Results 131 to 140 of about 3,864 (163)

The Non-Benzenoid Aromatic Hydrocarbon Pentalene

Nature, 1948
IT is an interesting fact that neitherjpentalene (1), nor heptalene (2), nor any derivatives of them have been definitely reported as being synthesized1 or found to occur naturally. Azulene (3) is, on the other hand, a substance which can be made by the established procedures of organic chemistry and it is known in Nature.
D P, CRAIG, A, MACCOLL
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Algebraic Kekulé Structures of Benzenoid Hydrocarbons

Journal of Chemical Information and Computer Sciences, 2004
An algebraic Kekulé structure of a benzenoid hydrocarbon is obtained from an ordinary Kekulé structure by inscribing into each hexagon the number of pi-electrons which (according to this Kekulé structure) belong to this hexagon. We show that in the case of catafusenes, there is a one-to-one correspondence between ordinary and algebraic Kekulé ...
Gutman, Ivan, Vukičević, Damir, Graovac, Ante, Randić, Milan   +3 more
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Nonaromatic benzenoid hydrocarbons

Pure and Applied Chemistry, 1990
Abstract
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Perimeter Topology of Benzenoid Polycyclic Hydrocarbons.

ChemInform, 2005
The equivalence of the perimeter topological equations derived by Dias and the 13 possible modes of hexagon adjacency in fused benzenoid systems subsequently presented by Cyvin, Gutman, and collaborators is shown. The aufbau principle for generation of all fused total resonant sextet (TRS) benzenoid hydrocarbons is proved.
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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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