Tetrameric self-assembly of a Cu(II) complex containing schiff-base ligand and its unusually high catecholase-like activity

We report a new tetrameric supramolecular Cu(II) complex (Cu ₄L₄ = tetrakis(N,N'-bis(salicylidene)-2,2'- ethylenedianiline) Copper(II)) with a Schiff-base ligand (H₂L = N,N'-bis (salicylaldimine)-1,2-ethylenediamine) containing two N,O-bidentate chelate groups. Though the copper sites of Cu₄L₄ are non-coupled, the complex exhibits a unsually high catecholase-like activity (k_cat = 935 h^-1) when the Cu₄L₄ solution is treated with 3,5- di-tert-butylcatechol (3,5-DTBC) at basic condition in the presence of air. Combined information obtained from UV-VIS and EPR measurements could lead the suggestion of the reaction pathway in which the substrate may bind to Cu(II) ions by anti-anti didentate bridging mode.