Tuning the thermodynamic onset potential of electrocatalytic O2 reduction reaction by synthetic iron–porphyrin complexes

Abstract

A porphyrin ligand with two β-pyrrolic electron withdrawing ester groups is synthesized and its Co complex is crystallographically characterized. The iron complex of this porphyrin ligand shows an ∼200 mV positive shift in its Fe^III/II potential in organic as well as aqueous solvents and in the onset potential of ORR relative to that of an unsubstituted porphyrin.