Graph–topological approach to magnetic properties of benzenoid hydrocarbons

Ciesielski, Arkadiusz; Krygowski, Tadeusz M.; Cyrański, Michał K.; Dobrowolski, Michał A.; Aihara, Jun‐ichi

doi:10.1039/b913895a

Cited by 39 publications

(138 citation statements)

References 66 publications

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“…Specifically, we determined the tensor perpendicular to the plane of the ring under examination evaluated at the distance of 1 Å [NICS(1) yy ]. From recent studies [19][20][21], NICS(1) yy is considered a reliable parameter to estimate local aromaticity of PAH rings. Negative NICS(1) yy values denote aromatic rings.…”

Section: Geometries and Nucleus Independent Chemical Shiftsmentioning

confidence: 99%

Physicochemical characterization of environmental mutagens: 3-nitro-6-azabenzo[a]pyrene and its N-oxide derivative

Alparone

Librando

2012

Monatsh Chem

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Molecular geometries, nucleus independent chemical shifts, electronic, infrared and Raman spectra, vertical ionization energy and electron affinity, dipole moment, and electronic polarizabilities of 3-nitro-6-azabenzo[a]pyrene and its N-oxide derivative were calculated for the gas phase using semiempirical and density functional theory. The influence of the N-oxidation on structural, electronic, and spectroscopic properties is discussed. The infrared spectral region around 1,300 cm -1 involving the azabenzene N-O and the NO 2 stretching vibrations is potentially useful to distinguish 3-nitro-6-azabenzo[a]pyrene from its N-oxide derivative. The calculated vertical ionization energy for 3-nitro-6-azabenzo[a]pyrene N-oxide is smaller than that of its parent compound, whereas the vertical electron affinity is higher in agreement with the experimental electrochemical reduction potentials. Both dipole moment and polarizability increase on passing from 3-nitro-6-azabenzo[a]pyrene to its N-oxide derivative, the contribution from the N-O bond formation being substantial. The electric property enhancements are explained through atomic charges and spectral shifts. Present results support the higher mutagenic activity for the N-oxide derivative in comparison with its parent compound.

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Section: Geometries and Nucleus Independent Chemical Shiftsmentioning

confidence: 99%

Physicochemical characterization of environmental mutagens: 3-nitro-6-azabenzo[a]pyrene and its N-oxide derivative

Alparone

Librando

2012

Monatsh Chem

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“…The overall molecular p-electron current is obtained by adding contributions from all conjugated circuits from all Kekulé valence structures. Although that this model has been very briefly outlined several years ago in a review article on aromaticity [10] it has not been used until very recently [11,12].…”

mentioning

confidence: 99%

π‐electron currents in polycyclic conjugated hydrocarbons: Coronene and its isomers having five and seven member rings

Randić

Novič

Vračko

et al. 2011

Int J of Quantum Chemistry

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ABSTRACT:We have outlined novel graph theoretical model for computing p-electron currents in p-electron polycyclic conjugated hydrocarbons. We start with Kekulé valence structures of a polycyclic conjugated hydrocarbon and their conjugated circuits. To each 4nþ2 conjugated circuits we assign counter clockwise current i and to each 4n conjugated circuit we assign clockwise current i. By adding the contributions from all conjugated circuits in a single Kekulé valence structure one obtains p-electron current pattern for the particular Kekulé valence structure. By adding the conjugated circuit currents in all Kekulé valence structure one obtains the pattern of p-electron currents for considered molecule. We report here p-electron current patters for coronene and 17 its isomers, which have been recently considered by Balaban et al., obtained by replacing one or more pairs of peripheral benzene rings with five and seven member rings. Our results are compared with their reported p-electron current density patters computed by ab initio molecular orbital (MO) computations and satisfactory parallelism is found between two so disparate approaches. V C 2011 Wiley Periodicals, Inc. Int J Quantum Chem 112: [972][973][974][975][976][977][978][979][980][981][982][983][984][985] 2012

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“…In case I, the most efficient separation of double bonds is achieved. Local descriptors of aromaticity (such as HOMA [26] or NICS [27,28]) confirm that the separated sextets in these Clar structures have the most efficient π-electron delocalization [23,29].…”

Section: Open Accessmentioning

confidence: 88%

How to Find the Fries Structures for Benzenoid Hydrocarbons

2010

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An efficient algorithm leading to the Fries canonical structure is presented for benzenoid hydrocarbons. This is a purely topological approach, which is based on adjacency matrices and the Hadamard procedure of matrix multiplication. The idea is presented for naphthalene, as an example. The Fries canonical-structures are also derived for anthracene, coronene, triphenylene, phenanthrene, benz[a]pyrene, and one large benzenoid system. The Fries concept can be convenient for obtaining Clar structures with the maximum number of sextets, which in turn effectively represent π-electron (de)localization in benzenoid hydrocarbons.

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Graph–topological approach to magnetic properties of benzenoid hydrocarbons

Cited by 39 publications

References 66 publications

Physicochemical characterization of environmental mutagens: 3-nitro-6-azabenzo[a]pyrene and its N-oxide derivative

Physicochemical characterization of environmental mutagens: 3-nitro-6-azabenzo[a]pyrene and its N-oxide derivative

π‐electron currents in polycyclic conjugated hydrocarbons: Coronene and its isomers having five and seven member rings

How to Find the Fries Structures for Benzenoid Hydrocarbons

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