Abstract
This work presents two square-planar Co(III) complexes within a N-4 coordination sphere created by two related pyrrolecarboxamide ligands. Both complexes functioned as catalysts for the hydrazine-mediated reduction of aromatic, heterocyclic, as well as aliphatic nitro substrates. Binding studies provided evidence that the square-planar Co(III) complexes bind two equivalents of a substrate whereas mechanistic studies established the involvement of a Co3+-Co2+ based redox cycle in the catalysis. The Co(III) complex having electron-withdrawing -Cl substituents on the ligand was noted to be a much better catalyst than the one with electron-donating -CH3 substituents.