Mixed-Ligand Nickel(II) Complexes Containing Sulfathiazole and Cephalosporin Antibiotics: Synthesis, Characterization, and Antibacterial Activity

Abstract

Nickel(II) reacts with cephalosporins plus sulfathiazole (Hstz) to form the following mixed-ligand complexes of general formulae [Ni(L)(stz) ( H 2 O ) x ] n ( L 1 , 4 , x = 1 ; L 2 , 3 , x = 0 ; L = monoanion of cefazolin HL 1 , cephalothin HL 2 , cefotaxime HL 3 , ceftriaxone HL 4 ) and [Ni( L 5 )(stz)]Cl (cefepime L 5 ), which were characterized by physicochemical and spectroscopic methods. Their spectra indicated that cephalosporins are acting as multidentate chelating agents, via the lactam carbonyl and carboxylate and N-azomoieties. The complexes are insoluble in water and common organic solvents but soluble in DMSO, where the [Ni( L 5 )(stz)]Cl complex is 1 : 1 electrolyte. They probably have polymeric structures. They have been screened for antibacterial activity, and the results are compared with the activity of commercial cephalosporins.