DFT studies of the toxicity of alkylphenols to Tetrahymena pyriformis

Abstract New toxicity descriptors based on Cu(II) coordination ability of alkylphenols and subsequent O → Cu electron density transfer are introduced. Geometries of phenols and of their Cu(II) complexes are optimized at the DFT level of theory. The amount of electron density transfer is evaluated using the copper charge or the electron density Laplacian at the Cu–O bond critical point. Statistical parameters for the linear dependence of the published toxicity data on the above predictors for para- and meta-substituted alkylphenols are better than the classical ones. Analogous treatments for ortho-substituted alkylphenols produce much worse results which can be significantly improved by including additional classical predictors.