Modulation spectroscopy. Kinetics for the self-reactions of some α-aminoalkyl radicals in solution

Abstract

The optical spectra and reaction kinetics of some a-aminoalkyl radicals, RĊHN(CH2R)2; R≡H, Me, Ph, were measured in solution using the technique of modulation spectroscopy. These radicals undergo diffusion controlled self-reaction with rate constants [Formula: see text]. When R≡Ph, the absorption spectrum has a well defined maximum at 346 nm; ε = 3390 M−1 cm−1, while the spectra when R≡H or Me were less intense [Formula: see text] and tailed into the visible. These spectra are substantially red-shifted when compared with those of simple alkyl radicals, an effect which is thought to be due to the interaction between the unpaired electron and the lone pair of electrons on nitrogen.