Structural descriptors area-weighted surface charge

QuaSAR descriptors [QuaSAR - Chemical Computing Group, Inc., 2007] include several types of traditional molecular descriptors Kier-Hall —> connectivity indices, —> structural keys. Estate indices, descriptors of physico-chemical properties (such as log P, molecular weight and molar refractivity), 3D molecular features (such as potential energy descriptors, surface area, volume and —> shape descriptors, conformation dependent partial charge descriptors), and some pharmacophore-based descriptors. 

TTie structural features are represented by molecular descriptors, which are numeric quantities related directly to the molecular structure rather than physicochemical properties. Examples of such descriptors include molecular weight, molecular connectivity indexes, molecular complexity (degree of substitution), atom counts and valencies, charge, molecular polarizability, moments of inertia, and surface area and volume. Once a set of descriptors has been developed and tested to remove interdependent/collinear variables, a linear regression equation is developed to correlate these variables with the retention parameter of interest, e.g., retention index, retention volume, or partition coefficient The final equation includes only those descriptors that ate statistically significant and provide the best fit to the data. For more details on QSRR and the development and use of molecular descriptors, the reader is referred to the literature [188,195,198,200-202 and references therein]. 

Among the several CODESSA descriptors, implemented in the homonymous software CODESSA (Comprehensive DEscriptors for Structural and Statistical Analysis) [Katritzky and Gordeeva, 1993 CODESSA- Katritzky, Lobanov et al., 1996 Katritzky, Lobanov et al, 1996], are molecular weight, molecular volume, —> count descriptors, —> topological indices, charge descriptors, shadow indices, charged partial surface area descriptors, quantum-chemical descriptors, and —> electric polarization descriptors. 

The descriptor uses readily calculable physicochemical properties from the topological structure. The descriptors used in this study were atomic weight, hydropho-bicity, molecular refractivity, atomic charge, polar surface area, hydrogen bond acceptors, and hydrogen bond donors. The authors note that Martin et al. [32] applied a similar approach for the design of diverse combinatorial libraries. 

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