We describe a two-beam thermal lens spectrophotometer that uses a xenon lamp as the excitation source and a low power diode pumped Nd-YAG laser as the probe light. The white light from the xenon source is filtered using a variable interference filter producing a partial monochromatic light within the spectral range 400-700 nm and with a spectral resolution of 10 nm. We measure the thermal lens spectrum of a nonfluorescent dye (Malachite Green) and show that this spectrum reproduces its absorbance spectra measured by the usual transmission method. A comparison of the thermal lens and the absorbance spectra of a fluorescent dye (Rhodamine B) reveals substantial differences. These differences can yield important applications of the device for the characterization of fluorescent materials.

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.

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Three mono-nitrobenzanthrone isomers (1-, 2-, and 3-nitrobenzanthrone; 1-, 2-, and 3-NBA) were synthesized by reacting benzanthrone (BA) with nitric acid (HNO3) in acetic anhydride at ice-cold conditions. The major product, 2-nitrobenzanthrone (2-NBA), was confirmed using GC-MS via comparisons with a standard sample. On the basis of the elution profiles and fragmentation patterns two other isomers formed were assigned to 1-, and 3-nitrobenzanthrone (1-, and 3-NBA). The average percent yields of 1-, 2-, and 3-NBA were 0.3 ± 0.1%, 10.5 ± 2.6 %, and 6.4 ± 1.3 %, respectively.