The role of molecular properties of mononitrofluoranthenes to their mutagenic activity: Insight from ab initio and DFT calculations

The molecular properties of the environmental mutagens nitrofluoranthenes (NFs; 1-, 2-, 3-, 7- and 8-NF), such as (hyper)polarizability, dipole moment, molecular electrostatic potential (MEP), spectroscopic characteristics, magnetic index (NICS) and others, obtained by means of ab initio (MP2) and density functional theory (DFT) approaches have been correlated with the observed mutagenic activities. A very good linear correlation ( R av = 0.99) between average polarizability ( ) and experimental mutagenic activities of NFs in different Salmonella typhimurium strains from two independent experimental studies (Vance and Levin, Environ. Mutagen. 6 (1984) 797 and Zielinska et al. , Mutation Res. 206 (1988) 131) was established. Higher values of polarizability derivatives with respect to the nsNO+CN vibrational coordinate for 8-NF and 3-NF compared to 1-NF and 7-NF and, consequently, higher Raman activities in the spectra that are in correlation with mutagenic activities, implicate significant intermolecular interactions along this vibrational coordinate. The results indicate that the binding of NFs to enzymes is the main step in mutagenic pathway of these nitro derivatives.