Results 111 to 120 of about 489,454 (164)

Estimation of the number of benzenoid hydrocarbons

Chemical Physics Letters, 1988
Abstract A method for the estimation of B h , the number of benzenoid systems with h hexagons, is presented. B 13 is predicted to lie between 3.200×10 6 and 3.202×10 6 . This is a significant improvement on the earlier result which located B 13 between 3.080×10 6 and 3.300×10 ...
David Aboav, Ivan Gutman
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Edge Effects in Benzenoid and Total Resonant Sextet Benzenoid Hydrocarbons and Clar's Sextet Principle.

Journal of Physical Chemistry A, 2019
Because the effect of a benzenoid perimeter edge on a sextet pattern is of paramount importance, trends in the degree of sextet aromaticity are determined.
Jerry Ray Dias
semanticscholar   +1 more source

On dioxo derivatives of benzenoid hydrocarbons

Journal of Molecular Structure: THEOCHEM, 1999
Abstract Extending a problem occurring in connection with the stability order of the tautomers of hypericin, we examine the topological factors influencing the stability of the isomeric dioxo derivatives of benzenoid hydrocarbons, in particular the rules determining the number of Kekule structures in them. Depending on the position of the oxo groups,
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Magnetically Induced Current Density in Non-Planar Fully Benzenoid Hydrocarbons.

Journal of Physical Chemistry A, 2019
In our recent paper the effects of molecular planarity on the local aromaticity in several series of increasingly planar fully benzenoid hydrocarbons were examined.
Marija Antić, Slađana Đorđević, Boris Furtula, S. Radenković   +3 more
semanticscholar   +1 more source

Topological Ring-Currents and Clar Sextets in Fully Benzenoid Hydrocarbons I. Structures with Fewer than 18 Rings.

Journal of Physical Chemistry A, 2018
It is well-known that the very special family of conjugated systems described as "fully benzenoid hydrocarbons" have a unique Clar structure that causes all of their rings to be classified as either "full" or "empty".
T. Dickens, R. Mallion
semanticscholar   +1 more source

Enumeration and classification of benzenoid hydrocarbons

Journal of Computational Chemistry, 1987
AbstractThe enumeration of benzenoids is studied with the aid of different modifications of a computer program. Known values for the number of cata‐condensed and of all benzenoids withh(number of hexagons) up to eight are reproduced. These benzenoids are classified into (a) unbranched of different symmetries and branched cata‐condensed, and (b) normal,
J. Brunvoll, S. J. Cyvin, B. N. Cyvin
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Topological Ring-Currents and Clar Sextets in Fully Benzenoid Hydrocarbons. II. Large Structures Containing More than 18 Rings.

Journal of Physical Chemistry A, 2018
In previous work, π-electron ring currents in several fully benzenoid hydrocarbons were calculated by means of the quasi-graph-theoretical, parameter-free Hückel-London-Pople-McWeeny (HLPM) method.
T. Dickens, R. Mallion
semanticscholar   +1 more source

Benzenoid hydrocarbons in space: The evidence and implications

1990
Many different celestial objects emit an infrared sprectrum which has been attributed to infrared fluorescence from a family of highly vibrationally excited benzenoid hydrocarbons referred to as polycyclic aromatic hydrocarbons (PAHs). The most intense emitters contain between 20 to 50 carbon atoms, although larger species also contribute to the ...
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Giant Benzenoid Hydrocarbons. Superphenalene Resonance Energy

Polycyclic Aromatic Compounds, 1999
Abstract We calculated molecular resonance energy for “0superphenalene”, a recently reported giant benzenoid which can be viewed as obtained from three fused “superbenzenes” (hexa-peri-hexabenzocoronenes). Using the Method of Conjugated Circuits we derived quantitative characterization of Clar's qualitative description of the considered benzenoids as ...
Randic, M., Guo, X. F.
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An Algorithm to generate the compact name of benzenoid hydrocarbons

Computers & Chemistry, 1985
Abstract A computer program that facilitates handling of the new compact nomenclature of condensed benzenoid hydrocarbons is presented. It allows derivation of the hydrocarbon name from the Cartesian coordinates of the carbon atoms. The program also provides a user with the possibility of verification of trial hydrocarbon names according to the rules
J. Ciosowski, A. M. Turek
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