نتایج جستجو برای: kekulé structure
تعداد نتایج: 1567986 فیلتر نتایج به سال:
As a general case of molecular graphs of benzenoid hydrocarbons, we study plane bipartite graphs with Kekulé structures (1-factors). A bipartite graph G is called elementary if G is connected and every edge belongs to a 1-factor of G. Some properties of the minimal and the maximal 1-factor of a plane elementary graph are given. A peripheral face f of a plane elementary graph is reducible, if th...
Several sequences of graphs are introduced whose perfect matching numbers, or Kekulé numbers, K(G), are either Fibonacci or Lucas numbers, or their multiples. Since the ratio of the K(G)s of consecutive members converges to the golden ratio, these sequences of graphs belong to another class of golden family graphs.
Setting up spatially separated HOMO and LUMO regions in a non-Kekulé structured trinuclear Ir(III)-Ru(II)-Ir(III) system and using oxidative-reduction electrochemiluminescence leads to emissions that are not detected in photoluminescence. Moreover, the new design allows tuning of the wavelength of emission in a stepless fashion as a function of the selected potential range.
Published, JBC Papers in Press, October 17, 2005, DOI 10.1074/jbc.R500015200 Thomas Kolter, Florian Winau, Ulrich E. Schaible, Matthias Leippe, and Konrad Sandhoff From the Kekulé-Institut für Organische Chemie und Biochemie, D-53121 Bonn, Germany, the Max-Planck-Institut für Infektionsbiologie, Abteilung Immunologie, D-10117 Berlin, Germany, and the Zoologisches Institut der Universität Kiel, ...
Possible dimerization patterns and electronic structures in fullerene tubules as the one-dimensional π-conjugated systems are studied with the extended Su-Schrieffer-Heeger model. We assume various lattice geometries, including helical and nonhelical tubules. The model is solved for the half-filling case of π-electrons. (1) When the undimerized systems do not have a gap, the Kekulé structures p...
We classify all possible 36 gap-opening instabilities in graphenelike structures in two dimensions, i.e., masses of Dirac Hamiltonian when the spin, valley, and superconducting channels are included. These 36 order parameters break up into 56 possible quintuplets of masses that add in quadrature and hence do not compete and thus can coexist. There is additionally a sixth competing mass, the one...
Calculations based on density functional theory demonstrate the occurrence of local deformations of the perfect honeycomb lattice in nanographenes to form arrangements, with triangular symmetry, composed of six-membered ring patterns. The formation of these locally regular superstructures, which can be considered as benzenoid-like domains on the 2D graphene lattice, is ascribed to the gain in r...
The study of the polyfluorination and polytrifluoromethylation effects on electronic structure and intrinsic acidities has been performed using DFT B3LYP and NBO calculations for the valence isomers of benzene and phenol, i.e., the structures of prismane, benzvalene, Kekulé, and Dewar systems. Also the isodesmic reaction analysis approach to estimate the effects of the substituents on the acidi...
Possible dimerization patterns and electronic structures in fullerene tubules as the π-conjugated systems are studied with the extended Su-Schrieffer-Heeger model. We assume various lattice geometries, including helical and nonhelical tubules, and tubules with end caps. The model is solved for the half-filling case of π-electrons. (1) When the undimerized systems do not have a gap, the Kekulé s...
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