منابع مشابه
Aromaticity Alexandru
Aromaticity has been lately in the center of attention of chemists with books [1-3], journal special issues [4-10], reviews [11, 12], and publications (these are too numerous to cite). The discoveries of fullerenes, nanotubes, nanocones, and nanotori as well as the recent techniques for obtaining graphene sheets with monatomic thickness and astounding properties have enlarged our views about th...
متن کاملShannon entropy as a new measure of aromaticity, Shannon aromaticity.
Based on the local Shannon entropy concept in information theory, a new measure of aromaticity is introduced. This index, which describes the probability of electronic charge distribution between atoms in a given ring, is called Shannon aromaticity (SA). Using B3LYP method and different basis sets (6-31G**, 6-31+G** and 6-311++G**), the SA values of some five-membered heterocycles, C(4)H(4)X, a...
متن کاملAromaticity in cyanuric acid
This study analyzes the aromatic nature of cyanuric acid (hexahydrotriazine) and some of its derivatives, in terms of aromatic stabilization energy (ASE) and electronic behavior. The simplest molecule (C(3)N(3)O(3)H(3)) is the most aromatic item out of the entire set, but some of the others also display aromatic character. The structure of all the rings is analyzed considering their molecular o...
متن کاملTunable aromaticity in bicalicenes.
The unusual aromatic stability of cyclic bicalicene has been suggested to come from a tetraionic structure, where positive and negative charges are located on the cyclopropene and cyclopentadiene rings, respectively. Energetic, magnetic, geometric and electron delocalization analysis performed on a series of bicalicene derivatives, incorporating different electron donating and withdrawing group...
متن کاملAromaticity and Diatropicity
Aromaticity can be interpreted as extra stabilization of a cyclic unsaturated molecule arising from cyclic conjugation of mr-electrons. The extra stabilization energy is estimated relative to the r-electron energy of a hypothetical reference molecule formed by the "localized" ir bonds. It is termed the resonance energy due to aromaticity. Our graph theory of aromaticity defines this type of res...
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ژورنال
عنوان ژورنال: Nature
سال: 1975
ISSN: 0028-0836,1476-4687
DOI: 10.1038/257073b0