A novel 1,2,4-triazole-based copper(II) complex: synthesis, characterization, magnetic property and nuclease activity.

Abstract A novel binuclear copper(II) complex [Cu 2 L( μ -SO 4 )](PF 6 ) 2 ( 1 ) (L = 3,5-bis (bis(pyridine-2-ylmethyl)amino)methyl)-4 H -1,2,4-triazol-4-amine) has been synthesized and structurally characterized. X-ray structure shows that the two copper(II) atoms are bridged by one bidentate sulfate ion and the 1,2,4-triazole ring of L with Cu1⋯Cu2 distance of 4.404 A. Each copper(II) center has a distorted trigonal–bipyramidal configuration. Variable-temperature magnetic susceptibility studies (2–300 K) indicate the existence of weak antiferromagnetic coupling between the copper(II) ions in complex 1 . The interaction of complex 1 with calf thymus DNA (CT-DNA) has been studied by UV absorption, fluorescence spectroscopy, circular dichroism spectroscopy, viscosity and cyclic voltammetry. Furthermore, complex 1 was able to promote single and double strand DNA cleavage in both aerobic and anaerobic conditions, the pseudo-Michaelis–Menten kinetic parameters k cat  = 2.58 h −1 and K m  = 1.2 × 10 −4  M were obtained for 1 . The hydrolytic cleavage of DNA by the complex was supported by the evidence from free radical quenching, anaerobic experiment, thiobarbituric acid-reactive substances (TBARS) assay.