Solvent dynamical effects on the electron self-exchange rate of the TEMPO•/TEMPO+ couple (TEMPO=2,2,6,6-tetramethyl-1-piperidinyloxy radical) -: Part 1.: ESR-linebroadening measurements at T=298 K

Rate constants of the electron self-exchange for the TEMPO./TEMPO+ couple were measured in acetonitrile, benzonitrile, deuterium oxide, propylene carbonate, THF and water at T = 298 K. The experimental rate constants cover a range of 0.88 x 10(8) less than or equal to k(et) less than or equal to 5.0 x 10(8) M-1 s(-1) and clearly show a solvent dynamical friction effect controlled by the longitudinal relaxation time of the solvent tau(L).