Semi-Empirical Investigation of the Carcinogenicity and Phototoxicity of Dinitro-Polycyclic Aromatic Hydrocarbons

Marie Kellemen and Kathryn L. Rowberg


water pollution, air pollution, , polycyclic aromatic hydrocarbons, , carcinogens, , phototoxicity, hazardous materials, mobile source emissions


Polycyclic aromatic hydrocarbons (PAHs) are a class of molecules with various degrees of phototoxic, mutagenic, and carcinogenic activity. Substituted PAHs are known to have different levels of these biologic activities than their parent compounds. The purpose of this work was to examine how the orientation of disubstituents affects PAH phototoxicity and carcinogenicity through the evaluation of the HOMO-LUMO gap and molecular planarity. In this study, 34 PAHs were chosen as parent compounds and 308 dinitro-substituted PAHs were built and their geometry optimized. The molecular orbital energies (EHOMO and ELUMO) and the HOMO-LUMO energy gap were computed for all parent and derivative PAHs. Predictions of phototoxicity were based on the HOMO-LUMO energy gap which in turn depended upon the orientation of the two nitro substituents and the number of rings within the molecule. Predictions of carcinogenicity were based on the planarity of each PAH derivative which was determined by the placement of at least one substituent adjacent to a bay or fjord region.

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