Proton transfer reactions of methylanthracene radical cations with nitrogen-centered bases under non-steady-state conditions. a search for the possible effect of reactant impurities upon the kinetic data.

[reaction: see text] At a recent conference, the issue was raised that our earlier non-steady-state kinetic studies(1)(-)(3) may be in error because of the effects of possible impurities in the N-centered bases employed. This prompted our reinvestigation of these systems with that possibility in mind. It was pointed out that in a series of reactions, if a reactive impurity affects the kinetics in one reaction, then it would exert a consistent effect on the kinetics of all of the reactions in the series. Experimental data for three different series of reactions, proton transfer reactions of 2,6-dimethylpyridine, 2,6-diethylpyridine, and 2,6-diphenylpyridine with four different methylanthracene radical cations, were concurrently examined for possible reactant impurity problems. The analysis confirms that the simulated data for the simple second-order mechanism in the presence of a reactive impurity do not fit experimental data for the proton transfer reactions. The hypothesis that deviations from simple second-order kinetics are caused by the presence of reactive impurities is not valid. It was concluded that the presence of reactive impurities was not a significant problem in the studies of proton transfer reactions of methylanthracene radical cations with pyridine bases.