title: Novel annulene dications from methylated [2.2]metacyclophane monoenes and [e]-ring benzannelated dimethyldihydropyrene.
abstract: Tetramethyl- and hexamethyl-substituted [2.2]metacyclophane monoenes (10 and 11) are transformed into their corresponding trans-dimethyldihydroethanophenanthrenium dications (14(2+) and 15(2+)) in FSO(3)H x SbF(5) (4:1) and FSO(3)H x SbF(5) (1:1) with SO(2)ClF or SO(2) as the solvent; these 10 pi-dications are equivalent to the C-4/C-5 diprotonated dications of the 2,7-dimethyl derivative of trans-DMDHP, 3a. The trans-12c,12d-dimethyl-12c,12d-dihydrobenzo[e]pyrene (6) reacts with FSO(3)H/SO(2)ClF under surprisingly mild conditions to give initially a persistent diprotonated dication (6H(2)(2+)) and, subsequently, the oxidation dication (6(2+)); the 6(2+):6H(2)(2+) ratio reaches 4:1 after 1 week at low temperature. Protonation of the anti-metacyclophane (13) was also examined. Charge delocalization mode and tropicity in the resulting dications are gauged via detailed NMR studies at 500 MHz.
authors.affiliation: Department of Chemistry, Kent State University, Kent, Ohio 44242, USA. klaali@kent.edu
authors.forename: K K
authors.initials: KK
authors.lastname: Laali
authors.forename: T
authors.initials: T
authors.lastname: Okazaki
authors.forename: R H
authors.initials: RH
authors.lastname: Mitchell
authors.forename: T R
authors.initials: TR
authors.lastname: Ward
mesh_terms: D001952:Bridged-Ring Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D002412:Cations / Q000138:chemical synthesis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry
chemical_list: D001952:Bridged-Ring Compounds; D002412:Cations; D011084:Polycyclic Aromatic Hydrocarbons; C011169:annulenone