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QSAR APPROACH FOR ESTIMATING THE AQUATIC TOXICITY OF SOFT ELECTROPHILES [QSAR FOR SOFT ELECTROPHILES]
Citation:
Veith, G. AND O. Mekenyan. QSAR APPROACH FOR ESTIMATING THE AQUATIC TOXICITY OF SOFT ELECTROPHILES [QSAR FOR SOFT ELECTROPHILES]. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/178 (NTIS PB94163573), 1993.
Description:
This work demonstrated that descriptors of soft electrophilicity for aromatic chemicals such as average superdelocalizability and LUMO energy could be used together with the hydrophobicity descriptor, log P, to explain the variation of acute toxicity of substituted benzenes, phenols, and anilines to fish. he hydrophobicity and soft electrophilicity descriptors were shown to be orthogonal for the 114 chemicals studied. or proelectrophiles, the structure-toxicity relationships accurately predict toxicity when the steroelectronic parameters were computed for the metabolic activation products. he QSAR for acute toxicity using thee molecular descriptors defines a toxicity plane which included several modes of toxic action. ype (I) narcotics are chemicals located in the region of low reactivity where toxicity varies with hydrophobicity alone. ype (II) narcotics are more toxic than type (I) narcotics at similar values of log P, and the increase can be explained by stronger electronic interactions with cellular soft nucleophiles. ighly reactive soft electrophiles which have dissociating protons such as 2,4-dinitrophenol produce symptoms of respiratory uncouplers. hose without dissociating protons produce symptoms of reactive toxicity consistent with covalent binding.