共查询到20条相似文献,搜索用时 31 毫秒
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A Sablji? 《Journal of chromatography. A》1985,319(1):1-8
A comparative study was undertaken to test the ability of several different topological indices to predict the retention indices of chlorinated benzenes on polar and non-polar stationary phases using both correlation coefficients and correctly predicted elution sequences as criteria of fit. The test was performed on three topological indices: connectivity indices, Wiener numbers, and Balaban indices. The regression analyses showed that the molecular connectivity model predicted the retention indices of chlorinated benzenes more successfully than either Wiener numbers or Balaban indices. The results also demonstrated that the major structural property controlling chromatographic behavior was the size of the chlorinated benzene. In addition, the use of the new non-empirical heteroatom parameterization scheme in the calculation of Wiener numbers and Balaban indices was successfully tested for the first time. 相似文献
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The distance matrix in chemistry 总被引:2,自引:0,他引:2
Zlatko Mihalić Darko Veljan Dragan Amić Sonja Nikolić Dejan Plavšić Nenad Trinajstić 《Journal of mathematical chemistry》1992,11(1):223-258
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K. Balasubramanian 《SAR and QSAR in environmental research》2013,24(1-2):59-77
Abstract The objective of this article is to outline both graph-theoretically based and quantum chemically based structural indices of potential use in quantitative structure activity correlations. We consider graph-theoretical indices such as the connectivity index, topological index, Wiener index and molecular ID indices. Several structural and geometry-dependent indices can be derived from semiempirical and ab initio quantum calculations based on the charge densities, overlap matrices, frontier orbitals, molecular hardness, free valence, density matrices, quantum spectral difference indices, quantum spectral indices and bond matrices. Finally, the use of electrostatic potentials and charge densities for the prediction of reactive sites will be discussed. 相似文献
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W. R. Müller K. Szymanski J. V. Knop N. Trinajsti 《Journal of computational chemistry》1987,8(2):170-173
A simple computer-oriented method is presented for constructing the (molecular) distance matrix. The distance matrix considered is the graph-theoretical (topological) distance matrix. 相似文献
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Mozrzymas A 《Computational Biology and Chemistry》2011,35(6):347-352
The extensions of generalized (molecular) graph-theoretical matrix and vector-matrix-vector procedure are considered. The elements of the generalized matrix are redefined in order to describe molecules containing heteroatoms and multiple bonds. The adjacency, distance, detour and reciprocal distance matrices of heterosystems, and corresponding vectors are derived from newly defined generalized graph matrix. The topological indices, which are most widely used in predicting physicochemical and biological properties/activities of various compounds, can be calculated from the new generalized vector-matrix-vector invariant. 相似文献
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Morikawa T Narita S Klein DJ 《Journal of chemical information and computer sciences》2004,44(6):1891-1896
This article first revises graph-theoretical (local aromaticity and overall molecular) indices, introduced by M. Randi? in 1975, for benzenoid hydrocarbons and somewhat improves them for computer enumeration. This goes beyond total Kekulé structure enumeration, yielding an index calculation useful for the quantitative estimation of localization of different Kekuléan substructures (including ethylene-, benzene-, annulene-, and radialene-units). This may be viewed as a "molecules-in molecule" approach to polycyclic aromatic hydrocarbons within the context of graph theoretical partitioning. 相似文献
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The newly developed topological indices Am1-Am3 and the molecular connectivity indices mX were applied to multivariate analysis in structure-property correlation studies. The topological indices calculated from the chemical structures of some hydrocarbons were used to represent the molecular structures. The prediction of the retention indices of the hydrocarbons on three different kinds of stationary phase in gas chromatography can be achieved applying artificial neural networks and multiple linear regression models. The results from the artificial neural networks approach were compared with those of multiple linear regression models. It is shown that the predictive ability of artificial neural networks is superior to that of multiple linear regression method under the experimental conditions in this paper. Both the topological indices 2X and Am1 can improve the predicted results of the retention indices of the hydrocarbons on the stationary phase studied. 相似文献
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A new extension of the generalized topological indices (GTI) approach is carried out to represent “simple” and “composite”
topological indices (TIs) in an unified way. This approach defines a GTI-space from which both simple and composite TIs represent
particular subspaces. Accordingly, simple TIs such as Wiener, Balaban, Zagreb, Harary and Randić connectivity indices are
expressed by means of the same GTI representation introduced for composite TIs such as hyper-Wiener, molecular topological
index (MTI), Gutman index and reverse MTI. Using GTI-space approach we easily identify mathematical relations between some
composite and simple indices, such as the relationship between hyper-Wiener and Wiener index and the relation between MTI
and first Zagreb index. The relation of the GTI-space with the sub-structural cluster expansion of property/activity is also
analysed and some routes for the applications of this approach to QSPR/QSAR are also given. 相似文献
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Molecular connectivity methods for the characterization of surface energetics of liquids and polymers 总被引:1,自引:0,他引:1
Bortolotti M Brugnara M Della Volpe C Maniglio D Siboni S 《Journal of colloid and interface science》2006,296(1):292-308
In the topological approach to structure-property relationships, the molecular structure is described in terms of appropriate weighted graphs to which suitable topological parameters, usually known as molecular connectivity indices, can be associated. Molecular connectivity indices are here applied to the prediction of surface free energy and Good-van Oss-Chaudhury acid-base components of organic compounds. To this aim, some quantitative structure-property relationships (QSPRs) are determined, involving both topological indices and group indicator variables of the customary functional group theory. The semiempirical models obtained to appear satisfactory and show significant advantages with respect to the models based on the purely functional group approach. 相似文献
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Novel chirality descriptors derived from molecular topology 总被引:1,自引:0,他引:1
Golbraikh A Bonchev D Tropsha A 《Journal of chemical information and computer sciences》2001,41(1):147-158
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