Kinetic and spectroscopic observations on the azidyl, N3·, radical oxidation of fac-(Lspectator)ReI(CO)3(Lacceptor) to fac-(Lspectator)ReII(CO)3(Lacceptor), Lspectator = 4,4'-bpy, Lacceptor=dipyridyl[3,2-a:2'3'-c]phenazine or Lspectator = Cl-, Lacceptor = bathocuproindisulfonate. A revisitation to the self-exchange rate constants of the N3·/N3- and Re(II)/Re(I) couples and to the redox potential of the N3· radical