Comparative QSAR study of phenol derivatives with the help of density functional theory.

Quantum chemical reactivity descriptors based QSAR study of 50 phenol derivatives is presented in this paper. Four different methods have been employed to certify the reliability of QSAR study. The molecular weight, hardness, chemical potential, total energy, and electrophilicity index provide valuable information and have a significant role in the assessment of the toxicity of phenols. The first model has been drawn up with the help of AM1 calculations and in this model the correlation coefficient r2 is 0.88 and the cross-validation coefficient r(cv)2 is 0.78. Second and third models have been designed with the PM3 and PM5 calculations, respectively. The values of correlation coefficient r2 and cross-validation coefficient r(cv)2 in the second case are 0.85 and .070, while in the third case they are 0.85 and 0.71. Finally, the DFT calculations have been made for the same series of compounds by using a B88-PW91 GGA energy functional with the DZVP basis set. The DFT models have a higher predictive power than AM1, PM3, and PM5 methods, and the reliability of this model is clear from its correlation coefficient r2 0.91 and cross-validation coefficient r(cv)2 0.88. This study is also helpful in determining the effect of any particular phenol derivative of this series over Tetrahymena pyriformis.