Synthesis, characterization and DNA cleavage activity of nickel(II) adducts with aromatic heterocyclic bases

Abstract

Mixed ligand complexes of nickel(II) with 2,4-dihydroxyacetophenone oxime (DAPO) and 2,4-dihydroxybenzophenone oxime (DBPO) as primary ligands, and pyridine (Py) and imidazole (Im) as secondary ligands were synthesized and characterized by molar conductivity, magnetic moments measurements, as well as by electronic, IR, and 1 H-NMR spectroscopy. Electrochemical studies were performed by cyclic voltammetry. The active signals are assignable to the Ni III/II and Ni II/I redox couples. The binding interactions between the metal complexes and calf thymus DNA were investigated by absorption and thermal denaturation. The cleavage activity of the complexes was determined using double-stranded pBR322 circular plasmid DNA by gel electrophoresis. All complexes showed increased nuclease activity in the presence of the oxidant H 2 O 2 . The nuclease activities of mixed ligand complexes were compared with those of the parent copper(II) complexes.

Synthesis, DNA Binding, and Oxidative Cleavage Studies of Fe(II) and Co(III) Complexes Containing Bioactive Ligands

“…[46] Synthesis of [Co(L 1 L 2 )] (PF 6 ) 3 (2). To a 50 ml methanolic solution of [Co(phen) 2 Cl 2 ]Cl.3H 2 O (0.57 g, 1 mmol) was added to a methanolic solution of 2-seleno-4-methylquinoline(L 1 ) (0.222 g, 1mmol).…”

“…where ε a , ε b , and ε f are the apparent, bound, and free metal complex extinction coefficients, respectively, at 322 nm for (1) and 328 nm for (2). A plot of [DNA]/(ε b -ε f ) versus [DNA] gave a slope of 1/(ε b -ε f ) and a y intercept equal to l/K b (ε b -ε f ), where K b is ratio of the slope to the y intercept.…”

“…The peak due to aromatic ring at 7.28 ppm in the 1 H NMR spectra of the ligand is shifted to 7.5 ppm in the spectra of (2). The peak due to SeH group at 10.8 ppm in the 1 H NMR spectra of the ligand is not appeared in the 1 H NMR spectra of the (2) indicating that the ligand is deprotonated …”

“…[1] Many coordination compounds of transition metal ions accomplish nucleolytic cleavage. [2] Studies of mixed ligand transition metal complexes, which bind at specific sites along a DNA strand as reactive models for protein-nucleic acid interaction, provide routes toward rational drug design as well as means to develop sensitive chemical probes for DNA. Thus, a number of metal chelates are of current interest for important applications in nucleic acid chemistry as probes of DNA structure in solution, reagents for mediation of strand scission of duplex DNA under physiological conditions, and chemotherapeutic agents and in genomic research.…”

Nanocrystalline Mixed Ligand Complexes of Cu (II), Ni (II), Co (II) with N, O Donor Ligands: Synthesis, Characterization, and Antimicrobial Activity

“…The N, O donor ligands have been used as chelating agents in the field of coordination chemistry and medicine. The importance of N, O donor ligands and their metal complexes in different biological activities is very well known 2 . These biological activities include anti-inflammatory, antimicrobial, anticancer and antidermal activity.…”