Tetrameric Self-Assembly of a Cu(II) Complex Containing Schiff-Base Ligand and Its Unusually High Catecholase-like Activity

Abstract

We report a new tetrameric supramolecular Cu(II) complex (Cu 4 L 4 = tetrakis(N,N'-bis(salicylidene)-2,2'-ethylenedianiline)Copper(II)) with a Schiff-base ligand (H 2 L = N,N'-bis (salicylaldimine)-1,2-ethylenediamine) containing two N,O-bidentate chelate groups. Though the copper sites of Cu 4 L 4 are non-coupled, the complex exhibits a unsually high catecholase-like activity (k cat = 935 h −1 ) when the Cu 4 L 4 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.

A new photoactivable NO‐releasing {Ru−NO}6 ruthenium nitrosyl complex with a tetradentate ligand containing aniline and pyridine moieties

“…The ligand, N,N'-(ethane-1,2-diyldi-o-phenylene)-bis(pyridine-2-carboxamide) (= H 2 EPBP), was prepared by following the previous method. [16] During the course of synthesizing [Ru(EPBP)(NO)Cl]C 2 H 5 OH, all the apparatuses containing the reaction mixtures were wrapped with aluminium foils to be protected from the a light. RuCl 3 (NO) • 2H 2 O (0.1 g, 0.421 mmol) and H 2 EPBP (0.178 g, 0.421 mmol) were dissolved in 100 mL of water/ethanol (1 : 19) to be stirred for half an hour at room temperature (Scheme 1).…”

Synthesis, characterization and catecholase biomimetic activity of novel cobalt(II), copper(II), and iron(II) complexes bearing phenylene-bis-benzimidazole ligand

“…Among the metal complex models of catechol oxidase, those of copper dinuclear bearing a symmetrical or asymmetrical ligand based on pyridine, imidazole, Schiff-Base, or pyrazole to mimic imidazole donors from the histidine group has attracted much attention [18][19][20][21][22][23]. Besides the use of dicopper complexes with high accessibility to the coordination sites results in a highly active catalyst for catechol oxidation.…”