“…In the latter case, the bromine atoms introduced into the β-pyrrole positions of the porphyrin ring withdraw electron density from the metal center, to destabilize the high-valent active species. In addition, these same bromine atoms distort the metalloporphyrin macrocycle, which acquires a saddle-type conformation[39] that diminishes selfoxidation and consequent catalyst degradation[9,17,33]. However, comparison of the efficiency of the second-generation cis-[Mn III DAPDPP]Cl with the efficiency of the generation [Mn III (PFTDCPP)]Cl obtained by Doro et al[40] demonstrates that the latter catalyst is much more efficient.…”