Abstract:

The DFT-B3LYP method, with the basic set 6-311G*[KG-*3]*, was employed to calculate the molecular geometries and electronic structures of 49 organic compounds. E_HOMO, E_LUMO, ΔE,EN_HOMO,E_NLUMO, E_T, Q_H, Q^-, μ and  Vwere selected as structural descriptors. The anesthesia activity(log 1/C) of these compounds to tadpoles along with hydrophobicity described by log K_OW, the above ten structural parameters, was used to established the quantitative structureactivity relationships (QSAR) by multiple linear regression. The R₂, q₂, SE  and F  for model (2) established in this study were 0.933 2, 0.930 1, 0.274 and 121.800, respectively. The result indicated that the model had good predictability. In light of the model, the toxic actions of organic compounds included two steps: one was the collection of the compounds in vivo, which was described by log K_OW; the next was the electronic reactions between the chemicals and macromolecular compounds, which were represented by  E_LUMOand E_NHOMO.

Key words: organic compound; density functional theory(DFT); quantitative structureactivity relationships(QSAR); anesthetic activity; tadpoles