HYDROGEN-ATOM EXCHANGE BETWEEN NITROXIDES AND HYDROXYLAMINES

Nitroxides and their hydroxylamines exchange hydrogen atoms. The exchange of hydrogen atoms between tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-l-oxyl) and the reduced form of the quaternary ammonium nitroxide (2,5,5-tri-methyl-2-[2-N,N,N-trimethy])amino]ethylpyrrolidine-l-oxyl iodide) follows the second-order rate law, rate = k0 [nitroxide]-[hydroxylamine] where k0 = 9.5±0.4 M-1 s-1. The reaction rate is catalyzed by copper ions. At low copper ion concentrations the catalyzed reaction obeys the rate law, rate = k1[Cu+] [nitroxide] where k1 = 2.2±0.1 X 104 M-1 s-1. These reactions can be used for studies of the kinetics of immunochemical reactions at membrane surfaces. © 1979, American Chemical Society. All rights reserved.