Studies on the quantitative structure-activity relationship of substituted biphenyls by density function theory (DFT)

Geometrical configurations of 16 substituted biphenyls were computed at the B3LYP/6-311G** level with Gaussian 98 program. Based on linear solvation energy theory, IgK(ow) as well as the structural and thermodynamic parameters obtained at this level was taken as theoretical descriptors, and corresponding equation predicting the toxicity of Daphnia magna (-IgEC(50)) was thus obtained, in which three parameters were contained, i.e., n-octanol/water partition coefficients (IgK(ow)), dipole moment of the molecules (mu) and entropy (S degrees). For this equation, R-2 = 0.9582, q(2) = 0.8921 and SD = 0.102. The absolute t-scores of three variables are larger than the standard one in the confidence range of 95%, which confirms the creditability and stability of this model.