Nickel(II) Complexes Derived from Bis-Schiff Bases: Synthesis, Crystal Structures, and Antimicrobial Activity

Nickel(II) complexes derived from the bis-Schiff bases N,N '-bis(5-methylsalicylidene)-1,2-diaminocyclohexane (H 2 L a ), N,N '-bis(5-methylsalicylidene)-1,2-diaminoethane (H 2 L b ) and N,N’ -bis(3,5-difluorosalicylidene)-1,2-diaminoethane (H 2 L c ), respectively, have been prepared and characterized by elemental analyses, IR, UV−Vis and single crystal XRD (CIF files CCDC nos. 1912770 ( I ), 1912771 ( II ), and 1912772 ( III )). The bis-Schiff base ligands coordinate to the nickel atoms through phenolate O and imine N atoms. Each metal atom in the complexes is in square planar coordination. The effects of the complexes on the antimicrobial activity against Staphylococcus aureus , Escherichia coli , and Candida albicans were studied, which indicate that the fluoro-substituted groups are essential for the biological process.