Aromaticity Alexandru
نویسندگان
چکیده
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 the power of electronic delocalization that occupies a prominent place in explaining the properties of aromatic systems. Although there is some disagreement on how to define and measure local and global aromaticity, there are no longer any voices asking for striking out the notion of aromaticity from the chemists’ vocabulary. I like Gernot Frenking’s metaphor [13] about
منابع مشابه
Patterns of ring current in coronene isomers.
The ipsocentric pseudo-p model is used to predict maps of induced current density for isomeric variations of coronene in which the central hexagonal ring is surrounded by 5, 6, and 7-membered rings. All isomers in the set are predicted to support strong diatropic perimeter ring currents, thereby conforming to the magnetic criterion of aromaticity.
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Substitution of two or four carbon atoms by nitrogen in the corannulene molecule as a carbon nanostructure was done and the obtained structures were optimized at MP2/6-31G(d) level of theory. Calculations of the nucleus-independent chemical shift (NICS) were performed to analyze the aromaticity of the corannulene rings and its derivatives upon doping with N at B3LYP/6-31G(d) level of theory. Re...
متن کاملAn analysis of the changes in aromaticity and planarity along the reaction path of the simplest Diels–Alder reaction. Exploring the validity of different indicators of aromaticity
In this work, we analyze the changes in aromaticity and planarity along the reaction path of the Diels–Alder reaction between ethene and 1,3-butadiene. To this end, a new index that quantifies the planarity of a given ring is defined. As expected, the planarity of the ring being formed in the Diels–Alder cycloaddition increases along the reaction path from reactants to product. On the other han...
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The effect of three in-plane (bond length alternation, bond length elongation, and clamping) and three out-of-plane deformations (boatlike, chairlike, and pyramidalization) on the aromaticity of the benzene molecule has been analyzed employing seven widely used indicators of aromaticity. It is shown that only the aromatic fluctuation index (FLU) is able to indicate the expected loss of aromatic...
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