Imidazole Schiff base ligands: Synthesis, coordination complexes and biological activities

1-(3-Aminopropyl)imidazole (Apim) reacts with salicylaldehyde and a selection of imidazole aldehydes and the resulting Schiff base ligands readily coordinate to Zn(II), Cu(II) and Ag(I) centres. X-ray crystal structures were obtained for two of the free ligands and also the Ag(I) complex of the Apim-salicylaldehyde ligand. Encouragingly, all of free ligands and most of their metal complexes are relatively non-toxic, in vivo, towards Galleria mellonella. Although the free ligands and the Cu(II) and Zn(II) complexes are inactive, in vitro, against a selection of microbial pathogens, most of the Ag(I) complexes exhibit moderate anti-bacterial activity and good anti-fungal activity.

Graphical abstractFive ligand systems and fifteen metal (M = Cu, Ag or Zn) complexes were synthesised and characterised. X-ray crystal structures were obtained for two of the metal-free ligands and also the Ag(I) complex of the Apim-salicylaldehyde ligand. Although the metal-free ligands and the Cu(II) and Zn(II) complexes are inactive, in vitro, against a selection of microbial pathogens, most of the Ag(I) complexes exhibit moderate anti-bacterial activity and good anti-fungal activity.Figure optionsDownload full-size imageDownload as PowerPoint slide