Mass Spectral Analysis of Nitropolycyclic Aromatic Hydrocarbons with Torsion Angle Obtained from Semiempirical Calculations

Abstract

The mass spectra of nitroarenes were studied under EI conditions. The spectra consist of the signals from loss of 30 and 46 mass units along with molecular ions and doubly charged ions of [M − 47]+. The ratios between [M − 30]+ and ([M − 46]+ + [M − 47]+) are well correlated with the torsion angles of O−N−C−C obtained from calculation using the PM3 method except that the nitro group is between two peri positions.

Prediction of mutagenic activity of nitronaphthalene isomers by infrared and Raman spectroscopy

“…In agreement with previous AM1 [9], PM3 [10] and B3LYP/6-31G* [11] computations, present results obtained at the B3LYP/cc-pVDZ level show that, 1-NN isomer is not planar with O N C 1 C 9 and O N C 1 C 2 dihedral angles of 24 • and 23 • , respectively. This is the consequence of the steric repulsion between the hydrogen atom in position 8 with the closest oxygen atom, contributing to reduce the -conjugation interaction between the nitro group and the NPH moiety.…”

“…Hitherto, experimental structures of NNs are lacking, while theoretical predictions have been previously obtained by means of AM1 [9] and PM3 [10] semiempirical methods and quite recently through density functional theory (DFT) computations [11]. NNs exist as two isomers: 1-NN is non-planar, while 2-NN shows a planar structure [9][10][11]. As reported in the literature, the mutagenic properties of NN isomers are somewhat different to each other [12,13].…”

Computational study on dipole moment, polarizability and second hyperpolarizability of nitronaphthalenes

“…As well established in the literature, introduction of diffuse functions as well as of electron correlation contributions are crucial for obtaining reliable values of electrical properties [41,42]. In fact on passing from 6-31G * to 6-31+G * <a e > and <c e > values increase by 16% and 240%, respectively, improving noticeably the 10 1.421 1.425 C 5 -C 10 1.423 1.422 C 5 -C 6 1.376 1.379 C 6 -C 7 1.415 1.419 C 7 -C 8 1.380 1.378 C 8 -C 9 1.425 1.424 C 1 -C 9 1.435 1.419 C 9 -C 10 1 24.0 C 2 -C 1 -N 11 -O 12 23.1 C 1 -C 2 -N 11 -O 13 0.0 C 3 -C 2 -N 11 -O 13 0.0 C 1 -C 9 -C 10 -C 5 179.0 180.0 C 4 -C 10 -C 9 -C 8 179.1 180.0…”

“…Hitherto, experimental structure of NN isomers is unknown. At AM1 [5], PM3 [6] and B3LYP/6-31G * [7] levels of theory 1-NN exhibits O-N-C-C dihedral angle of 60°, 28°and 25°, respectively, whereas 2-NN isomer is planar. There are indications showing that, mutagenic potency of NPAHs is ruled by the planarity between nitro substituents and aromatic system [8].…”

Mass spectra of nitro‐β,β‐dihalostyrenes

“…In aromatic systems, ortho ‐effects often lead to more complicated but distinct fragmentation patterns, which are useful for differentiation of isomers in multiply substituted aromatic compounds 3,4. The EI mass spectra of aromatic nitro compounds and styrenes have been extensively studied5–7 and it has been shown that nitro and vinyl groups are the fragmentation centers under EI conditions. The EI fragmentation pathways of nitrostyrenes have also been investigated 6.…”