Topological descriptors 140 INDEX

Some further topological descriptors are the Kier-Hall connectivity indices [13] and the electrotopological state index (or -state index) [14]. A comprehensive overview of topological molecular desaiptors is given by Todeschini and Consonni [15]. 

Another set of particularly useful 2D-based topological descriptors are the so-called electrotopological state index (E-state) descriptors developed by Kier and Hall [36],... 

The data containing 324 descriptor values of 88 molecules was given as an input to VSMP program, to build models based on three and four descriptors, keeping the interdescriptor correlation below 0.75. The best three-descriptors model, Eq. 80, was based on descriptors 254 (atomic type E-state index), 311 (AlogP98), and 320 (2D Van der Waals surface area) with a correlation coefficient, r, of 0.8425, and the cross-validated correlation coefficient, q, of 0.8239. The correlation coefficients of the other two VSMP models, Eqs. 81 and 82 were 0.8411 and 0.8329, respectively. Significantly, the descriptors 254 and 311 were selected in all the best three-descriptors models of VSMP. The three descriptors, in the models 80, 81, and 82 were 320, 144 (Kappa shape index of order 1), and 30 (topological Xu index), respectively. 

MDL QSAR MDL Information Systems, Inc. www.mdl.com/products/predictive/qsar/index.jsp Molecular property descriptors, total topological descriptors, E-state indices... 

Very similar to the electronic-topological descriptors, electron charge density connectivity index is defined for an - H-depleted molecular graph in which net atomic charges, calculated by computational chemistry, are used as weights for vertices [Estrada and Montero, 1993 Estrada, 1995d] ... 

Another topological descriptor specifically proposed for cis/trans isomerism is the Pogliani cis/trans connectivity index xcr> defined in terms of the - Randic connectivity index y as ... 

A vector of molecular topological descriptors can be calculated for the whole iterated line graph sequence. For example, a line graph Randic connectivity index was calculated as ... 

Galvez, J., Garda, R., Salabert, M.T. and Soler, R. (1994b). Charge Indexes. New Topological Descriptors. J.Chem.lnf.Comput.Sci.,34,520-525. 

Gupta, S., Singh, M. and Madan, A.K. (1999). Superpendentic Index A Novel Topological Descriptor for Predicting Biological Activity. J.Chem.Inf.Comput.Sci., 39, 272-277. 

Sharma, V., Goswami, R. and Madan, A.K. (1997). Eccentric Coimectivity Index A Novel Highly Discriminating Topological Descriptor for Structure-Property and Structure-Activity Studies. J.Chem.Inf ComputScL, 37,273-282. 

Another series of successfully applied topological descriptors is derived from graph theory using atom connectivity information of a molecule. An example is the connectivity index developed by Randic [21], In the simple form,... 

Wiener Index is the first published topological descriptor calculated by the sum of the number of minimum bonds between all nonhydrogen atoms. 

Approximate relationships between the Dewar index and topological descriptors were derived by Gutman [Gutman, 1977]. 

Connective eccentricity index a novel topological descriptor for predicting biological activity. /. Mol. Graph. Model, 18, 18-25. 

Ren, B. (2003a) Atom-type-based AI topological descriptors for quantitative structure-retention index correlations of aldehydes and ketones. Chemom. Intell. Lab. Syst., 66, 29-39. 

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