Comparison of mononuclear and dinuclear copper(ii) biomimetic complexes: spectroelectrochemical mechanistic study of their catalytic pathways

0561664 - ÚFCH JH 2023 RIV GB eng J - Journal Article
Sýs, M. - Kocábová, Jana - Klikarová, J. - Novák, M. - Jirásko, R. - Obluková, Michaela - Mikysek, T. - Sokolová, Romana
Comparison of mononuclear and dinuclear copper(ii) biomimetic complexes: spectroelectrochemical mechanistic study of their catalytic pathways.
Dalton Transactions. Roč. 51, č. 36 (2022), s. 13703-13715. ISSN 1477-9226. E-ISSN 1477-9234
R&D Projects: GA ČR(CZ) GA19-03160S
Institutional support: RVO:61388955
Keywords : spectroelectrochemistry * catechol oxidase activity * tyrosinase
OECD category: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Impact factor: 4, year: 2022
Method of publishing: Limited access

Two catecholase-like biomimetic catalysts, namely, two dinuclear copper complexes [Cu-2(L1)(OH)(H2O)(EtOH)][ClO4](2) (C1) and [Cu2Ac2O(L1)ClO4] (C2) with the 2,6-bis(4-methyl piperazin-1-yl-methyl)-4-formyl-phenoxy ligand (L1) together with the mononuclear complex Cu(ClO4)(2)(L2) (C3) containing ligand 1,2-(C5H4N-6-OCH3-2-CH=N)(2)CH2CH2 (L2), were synthesized. Their catalytic pathways were investigated and compared. The evaluation of the catalytic activity of compound C1 (and C2, C3) using the Michaelis-Menten model was represented by values of K-M = 272.93 (223.02, 1616) mu mol L-1 and V-max of 0.981 (1.617, 1.689) mu mol L-1 s(-1). The role of water content in the solvent is also discussed. The dinuclear complexes C1 and C2 were found to be more efficient catalysts than mononuclear complex C3. The mode of catalytic action was characterized via cyclic voltammetry, spectrophotometry, and UV-Vis spectroelectrochemistry. The catalytic mechanism of 3,5-di-tert butyl catechol oxidation in the presence of oxygen was proposed. The reaction circle was proved by the confirmation of the chemical reversibility of complex reduction. The advantage of the in situ spectroelectrochemical measurement enabled to control the reduction of quinone formed by the chemical reaction of catechol with oxygen in solution. At this step, the simultaneous change in the absorption spectrum indicated a change in the copper redox state of the catalyst.
Permanent Link: https://hdl.handle.net/11104/0334189