF3OCFCF3· and CF3OCF2CF2· radicals were investigated by density func-tional theory(DFT) method. The calculated results indicate that all the three radicals have pyramidal shapes at their centers, and the αC is one top of the pyramids. Based on the DFT optimized geometries, the hyperfine coupling con-stants(hfcc’s) of the 19F atoms of the three radicals were calculated by B3LYP, MP2(full) and QCISD(full) methods. The calculated values agree with the experimental values, especiall...     

1-碘丙烷分子的电子动量谱学研究：自旋-轨道耦合效应与分子内轨道相互作用

利用不对称不共面电子动量谱仪,在2.5 keV碰撞能量下,采用高精度的SAC-CI方法计算了1-碘丙烷分子束缚能谱,同时采用Hartree-Fock、B3LYP/aug-cc-pVTZ（C,H）6-311G＊＊（I）方法计算其电子动量分布. 并对电离能峰进行了标示. 结合非相对论与相对论计算方法以及自然键轨道分析,对最外层两个轨道（碘的5p孤对）的自旋-轨道耦合效应与分子内轨道相互作用进行了比较. 两种相互作用对电子动量分布的不同影响是可观的. 实验结果与相对论计算的结果一致,表明1-碘丙烷分子内自旋-轨道耦合效应占主导.     

s-p Separation Model Indo-Mo Method and the Theoretical Study of 1H Hyperfine Coupling Constant

We have recently developed a modification of the traditional semiempirical INDO-MO method especially useful for open shell problems: INDO with s-p separation (J. Chin. Chem. Soc., 32, 385(1985)). In order to show the reliability of our new method fifty seven free radicals and radical ions were selected as examples for our MO calculation. We are particularly interested in the unpaired electron distribution of hydrogen atoms. A linear correlation analysis between the spin density and the isotropic hyperfine coupling constant (a_H) for ¹H has been carried out for these radicals and ions. Most of our calculated a_H's are better than the results reported using the conventional INDO method.     

Ab initio Study of Anharmonic Force Field and Spectroscopic Constants for Germanium Dichloride

Ab initio study of the equilibrium structure, spectroscopy constants, and anharmonic force field for several isotopomers of germanium dichloride (⁷⁰GeCl₂, ⁷²GeCl₂, and ⁷⁶GeCl₂) have been carried out at the MP2 and CCSD(T) levels of theory using cc-pVTZ basis set. The calculated geometries, rotational constants, vibration-rotation interaction constants, harmonic frequencies, anharmonic constants, quartic and sextic centrifugal distortion constants, cubic and quartic force constants are compared with experimental data. For small mass differences of the Ge isotopes, the isotopic effects for germanium dichloride are much weaker. The agreements are satisfactory for these two methods, but the deviations of CCSD(T) results are slightly larger than that of MP2, because of CCSD(T)'s inadequate treatment of electron correlation in hypervalent Cl atom.     

三苯基锡(Ⅳ)荒酸盐Ph3SnS2CN(C2H5)2的波谱及结构研究

合成了三苯基锡(Ⅳ)Ⅳ，Ⅳ-二乙基荒酸盐。通过元素分析、红外光谱和核磁共振氢谱对其结构进行了表征。用X-射线单晶衍射测定了该化合物的晶体结构；结果表明，化合物中锡原子呈五配位畸变三角双锥构型。     

A Theoretical Account of the Coupling between Metal- and Ligand-centred Spins

This study addresses the magnetic interaction between paramagnetic metal ions and the radical ligands taking the [Cu^II(hfac)₂(imVDZ)] and [M^II(hfac)₂(pyDTDA)] (imVDZ=1,5-dimethyl-3-(1-methyl-2-imidazolyl)-6-oxoverdazyl; hfac=(1,1,1,5,5,5)hexafluroacetylacetonate; pyDTDA=4-(2′-pyridyl)-1,2,3,5-dithiadiazolyl), (M=Cu, Ni, Co, Fe, Mn) compounds as reference systems. The coupling between the metal and ligand spins is quantified in terms of the exchange coupling constant (J) in the platform of density functional theory (DFT) and the wave function-based complete active space self-consistent field (CASSCF) method. Application of DFT and broken symmetry (BS) formalism results ferromagnetic coupling for all the transition metal complexes except the Mn(II) complex. This DFT-BS prediction of magnetic nature matches with the experimental finding for all the complexes other than the Fe(II)-pyDTDA complex, for which an antiferromagnetic coupling between high spin iron and the thiazyl ligand has been reported. However, evaluation of spin state energetics through the multiconfigurational wave function-based method produces the S=3/2 ground spin state for the iron-thiazyl in parity with experiment. Electronic structure analyses find the overlap between the metal- and ligand-based singly occupied molecular orbitals (SOMOs) to be one of the major reasons attributing to different extent of exchange coupling in the systems under investigation.