Prediction of halocarbon toxicity from structure: a hierarchical QSAR approach.

Mathematical structural invariants and quantum theoretical descriptors have been used extensively in quantitative structure-activity relationships (QSARs) for the estimation of pharmaceutical activities, biological properties, physicochemical properties, and the toxicities of chemicals. Recently our research team has explored the relative importance of various levels of chemodescriptors, i.e. topostructural (TS), topochemical (TC), geometrical (3D), and quantum theoretical descriptors, in property estimation. This study examines the contribution of chemodescriptors ranging from topostructural to quantum theoretic calculations, up to the Gaussian STO-3G level, in predicting the results of six indicators of oxidative stress for a set of 20 halocarbons. Using quantum theoretical calculations in this study is of particular interest as molecular energetics is related to the likelihood of electron attachment and free radical formation, the mechanism of toxicity for these chemicals and should aid in modeling their potential for oxidative stress.