Density functional theory calculation of lipophilicity for organophosphate type pesticides

Density functional method with continuum solvation model is used for the calculation of the partition coefficient log KOW and the determination of lipophilicity of 22 most frequently used organophosphate type pesticides. Excellent agreement with experimental data is obtained using three different density functional approximations (one local, one general gradient and one hybrid), and our results highlight DFT as a reliable and trustworthy method for the calculation of lipophilicity for this important class of molecules. Furthermore, the calculated lipophilicity results are associated with the experimentally determined LD50 and LC50 values, showing that the most toxic pesticides are those with transient characteristics (medium lipophilicity), although this conclusion must be taken with a caution, due to the many factors influencing the ingestion and action of a certain substance in the body besides lipophilicity.