DNA binding and antimicrobial studies of polymer–copper(II) complexes containing 1,10-phenanthroline and l-phenylalanine ligands

Abstract

Some water-soluble polymer–copper(II) complexes, [Cu(phen)( l-phe)(BPEI)]ClO 4·4H 2O (phen = 1,10-phenanthroline, l-phe = l-phenylalanine, and BPEI = branched polyethyleneimine), with various amounts of copper(II) chelates in the polymer chain, were prepared by ligand substitution method in water–ethanol medium and characterized by infra-red, UV–visible, EPR spectral and elemental analysis methods. Binding of these complexes with calf thymus DNA (CT DNA) has been investigated by absorption spectroscopy, emission spectroscopy and gel electrophoresis techniques. The experimental results indicate that the amount of copper(II) chelate content in the polymer backbone have marked effect on the binding affinity to CT DNA. Interactions like electrostatic interaction, van der Waals interaction, hydrogen bonding and/or partial intercalation binding modes exist in this system. A sample of polymer–copper(II) complex was tested for its antibacterial and antifungal activity against certain human pathogenic organisms and it was found to have good antibacterial and antifungal activities.