Spectroelectrochemistry of copper(II) complexes with deprotonated tetradentate pyridine-2-carboxamide ligands: EC reaction of the electrogenerated Cu(III) species

The electrochemistry of [CuL1] 1 and [CuL2] 2 [H2L1=1,2-bis(pyridine-2-carboxamido)benzene, H2L2=3,4-bis(pyridine-2-carboxamido)toluene] was investigated. Both complexes show a quasi-reversible Cu(II/I) reduction near −1.6 V vs Fc+/Fc. Spectroelectrochemistry confirmed that the Cu(III) state is accessible near +0.4 V, and undergoes an EC reaction (k≃10 s−1) to generate a new Cu(II) species.