Interaction with DNA of a heteronuclear [Na2Cu4] coordination cluster obtained from the assembly of two hydroxo-bridged [CuII2] units by a dimeric sodium nitrate template

Abstract

The heteronuclear [Na(2)Cu(4)(bemp)(2)(OH)(2)(NO(3))(2)(OH(2))(4)] x 5 H(2)O (1 x 5H(2)O; H(3)bemp: 2,6-bis-[(2-hydroxyethylimino)-methyl]-4-methyl-phenol) cluster has been synthesized in aqueous-methanol at room temperature and structurally characterized. The water soluble complex is obtained from the template assembly of two [Cu(2)(bemp)(OH)] neutral fragments through their weak oxophillic interactions with two interconnected NaNO(3) units as core. Four [Na(2)Cu(4)] units form a metal-organic cage arrangement in the crystal lattice that traps a (H(2)O)(7) cluster. Variable-temperature magnetic susceptibility measurements (2-300 K) reveals a strong antiferromagnetic coupling between the Cu(II) ions within the dimers with J = -124.1 cm(-1) (in the H = -2JS(1)S(2) convention). The interaction of complex 1 x 3H(2)O with calf thymus DNA (binding constant K(b), 4.6 x 10(4) M(-1)) in Tris buffer was studied by UV-visible and emission titration, and cyclic voltammetry. The hexanuclear Na(2)Cu(4) complex also binds double-stranded supercoiled plasmid pBR322 DNA and displays efficient hydrolytic cleavage. The hydrolytic mechanism is supported by evidence from DNA relegation employing T4 ligase assay and reactive oxygen species (ROS) quenching cleavage experiments.

Synthesis, structure, spectral characterization and DNA binding affinity of new water soluble trinuclear copper(II) complexes with partial cubane Cu3O4 cores

“…The weak binding interaction of the complexes with DNA is most possibly due to the anionic nature of the complexes. The observed binding constant values are comparable to that of some copper(II) clusters reported in the literature [19,23].…”

“…The investigation reported that animals treated with the complexes showed several health benefits such as inhibiting tumor growth and metastasis slow-down, host organism survivability, and induction of morphological differentiation of cancerous cells [21]. There are reports in the literature on multinuclear copper(II) complexes which can efficiently promote the binding and cleavage of biological macromolecules [12,[22][23][24]. However, the systematic and detailed study of such binding and cleavage of biological macromolecules has been sporadic, probably due to the unavailability of structurally characterized highly water soluble trinuclear copper(II) complexes [25,26].…”

Synthesis, structure, cytotoxic activities and DNA-binding properties of tetracopper(II) complexes with dissymmetrical N,N′-bis(substituted)oxamides as ligands

“…Compared to the number of studies dealing with mono-and binuclear complexes [23][24][25][26][27][28][29][30], relatively few studies on tetranuclear complexes have been reported [31][32][33][34][35]. However, the enhancement of DNA-binding activity for tetranuclear complexes [31][32][33][34][35] stimulates us to design and synthesize new tetranuclear complexes to evaluate DNA-binding properties and in vitro antitumor activities.…”

“…Along this line, lots of copper(II) complexes, which possess biologically accessible redox potentials and demonstrate high nucleobase affinity, have been synthesized and their interactions with DNA extensively studied [12][13][14][15][16][17][18][19][20][21][22]. Compared to the number of studies dealing with mono-and binuclear complexes [23][24][25][26][27][28][29][30], relatively few studies on tetranuclear complexes have been reported [31][32][33][34][35]. However, the enhancement of DNA-binding activity for tetranuclear complexes [31][32][33][34][35] stimulates us to design and synthesize new tetranuclear complexes to evaluate DNA-binding properties and in vitro antitumor activities.…”

Synthesis, structure, and magnetic properties of a tetranuclear copper(fII) complex with a triazenido ligand

“…Polynuclear copper complexes have received increasing attention in recent years, owing to their applications in metallobiochemistry [1][2][3], materials science [4][5][6][7], and theoretical chemistry [8]. Particular interest has been directed toward the exchange phenomena in di-and polynuclear complexes of copper(II), which have led to valuable insights into their magnetostructural correlations [9,10].…”