A Dinuclear Copper(II) Complex with Adeninate Bridge Ligands and Prominent DNA Cleavage Activity. Structural and Spectroscopic Characterization and Magnetic Properties

Abstract

A new dinuclear copper(II) complex has been synthesized and structurally characterized: [Cu(mu-ade)(tolSO3)(phen)]2.2H2O (Hade = adenine, tolSO3- = toluenesulfonate anion). Its magnetic properties and electronic paramagnetic resonance (EPR) spectra have been studied in detail. The compound has two metal centers bridged by two adeninate NCN groups. The coordination geometry of the copper(II) ions in the dinuclear entity is distorted square pyramidal, with the four equatorial positions occupied by two phenanthroline N atoms and two N atoms from different adenine molecules. The axial position is occupied by one sulfonate O atom. Magnetic susceptibility data show antiferromagnetic behavior with an estimated exchange constant of -2J = 65 cm-1. The EPR spectrum has been obtained at both X- and Q-band frequencies; a study at different temperatures has been carried out at the latter. Above 20 K, the Q-band spectra are characteristic of S = 1 species with a small zero-field splitting parameter (D = 0.0970 cm-1). A detailed study of the DNA-complex interaction has been performed. The title complex efficiently cleaves the pUC18 plasmid in the presence of reducing agents. Both the kinetics and the mechanism of the cleavage reaction are examined and described herein.

Synthesis of novel substituted purine derivatives and identification of the cell death mechanism

“…Therefore the effect of cyclopentyl substitution at N-9 position was not very significant (Table-2 hours of treatment.. When we evaluated the group of 9-acetate substituted purines (38)(39)(40)(41), the 4-(4-trifluoromethylphenyl)piperazine substituted at C-6, the analogue 41,was the only 9-acetate derivative with an apparent IC 50 (Table-2). The data presented in Table- Figure 4).…”

“…(28)(29)(30)(31)(32)(33)(34)(36)(37)(38)(39)(40)(41) were synthesized and their anti-cancer activities were identified. Among these 36 compounds, N 6 -(4-trifluoromethylphenyl)piperazine derivative(17) without any substitution at N-9 position and its 9-(p-toluene-sulfonyl)/9-cyclopentyl analogues(28,36) were further analyzed for their activity against a hepatocellular carcinoma(HCC) panel due to their promising cytotoxicities.…”

DNA Cleavage by Structurally Characterized Dinuclear Copper(II) Complexes Based on Triazine

“…Comparable and even higher enhancements by copper(II) complexes have been reported for DNA cleavage when rates were compared at the saturation levels under pseudo-Michaelis-Menten kinetics. [46,47,51,55] Under similar physiological conditions, the trinuclear copper(II) complex [Cu 3 (TDAT) 2 Cl 3 ]Cl 3 ·2H 2 O derived from 2,4,6-tris(di-2-pyridylamine)-1,3,5-triazine (TDAT) also exhibited efficient oxidative DNA cleavage. [56] The lack of DNA cleavage activity by the bridged dihydroxido complex 1 does not seem to be unusual in light of the short Cu···Cu distance of 2.9808(9) Å in the bridging moiety of the Cu(μ-OH) 2 Cu unit.…”

Hairpin-shaped tetranuclear palladium(II) complex: Synthesis, crystal structure, DNA binding and cytotoxicity activity studies

“…When circular plasmid DNA is subject to electrophoresis, relatively fast migration will be observed for the intact supercoiled form (Form I), the slower-moving migration is open circular form (Form II) which was generated from supercoil when scission occurred on its one strand, and a linear form (Form III) which was generated when both strands were cleaved migrates between Form I and II [41,42]. Fig.…”