Spectroscopic Elaboration and Structural Characterizations of New Fe(III), Pd(II), and Au(III) Ampicillin Complexes: Metal-Antibiotic Ligational Behaviors

Abstract

Two modes of complexation were resulted upon the chemical interactions of ampicillin (amp) antibiotic drug with iron(III), palladium(II), and gold(III) metal ions in 50/50 % of methanol/distilled water mixed solvent. The chemical formulas of FeIII, PdII, and AuIII complexes are [Fe2(amp)(Cl)5(H2O)3].3H2O, [Pd(amp)2].2H2O and [Au2(amp)(Cl)4].Cl.2H2O. These complexes were characterized using elemental analyses, molar conductivity, (infrared,1H-NMR, UV-vis.) spectra, effective magnetic moment in Bohr magnetons, thermal analysis (TG), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), as well as transmitting electron microscopy (TEM). The binuclear complexes of FeIII and AuIII ions are coordinated toward the oxygen of carbonyl amide and nitrogen of –NH2 groups and oxygens of carbonyl β-lactam ring and deprotonated of the −COOH group, while the mononuclear complex of PdII ions coordinated through oxygens of β-lactam and carboxylate groups. Magnetic susceptibilities of the solid samples indicated that the PdII and AuIII complexes have a diamagnetic form but the FeIII complex has a paramagnetic nature with octahedral ligational statement. The antibacterial and antifungal activities of the respected complexes were tested against some kind of bacteria and fungi strains if comparable with the ampicillin free drug. In vitro cytotoxicity assays of the gold(III) complex were determined against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.