title: 13C NMR/DFT/GIAO studies of phenylene bis(1,3-dioxolanium) dications and 2,4,6-triphenylene tris(1,3-dioxolanium) trication.
abstract: The o-, m-, and p-phenylene bis(1,3-dioxolanium) dications (4-6) and 2,4,6-triphenylene tris(1,3-dioxolanium) trication (7) have been prepared by the ionization of the corresponding 2-methoxyethyl benzoates in FSO(3)H or CF(3)SO(3)H at 40 and 60 degrees C, respectively. The charge delocalization in these carbocations was probed by (13)C NMR chemical shifts and substantiated by GIAO/DFT calculations. Relatively less charge is delocalized into the aromatic ring of the carbotrication 7. The rotational barrier around the C(+)-Ar bond for carbodications 4 and 5 was also estimated to be 8-10 kcal/mol.
authors.affiliation: Department of Chemistry, University of Missouri-Rolla, 142 Schrenk Hall, Rolla, Missouri 65409-0010, USA. olah@usc.edu
authors.forename: V Prakash
authors.initials: VP
authors.lastname: Reddy
authors.forename: Golam
authors.initials: G
authors.lastname: Rasul
authors.forename: G K Surya
authors.initials: GK
authors.lastname: Prakash
authors.forename: George A
authors.initials: GA
authors.lastname: Olah