Since the only possible chloride source in this system could have been DCM, we repeated the reaction of 8 with t BuOOH in o-difluorobenzene (DFB) -a non-chlorinated solvent. This time, the color of the obtained solution visually resembled that produced by the decay of 9 in DCM (Fig. ). Yet, while sharing with the latter the absorption peaks at 477, 503 and 612 nm, its spectrum lacked the broad shoulder in the 700-900 nm region (Figure , plots C vs A). Treating the same DFB solution with an excess of anhydrous HCl resulted in an immediate color change from brown to green (Fig. ). The corresponding spectrum exhibited a very broad peak centered at λmax = 710 nm, as observed for 11, while the characteristic peaks of 10 at 477 and 503 nm disappeared (Figure , plots D vs B). Furthermore, a 1:1 superposition of the absorption spectra of both DFB solutions (i.e. before and after the addition of HCl) yielded a spectrum nearly identical to that obtained in the initial decay of 9 in DCM (Figure , plots E vs A). Thus, the observed decay of the Mn(IV)-oxo species in DCM produces two different Mn(III) species -10 and 11 -as shown in Figure .