A DFT Study of Vibrational Spectra and Mutagenicity Predictions of Mononitrated Fluoranthenes

Abstract

The Raman and infrared (IR) spectra of the mononitrated fluoranthenes (1-, 2-, 3-, 7-, and 8-nitrofluoranthene), important environmental pollutants that induce mutagenic/carcinogenic effects upon mammalian and bacterial cells, were studied via density functional theory, using optimized geometries at the B3LYP/6-311+G(d,p) and PBE0/6-311+G(d,p) levels of theory. The predicted harmonic vibrational frequencies were used in normal mode assignments. To validate the spectra, experimental fluoranthene and 3-nitrofluoranthene were used to benchmark the predicted spectra. The scaled harmonic frequencies below 2000 cm −1 are in good agreement to experiment to <5 cm −1 and 10 cm −1 or better at the B3LYP/6-311+G(d,p) and PBE0/6-311+G(d,p) levels, respectively. The high intensity nitro asymmetric/symmetric stretch modes (ν asym /ν sym NO 2 ), ν(C C) and ν(C H) stretch frequencies were then considered, and used in distinguishing nitrofluoranthene isomers. The ν sym (NO 2 ) frequency shifts are correlated to the observed mutagenic potencies, thus shedding light on their relative reactivity. The observed differential mutagenic-vibrational correlations, and implications of the ν NO2 shifts/biological mutagenic potencies between nitrofluoranthene isomers are then discussed.

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

“…In the Raman spectrum of 3-NF, the most intense peak in the range 500-1500 cm -1 corresponds to symmetric N-O bonds stretching coupled with C-N bond stretching (ν sNO+CN ). It is located at 1332 cm -1 by the scaled B3LYP/aug-cc-pVDZ calculations, in excellent agreement with the experimental value obtained by Onchoke 10 at 1329 cm -1 and the peak at 1332 cm -1 presented by Michl et al 53 The most intense peak in the Raman spectra of 8-NF and 2-NF corresponds also to the ν sNO+CN vibration and is located at 1343 (in agreement with the experimental value 53 of 1340 cm -1 ) and 1345 cm -1 , respectively. The peaks of most intense bands in the Raman spectra of 1-NF and 7-NF correspond to the ring stretching vibration, ν ring , and the ν sNO+CN vibration.…”

“…6 Nitrofluroanthenes have also been investigated theoretically. [10][11][12][13] The simulated IR and Raman were assigned, analysed and compared with available experimental data. 10 Onchoke also obtained good agreement between simulated and observed UV/Vis spectra of NFs.…”

“…[10][11][12][13] The simulated IR and Raman were assigned, analysed and compared with available experimental data. 10 Onchoke also obtained good agreement between simulated and observed UV/Vis spectra of NFs. 12 However, only slight correlations were observed between mutagenicity and the investigated properties, and polarizability was not taken into consideration.…”

Polycyclic Aromatic Hydrocarbons in Soil Samples from Diboll, East Texas (USA)

“…The choice of the six PAHs was based on their reported abundancies (FL and PY), their ring structures (4 rings) and their mutagenic potencies to animals. While BaA is a carcinogen [24], it is the nitrated, hydroxyl, and other metabolites of BA, BaA, CHR, FLT, PY, TP that are known carcinogens or mutagenic substances [25][26][27][28][29][30][31][32][33][34]. Thus, the monitoring of PAHs in the environment is essential for the planning of sound environmental actions, evaluating potential health risks posed to humans and organisms.…”