DETECTION OF SUPEROXIDE ION IN AQUEOUS-MEDIA BY N-HALOPIPERIDINES

The reaction between N-chloro-or N-bromo-2,2,6, 6-tetramethylpiperidines and superoxide radical has been studied. 2,2,6,6-tetramethylpiperidines are the main reaction products, while the corresponding piperidinoxyl spin label, has been formed as secondary reaction product with a yield which is independent of the concentration of reagents. In this way N-halopiperidines can be used as specific spin-trappers of superoxide ion. A kinetic scheme which takes into account the consecutive reaction between piperidinoxyl and superoxide is proposed and the relative kinetic constant are given. © 1979.