A new C2-symmetric diaza-crown ether–CuII mononuclear complex containing 1,2,3-triazole ligands

A novel C2-symmetric lariat ether containing two [1,2,3]triazolo-ligands as sidearms was prepared via a click chemistry approach from known N,N′-dipropargyl-4,13-diaza-18-crown-6 (1). The ligand (2) readily forms a stable 1:1-complex with cupric perchlorate. A single crystal structure of the centro-symmetric mononuclear complex (3) could be determined. The CuII center displays a distorted six-coordinated octahedral geometry where two triazoles and two pivot nitrogens constitute the basal plane. The axial positions are occupied by two oxygens of the crown ether part. The cyclic voltammograms of a DMF solution of the complex showed two redox processes in our experimental conditions.