Nickel and Copper Complexes of Pyrrolecarboxamide Ligands - Stabilization of M3+ Species and Isolation of Nil Complexes

We report Ni-II arid Cu-II complexes or a tow py rroleca rho x amide ligands containing -H, -Cl, and -CH3 substituents on the phe.nylene ring. Solid-state X-ray diffraction and solution-based spectral studies substantiated a square-planar g eometTy around the metal ions in all six of the NV complexes. Electrochemical studies showed that the electronic substituents considerably influence the M3+/2+ redox potentials. All ot the complexes Lxhibil, considerably low M3+/2+ rodox potentials owing to their tetraanionic coordination environments. Chemical and/or electrochemical oxidation has res-ulted in the isolation of NI3+ complexes and the generation of Cu3+ species. The spectroscopic studies revealed squareplanar geometries around the metal ions in the resultant Ni3+ and Cu3+ complexes.