Chemical reversibility is observed in the cyclic voltammogram of 9-neopentyl-9-azabicyclo [3.3. l] nonane (3), allowing measurement of its E"'value, 0.83 V vs. SCE in acetonitrile. Replacement of the tert-butyl group of 3 by isopropyl or phenyl leads to a much shorter radical cation lifetime, and E"'could not be reliably measured for the 9-isobutyl or 9-benzyl compounds 6 or 7. The barrier for nitrogen inversion of 3, which must be accompanied by ...