Complex compounds of Sm(III) with chlorhexidine synthesis, characterization, luminescent properties and antibacterial activity

Three new samarium(III) complex compounds with chlorhexidine as ligand and mixed ligands
chlorhexidine/o-phenanthroline have been prepared and characterized by elemental and thermogravimetrical
analyses, infrared, electronic and luminescence spectra. The complexes corresponded to the formulas:
[Sm(CHX)(NO) 3 2]’ NO3, [Sm(CHX)(o-phen)2]’ (NO3)3 and [Sm2(CHX)(o-phen)2(NO3)4]×(NO3)2, where CHX was the chlorhexidine. Chlorhexidine acted as neutral tetradentate NNNN donor, coordinating through the
four imine nitrogen atoms. The two mixed ligands complexes showed a strong luminescent emission in
solid state, characteristic of samarium(III) ion. The metal complexes and the chlorhexidine diacetate were
in vitro evaluated for their antimicrobial activity against two Gram negative bacteria. The results revealed
that all compounds were very effective in reducing the bacterial growth rate, even at low concentration.