CH2=CHCl与O(3P)反应的理论研究

用量子化学密度泛函理论和QCISD(Quadratic configuration interaction calculation)方法,对0(^3P)与CH2CHCl的反应进行了理论研究．在UB3LYP／6—311 G(d,p),UB3LYP／6—31 (3df,3pd)计算水平上,优化了反应物、产物、中间体和过渡态的几何构型,并在UQCISD(T)／6—311 G(2df,2pO)水平上计算了单点能量．为了确证过渡态的真实性,在UB3LYP／6—311 G(3df,3pd)水平上进行了内禀坐标(IRC)计算和频率分析,并确定了反应机理．研究结果表明,反应主要产物为CH2CHO和Cl．     

O(3P)+O2H→OH+O2反应机理的密度泛函理论研究

用密度泛函理论方法研究了O(3P)与O2H反应生成羟基和氧分子的反应机理. 在PW91/6-31+G水平上用梯度解析技术全自由度优化上述反应物、产物和反应路径上的中间体及过渡态几何构型, 并通过频率振动分析加以确认, 计算IRC反应路径及中间体异构化过程, 确定了此反应的可能反应通道. 结果表明: 该反应是多通道多步骤的强放热反应. 首先形成顺式或反式O3H富能中间体, 此过程无能垒; 然后跨过一个能垒分解成产物OH和O2. 通道IM1→TS1比IM2→TS2克服的能垒要大, 反应放热372.822 kJ*mol-1. IM1TS3IM2 可相互转化.     

亚甲基自由基(3CH2)与So反应机理的理论研究

白洪涛,黄旭日,于广涛,李吉来,于健康,孙家钟. 亚甲基自由基(3CH2)与SO反应机理的理论研究[J]. 化学学报, 2006, 64(2): 139-144.     

BrONO2光解反应的理论研究

采用密度泛函方法,研究了大气臭氧层主要破坏物BrONO2的光解反应机理,在UB3LYP/6-311++G**水平上优化了反应物、产物、中间体和过渡态的几何构型,并在UQCISD(T)/6-311++G**水平上计算了单点能量,为了确证过渡态的真实性,在UB3LYP/6-311++G**水平上进行了内禀反应坐标(IRC)计算和频率分析.研究结果表明,BrONO2的光解反应有两条反应通道,其中生成BrO+NO2的反应活化能较小(14.89 kJ·mol-1),较易发生.     

(CH2)2N和(CH3)2NH+的密度泛函理论计算

用密度泛函理论UB3LYP／6-31G（d,p）方法研究了二甲胺自由基（CH3）2N及其质子化离子（CH3）2NH 的构象和超精细结构．在由构象研究得到的两种自由基的最稳定结构上,用密度泛函的UB3LYP和UB3PW91方法及从头计算的UHF、UMP2（FULL）方法计算了α-质子、β-质子和N核上的超精细偶合常数A（Hα）、A（Hβ）和A（N）结果表明：两种自由基中甲基内旋转的位垒均很低,分别为0．46kJ·mol-1（（CH3）2NH ）和2．6kJ·mol-1（（CH3）2N）．UB3LYP／6-31G（d,p）和UB3PW91／6-31G（d,p）计算的A（Hα）、A（Hβ）和A（N）与ESR实验结果符合得很好,UMP2／6-31G（d,p）方法的计算值与实验值符合得也较好．     

NH2(～X2B1)与CH4反应机理的理论研究

在密度泛函理论B3LYP／6－311G^*水平下，研究了NH2与CH4的反应机理。通过振动频率和内禀反应坐标（IRC）分析，对反应过渡态进行了确认。在QCISD（T）／6－311G^*水平下进行了单点能计算，并进行了零点能校正，结果表明，反应NH2＋CH4→N3＋CH3是主要的反应通道。     

O(3P)+O2H——OH+O2反应机理的密度泛函理论研究

用密度泛函理论方法研究了O(³P)与O₂H反应生成羟基和氧分子的反应机理.在PW91/6-31+G^*水平上用梯度解析技术全自由度优化上述反应物、产物和反应路径上的中间体及过渡态几何构型,并通过频率振动分析加以确认,计算IRC反应路径及中间体异构化过程,确定了此反应的可能反应通道.结果表明:该反应是多通道多步骤的强放热反应.首先形成顺式或反式O₃H富能中间体,此过程无能垒;然后跨过一个能垒分解成产物OH和O₂.通道IM1→TS1比IM2→TS2克服的能垒要大,反应放热372.822kJ.mol^-1.IM1TS3IM2可相互转化.     

CH3O和CO在Pd(111)表面偶联反应机理的理论研究

采用DMol³程序包中的GGA-PW91方法, 结合周期平板模型, 对CH₃O和CO在Pd(111)表面的反应进行了系统研究. 计算结果表明, 吸附在Pd(111)表面顶位上的CO分子中C原子所带正电荷最多, 容易与亲核试剂反应, 化学吸附能稍低, 有利于在表面上移动发生亲电插入反应; CH₃O 在Pd(111)表面fcc穴位吸附稳定, O原子上所带的负电荷较多, 易被亲电试剂进攻. 过渡态搜索表明, Pd(111)表面顶位上的CO与fcc穴位上CH₃O反应生成CH₃OOC的为放热反应, 反应能垒较低, 有利于偶联反应的进行.     

Cu_2O(111)催化水煤气变换反应机理的理论研究

采用密度泛函理论结合周期平板模型方法系统地研究了水煤气变换反应在Cu_2O(111)表面上的反应机理,包括氧化还原机理、羧基机理和甲酸根机理.结果表明,在Cu_2O(111)表面,羧基机理和甲酸根机理均可行,且甲酸根机理更为有利,其最佳反应途径为H_2O~*→H~*+OH~*;CO(g)+H~*+OH~*→trans-HCOOH~*(1)→cis-HCOOH~*→CO_2~*+H_2(g).其中trans-HCOOH~*(1)→cis-HCOOH~*为其决速步,该基元反应的能垒仅为59 kJ·mol~(-1).羧基机理的最优反应路径同样是以H_2O的解离反应开始,随后CO(g)+OH~*→cis-COOH~*→trans-COOH~*→CO_2(g)+H~*,最后产生的两个吸附的H原子先迁移再结合生成H_2,整个反应的控速步骤为H原子的迁移,迁移能垒为96 kJ·mol~(-1).氧化还原机理则由于OH解离需要越过一个很高的能垒(254 vs.187 kJ·mol~(-1))而不可行.     

二重态下反应HCCO(2A″)+O2(3∑-g)的势能面理论研究

选用cc-p VDZ,cc-pVTZ基组用密度泛函方法(B3LYP)研究了基态羰游基自由基HCCO(2A″)与基态氧分子O2(3∑g^-)反应的机理,在B3LYP／cc-pVDZ优化的几何构型基础上,使用CCSD(T)／cc-pVDZ方法进行了单点能校正．此外,还采用基于B3LYP／6-31G^*几何构型及振动频率的G383理论对所有驻点进行了更精确的能量计算．结果表明,只需越过6．31kJ／mol或6．23kJ／mol的位垒,氧分子中的一个氧原子便很容易地与羰游基中紧邻氢原子的碳原子相结合得到两个总能较比反应物低88．11kJ／mol或84．85kJ／mol的开环中间体,此二开环中间体很容易发生C-C-O-C环合或C-O-O环合从而转化为更稳定的环式异构体(总能较比反应物低149．81kJ／mol和54．97kJ／mol),转化位垒分别为8．73kJ／mol和86．44kJ／mol,该二环式异构体均很容易分解为反应的最终产物H CO CO2,其它可能的通道也在本文中有所探讨。     

二苯基乙二酮结构和电子光谱的理论研究

基于二苯基乙二酮结构优化,在TD-B3LYP/6-31+G*水平上讨论了两个异构体在气相和液相中的吸收和发射光谱.溶液中的计算采用可极化连续介质模型.结果表明,溶剂极性增加更有利于顺式非平面构型的形成,两个异构体的T1和S1态以及顺式非平面结构的S2态都源于双羰基上的n→π*.     

DFT studies of the phosphinidene derivative HPNaF and its insertion reaction with R–H(R=F,OH, NH<Subscript>2</Subscript>, CH<Subscript>3</Subscript>)

The formations of the phosphinidene derivative HPNaF and its insertion reactions with R–H (R=F, OH, NH₂, CH₃) have been systematically investigated employing the density functional theory (DFT), such as the B3LYP and MPW1PW91 methods. A comparison with the results of MP2 calculations shows that MPW1PW91 underestimates the barrier heights for the four reactions considered. Similarly, the same is also true for the B3LYP method depending on the selected reactions, but by much less than MPW1PW91, where the barrier heights of the four reactions are 25.2, 85.7, 119.0, and 142.4 kJ/mol at the B3LYP/6-311+G* level of theory, respectively. All the mechanisms of the four reactions are identical to each other, i.e., an intermediate has been located during the insertion reaction. Then, the intermediate could dissociate to substituted phosphinidane(H₂RP) and NaF with a barrier corresponding to their respective dissociation energies. Correspondingly, the reaction energies for the four reactions are −92.2, −68.1, −57.2, and −44.3 kJ/mol at the B3LYP/6-311+G* level of theory, respectively, where both the B3LYP and MPW1PW91 methods underestimate the reaction energies compared with the MP2 results. The linear correlations between the calculated barrier heights and the reaction energies have also been observed. As a result, the relative reactivity among the four insertion reactions should be as follows: H–F > H–OH > H–NH₂ > H–CH₃.     

Theoretical studies of the geometries of H2GeNaF and its insertion reaction with R?H (RF,OH, NH2, CH3)

The geometries and insertion reactions of germylene H₂GeNaF with R? H (R?F, OH, NH₂, CH₃) have been investigated at the B3LYP/6‐311+G level of theory. The potential barriers of the four reactions are ～52, 120, 184, and 257 kJ/mol, including the ZPVE corrections, respectively. Here, all the mechanisms of the four reactions are identical to each other; i.e., an intermediate has been located during the insertion reaction. The intermediate could dissociate into substituted germylane and NaF with the barrier corresponding to the dissociation energy. Correspondingly, the reaction energies for the four reactions are ?43, ?4, 21, and 51 kJ/mol, respectively. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

Al(H2O)63+水交换反应溶剂效应的量子化学团簇模型-密度泛函理论方法研究

在气相模型、极化连续模型、超分子模型和超分子-极化连续模型的基础上,采用量子化学团簇模型密度泛函理论方法,在B3LYP/6-311+G(d,p)基组水平下系统地开展了以下研究:优化得到Al(H2O)63+水交换反应的反应物、过渡态和产物构型,采用MP2方法在相同基组水平下计算得到相应的单点能,考虑零点振动能、热力学校正项和熵等参数的影响,计算得到Al(H2O)63+水交换反应的Gibbs自由能变和反应速率常数kex.计算结果表明:GP-SM//MP2-PCM和GP-SM-PCM//MP2-PCM模型得到的kex相近,并且与文献值相符,说明GP-SM//MP2-PCM模型可以充分考虑真实溶剂效应和主体溶剂效应,适用于Al(H3O)63+体系水交换反应的模拟.     

钠氟类硅烯插入RH键(R=F,OH,NH2,CH3)反应的理论研究

用密度泛函方法研究了钠氟类硅烯插入R_H键(R=F,OH,NH2,CH3)的反应机理.4个反应的机制类似,反应经历了类硅烯的亲电接近、亲核插入和取代三个阶段之后,形成中间络合物,4个反应的势垒分别为0.9,61.7,114.6和190.6kJ/mol(经零点能校正).中间络合物可以解离为取代硅烷和NaF,这是一个无过渡态的过程.反应能分别是-122.6,-96.3,-6.8和50.2kJ/mol.     

Trends in the Structural and Vibrational Properties of the Disulfanes S2X2 (X = H,Halogen, CH3, CF3)

The geometrical parameters and associated force constants for the molecules XSSX (X = H, halogen, CH₃, CF₃) were studied using DFT quantum chemistry calculations. The study showed rather monotonic trends in these properties related to the SS bonds, although an anomalous behavior is noted when the substituent is CF₃. The calculated vibrational frequencies allowed a confirmation of published band assignments, but corrections were necessary for S₂F₂ and S₂H₂.     

C3H2环丙烯基自由基与O(3P)反应机理的理论研究

本文用量子化学密度泛函方法对C3H2 (环丙烯基自由基)与O(3P)反应的机理进行了理论研究。在B3LYP/6-311++G**计算水平上优化了各驻点（过渡态,中间体,产物）的几何结构,在QCISD(T)/6-311++G**水平下计算了各物质的单点能量,在两种水平下计算了298K和600K时的能量。计算结果表明：C3H2 + O(3P) 反应可以生成P1 (C2H +HCO),P2 (C2H2 + CO) 和P3 (HC3O+H)三种产物。生成P1反应通道的能垒最低,即P1为主要产物,与实验的结果一致。产物P1可以通过路径：R→ IM1→ IM2→ P1获得。本文详细地讨论了C3H2 + O(3P) 的反应机理,并从理论上对实验结果进行了验证。研究结果有助于深入理解C3H2 + O(3P)反应机理以及C3H2在大气中的燃烧过程。     

Competitive Intramolecular Aryl‐ and Alkyl‐C?H Bond Activation and Ligand Evaporation from Gaseous Bisimino Complexes [Pt(L)(CH3)((CH3)2S)]+ (L=C6H5NC(CH3)?C(CH3)NC6H5)

Mechanistic details for the formation of methane from the title compound as well as the combined elimination of (CH₃)₂S/CH₄ are derived from various mass‐spectrometric experiments including deuterium‐labeling studies and DFT calculations. For the first process, i.e., methane formation, we have identified three competing pathways in which the intact, Pt‐bonded methyl group combines with a H‐atom that originates from a phenyl substituent (ca. 7%), the dimethyl sulfide ligand (ca. 41%), and a methyl group of the diazabutadiene backbone (ca. 52%). In contrast, in the combined (CH₃)₂S/CH₄ elimination, the methane is specifically formed from the Pt‐bound CH₃ group and a H‐atom provided by one of the phenyl groups (‘cyclometalation’).     

Theoretical determination of the favorable mechanism of the reaction between AlX and HX (X = Br, Cl, and F)

The reaction mechanism between AlX and HX (X = Br, Cl, and F) have been characterized in detail using DFT as well as the ab initio method. The reaction yielding AlX₃ and molecular hydrogen was calculated to be highly exothermic. The present calculations also show that the possible routes to the trihalides species start more favorable with the primary insertion product AlX₂H than with the biadduct AlX(HX)₂ one.