Oxidative Cleavage of DNA by a New Ferromagnetic Linear Trinuclear Copper(II) Complex in the Presence of H₂O₂/Sodium Ascorbate

Abstract

A new trinuclear copper(II) complex has been synthesized and structurally characterized: [Cu(3)(L)(2)(HCOO)(2)(OH)(2)](infinity) (HL = (N-pyrid-2-ylmethyl)benzenesulfonylamide). In the complex, the central copper ion is six-coordinated. The coordination spheres of the terminal copper atoms are square pyramidal, the apical positions being occupied by a sulfonamido oxygen of the contiguous trimer. As a consequence, the complex can be considered a chain of trinuclear species. The three copper atoms are in a strict linear arrangement, and adjacent coppers are connected by a hydroxo bridge and a bidentate syn-syn carboxylato group. The mixed bridging by a hydroxide oxygen atom and a bidentate formato group leads to a noncoplanarity of the adjacent basal coordination planes with a dihedral angle of 61.4(2) degrees. Susceptibility measurements (2-300 K) reveal a strong ferromagnetic coupling, J = 79 cm(-1), leading to a quartet ground state that is confirmed by the EPR spectrum. The ferromagnetic coupling arises from the countercomplementarity of the hydroxo and formato bridges. The trinuclear complex cleaves DNA efficiently, in the presence of hydrogen peroxide/sodium ascorbate. tert-Butyl alcohol and sodium azide inhibit the oxidative cleavage, suggesting that the hydroxyl radical and singlet oxygen are involved in the DNA degradation.

Study on the generation mechanism of reactive oxygen species on calcium peroxide by chemiluminescence and UV‐visible spectra

“…The strong CL phenomenon indicated that ROS was released on CaO 2 . In order to acquire sufficient evidence, ascorbic acid, a well-known ROS scavenger (22)(23)(24), was chosen for further experiments. As shown in Fig.…”

Arm effects of mononuclear armed cyclen copper complexes on DNA cleavage

“…4) [18,38]. The DNA cleavage was obviously inhibited after the addition of NaN 3 (lane 3) or superoxide dismutase SOD (lane 4), which suggests that singlet oxygen ( 1 O 2 ) and the superoxide radical (O 2 -) are responsible for strand scission.…”

Synthesis, Structure, Cytotoxic Activities and DNA-Binding Properties of a 1D Copper(II) Complex Bridged both by Oxamidate and Terephthalato Groups

“…It is well known that modes of DNA non-covalent interaction with metal complexes include electrostatic effect, groove binding and intercalation; and effectiveness mainly depends on the mode and affinity of the binding between the complexes and DNA [8,9]. Along this line, many of transition metal complexes have been synthesized and their interactions with DNA studied [10][11][12][13][14][15][16][17][18][19]. Furthermore, significant developments have occurred in recent years in the chemistry of polymer-metal complexes.…”