Mononuclear and Dinuclear Copper Complexes of Tridentate Redox‐active Ligands with Tunable H‐bonding Donors: Structure, Spectroscopy and H⁺/e⁻ Reactivity

Abstract

In this research article, we describe the synthesis and characterization of mononuclear and dinuclear Cu complexes bound by a family of tridentate redox‐active ligands with tunable H‐bonding donors. The mononuclear Cu‐anion complexes were oxidized to the corresponding “high‐valent” intermediates by oxidation of the redox‐active ligand. These species were capable of oxidizing phenols with weak O−H bonds via H‐atom abstraction. Thermodynamic analysis of the H‐atom abstractions, which included reduction potential measurements, pKa determination and kinetic studies, revealed that modification of the anion coordinated to the Cu and changes in the H‐bonding donor did not lead to major differences in the reactivity of the “high‐valent” CuY complexes (Y: hydroxide, phenolate and acetate), which indicated that the tridentate ligand scaffold acts as the H+ and e− acceptor.