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Abstract:
1H-NMR spectra of bis-bicyclic hydrazine radical cations allowed determination of the magnitude and sign
of the proton splitting constants under -2 G, and assignments to position using deuterium labeling were made for
several cases. ENDOR spectra measured the hydrogen splittings over 2 G. Bridgehead hydrogen splitting constants
for sesquibicyclic compounds (bis−N,N'−bicyclics) were observed in the range -0.10 to +O. 14 for six examples containing
2,3-diazabicyclo[2.2.2]octylr ings, -0.14 to -0.04 for two 2,3-diazabicyclo[2.2.2]octenylc ompounds, +0.02 to +0.21
for four compounds containing 5,6-diazabicyclo[3.2.2]nonyl and -nonenyl rings, and +0.35 to +0.84 for compounds
containing 2,3-diazabicyclo[2.2.1] heptyl rings. There is not a simple correlation of these bridgehead splitting constants
with the lone pair N, C-Hb dihedral angle. For the nine sesquibicyclic hydrazine radical cations studied, the exo
splittings in dimethylene bridges were positive, and the endo splittings were negative in sign. Examination of the W
and non-W exo y hydrogen splittings in systems containing bicyclo[2.2.2]octyl rings allowed estimation of the energy
difference between double nitrogen inversion conformations
