预测[Si，C，S]^＋和[Si，C，S]^-体系的稳定异构体

采用DFT,QCISD及CCSD(T)方法分别对二重态的[Si,C,S] 和[Si,C,S]-体系势能面进行理论计算,用QCISD/6-311 G(d)方法,在[Si,C,S] 和[Si,C,S]-体系中,我们分别得到了2个过渡态连接的3个稳定体和2个过渡态连接的4个稳定体,经热力学及动力学分析发现,[Si,C,S] 上体系只有二重态线性的离子[Si-C-S] 可能稳定存在,而[Si,C,S]-体系有二重态线性的离子[Si-C-S]-和三元环c-[SiCS]-可能稳定存在.     

预测[Si, C, S]＋和[Si, C, S]－体系的稳定异构体

采用DFT, QCISD及CCSD(T)方法分别对二重态的[Si, C, S]＋和[Si, C, S]－体系势能面进行理论计算, 用QCISD/6-311＋G(d)方法, 在[Si, C, S]＋和[Si, C, S]－体系中, 我们分别得到了2个过渡态连接的3个稳定体和2个过渡态连接的4个稳定体, 经热力学及动力学分析发现, [Si, C, S]＋体系只有二重态线性的离子[Si—C—S]＋可能稳定存在, 而[Si, C, S]－体系有二重态线性的离子[Si—C—S]－和三元环c-[SiCS]－可能稳定存在.     

[C, N, N, P]体系异构体结构与稳定性

在B3LYP/6-311G(d)和QCISD(t)/6-311+G(2df)水平下计算得到了[C, N, N, P]体系的9个异构体、20个过渡态及一些相关的解离碎片, 并研究了异构体之间的异构化过程, 讨论了该体系异构体的结构与稳定性. 结果表明在得到的9个异构体中, 具有2A′电子态的、非线型链状NCNP, NCPN, CNPN和CNNP 4个异构体是较稳定的. 其余异构体由于易于重排或是解离, 稳定性较低. 研究同时给出了这4个异构体的振动频率、转动常数、偶极矩、第一绝热电离能和绝热电子亲合能等相关数据, 为可能的实验和星际光谱观测提供相关的理论数据. 得到的计算结果与等价电子体系SiNNP进行了比较.     

Theoretical Study on the Structures and Stability of Isomers and Complex of[Si,C,O,O] Sytem

A detailed singlet potential energy surface(PES) of [Si,C,O,O] system including a van der Waals (vdW) comples SiO……CO2,eight isomers,and twelve transiton states is investigated by MP2 and QCISD(T) (single-point)methods.At the final QCISD(T)/6-311 G(2df)//MP2/6-311G(d) level with zero-point energy included,the complex SiO……CO is found to be thermodynamically and kinetically the most stable species.Although eight ismoers are located as local energy minima,they are rather unstable toward isomerization to the dissociation fragments or comples.For the reaction of silocon atoms with carbon dioxide,two competitive reaction channels are found,and the primary pathway,which leads to the products of SiO and CO fragments,is the direct oxygen-abstraction process from carbon dioxide by silicon atom with a41.16 kJ/mol reaction barrier height.Our predications are in good agreement with previous experimental and theoretical studies.     

S2O2分子稳定结构的密度泛函理论研究

采用密度泛函理论中的B3LYP方法,在6-311+G(3df)和Aug-cc-pVTZ水平上,研究了单态S2O2分子的各种可能的异构体及其相对稳定性。结果表明,具有C2v对称性的三角平面分叉异构体的热力学稳定性要高于目前实验上唯一被发现的具有C2v对称性的cis-OSSO异构体,同时trans-OSSO的稳定性与顺式异构体十分接近,这2种异构体应该可以在实验上被观察到。同时本文还讨论了3个最稳定构型的前线分子轨道和链型OSSO的内扭转势能。     

杂多阴离子[GeMo12O40]4-α/β异构体的密度泛函研究

采用密度泛函方法，在DND基组水平上，对[GeMo12O40]^4-杂多阴离子最常见的α和β异构体进行了几何构型优化，得到了与X射线晶体衍射实验结果相一致的结构参数，并在此基础上进行了振动频率分析，得到了杂多阴离子的电子结构、热力学特性和振动光谱，通过定义α，β异构体异构化反应的Gibbs函变△Gα-β与温度的关系，研究了这两种异构体的相对稳定性．结果表明：低温时α异构体更稳定，高温时β异构体更稳定些，550K左右为转变点．振动频率分析得到2种异构体的最强峰位于4个频率位置，分别指认为vax(Mo-Od)，vas(Mo-Od)，vas(Mo-Oc-Mo)，vas(Ge-Oa)，vas(Mo-Ob-Mo)振动，与红外光谱(IR)的特征振动峰相对应，观察到了特征频率的振动模式，从理论计算角度说明了Rocchiccioli—Deltcheff关于振动模式的设想是合理的．     

RuX^2+(X=O, H,N, C)分子离子的势能函数与稳定性

用密度泛函B3LYP方法对RuX^2+(X=O,H,N,C)分子离子进行了理认研究,结果表明：PuO^2+,PuH^2+,PuN^2+和PuC^2+分子离子能稳定存在,基态电子状态是X5^Σ^-(PuO^2+),X8^Σ^-(PuH^2+),X4^Σ^+(PuN^2+)和X9^Σ^-(PuC^2+),势能函数为Murrell-Sorbie热函数,并导出了相应的几何性质,力学性质和光谱数据。     

[Si,N,N,P]体系异构体结构与稳定性

在B3LYP/6-311G(d)和QCISD(t)/6-311+G(2df)(单点)水平下计算得到了[Si,N,N,P]体系势能面上的一些驻点, 研究了异构体之间的异构化过程, 并讨论了该体系异构体的结构与稳定性. 结果表明在[Si,N,N,P]体系中的11个异构体中只有含有Si-P交叉成键的类蝶型四元环异构体SiNPN(E1, ²A″)是稳定的, 其他异构体由于易于重排或是解离, 稳定性较低. 研究同时给出了E1的电子与几何结构、振动频率及指认、偶极矩和转动常数等相关数据. 分析结果表明通过中间体E3(SiNPN)的反应SiN(²Π) + PN(¹Σ)→E1是由SiN(²Π)和PN(¹Σ)碎片产生E1的最有利途径, 因此E1可成为星际观测的目标. G2级别下此反应的反应焓变为215.25 kJ/mol (298.15 K), 而异构体E1在298.15 K下的标准生成焓为457.99 kJ/mol.     

RuX^2+(X=O,H,N,C)分子离子的势能函数与稳定性

用密度泛函B3LYP方法对RuX^2+(X=O,H,N,C)分子离子进行了理认研究,结果表明：PuO^2+,PuH^2+,PuN^2+和PuC^2+分子离子能稳定存在,基态电子状态是X5^Σ^-(PuO^2+),X8^Σ^-(PuH^2+),X4^Σ^+(PuN^2+)和X9^Σ^-(PuC^2+),势能函数为Murrell-Sorbie热函数,并导出了相应的几何性质,力学性质和光谱数据。     

PuX2+(X=O,H,N,C)分子离子的势能函数与稳定性

用密度泛函B3LYP方法对PuX2+(X=O,H,N,C)分子离子进行了理论研究,结果表明:PuO2+,PuH2+,PuN2+和PuC2+分子离子能稳定存在,基态电子状态是X5∑-(PuO2+),X8∑-(PuH2+),X4∑+(PuN2+)和X9∑-(PuC2+),势能函数为Murrell-Sorbie势函数,并导出了相应的几何性质,力学性质和光谱数据.     

Theoretical Study on the Structures and Stability of Isomers and Complex of [Si, C, O, O] System

Introduction[Si,C ,O ,O]systemhasattractedmuchattentioninthefieldsofchemistryandmaterials1 3becauseofthefollow ingseveralcauses .First,theinterestisthepotentialimpor tanceininterstellarspace .Heretofore ,SiC ,SiOandCOhavebeendetectedwithintheinterstellarmediumformanyyears,butno [Si,C ,O ,O]isomerswereobservedinthenebulae .FormanySi containingsystemshavebeenstudiedexperimentallyandtheoretically ,4 8andinviewofthepossibleexistenceofthe [Si,C ,O ,O]radicalininterstellarspace ,weselectthe…     

Predicting Potential Stable Isomers on the Singlet Surface of the [H,P,C,S] System by the MP2 and QCISD(T) Methods

A detailed singlet potential energy surface of [H,P, C,S] system is investigated by means of the MP2 and QCISD(T) methods. Eight isomers are located on the potential energy surface, and at the final QCISD(T)/6-311++G (3df,2p)//MP2/6-311++G(d,p) level with zero-point energy correction, the chainlike isomer HPCS is found to be kinetically and thermodynamically the most stable species followed by the chainlike HSCP, planar three-membered ring HC(S)P, chainlike HCPS, and stereo three-membered ring HP(C)S, which are predicted to be also kinetically stable isomers and should be experimentally observable provided that accurate experimental conditions are available. The dissociation processes from the kinetically and thermodynamically most stable species HPCS to the low-lying molecular dissociation fragments are not more favorable in energy than the isomerization process from HPCS to HSCP. Therefore, the experimental observation for potential isomer HSCP with C ≡ P triple bond is possible by means of photoisomerization technology using HPCS as precursor.     

Air stable,sterically hindered ferrocenyl dialkylphosphines for palladium-catalyzed C[bond]C,C[bond]N,and C[bond]O bond-forming cross-couplings

Pentaphenylferrocenyl di-tert-butylphosphine has been prepared in high yield from a two-step synthetic procedure, and the scope of various cross-coupling processes catalyzed by complexes bearing this ligand has been investigated. This ligand creates a remarkably general palladium catalyst for aryl halide amination and for Suzuki coupling. Turnovers of roughly 1000 were observed for aminations with unactivated aryl bromides or chlorides. In addition, complexes of this ligand catalyzed the formation of selected aryl ethers under mild conditions. The reactions encompassed electron-rich and electron-poor aryl bromides and chlorides. In the presence of catalysts containing this ligand, these aryl halides coupled with acyclic or cyclic secondary alkyl- and arylamines, with primary alkyl- and arylamines, and with aryl- and primary alkylboronic acids. These last couplings provide the first general procedure for reaction of terminal alkylboronic acids with aryl halides without toxic or expensive bases. The ligand not only generates highly active palladium catalysts, but it is air stable in solution and in the solid state. Palladium(0) complexes of this ligand are also air stable as a solid and react only slowly with oxygen in solution.     

Deactivation Mechanism for COS Hydrolysis over TGH Catalyst --- FT-IR Study of the

The adsorptions of COS, H2S and O2 were investigated over the TGH catalyst in this paper.It was found that the numbers of basic centers and basic intensities were reduced over the deactivated TGH catalyst. The FT-IR results of COS+H2S+O2 co-adsorption on the TGH catalyst show that the main causes of catalyst deactivation is the formation of element sulfur and trace sulfate.     

C36X(X=O,NH,S)各种可能异构体的芳香性研究

采用拓扑共振能方法对富勒烯C36X(X=O,NH,S)开环结构中的所有可能的异构体及阳离子和阴离子芳香性进行了理论研究. 计算结果表明,C36X的芳香性高于C36. C36X的阳离子因其共振能为负值而具有反芳香性. 反之,C36X的阴离子因共振能为正值而具有芳香性和较高的稳定性. C36的D6h和D2d异构体中杂原子X插入在5-5键时得到的化合物最稳定. 从理论上预测了C36X的负离子能形成稳定的金属富勒烯. 对C36X的阳离子和阴离子的芳香性进行了解释.     

1,1'-Di(heteroatom)-functionalised ferrocenes as [N,N], [O,O] and [S,S] chelate ligands in transition metal chemistry

Dppf is one of the most useful and popular ligands in coordination chemistry. Its overwhelming success has overshadowed and arguably even delayed the development and use of closely related ferrocene-based ligands with two ligating N, O or S atoms. Recently, however, dynamic progress concerning such homo-donor ligands can be noted. This tutorial review describes the main results obtained over the past decade in order to introduce the reader to an exciting field which currently shows particularly rapid development. The material is organised in sections according to ligand type, followed by a section which summarises the applications reported so far.     

C78O异构体的电子结构和光谱

The semi-empirical INDO method was used to study the electronic structures and the spectra of all of the 34 possible isomers of C78O based on C78 with group C2v. This calculation can simulate positions of an additional oxygen atom in C78 and predict the spectroscopic characteristics of the isomers. The most stable geometry of C78O is the 73,78-C78O molecule with an epoxide structure. The added 73,78-bond is located between two hexagons (6-6) and is intersected by the shortest C2 axis in C78 with group C2v. Atomic orbitals of the oxygen atom play an important role in lowering HOMO energy of 73,78-C78O. Compared with C78 with group C2v, the blue-shift in the electronic absorption spectrum for 73,78-C78O was observed.The reason of the blue-shift effect was discussed, and the electronic transitions were assigned based on the theoretical calculations.