Patterns of pi-electron delocalization in aromatic and antiaromatic organic compounds in the light of Hückel's 4n + 2 rule.

Institut de Química Computacional and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona, Catalonia, Spain.
Physical Chemistry Chemical Physics (Impact Factor: 4.2). 07/2010; 12(26):7126-37. DOI: 10.1039/b924972a
Source: PubMed

ABSTRACT The total pi-electron delocalization of a series of classical aromatic and antiaromatic organic compounds is separated into ortho (1,2), meta (1,3), para (1,4), and successive contributions (the so-called delocalization crossed terms) and the changes that take place in these crossed terms when two electrons are added or removed are analyzed. Our results show that these changes follow a similar alternation pattern in all cases. The patterns found represent a kind of electronic footprints that makes it possible to discern between aromatic and antiaromatic systems.

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