Synthesis, characterization and electrochemical studies of mixed ligand complexes of ruthenium(ii) with DNA

Abstract

Two mixed ligand complexes of ruthenium(ii) [Ru(bzimpy)(bpy)(OH(2))](2+) (1) and [Ru(bzimpy)(phen)(OH(2))](2+) (2) have been synthesized and characterized by FAB mass, (1)H NMR, cyclic voltammetry and spectroelectrochemical measurements. Controlled potential electrolysis of these complexes results in the conversion of ruthenium(ii) to ruthenium(iii) at 0.6 V and ruthenium(iii) to ruthenium(iv) at 0.8 V vs. SCE. The binding constant of these complexes with DNA has been determined electrochemically and found to be (3.58 +/- 0.25) x 10(4) and (2.87+/- 0.2) x 10(4) M(-1). Viscosity measurements suggest that these complexes bind with DNA through intercalation. Such intercalative binding to DNA has been found to induce chirality to the two complexes. Electrochemically generated ruthenium(iv) species of these complexes have been found to bring about oxidative cleavage in DNA.

A Planar Schiff Base Platinum(II) Complex: Crystal Structure, Cytotoxicity and Interaction with DNA

“…These results indicated that the complex may possess the potent DNA cleavage ability at the concentrations higher than 80 µM. 38) In summary, the results of fluorescence emission titration indicated that the complex had a low quenching constant K q …”

Copper(II) Terpyridine Complexes: Effect of Substituent on DNA Binding and Nuclease Activity

“…[11] Ruthenium(II) polypyridyl complexes have attracted comprehensive attention due to their significance in the development of new therapeutic agents and novel nucleic acid structural probes. [12][13][14] A number of dinuclear iron complexes are known to exhibit hydrolytic cleavage of duplex DNA. [15][16] Nickel(II) and cobalt(II) macrocyclic complexes have been [a] Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai, 600020 Tamil Nadu, India Fax: +91-44-2491-1589 E-mail: bunair@clri.info is more uniformly distributed in the case of tolylterpyridine (complex 1), which possibly leads to better stacking interactions with the DNA bases and hence a higher binding constant value for complex 1.…”

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“…The formal potential Ef shift slightly towards the positive side and is attributed to characteristic behaviour of intercalation of the complexes into the DNA double-helix and suggests that extract bind to DNA at different rates 18 .…”