Flash Communication: Copper Complexes Supported by Macrocyclic N‑Heterocyclic Carbene Ligands with Ether or Secondary Amine Donors

In this regard, pincer-type ligand frameworks have been described, but macrocyclic variants remain rare. Herein, we describe the synthesis of macrocyclic carbene ligand frameworks featuring a carbazolide backbone and an ether or secondary amine donor.

While the ether was synthesized through conventional methods, the amine variant required microwave heating. Carbazolide-bis(imidazolium) pro-ligands were isolated as air-stable compounds. Metalation with Cu(acac)₂ led to the formation of square-planar Cu(II) complexes characterized by single-crystal X-ray diffraction and cyclic voltammetry.