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Use of Charge‐Charge Repulsion to Enhance π‐Electron Delocalization into Anti‐Aromatic and Aromatic Systems
Author(s) -
Sumita Akinari,
Gasonoo Makafui,
Boblak Kenneth J.,
Ohwada Tomohiko,
Klumpp Douglas A
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201606036
Subject(s) - carbocation , delocalized electron , substituent , aromaticity , chemistry , ion , electron , charge (physics) , electron delocalization , computational chemistry , chemical physics , character (mathematics) , photochemistry , organic chemistry , molecule , physics , geometry , mathematics , quantum mechanics
Abstract A series of 9‐fluorenyl cations has been studied and it is shown that increasing charge on a heterocyclic substituent group enhances the anti‐aromatic character of the carbocation system. Similarly, a series of dibenzosuberenyl cations has been studied and increasing charge on a substituent group is shown to enhance aromatic character in the carbocation system. These studies include the direct observations of dicationic and tricationic species using stable‐ion conditions and low temperature NMR. The structures of these ions were further characterized using DFT calculations, confirming that highly charged organic ions may exhibit unusual distributions of π‐electrons and delocalization of electrons in 4 n or 4 n +2 π‐systems.