Metal-Based Antibacterial Agents: Synthesis, Characterization, and Biological Evaluation of Ternary Mn(II) and Co(II) Complexes Containing Sulfamethoxazole and Cephalosporins

Manganese(II) and cobalt(II) react with cephalosporins antibiotics (cefazolin, ceftriaxone, and cefepime) plus sulfamethoxazole (Hsmz) to form the following mixed ligand complexes of general formulas [M(L)(smz)(H2O)(2)] (L-1,L-2, L = monoanion of cefazolin HL1, ceftriaxone HL2; M = Mn(II), Co(II)) and [M(L-3)(smz)(H2O)Cl] (cefepime L-3), which were characterized by physicochemical and spectroscopic methods. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental and thermal analyses, infrared, electronic spectra, magnetic susceptibility, EPR, and conductivity measurements. An octahedral geometry has been suggested for the complexes. Their spectra indicated that cephalosporins and Hsmz are acting as monoanionic bidentate chelating agents. They have been screened for their antibacterial activity and the results are compared with the activity of commercial cephalosporins.