Spectral and Biological Characterization of Some Copper(II) Complex Compounds with Chlorhexidine

Three copper(II) complex compounds with chlorhexidine diacetate as ligand have been characterized by magnetic susceptibility measurements, infrared, electronic and EPR spectra. The complexes correspond to the formulae: [Cu(CHX)Cl-2]center dot 2H(2)O, [Cu(CHX)Br-2]center dot 1.5H(2)O and [Cu(CHX)](CH3COO)(2 center dot)C2H5OH, where CHX = chlorhexidine. Chlorhexidine acts as neutral tetradentate NNNN donor, coordinating through the four imine nitrogen atoms. The bonding parameters of the Cu(II) complexes determined from the EPR spectra indicate strong in-plane g bonding, showing that the chlorhexidine is not only a good sigma-donor, but also a good pi-donor. Disc diffusion method was used to evaluate the antimicrobial activity against four bacterial and one fungal cultures and the complexes show to be moderate antibacterial and weak antifungal agents.