多氯代二苯并呋喃在不同色谱柱上的气相色谱保留行为——定量结构-色谱保留关系(QSRR)的研究

 以一种拟原子的方式处理多氯代二苯并呋喃 (PCDFs)异构体中的苯环 ,将PCDFs异构体中的原子或基团分为 3类 ,即 :氯原子 (Cl) (记为“1”) ,氧原子 (O) (记为“2”)及拟原子 (B) (记为“3”)。在烷烃分子距边矢量的基础上 ,提出一种以基团为基准的分子距离边数矢量 (μ矢量 ) ,借助多元线性回归方法分别建立了多氯代二苯并呋喃在不同色谱柱上的色谱保留指数与表征其结构的 μ矢量间的定量结构 色谱保留关系 (QSRR)相关模型。各样本总体所建模型的相关系数均在 0 98以上。     

甲基烷烃结构与色谱保留指数相关性的拓扑指数法研究

计算了207个甲基烷烃的127个拓扑指数变量,把变量选择方法GAPLS方法引入到定量结构与气相色谱保留关系研究中,对127个拓扑指数变量进行选择,得到了含7个变量的化合物的定量结构与色谱保留指数关系(QSRR)模型,其复相关系数的平方为0.99998,标准偏差为2.88。交互验证的复相关系数为0.99997,交互验证的预测标准偏差为2.95,表明该模型具有良好的稳定性和可靠性。对获得的7个变量进行了合理的结构解释,表明甲基烷烃色谱保留指数完全能用拓扑指数来精确表征。     

拓扑-量子指数醛酮气相色谱保留指数及沸点的定量构效关系

通过对醛酮化合物分子结构特征及其气相色谱保留指数(RI)和沸点与分子结构间关系的研究,提出了分子极化效应指数(MPEI)、奇偶指数(OEI)、立体效应指数(SVij)、顶点度-距离指数(VDI)及键连接矩阵特征根(∑X1CH)等拓扑-量子结构参数,用多元线性回归(MLR)方法获得了醛酮类化合物的沸点及其在不同极性色谱柱上的气相色谱保留指数与这些拓扑-量子指数间良好的定量结构-性质相关(QSPR)模型,相关系数均大于0.99。5个分子结构参数具有明确的物理化学意义且易于计算和运用。与文献研究的比较结果表明:由上述分子结构参数得出的模型方程适用于各类醛酮化合物的气相色谱保留指数及沸点的预测且具有较好的稳定性和准确性。     

电拓扑状态预测多氯二苯并噻吩及噻吩砜化合物的气相色谱保留指数

以原子类型电拓扑状态指数(ETSI)有效表征了135 个多氯二苯并噻吩(PCDT)和135 个多氯二苯并噻吩砜(PCDTO₂)的分子结构, 应用基于预测的变量选择与模型化(VSMP)方法建立PCDT 和PCDTO₂ 化合物在DB-5 气相色谱柱上的气相色谱保留指数(RI)与分子结构(ETSI)的定量相关模型, 模型的相关系数r² 分别为0.9939 和0.9729, LOO 交叉验证相关系数 q² 分别为0.9921 和0.9692. 为验证模型稳定性和预测能力, 应用17 个PCDT 和PCDTO₂ 训练集样本构建的QSRR 模型的r² 分别为0.9959 和0.9783, LOO 交叉验证相关系数 q² 分别为0.9921 和0.9740, 说明模型具有良好的稳定性. 以此模型预测外部8 个检验集及110 个预测集的RI 值, 8 个检验集样本的结果表明训练集模型具有良好预测能力.     

多氯代二苯并呋喃分子空间坐标与光解半衰期的QSPR研究

运用Chem Office软件绘制48种多氯代二苯并呋喃的三维图,得到对应的分子空间坐标P(x,y,z)。采用自定义的原子空间距离指数、分子电性距离矢量和氯原子数对多氯代二苯并呋喃分子结构进行表征,用多元线性回归和BP人工神经网络建立分子空间结构与光解半衰期的构效关系模型。结果表明BP优于MLR,相关系数R_1=0. 9991,R_2=0. 9985,模型具有良好的稳定性和预测能力,为环境中持久性有机污染物光降解的QSPR研究提供了新思路。     

电拓扑状态指数在有机污染物理化性质和毒理学性质预测中的应用

电拓扑状态指数既表征了各原子在分子中的拓扑信息,也描述了分子中所有原子之间的电性关系.本文概述了电拓扑状态指数的原理和特点,描述了电拓扑状态指数在预测有机污染物理化性质及毒理学性质中的应用.对建立的定量构效关系/定量结构性质关系(QSAR/QSPR)模型的分析表明,有机污染物的沸点、色谱保留指数、溶解度等理化性质以及生物毒性、生物降解性与电拓扑状态指数均具有良好的相关性.     

基于分子相互作用力场分析的多氯代二苯并二噁英定量结构-色谱保留关系

提出了基于分子相互作用力场(MIF)、应用偏最小二乘(PLS)与多区组偏最小二乘(MBPLS)分析相结合,建立并检验多氯代二苯并二噁英(PCDD)定量结构-色谱保留关系(QSRR)模型的研究方法。分别以表征van der Waals、氢键和疏水效应的C3、H和DRY探针,计算75种PCDD的分子相互作用力场,并与其气相色谱Kov偄ts保留指数进行PLS与MBPLS分析,建立了拟合与预测效果良好的QSRR模型。其中MBPLS模型相关系数r2为0.998;交叉验证的相关系数q2为0.994。采用投影变量重要性方法判断了各种效应在PCDD色谱保留中的贡献。结果表明:van der Waals作用的影响最大,其次为疏水效应,而氢键效应影响较小。     

基于分子相互作用力场分析的多氯代二苯并二嗯英定量结构-色谱保留关系

提出了基于分子相互作用力场（MIF）、应用偏最小二乘（PLS）与多区组偏最小二乘（MBPLS）分析相结合，建立并检验多氯代二苯并二嗯英（PCDD）定量结构一色谱保留关系（QSRR）模型的研究方法。分别以表征van der Waals、氢键和疏水效应的C3、H和DRY探针，计算75种PCDD的分子相互作用力场，并与其气相色谱Kovats保留指数进行PLS与MBPLS分析，建立了拟合与预测效果良好的QSRR模型。其中MBPLS模型相关系数r^2为0．998；交叉验证的相关系数q^2为0．994。采用投影变量重要性方法判断了各种效应在PCDD色谱保留中的贡献。结果表明：van der Waals作用的影响最大，其次为疏水效应，而氢键效应影响较小。     

烷烃同系物气相色谱保留指数的分子拓扑研究

定义了分子中原子的平衡电负性,并用原子的平衡电负性对分子图进行着色,在距离矩阵的基础上结合分子中各原子的支化度构建了一种新的拓扑指数N1,N2和N3。该拓扑指数对分子结构实现惟一性表征,具有优良的结构选择性。将拓扑指数N1,N2和N3与烷烃在固定相角鲨烷(柱温50　℃)及SE-30(柱温80　℃)上的气相色谱保留指数进行多元线性回归,结果表明烷烃的气相色谱保留指数可分别定量描述为I(Squalane)=23.97842N1-3.86562N2+0.787379N3+42.33061,I(SE-30)=23.83937N1-3.5687N2+0.939876N3+22.11952。用上述回归方程对烷烃的气相色谱保留指数进行预测,结果表明预测值与实验值的平均相对误差均为1.31%,预测结果误差在实验误差范围内。     

有机磷酸酯类化合物气相色谱定量结构保留关系研究

采用分子电性距离矢量(MEDV)表征有机磷酸酯类化合物的分子结构,运用多元线性回归建立定量结构-色谱保留关系(QSRR)模型,同时采用逐步回归结合统计检测对模型进行变量筛选,建立了35个有机磷酸酯类化合物在3种不同固定相(OV-101,DB-1701和DB-WX)上气相色谱保留指数(RI)与MEDV的定量相关模型.在3种固定相上的QSRR模型的建模计算值复相关系数(R)、留一法(leave-one-out)交互校验复相关系数(QCV)分别为0.998 0和0.995 1(OV-101);0.996 3和0.989 6(DB-1701);0.993 7和0.984 1(DB-WX),表明模型具有良好估计能力与稳定性.     

Molecular graph fingerprint: a new molecular structural characterization method for the modelling and prediction of chromatographic retention behaviour of several persistent organic pollutants

How to extract and characterize information on molecular microstructures is deemed to be the key task to accurately simulate and predict molecular properties. In terms of atomic attributes, atoms in a molecule are divided into three levels. Based upon that, inter-atomic correlations are mapped to certain reasonable spatial coordinates in virtue of radial distribution function, generating the novel molecular graph fingerprint (MoGF), which essentially provides insight into molecular inner structures. MoGF, committing itself to transformation of molecular structures into characteristic graph curves, shows valuable advantages such as easy calculation, experimental parameters-free, rich information content, and structural significance and intuitive expressions. QSRR studies were performed for 115 polychlorinated dibenzofurans (PCDFs), 41 polychlorinated dibenzo-p-dioxins (PCDDs), 62 polychlorinated naphthalenes (PCNs), and 210 polychlorinated biphenyls (PCBs including the biphenyl)) tested for their retention behaviours on gas chromatographic column DB-5. The resulting PLS models showed good performances with correlation coefficients for both training and test sets above 0.97.     

Structural Characterization and Toxicity Prediction of Some Organic Compounds

A new molecular structural characterization(MSC)method called molecular vertexes correlative index(MVCI)was constructed in this paper.The index was used to describe the structures of 45 compounds and a quantitative structure-activity relationship(QSAR)model of toxicity(–lgEC50)was obtained through multiple linear regression(MLR)and stepwise multiple regression(SMR).The correlation coefficient(R)of the model was 0.912,and the standard deviation(SD)of the model was 0.525.The estimation stability and prediction ability of the model were strictly analyzed by both internal and external validations.The Leave-One-Out(LOO)Cross-Validation(CV)correlation coefficient(RCV)was 0.816 and the standard deviation(SDCV)was 0.739,respectively.For the external validation,the correlation coefficient(Rtest)was 0.905 and the standard deviation(SDtest)was 0.520,respectively.The results showed that the index was superior in molecular structural representation.The stability and predictability of the model were good.     

Structural Characterization and Acute Toxicity Prediction of Substituted Aromatic Compounds by Using Molecular Vertexes Correlative Index

A molecular structural characterization (MSC) method called molecular vertexes correlative index (MVCI) was used to describe the structures of 30 substituted aromatic compounds. Through multiple linear regression (MLR) and stepwise multiple regression (SMR), a quantitative structure-toxicity relationship (QSTR) model with 4 variables was obtained. The correlation coefficient (R) of the model was 0.9467. Through partial least-squares regression (PLS), another QSTR model with 5 principal components was obtained. The correlation coefficient (R) of the model was 0.9518. Both models were evaluated by performing the cross-validation with the leave-one-out (LOO) procedure and the Cross-Validation (CV) correlation coefficients (RCV) were 0.9208 and 0.9214, respectively. The results suggested good stability and predictability of the models, and the molecular vertexes correlative index could successfully describe the structures of the substituted aromatic compounds.     

三维全息原子场作用矢量用于HEPT类抗艾滋病药物的QSAR研究

采用本实验室新近提出的三维全息原子场作用矢量表征34个1-[(2-羟乙氧)甲基]-6-苯硫基胸腺嘧啶(HEPT)类抗艾滋病药物结构并与其活性建立定量构效关系模型. 采用逐步回归对变量进行筛选后, 运用多元线性回归(multiple linear regression, MLR)建模的复相关系数(R2cum)、交互校验的复相关系数(Q2cum)和模型的标准偏差(SD)分别为R2cum=0.928、Q2cum=0.883与SD=0.43, 均优于Hancsh报道的值(R2cum=0.911、Q2cum=0.863与SD=0.45). 模型具有良好的稳定性和预测能力, 表明三维全息原子场作用矢量能较好表征该类分子结构信息, 值得进一步推广应用.     

Structural characterization and prediction of Kovats retention indices (RI) for alkylbenzene compounds

A new molecular structural characterization (MSC) method called the molecular vertex eigenvalue correlative index (MVECI) is constructed and used to describe the structures of 122 alkylbenzene compounds. Through multiple linear regression (MLR) and stepwise multiple regression (SMR), a quantitative structure-retention relationship (QSRR) model with correlation coefficient (R) of 0.995 is obtained. Through partial least-square regression (PLS), another QSRR model with correlation coefficient (R) of 0.991 is obtained. The estimation stability and prediction ability of the two models are strictly analyzed by both internal and external validations. For the internal validation, the cross-validation (CV) correlation coefficients (R _CV) of the two models are 0.993 and 0.988. For the external validation, the correlation coefficients (R _test) of the two models are 0.996 and 0.995, respectively. The results show that the stability and predictability of the models are good, and the molecular vertex eigenvalue correlative index can successfully describe the structures of alkylbenzene compounds.     

General description of mechanical anisotropy of semicrystalline polymers in relation to orientation of structural units composed of crystalline and noncrystalline materials

A mathematical representation of the transformation of an orientation function between two sets of Cartesian coordinates is discussed in terms of a series expansion of the distribution function in generalized spherical harmonics. A general procedure for calculating the mechanical anisotropy of a single-phase system (a polycrystalline material) from the orientation of its structural units and the intrinsic mechanical anisotropy of the structural unit is discussed in relation to the transformation of the orientation distribution function, i.e., mutual conversion of the coefficients in the expansion of the distribution function between the two sets of Cartesian coordinates. The procedure is extended to a two-phase systems (semicrystalline polymers) containing structural units composed of crystalline and noncrystalline materials in three different geometrical arrangements.