Copper 1,19-Diaza-21,24-dicarbacorrole: A Corrole Analogue with an N−N Linkage Stabilizes a Ground-State Singlet Organocopper Species

A copper complex of a heterocorrole analogue with an N–N linkage, 1,19-diaza-21,24-dicarbadibenzocorrole (Cu-5), was successfully synthesized via oxidative metalation–cyclization of a tetrapyrrolic precursor. The N–N linkage in the skeleton of Cu-5, which serves as a mediator of π-electron delocalization, features an 18π aromatic system. The electronic structure of Cu-5 is best described as a ground-state singlet species stabilized by the distinct NNCC coordination core. This finding shows how the ligand's design can be used to modulate the Cu (Formula presented.) orbital energy, thereby making such compounds invaluable for copper-based catalytic applications.