多氯10-氧吩噁噻系列化合物的热力学性质及稳定性的密度泛函理论方法研究

采用Gaussian 03程序中的密度泛函理论(DFT)方法,在BHandHLYP/6-311G**水平上对135个多氯10-氧吩噁噻系列化合物(PCPTO)进行了全优化和振动分析计算,得到了各分子在298.15K,1.013×105Pa标准状态下的热力学参数.设计等键反应,计算了PCPTO系列化合物的标准生成热(△fH)和标准生成自由能(△fG),同时研究了这些参数与氯原子的取代位置及取代数目(NPCS)之间的关系.结果表明:熵(S),△fH,△fG与NPCS之间有很强的相关性(R2≥0.991).根据△fG的相对大小,从理论上求得异构体的相对稳定性.以Gaussian 03程序的输出文件为基础,采用统计热力学程序计算了PCPTO化合物在200至1000K的摩尔恒压热容(Cp,m),并用最小二乘法求得Cp,m与温度之间的相关方程,结果发现Cp,m与T,T-1和T-2之间有着很好的相关性(R2=1.000).     

多溴代二苯硫醚系列化合物的热力学性质和稳定性的理论研究

在B3LYP/6-31G*水平上对209个多溴代二苯硫醚(PBDS)系列化合物进行了全优化和振动分析计算,得到各分子在298.15K,1.013×105Pa标准状态下的热力学参数.研究了热力学参数S与溴原子的取代位置及取代数目(NPBS)之间的关系,结果表明:S与NPBS之间有很强的相关性(R2=0.993).设计等键反应,计算了PBDS系列化合物的标准生成热(△fH)和标准生成自由能(△fG).根据异构体标准生成自由能的相对大小,从理论上求得异构体的相对稳定性.以Gaussian03程序的输出文件为基础,采用统计热力学程序计算了PBDS化合物在200至1000K的摩尔恒压热容(Cp,m),并用最小二乘法求得Cp,m与温度之间的相关方程,发现Cp,m与T,T-1和T-2之间有着很好的相关性(R2=1.000).     

Theoretical Studies on the Molecular Structures and Thermodynamic Properties of Polychlorinated Fluorenes

Geometric structures of 135 polychlorinated fluorene (PCFR) molecules were optimized using density functional theory (DFT) at the B3LYP/6-311G** level and their thermodynamic properties in the ideal gas state were calculated. The relations of these thermodynamic properties with the number and position of chlorine atoms were also explored, from which the relative stability of PCFR congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation (Δr,fGθ). The results show that the geometric configuration of PCFR isomers is determined by the position of chlorine atoms. There exist two types of intramolecular weak interactions, i.e., C-H···Cl and Cl···Cl interactions in PCFR molecules. The change of ΔfHθ and ΔfGθ of most stable PCFR isomers with increasing the number of chlorine atoms is different from that in most unstable PCFR congeners. The values of ΔfHθ and ΔfGθ for PCFR isomers with the same number of chlorine atoms strongly depend on the position of chlorine atoms and the relative stability of PCFR congeners is mainly determined by intramolecular delocalized π bond and Cl···Cl nuclear repulsive interaction.     

DFT Study on the Thermodynamic Properties of Poly-bromine Carbazole

The molecular structures of 135 poly-bromine carbazole (PBCZs) compounds were fully optimized at the B3LYP/6-31G* level, and their thermodynamic properties at 98.15 K, 1.013 ×105 Pa were consequently obtained. Based on our isodesmic reaction, standard formation heat (ΔfH) and standard formation free energy (ΔfG) of PBCZs were calculated. Furthermore, the relationship between thermodynamic parameters and the position and number (NPBS) of Brsubstitution were also discussed. To our interest, a good dependence can be observed among entropy (S), ΔfH, ΔfG and NPBS. Ultimately, the theoretical stability order of isomers can be decided judging from the ΔfG value.     

DFT Study on the Correlation between Thermodynamical Property and Molecular Structure of Polybromo-phenoxathiin

Complete optimization was conducted for 136 polybromo-phenoxathiin congeners(PBPTs) on the B3LYP/6-31G* level with Gaussian 03 program.The structural parameters and thermodynamical parameters of each molecule were obtained under the standard state of 298.15 K and 1.013×105 Pa.Reverse linear regression was employed to establish the quantitative structure-property correlation models between heat capacity at constant volume(CVθ),entropy(Sθ),standard heat of formation(△fHθ) and standard free energy of formation(△fGθ) of PBPTs and the structural parameters(the most negative atomic charge(q-) and molecular average polarizability(α)).These models presented better correlations(r20.97).And they were validated by variance inflation factor(VIF) and t-test,which can better explain the regularity of thermodynamical property of PBPTs,and has good stability and great prediction ability.     

Theoretical Studies on the Molecular Structures and Thermodynamic Properties of Polychlorinated Acenaphthylenes

Geometric structures of 135 polychlorinated acenaphthylene (PCAC) molecules were optimized using density functional theory (DFT) at the B3LYP/6-311G** level and some thermodynamic properties of them in the ideal gas state were calculated. The relations of these thermodynamic properties with the number and position of chlorine atoms were also explored, from which the relative stability of PCAC congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation (△r,fGθ). The results show that all PCAC isomers have planar geometric configuration. There exists intramolecular Cl···Cl weak interaction in some PCAC molecules. The change of △fHθ and fGθ of most stable PCAC isomers with increasing the number of chlorine atoms is different from that in the least stable PCAC congeners. The values of fHθ and fGθ for PCAC isomers with the same number of chlorine atoms show a strong dependence on the position of chlorine atoms and the relative stability of PCAC congeners has close relation with the intramolecular Cl···Cl nuclear repulsive interaction.     

Comparative Study on Thermodynamic Properties and Stabilities of Polychloro-phenazines and Polychlorinated Dibenzo-p-dioxin

The thermodynamic properties and molecular volumes （Vm） of 76 polychlorophenazines （PCPZs） have been calculated at the B3LYP/6-31G^＊ level by using density functional theory. The isodesmic reactions were designed to calculate standard enthalpy of formation （△fH^θ） and standard free energy of formation （△fG^θ） of PCPZ congeners. According to the relative magnitude of their △fG^θ, the order of relative stability of PCPZ congeners was theoretically proposed. Comparing the results with those of polychlorinated dibenzo-p-dioxin （PCDD） isomers, it was found that S^θ, △fH^θ, △fG^θ, Vm and the order of relative stability of PCPZ congeners were quite similar to those of PCDDs.     

多氯咔唑系列化合物的热力学性质的密度泛函理论研究

采用Gaussian 03程序中的密度泛函(DFT)方法, 在B3LYP/6-31G*水平上对135个多氯咔唑系列化合物(PCCZs)进行了全优化计算, 得到了298.15 K, 1.013×105 Pa标准状态下各分子的热力学性质. 设计等键反应, 计算了PCCZs系列化合物的标准生成热(ΔfHÖ)和标准生成自由能(ΔfGÖ), 研究了这些参数与氯原子的取代位置及取代数目(NPCS)之间的关系, 结果表明: 熵(SÖ), ΔfHÖ, ΔfGÖ与NPCS之间有很强的相关性. 并根据ΔfGÖ的相对大小, 从理论上求得异构体的相对稳定性的顺序. 此外, 以Gaussian 03程序的输出文件为基础, 采用统计热力学程序计算了PCCZs化合物在200至1800 K的摩尔恒压热容(Cp,m), 并用最小二乘法求得Cp,m与温度之间的相关方程, 发现Cp,m与T, T－1和T－2之间有着很好的相关性.     

多氯代吩噁嗪热力学性质的密度泛函理论研究

在B3LYP/6-31G*水平上对135个多氯代吩噁嗪(PCPXs)系列化合物进行了全优化和振动分析计算, 得到各分子在298.15 K, 1.013×105 Pa标准状态下的热力学性质. 设计等键反应, 计算了PCPXs系列化合物的标准生成热(Δf )和标准生成自由能(Δf ), 研究了这些参数与氯原子的取代位置及取代数目(NPCS)之间的关系, 结果表明: 熵( )、Δf , Δf 与NPCS之间有很强的相关性. 根据异构体标准生成自由能的相对大小, 从理论上求得异构体的相对稳定性. 以Gaussian 03程序的输出文件为基础, 采用统计热力学程序计算了PCPXs化合物在200 K至1800 K的摩尔恒压热容(Cp,m), 并用最小二乘法求得Cp,m与温度之间的相关方程, 发现Cp,m与T, T－1和T－2之间有着很好的相关性.     

Thermodynamic Properties and Relative Stability of Polyhydroxylated Dibenzo-p dioxins Calculated by Density Functional Theory

In this work, partial thermodynamic properties of polyhydroxylated dibenzo-p-dioxins (PHODDs) are calculated by density functional theory (DFT) with the Gaussian 03 program at the B3LYP/6-311G** level. By comparing the total energy Eθ values, it is found that two types of hydrogen bonds exist in PHODDs, one between a hydroxyl and the parent compound (dibenzop-dioxin) with bond energy of approximate 15.7 kJ/mol and the other between two ortho hydroxyl groups with higher bond energy of about 18.3 kJ/mol. Hydrogen bonds have an effect on the conformation stability. On the basis of evaluating the strength of these two types of hydrogen bonds, 75 most stable congeners are ascertained. The relations of calculated thermodynamic parameters (total energy Eθ, zero-point vibrational energy ZPE, correction value of thermal energy Ethθ, heat capacity at constant volume CVθ) with the number and position of hydroxyl substitution (NPHOS) are also discussed. The results show that the NPHOS models can be used to predict the thermodynamic properties for PHODD congeners. In addition, the values of molar heat capacities at constant pressure (Cp,m) from 200 to 1000 K for PHODD congeners are calculated, and the temperature dependence relation of Cp,m is obtained with the least-squares method.     

多溴吩噻嗪系列化合物的稳定性和热力学性质的密度泛函理论研究

用Gaussian 03程序, 在B3LYP/6-31G*水平上全优化计算了吩噻嗪和135个多溴吩噻嗪系列化合物(PBPTHs)在298.15 K和101.3 kPa状态时的热力学参数. 设计等键反应, 计算了PBPTHs系列化合物的标准生成热( )和标准生成自由能( ). 同时研究了这些参数与溴原子的取代位置及取代数目(NPBS)之间的关系. 结果表明: 多溴吩噻嗪的热能校正值(Eth)、恒容热容( )、标准熵( )、标准焓( )以及标准自由能( )与NPBS之间有很强的相关性(r2≥0.998). 在相关方程中, 溴原子的取代个数对多溴代吩噻嗪热力学数值的大小有很大影响. 根据 的相对大小, 从理论上求得异构体的相对稳定性顺序.     

三聚氰胺的生成焓、热容和熵

通过多种热化学方法研究了三聚氰胺的热力学性质. 首先用氧弹式燃烧热量计测定了三聚氰胺在298.15 K 时的燃烧热, 根据燃烧热结果, 计算出三聚氰胺的标准摩尔燃烧焓和标准摩尔生成焓, 分别为: △cHΘm=(-2455.17±4.65) kJ·mol-1; △fHΘm =(-763.38±5.16) kJ·mol-1. 然后根据键焓与燃烧焓之间的关系, 估算出三聚氰胺中的C≈N(此键介于单键与双键之间)键能为458.30 kJ·mol-1, 此值介于碳氮单键键能和双键键能之间. 通过绝热热量计测定了三聚氰胺从80到385 K的低温热容. 根据热容值, 计算了此温度区间的标准摩尔生成焓, 其与温度呈线性关系. 另外, 三聚氰胺的热稳定性也用热重-差示扫描量热(TG-DSC)法进行了分析, 确定其分解的DSC曲线的峰顶温度为603.37 K.     

多溴代二苯胺热力学性质的密度泛函理论研究

在B3LYP/6-31G*水平上对209个多溴代二苯胺(PBDPA)系列化合物进行了全优化和振动分析计算, 得到各分子在298.15 K, 101.3 kPa标准状态下的热力学参数. 设计等键反应, 计算了PBDPA系列化合物的标准生成热(ΔfHÖ)和标准生成自由能(ΔfGÖ). 研究了热力学参数SÖ与溴原子的取代位置及取代数目(NPBS)之间的关系, 结果表明: PBDPA系列化合物的SÖ, ΔfHÖ和ΔfGÖ与NPBS之间有很强的相关性(R2≥0.984). 根据异构体标准生成自由能的相对大小, 从理论上求得异构体的相对稳定性. 以Gaussian 03程序的输出文件为基础, 采用统计热力学程序计算了PBDPA化合物在200 K至1000 K的摩尔恒压热容(Cp,m), 并用最小二乘法求得Cp,m与温度之间的相关方程, 发现Cp,m与T, T－1和T－2之间有着很好的相关性(R2＝1.000).     

用均根拓扑指数与路径数预测链烷烃的沸点和热力学性质

以距离矩阵为基础，建构调和均根拓扑指数（K），以表征链烷烃分子的大小 和分支情况，85种链烷烃的沸点(T_b)、标准生成焓(Δ_rH_m~θ)、标准熵(S_m~θ )、标准生成自由能(Δ_fG_m~θ)与K及路径数(P_2, P_3)的回归方程为: ln(793- T_b) = 6.48346-0.10092K + 0.00131P_2-0.01110P_3, R = 0.9996; -Δ_fH_m~θ = 62.664 + 25.331 K + 6.597 P_2 - 0.678 P_3, R = 0.9984; S_m~θ = 170. 691 + 67.425 K - 4.712P_2 + 5.251 P_3, R = 0.9989; Δ_fG_m~θ = -45.677 + 10.060 K + 0.555 P_2 + 2.342P_3, R = 0.9935。它们的计算值与相应实验值 都非常吻合。结果表明，K对链烷烃具有良好的结构选择性和性质相关性。     

Determination of combustion energies and the standard enthalpies of formation for the complexes of RE(Et_2dtc)_3(phen)

Solid complexes, RE(Et2dtc)3(phen) (RE=La, Pr, Nd, Sm-Lu), were synthesized with sodium diethyldithiocarbamate (NaEt2dtc3H2O),1,10-phenanthroline (o-phen·H2O) and hydrated lanthanide chlorides in absolute ethanol. The constant-volume combustion energies of complexes,ΔcU, were determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion,ΔcHmθ, and standard enthalpies of formation,ΔfHmθ, were calculated for these complexes, respectively. The experiment results showed the "tripartite effect" of rare earth.     

铜(II)与四(间甲基)苯基卟啉镉(II)取代反应动力学

用分光光度法研究了二甲亚砜溶液中, 氯化铜与meso-四(间甲基)苯基卟啉镉(Ⅱ)(Cd(Ⅱ)P)亲电取代反应的动力学. 讨论了影响反应的因素, CuCl_2+Cd(Ⅱ)P→Cu(Ⅱ)P+CdCl_2提出了反应机理并进行了验证. 用AST286微机对实验数据进行非线性最小二乘法拟合, 得到拟合曲线及似平衡步的平衡常数K及其它基元步骤的速率常数k_1, k_(-1), k_2. 研究了温度对反应的影响, 求得似平衡步的△_rH_m~-θ-, △_rS_m~-θ-及其它基元步骤的活化参数△~≠H_m, △~≠S_m.     

多氯代菲分子结构和热力学性质的密度泛函理论研究

采用密度泛函理论方法在B3LYP/6-311G(d, p)水平上对527个多氯代菲分子的几何结构进行了全优化并计算得到它们的热力学性质(等容热容( )、熵(S$)、标准生成焓(ΔfH$)和标准生成Gibbs自由能(ΔfG$)), 研究了这些性质与取代的氯原子数目和位置的关系, 根据各异构体的相对标准生成Gibbs自由能(Δr,fG$)的大小, 得到它们的热力学稳定性顺序. 计算结果表明: 绝大多数多氯代菲分子具有非平面的几何构型, 在多氯代菲分子中存在三种类型的分子内弱相互作用(H…H、C—H…Cl和Cl…Cl相互作用), 随着分子中取代的氯原子数目的增加, 多氯代菲最稳定异构体的ΔfH$和ΔfG$开始时逐渐减小, 然后又快速增加. 具有相同数目氯原子的多氯代菲异构体的ΔfH$和ΔfG$与氯原子的取代位置有很大的关系. 多氯代菲异构体的相对热力学稳定性主要由分子内的离域π键和Cl…Cl核排斥作用的强弱决定.     

DFT Study on Some Properties of Polybrominated Phenoxathiin 10-Oxides

With the B3LYP calculation method of density functional theory(DFT)and the 6-31G* basis set,full optimization calculation was made for phenoxathiin10-oxide(PTO)and 135 polybromine phenoxathiin 10-oxides(PBPTOs)with the Gaussian 03 program and molar heat capacity in constant volume(CVθ)value of each molecule in the standard state was obtained.The relation between CVθ and the substitution position and number of bromine atom(NPBS)was studied,and the results indicated good correlation(R2 = 1.000)between CVθ and NPBS of PBPTO compounds.Based on the output file of Gaussian 03 program,molar heat capacity at constant pressure(Cp,m)of PBPTO compounds from 200 to 1,000 K was calculated with the statistical thermodynamics program,and the correlation equation between Cp,m and temperature(T,T-1 and T-2)was obtained with the least-squares method,and the correlation coefficient of the correlation equation(R2)was 1.000.In addition,based on the partition function of each molecule calculated by vibration analysis,the relative rate constant of formation of each molecule was calculated.     

硝酸咪康唑与牛血清白蛋白作用的热力学特征研究

在模拟动物体生理条件和不同温度下,用荧光猝灭光谱、同步荧光光谱、三维荧光光谱和紫外可见吸收光谱等,研究了不同温度下硝酸咪康唑(Miconazole Nitrate,MIN)与牛血清白蛋白(BSA)相互作用的光谱行为。用Stern-Volmer方程、Lineweav-er-Burk双倒数方程和热力学方程等处理实验数据,得到在16～37℃温度范围内的作用常数KLB及热力学参数;发现MIN与BSA可结合形成具有一定结构的复合物,其荧光猝灭作用更符合静态猝灭作用特征,作用力可能主要是静电力;同时探讨了MIN对BSA构象的影响。为研究MIN的治病机制和生物学效应等提供了重要信息。     

聚氧乙烯月桂醚在含醇的非水体系中的热力学性质的微量量热法研究

对于非离子表面活性剂聚氧乙烯月桂醚(Brij-35)/N,N-二甲基甲酰胺(DMF)/长链醇(庚醇,辛醇,壬醇,癸醇)体系,利用滴定微量量热仪测定了胶束形成过程的热功率-时间曲线.根据热力学理论,测定了临界胶束浓度和胶束形成热(ΔHmθ),计算了热力学函数(ΔGmθ和ΔSmθ).讨论了温度、醇中的碳原子数、醇的浓度与临界胶束浓度和热力学函数之间的关系.结果表明:聚氧乙烯月桂醚(Brij-35)/DMF/长链醇体系:(1)在含有相同浓度的各种醇的体系中,ΔHmθ和ΔSmθ的值随着温度的升高而增大;CMC,ΔGmθ的值随着温度的升高而降低;(2)在相同温度及相同浓度的醇体系中,CMC,ΔHmθ,ΔGmθ和ΔSmθ的值都随着醇中碳原子数的增加而降低;(3)在相同温度及相同醇的体系中,CMC,ΔHmθ,ΔSmθ和ΔGmθ的值随着醇的浓度的增加都减小.