HYDROGEN SPLITTINGS OF BIS-BICYCLIC HYDRAZINE RADICAL CATIONS

H-1-NMR spectra of bis-bicyclic hydrazine radical cations allowed dete rmination of the magnitude and sign of the proton splitting constants under approximately 2 G, and assignments to position using deuterium l abeling were made for several cases. ENDOR spectra measured the hydrog en splittings over 2 G. Bridgehead hydrogen splitting constants for se squibicyclic compounds (bis-N,N'-bicyclics) were observed in the range -0.10 to +0.14 for six examples containing 2,3-diazabicyclo[2.2.2]oct yl rings, -0.14 to -0.04 for two 2,3-diazabicyclo[2.2.2]octenyl compou nds, +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 containi ng 2,3-diazabicyclo[2.2.1]heptyl rings. There is not a simple correlat ion of these bridgehead splitting constants with the lone pair N, C-H( b) dihedral angle. For the nine sesquibicyclic hydrazine radical catio ns studied, the exo splittings in dimethylene bridges were positive, a nd the endo splittings were negative in sign. Examination of the W and non-W exo gamma hydrogen splittings in systems containing bicyclo[2.2 .2]octyl rings allowed estimation of the energy difference between dou ble nitrogen inversion conformations.