Factors Affecting the Stability and Equilibria of Free Radicals. XIII. N-Alkoxy- and N-Aralkoxypicrylamines and ESR Spectra of the Corresponding Capto-Dative Persistent Aminyls

Article abstract of DOI:10.1016/0022-2364(87)90314-3

Five O-alkylhydroxylamines and three aralkylhydroxylamines have been picrylated to give O-alkyl-N-picrylhydroxylamines.These were converted to the corresponding N-(ar)alkoxy-picryl-aminyl radicals in toluene solution, and the ESR spectra were recorded.Simulations of the spectra with reasonable parameters and g values confirm the expected radical structures.Hyperfine coupling constants for nuclei in the picryl (acceptor) ring are smaller than those for the (ar)alkoxy group.This indication of competitive electron pair delocalization to the picryl ring, together with the long lifetimes of these radicals (compared with the symmetrically substituted diphenylaminyls), both support the concept of captodative stabilization.