Stable ion study of regioisomeric carboxonium-substituted pyrenium ions: directive effects, charge delocalization mode, and conformational aspects.
Regioisomeric monoacyl- and monobenzoyl-substituted pyrenes are diprotonated in FSO(3)H.SbF(5) (4:1)/SO(2)ClF to give persistent carboxonium-pyrenium dications, whereas diacetyl- and dibenzoylpyrenes are diprotonated to give dicarboxonium dications. The resulting dications were studied by low-temperature NMR at 500 MHz. Conformational aspects of the carboxonium group in various regioisomers are addressed by a combination of NOED spectra and 2D-NMR and AM1 calculations. Charge delocalization pathways are gauged and compared on the basis of the magnitude of Deltadelta (13)C values.
Laali
K K
KK
Department of Chemistry, Kent State University, Kent, Ohio 44242, USA. klaali@kent.edu
Okazaki
T
T
Hansen
P E
PE
D000107:Acetylation; D001565:Benzoates / Q000138:chemical synthesis / Q000737:chemistry; D007202:Indicators and Reagents; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011721:Pyrenes / Q000138:chemical synthesis* / Q000737:chemistry*; D013329:Structure-Activity Relationship
D001565:Benzoates; D007202:Indicators and Reagents; D011721:Pyrenes