Spectroscopic and DNA interaction studies on mixed ligand copper(II) complexes of dicyanamide with ethylenediamine or 1,3-diaminopropane

Mixed ligand copper(II) complexes of dicyanamide with different polyamines, viz. ethylenediamine (1) and 1,3-diaminopropane (2), have been synthesized and characterized. The crystal structure of complex 1 contains a five-coordinated copper in a distorted square-pyramidal environment and forms 1D zig-zag polymeric chain via the bridging ligand dicyanamide. Hydrogen bonding contributes supramolecular architecture in the crystal. Electronic spectral studies suggest the distorted square-pyramidal structure of the complexes. The interaction of the copper(II) complexes with calf-thymus DNA reveals nonintercalative binding mode. The two complexes have antimicrobial activity against the bacteria (viz. Salmonella paratyphi), which is responsible for paratyphoid fever.