title: Use of Charge-Charge Repulsion to Enhance π-Electron Delocalization into Anti-Aromatic and Aromatic Systems.
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 4n or 4n+2 π-systems.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Akinari
authors.initials: A
authors.lastname: Sumita
authors.affiliation: Department of Chemistry, Northern Illinois University, DeKalb, Illinois, USA.
authors.forename: Makafui
authors.initials: M
authors.lastname: Gasonoo
authors.affiliation: Department of Chemistry, Northern Illinois University, DeKalb, Illinois, USA.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Boblak
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Ohwada
authors.affiliation: Department of Chemistry, Northern Illinois University, DeKalb, Illinois, USA.
authors.forename: Douglas A
authors.identifier: http://orcid.org/0000-0001-5271-699X
authors.initials: DA
authors.lastname: Klumpp
keywords: anti-aromatic; aromatic; dication; superacid; trication