QSAR STUDY ON THE ACUTE TOXICITY OF ALKYL HALIDES TO PIMEPHALES PROMELAS
Xiaodong Jian · Environmental Chemistry · 2010
The DFT-B3LYP method,with the basis sets 6-311+g(d,p),was employed to calculate the molecular geometries and electronic structures,and to analyze frequency of 27 alkyl halides.Then 282 molecular descriptors were calculated,divided into compositional,topological,geometrical,electrostatic,quantum-chemical and thermodynamic parameters.Heuristic strategies was used for the effective search of the best descriptors in the large space of the natural descriptors,then established the quantitative structure-activity relationship (QSAR) by multivariate linear regressions(MLR) and support vector machine(SVM).Three molecular descriptors(KH1,IC0,EHOMO-LUMO) were found to relate significantly to acute toxicities.The proposed QSAR models by MLR and SVM are robust and satisfactory,the values predicted by the two model are in good agreement with the experiment values.All the descriptors utilized are calculated solely from the structures of the molecules,which makes it feasible to predict LC50 of alkyl halides to Pimephales promelas.