DNA Interaction studies of novel 3d metal complexes with biologically important ligands

Abstract

newlineThe new ligand 1-Benzyl-3-(4-ethyl-pyridin-2-yl)-thiourea(4ETU), and two copper(I) complexes [Cu(4ETU)2Cl] (1), [Cu(4ETU)(B)Cl] (2) where 4ETU=1-Benzyl-3-(4-ethyl-pyridin-2-yl)-thiourea, B is a N,N-donor heterocyclic base, viz. 1,10-phenanthroline (phen, 2), were synthesized, characterized by various physico-chemical and spectroscopic techniques. 4ETU crystallizes in P21/c space group of the monoclinic crystal system having two independent molecules in the crystallographic asymmetric unit, with cell parameters a = 25.227(4)Å, b = 14.881(2)Å, c = 7.6867(10)Å. The elemental analysis suggests that the stoichiometry to be 1:2 (metal:ligand) for 1 and 1:1:1(metal:ligand:B) for 2. PXRD analysis provides the crystalline nature of the metal newlinecomplexes. IR data coupled with electronic spectra and molar conductance values suggest that the complex 1 shows the presence of a trigonal planar geometry and the complex 2 shows the presence of a tetrahedral geometry newlineabout the Cu(I) centre. Binding interactions of the complexes with calf thymus (CT) DNA have been investigated by absorption, emission, DNA thermal denaturation and viscosity studies. The phen complex displays significant binding propensity to the CT DNA giving an order: 2 (phen) gt 1. Complex 2 shows efficient oxidative cleavage of SC-DNA in the presence of H2O2 involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and KI. The compounds were screened for their in vitro anti-bacterial activity using Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus) and Gram-negative newlinebacteria (Esherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia).