Seven coordinated cobalt(II) complexes with 2,6-diacetylpyridine bis(4-acylhydrazone) ligands: Synthesis, characterization, DNA-binding and nuclease activity

WOS: 000355127300028A new series of pentadentate 2,6-diacetylpyridine bis(4-acylhydrazone)s (H2L1 and H2L2) based seven-coordinated cobalt(II) complexes, [Co(L-n)X-2] (n = 1 and X = DMF for (1); n = 2 and X = H2O for (2)); [Co(H2Ln)Y-2] (n = 1 or 2; Y = N-3 or NCS ), has been synthesized and characterized by using spectroscopic techniques. Single crystal X-ray study of [Co(L-1)(DMF)(2)] (1) complex exhibits pentagonal-bipyramidal coordination geometry where the pentadentate N3O2 ligand in the equatorial plane of the bipyramid and two dimethylformamide molecules in the axial area. Interaction of the cobalt(II) complexes with CT DNA has been investigated by absorption titration method and viscosity measurements which reveal that the cobalt(II) complexes could bind with CT DNA through intercalation. Cleavage activity of the complexes (1) and (2) with pBR 322 plasmid DNA was evaluated by agarose gel electrophoresis demonstrating that the ability of the complexes to cleave the pBR 322 plasmid DNA via oxidative pathway, possibly due to the involvement of a diffusible hydroxyl radical mechanism in presence and absence of an oxidative agent. The nuclease activity of the Co(II) complexes has strong dependence on the concentration of complex and reaction time, both in presence and absence of hydrogen peroxide.Scientific and Technological Research Council of Turkey (TUBITAK) [TBAG-112T315]This work was funded by the Scientific and Technological Research Council of Turkey (TUBITAK, TBAG-112T315)

Synthesis, structural characterization and DNA interaction of zinc complex from 2,6-diacetylpyridine dihydrazone and {4-[(2E)-2-(hydroxyimino)acetyl]phenoxy} acetic acid

WOS: 000351800900007PubMed: 25704313A new water soluble zinc complex has been prepared and structurally characterized. The Zn(II) complex was synthesized by the reaction of 2,6-diacetylpyridine dihydrazone (dph) with {4-[(2E)-2-(hydroxyimino) acetyl]phenoxy} acetic acid (H2L) in the presence of zinc(II) acetate. Single crystal X-ray diffraction study revealed that the zinc ion is situated in distorted trigonal-bipyramidal environment where the equatorial position is occupied by the nitrogen atom of pyridine ring and the oxygen atoms of acetate groups of two oxime ligands (H2L) whereas the axial positions of the zinc complex are occupied by the imine nitrogen atoms of dph ligand. Characterization of the complex with FTIR, H-1 and C-13 NMR, UV-vis and elemental analysis also confirmed the proposed structure. Interaction of the Zn(II) complex with calf-thymus DNA (CT-DNA) was investigated through UV-vis spectroscopy and viscosity measurements. The results suggest that the complex preferably bind to DNA through the groove binding mode. The zinc complex cleaves plasmid pBR 322 DNA in the presence and absence of an oxidative agent (H2O2), possibly through a hydrolytic pathway which is also supported by DNA cleave experiments in the presence of different radical scavengers. The nuclease activity of the zinc complex significantly depends on concentration of the complex and incubation time both in the presence and absence of H2O2. DNA cleave activity is inhibited in the presence of methyl green indicating that the zinc complex seems to bind the major groove of DNA. (C) 2015 Elsevier B.V. All rights reserved.Scientific and Technological Research Council of Turkey - Turkey (TUBITAK) [TBAG-112T315]; Aksaray University, Science and Technology Application and Research Center, Turkey (State of Planning Organization) [2010K120480]This work was funded by the Scientific and Technological Research Council of Turkey - Turkey (TUBITAK, TBAG-112T315). The authors acknowledge the Aksaray University, Science and Technology Application and Research Center, Turkey, for the use of the Bruker Smart Breeze CCD diffractometer (purchased under-grant 2010K120480 of the State of Planning Organization)

Seven-coordinated cobalt(II) complexes with 2,6-diacetylpyridine bis(4-hydroxybenzoylhydrazone): synthesis, characterisation, DNA binding and cleavage properties

WOS: 000362878300001Synthesis and characterisation of three seven-coordinated cobalt(II) complexes of 2,6-diacetylpyridine bis(4-hydroxybenzoylhydrazone) (H4L) ligand, [Co(H2L)(H2O)(2)] (1), [Co(H4L)(N-3)(2)] (2) and [Co(H4L)(NCS)(2)] (3) are described. The structures of the complexes were characterised by elemental analysis, IR, UV-vis and magnetic susceptibility measurement. The molecular structure of the [Co(H4L)(NCS)(2)] (3) was also determined by X-ray crystallography. Single crystal X-ray revealed that the Co(II) complex (3) has a pentagonal-bipyramidal coordination geometry, with pentadentate N3O2 ligand in the equatorial plane of the bipyramid and two isothiocyanato groups in the axial area. Interaction of the cobalt(II) complexes with CT-DNA was investigated by absorption titration method and viscosity measurements. Cleavage activity of the complexes with pBR 322 plasmid DNA was evaluated by agarose gel electrophoresis in presence and absence of an oxidative agent, and the mechanism of DNA cleavage was investigated. The results suggest that the cobalt(II) complexes bind effectively and they exhibit nuclease activity, which has strong dependence on the concentration of complex and reaction time, both in presence and absence of hydrogen peroxide.Scientific and Technological Research Council of Turkey [TUBITAK] [TBAG-112T315]This work was funded by the Scientific and Technological Research Council of Turkey [TUBITAK, TBAG-112T315]