Brønsted plot of the logarithm of the bimolecular rate constant for deprotonation of the radical cations of N,N-dimethylaniline derivatives: (closed circles) 4-substituted-N,N-dimethylanilines, 1a-1e; (open circle) N,N,2-trimethylaniline, 2; (open squares) 2-tert-butyl-N,N-dimethylaniline, 3; and N,N,2,6-tetramethylaniline, 4.