连接性指数及其逆指数对-元醇折光指数的拓扑研究

定义了原子特征值βi和βi＇，由βi建构连接性指数^mXA，由βi＇建构其逆指数^mXB，运用定量结构-性质相关技术研究了42个-元醇分子的折光指数与分子结构间的定量关系。通过多元回归的方法建立了^mXZ和^mXB与折光指数的定量结构性质模型，回归方程为：nD=0．1419^0XA^-1＋0．0434^1XA^-1-0．2534^0XB^-1-0．1460^1XB^-1＋1．4659。对醇折光指数的计算结果表明，预测值与实验值的一致性令人满意，平均相对误差为0．15％。研究表明连接性指数及其逆指数在一起使用可以更好地反映出醇的构效关系。     

连接性指数及其逆指数对一元醇折光指数的拓扑研究

定义了原子特征值βi和β'i,由βi建构连接性指数mXA,由β'i建构其逆指数mXB,运用定量结构-性质相关技术研究了42个一元醇分子的折光指数与分子结构间的定量关系.通过多元回归的方法建立了mXA和mXB与折光指数的定量结构性质模型,回归方程为:nD=-0.14190X-1A+0.04341X-1A-0.25340X-1B-0.14601X-1B+1.4659.对醇折光指数的计算结果表明,预测值与实验值的一致性令人满意,平均相对误差为0.15%.研究表明连接性指数及其逆指数在一起使用可以更好地反映出醇的构效关系.     

新拓扑指数A_m在构效关系研究中的应用──Ⅰ.对烃类气相色谱的保留指数的分析

该文研究了本实验室提出的Am拓扑指数和烃类气相色谱保留指数的相关关系，并与分子联接性指数进行了对比分析，得到了比较理想的相关方程，使相关系数分别达到0.993以上。     

分子拓扑指数与链烷烃热力学性质的关系

碳原子个数N和路径数P3是表征链烷烃分子的大小、支化度和形状等结构特征的重要参数,引入烷烃所含甲基数的1.5次方M1和3次方M2表征取代基效应,运用多元线性模型研究了链烷烃标准生成焓、标准摩尔熵、标准生成吉布斯自由能等三种热力学性质与N,P3,M1和M2之间的定量关系,相关系数分别达到0.9993,0.9989和0.9972,标准偏差分别是2.2809kJ/mol,5.9093J/(mol·K),2.0585kJ/mol,其计算值与实验值非常接近.     

取代羧酸pKa的分子树拓扑研究

基于非氢原子i的酸性点价(δai)建构分子树拓扑指数(mT)及其分支指数(mTC)和叶指数(mTx),并提出表征诱导效应的叶指数(mT′x).通过最佳变量子集算法获得38种羧酸的pKa与0TC、1TC、0T′x的回归方程:pKa=3.0352-1.25700T′x-0.15540TC+0.07811TC,R=0.9766.通过Jackknife法检验,该模型具有总体稳健性.优于文献的七元最佳回归模型(R=0.957),与其分子力学方法(CoMFA)结果(R=0.988)较为接近.结果表明,所建拓扑指数是合理的,具有科学性基础.     

酚的拓扑指数在色谱分析中的应用

图论基础上的拓扑指数在研究物质的定量结构-性质相关性(QSPR)方面发挥了重要的作用. 在众多的拓扑指数中,Wiener指数和物性相关性好,容易计算,应用范围较广[1].在色谱分析中,色谱保留指数作为定性指标的保留值是一种较为可靠的参数.本文选择了酚中具有代表性的15种酚及色谱保留指数,通过对Wiener指数(W),官能团位置指数(Sox)和酚上的甲基数(X-CH3)与色谱保留指数的多元线性回归分析,得到了良好的相关性 .可以说,当测得某一色谱保留指数时可估计其结构特性,进而为酚类化合物的定性分析提供有利的信息.     

新拓扑指数Am构效关系研究中的应用：Ⅰ.以烃类气相色谱的保留指数…

该文研究了本实验提出的Ａｍ拓扑指数和烃类气相色谱保色指数的相关关系，并与分子联接性指数进行了对比分析，得到比较理想的相 关方程，使相关系数分别达到０．９９３以上。     

Wiener指数的新定义及其对气相色谱保留指数的相关性研究

1引言 Wiener于1947年提出的距离矩阵指数W，是世界上第一个分子拓扑指数，但由于Ⅳ所含信息较少，限制了Wiener指数在更广泛领域的应用。许多学者对此进行了改进并提出了许多距离矩阵指数，如Hosoya指数、Detour指数、Harary指数等。但是这些指数缺少分子结构中杂原子、多重键等信息，其应用仍然仅限于碳氢化合物。本研究采用原子的拓扑能量重新定义Wiener矩阵的矩阵元，将杂原子的信息引入Wiener指数中，重新定义Wiener指数为形^＋，并利用W^＋指数研究含杂原子胺、硫醚、卤代烷类化合物的气相色谱保留指数砌，将距离矩阵指数的应用扩展到含杂原子的体系。     

Condensed Extended Hyper-Wiener Index

According to the definitions of molecular connectivity and hyper-Wiener index, a novel set of hyper-Wiener indexes （Dn, ^mDn） were defined and named as condensed extended hyper-Wiener index, the potential usefulness of which in QSAR/QSPR is evaluated by its correlation with a number of C3-C8 alkanes as well as by a favorable comparison with models based on molecular connectivity index and overall Wiener index.     

拓扑指数F(′F)与气相色谱保留指数RI的相关性研究

用结构参数构成的矩阵定义了拓扑指数Ｆ（′Ｆ），计算了１０个系列９４个分子的 Ｆ（′Ｆ）值。发现Ｆ（′Ｆ）与这些化合物的气相色谱保留指数有好的相关性．相关系数均在０．９７ 以上。     

烷烃中碳氢键离解能的估算及其应用

将烷烃中的C－H键看成氢原子H与烷基Ri相连接而成的Ri－H键，以烷基的 HOMO能级和氢原子的轨道能来关联Ri－H键的离解能BDE。研究表明，烷烃分子中 Ri－H键的离能BDE与烷基Ri的极化效应指数PEI（Ri）有良好的线性关系：BDE＝ c+dPEI(Ri)。所得方程具有良好的估算精度。烷基Ri极化效应指数PEI（Ri）在羟 基自由基与烷烃反应速度常数的定量相关中，也得到良好的应用。     

取代基效应定量研究新进展

综述了最近20多年有机化学取代基效应定量研究所取得的诸多新进展.主要内容包括：（1）电负性均衡原理得到普遍认同并用于计算分子中电荷分布和基团的诱导效应,分子电负性计算方法在几何平均法、调和平均法、加权平均法的基础上又提出了价电子均衡方法,进一步扩展了电负性均衡原理的应用范围.（2）试剂亲电、亲核能力的实验测定,提出了以二苯甲基正离子和醌甲基化合物等作为参考化合物的标定方法,其研究范围被扩展到气相条件、有机金属反应和自由基体系,得到一系列试剂的亲核参数N和亲电参数E.理论上提出亲电性指数和亲核性指数的概念及其定量计算公式,并对实验测定参数和理论计算指数之间的关系进行了深入研究.（3）极化效应参数从最初的经验方法,进而采用量子化学方法计算,再用统计方法提出了烷基极化效应指数PEI和基团极化效应参数PEIX,被广泛用于解释和估算有机化合物的气相酸碱性、电离能、生成焓、键能、反应速率、水溶解性和色谱保留值.（4）直接由取代苯的紫外光谱吸收能量计算得到的取代基激发态参数exCC,不同于取代基在分子处于基态的极性参数和自由基状态下的自旋离域效应参数,该参数用于对位二取代苯、取代二苯乙烯、二取代氮苄叉苯胺等多类有机化合物紫外光谱的定量相关,结果良好.（5）立体屏蔽效应的提出区分了传统的三种立体效应.在羰基与亲核试剂加成反应立体选择性定量表示,提出了立体选择性指数Ci;在表示基团对反应中心表面积屏蔽的定量提出了屏蔽参数SR,进一步基于反应中心体积被屏蔽的角度提出了拓扑立体效应指数TSEI,这些参数在分子内二面角、反应的立体选择性、烯烃和烷基苯的生成焓、咪唑离子液体的酸性以及烷烃与羟基自由基的反应速率等方面得到良好的应用.此外,论文还对有机化学取代基效应定量研究中值得进一步深入探索的领域和问题提出了建议和展望.     

离子性指数、极化效应指数烷烃^13C NMR化学位移的 关系研究

定义了烷烃分子中碳原子的离子性指数(INI)，用离子性指数(INI)、极化效应指数(PEI)及N^i~H(i=αβΥ)结构信息参数研究了烷烃的^13CNMR化学位移模型，结果表明，烷烃^13CNMR化学位移(CS)可用下式来定量描述：CS=194.6156-37.7394(INI)+98.6505(ΣPEI)+27.1630(INI/ΣPEI)-652.9106(ΣPEI/INI)+0.7735N^α~H+2.2468N^β~H-0.1742N^γ~H。用上式估算了304个碳原子的化学位移，平均绝对误差仅为0.77δ，标准差0.9860δ，预测值与实验值非常吻合。     

单取代烷烃液相生成焓估算新方法

根据烷基R和取代基X(Cl、Br、I、OH、SH、NO2、CN、NH2、CHO和COOH等)本身的电子效应, 应用烷基R的极化效应指数PEI和取代基X的电负性χX定量描述单取代烷烃RX中R和X间的相互作用, 再结合已提出的C—C键和C—H键的键连接矩阵的特征根, 建立了一个估算单取代烷烃RX液相生成焓的方程： ΔfH0(RX, l)＝－39.5001ΣX1CC＋33.5508NCC－0.0789ΣX1CH－25.7087NCH＋0.1557ΣSij＋0.9976H(X)－ 27.6642 PEI(R)×χX＋31.5043χX 此方程用于估算RX的生成焓, 不仅结果非常令人满意(其相关系数R达到0.9999, 标准偏差SD仅为2.87 kJ•mol^-1), 而且方程中各项参数的物理意义也非常明确, 便于人们深入地理解分子结构与性能的关系. 应用去一法(leave-one-out)对以上方程进行交叉验证分析表明该方程具有较好的稳定性和较强的预测能力. 研究发现, 著名的Luo氏方程是上述方程的一种特殊形式, 上述方程是对Luo氏方程的一个较大扩展. 该方法为研究更复杂体系内基团之间的相互作用提供了一种新的方法和思路.     

On molecular polarizability: 3. Relationship to the ionization potential of haloalkanes, amines, alcohols, and ethers

The relationship between the ionization potential and the parameters molecular electronegativity and molecular polarizability for haloalkanes, amines, alcohols, and ethers was investigated. There is no good linear correlation between the ionization potential Ip and molecular electronegativity chi(eq) alone for these compounds. Ip can be modeled well with three parameters: chi(eq), polarizability effect index (PEI) of an alkyl group, and atomic polarizability (P). Further, a single expression for predicting the Ip values of aldehydes, esters, nitriles, and carboxylic acids was developed: Ip(Rz)(eV) = Ip(MeZ) + 1.4544delta chi(eq) - 1.6435delta sigmaPEI(Ri). Here Ip(MeZ) is the experimental ionization potential of monosubstituted methane MeZ. Delta chi(eq) and delta sigmaPEI(Ri) are the difference in the molecular electronegativity and the difference in the polarizability effect index of alkyl groups attached to the functional group Z between molecules MeZ and RZ, respectively.     

共轭烯烃的共轭极化势

Based on the conjugated polarization theory,it is expressed as the conjugated polarizability potential （CPP）that the discrepancy between the average electrostatic energy of dipolar state and the electrostatic energy of non-polar state in the conjugated polarizability procedure for the conjugated alkenes. The correlation between CPP and the energy of ultraviolet absorption maximum,and the correlation between the energy of frontier molecular orbital obtained by ab initio calculation of quantum chemistry and the energy of ultraviolet absorption maximum have been carried out for the conjugated alkenes. Both correlation equations show a similar estimated precision. Further, the contribution of alkyl polarizability effect to the stability of dipolar state for the alkyl substituted alkenes with the effective polarizability effect index（PEI（ef））was quantified. Relating the above two parameters CPP and PEI（ef）to the energy of ultraviolet absorption maximum of the substituted alkenes in a two-parameter expression with a good prediction ability was obtained:v=1.1746+5.0187CPP-0.43204PEI （ef）,R=0.9995,s=0.0403,F=10853.28,n=23. The investigated results also indicate that it is less effective to reduce the energy of ultraviolet absorption maximum by means of increasing the alkyl substituent groups than lengthening the conjugated backbone chain in the conjugated alkenes.     

醇溶剂对羰基(C=O)紫外吸收的定量影响

以各种醇为溶剂测定了丙酮和环己酮的羰基紫外吸收能量△E,讨论了△E与醇分子结构的关系。结果表明△E与醇分子中烷基的极化效应指数PEI有良好的线性关系:△E=a bPEI     

单取代烷烃定量结构-保留相关研究中的分子结构分区处理方法

将单取代烷烃RX(X=卤素,OH,SH,NH2等)分子结构分为两个区域(R和X)来提取分子结构参数,从三方面影响因素(烷基R、取代基X、R与X的相互作用)来定量关联RX的气相色谱保留时间。实验测定了37种单取代烷烃RX的气相色谱保留时间,并以键连接矩阵特征根之和EVM、烷基极化效应指数PEI、取代基质量分数w和取代基上氢原子所带部分正电荷ΔNH 4个参数为变量,建立了定量结构-保留相关模型。该模型具有良好的预测能力和外推能力,对醇在不同色谱柱上的保留指数进行了预测,结果与测定值符合得较好。     

Recent progress in quantifying substituent effects

This paper summarizes significant progress in quantifying organic substituent effects in the last 20 years. The main content is as follows: (1) The principle of electronegativity equalization has gained wide acceptance, and has been used to calculate the intramolecular charge distribution and inductive effect of groups. A valence electrons equalization method was proposed to compute the molecular electronegativity on the basis of geometric mean method, harmonic mean method, and weighted mean method. This new calculation method further extended the application of the principle of electronegativity equalization. (2) A scale method was established for experimentally determining the electrophilic and nucleophilic ability of reagents, in which benzhydryliumions and quinone methides were taken as the reference compounds, and the research field was extended to the gas phase conditions, organometallic reaction and radicals system. Moreover, the nucleophilicity parameters N and electrophilicity parameters E for a series of reagents were obtained. The definition and quantitative expression of electrophilicity index and nucleophilicity index were proposed theoretically, and the correlation between the parameters from experimental determination and the indexes from theoretical calculation was also investigated. (3) The polarizability effect parameter was initially calculated by empirical method and further developed by quantum chemistry method. Recently, the polarizability effect index of alkyl (PEI) and groups (PEI X ) were proposed by statistical method, and got wide applications in explaining and estimating gas-phase acidity and basicity, ionization energy, enthalpy of formation, bond energy, reaction rate, water solubility and chromatographic retention for organic compounds. (4) The excited-state substituent constant ex CC obtained directly from the UV absorption energy data of substituted benzenes, is different from the polar constants in molecular ground state and the radical spin-delocalization effects constants in molecular radical state. The proposed constant ex CC correlated well with the UV absorption energy of many kinds of organic compounds, such as 1,4-disubstituted benzenes, substituted stilbenes, and disubstituted N-benzylidenebenzenamine. (5) The establishment of the steric shielding effect distinguished the three traditional steric effects. The stereoselectivity index C i was proposed to quantify the stereoselectivity of the addition reaction of carbonyl with nucleophilic reagent. The shielding parameter S R was defined to quantitatively express the specific surface of the reaction center screened by a group. Further, the Topological Steric Effect Index (TSEI) of a group was proposed on the basis of the relative specific volume of reaction center screened by the atoms of substituents. These parameters can be applied in estimating the intramolecular dihedral angles, stereoselectivity of reaction, enthalpies of formation of alkenes and alkylbenzene, acidity of substitutedimidazolium ionic liquid, and the reaction rate of alkane and hydroxyl radical. In addition, some suggestions and prospects for further studies on quantifying the organic substituent effects were presented in this paper.     

有效碳链长度与脂肪醇的沸点

脂肪醇沸点(b.p.)变化规律可用下述关系式表示:ln(800.386-T~b)=6.64919-2.94828×10^-^2N~E~C~C+0.150955ΔPEI。式中N~E~C~C为醇中烷基的有效碳链长度, ΔPEI是具有相同碳原子数目的支链烷基与直链烷基的极化效应指数的差值, 它表示羟基对醇的沸点的影响。