Effect of Chelate Ring Size of Binuclear Copper(II) Complexes on Catecholase Activity and DNA Cleavage

Abstract

Catecholase activity of dicopper(II) complexes containing different numbers of chelate members in the pyridine groups of the ligand was studied to identify a functional model for copper enzyme catechol oxidase. Complexes [CuII(μ‐OH)CuII(L1)](ClO4) (1), [CuII(μ‐OH)CuII(L2)](ClO4) (2), and [CuII(μ‐OH)CuII(L3)](ClO4) (3) were synthesized and characterized by elemental analysis, FTIR, UV–Vis spectroscopy, mass spectrometry, and electrochemistry. Their catalytic activity in the oxidation of 3,5‐di‐tert‐butylcatechol was determined. Changing the number of members of the chelate rings altered the catalytic activity. Complex 2 showed the highest catalytic activity due to a high turnover rate, with efficiency of 3.40±0.61. Mechanistic investigations indicate that the catalytic reaction occurs through the reduction of Cu(II) to Cu(I) with formation of hydrogen peroxide. The spectroscopic and catecholase activity were further rationalized through DFT and TD‐DFT calculations. Interestingly, all three complexes also showed DNA binding properties, which were also corroborated via molecular docking studies.

Incorporation of β‐Alanine in Cu(II) ATCUN Peptide Complexes Increases ROS Levels, DNA Cleavage and Antiproliferative Activity**

“…The importance of the geometric flexibility of Cu(II) complexes for their oxidative nuclease activity has been previously reported. [ 30 , 31 ]…”

“…This is in accordance with previous results which indicated that an increase in ring size of the chelate results in an anodic shift of E 1/2 . [ 31 , 46 ]…”

Nuclease-like metalloscissors: Biomimetic candidates for cancer and bacterial and viral infections therapy

“…Of course, the ultimate goal of this diversity lies in the enhancement of the AMSs’ biological activity. Accordingly, these actively ongoing techniques are categorized as follow: i) Preparation of multinuclear complexes wherein the metal cores cooperate to provides an efficient active binding site for biomolecules [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] . ii) Variation of the first coordination sphere towards synthesis of homoleptic and hetroleptic complexes [66] , [67] , [68] , [69] , [70] , [71] .…”

“…ii) Variation of the first coordination sphere towards synthesis of homoleptic and hetroleptic complexes [66] , [67] , [68] , [69] , [70] , [71] . iii) Modification of the second coordination sphere via addition of the functional groups or by using the supramolecular hosts such as cyclodextrins (CDs) [56] , [57] , [72] , [73] , [74] , [75] , [76] , [77] , [78] , [79] , [80] , [81] , [82] , [83] . iv) Development of supramolecular systems by the self-assembly of metal complexes and organic building units [84] , [85] , [86] , [87] , [88] .…”

Study of the Catecholase Activity of new catalysts Based on Copper (II) and Heterocyclic Ligands

“…Catechol oxidase (CO), found in plants, bacteria, and fungi, is a copper (II) enzyme that catalyzes, in the presence of oxygen, the oxidation of o-diphenols to o-quinones (Figure 1) (Driessen, 1982). The latter selfoxidize and, after polymerization, form a high molecular weight black-brown pigment called melanin, which is a substance responsible for the post-mortem browning of plants and fruits (Homrich et al, 2021;Xue et al, 2011).…”