Synthesis, characterization and antimicrobial studies of Mn(II) complexes of acetylthiophene and acetyl Furan Schiff base derivatives

Abstract

Manganese (II) complexes of Schiff bases; 2-acetylthiophene 4‑phenylthiosemi-carbazone (AT-PTSC) and 2-furylmethylketone-4-phenylthiosemi-carbazone (AF‑PTSC) derived from condensation of 2-acetylthiophene and 2-furylmethylketone (2-acetylfuran) each with 4-phenylthiosemicarbazide in (1:1 molar ratio) ethanol, have been synthesized. The Schiff bases and the Mn(II) complexes were characterized on the basis of melting point/decomposition temperature, solubility, magnetic susceptibility, infrared spectra, molar conductance measurements,  elemental and gravimetric  analyses. The Mn(II) complexes show moderate values of decomposition temperatures. The Schiff bases and the complexes were soluble in some common organic solvents. Infrared spectral data of the Schiff bases and their complexes, indicate coordination of the Schiff bases to the metal(II) ion via azomethine nitrogen. The effective magnetic moment of the Mn(II) complexes suggested an octahedral geometry. The molar conductance values of the complexes show that the complexes are electrolytes. The results of the elemental analysis of the ligands and their complexes are in good agreement with the calculated values, suggesting a 1:2 (metal-ligand) ratio. Antimicrobial screenings of the ligands and their complexes were conducted against gram-positive (Staphylococcus aureus,) and two gram-negative (Salmonella typhii, and Escherichia coli) bacteria specie. Also three fungi mainly (Candida albicans, Mucus indicus and Aspergillus flavus) were tested. The results showed that both the ligands and the complexes are active against the bacteria and the fungi specie.

Keywords: Ligand, Schiff base, 4-phenylthiosemicarbazide, 2-acetylthiophene, 2-acetylfuran molar conductivity, magnetic susceptibility, elemental analysis.