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, <i>viz.</i> ethylenediamine (<b>1</b>) and 1,3-diaminopropane (<b>2</b>), have been synthesized and characterized. The crystal structure of complex <b>1</b> 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 (<i>viz. Salmonella paratyphi</i>), which is responsible for paratyphoid fever.