Results 141 to 150 of about 3,914 (183)

Szeged Indices of Benzenoid Hydrocarbons

Polycyclic Aromatic Compounds, 1996
Abstract The Szeged index (Sz) is a recently proposed structure descriptor based on distances between vertices of the molecular graph. Numerous properties of Sz were previously shown to parallel that of the long-known Wiener index (W). We report explicit combinatorial expressions for Sz of a variety of homologous series of benzenoid hydrocarbons ...
I. Gutmana, G. Dömötör, P. C. B. Lam, W. C. Shiu, L. Popović   +4 more
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Algebraic Kekulé Formulas for Benzenoid Hydrocarbons

Journal of Chemical Information and Computer Sciences, 2004
By assigning two pi-electrons of CC double bonds in a Kekulé valence structure to a benzene ring if not shared by adjacent rings and one pi-electron if CC double bond is shared by two rings we arrived at numerical valence formulas for benzenoid hydrocarbons.
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Characterization of all-benzenoid hydrocarbons

Journal of Molecular Structure: THEOCHEM, 1991
Abstract A benzenoid hydrocarbon is said to be all-benzenoid if its Clar formula contains only aromatic sextets and no double bonds. It is shown that the all-benzenoid hydrocarbons are characterized by the absence of fissures and coves in their perimeters.
I. Gutman, D. Babić
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Conjugated circuits in benzenoid hydrocarbons

Journal of Molecular Structure: THEOCHEM, 1989
Abstract A proof is provided for the previously known result that all conjugated circuits in a benzenoid hydrocarbon are of the size 4m + 2.
I. Gutman, S.J. Cyvin
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Thermochemical parameters for benzenoid hydrocarbons

Thermochimica Acta, 1974
Abstract The heats of atomization of aromatic hydrocarbons are correlated with an incremental 5-term scheme that includes CH and CC bond energy terms, resonance energies, and two steric parameters. Regression analysis of the experimental data with respect to the proposed parameters gives reasonable values for each term.
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Benzenoid hydrocarbons having eigenvalues of ±√2

J. Chem. Soc., Faraday Trans., 1991
The structural origin of eigenvalues ±√2 is discussed. Particular attention is given to the questions of how to recognise their occurrence without evaluating the complete eigenspectrum, and on how to construct and count such benzenoid species. The method is generally applicable and is illustrated with a detailed study of catacon-densed and some other ...
Yuansheng Jiang, Weizhou Yu, Edward C. Kirby   +2 more
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Resonance in catacondensed benzenoid hydrocarbons

International Journal of Quantum Chemistry, 1997
We consider resonance in cata-condensed benzenoids having six and seven fused benzene rings. The resonance relationship between the Kekule valence structures of the molecules is represented by the resonance graphs in which the vertices represent the Kekule valence structures, and the edges, the presence of the quantum chemical resonance integral ...
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A Periodic Table for Benzenoid Hydrocarbons

1990
The formulas for all benzenoid hydrocarbons are found in Table PAH6 which has x,y-coordinates of (d s , NIc). Recursive construction of this table was accomplished using an aufbau principle. This table complies to a sextet rule analogous to the octet rule for the periodic table of elements, and d s is analogous to the outer-shell electronic ...
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Mathematics of Periodic Tables for Benzenoid Hydrocarbons

Journal of Chemical Information and Modeling, 2007
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
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Clar's valence structures of benzenoid hydrocarbons

Journal of the Chemical Society, Faraday Transactions 2, 1988
The properties of Clar's valence structures for unbranched catacondensed benzenoid systems have been considered. These molecules can be represented as caterpillar trees, i.e. ayclic graphs with side branches of length one only. The sextet polynomials of the benzenoids are simply related to the characteristic polynomials of corresponding caterpillar ...
Sherif El-Basil, Milan Randi?
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