Manganese(II) chelates of bioinorganic and medicinal relevance: Synthesis, characterization, antibacterial activity and 3D-molecular modeling of some penta-coordinated manganese(II) chelates in O,N-donor coordination matrix of β-diketoenolates and picoli

Four new mixed-ligand complexes of manganese(II) of the composition [Mn(pa)(L)(H2O)], where paH = picolinic acid and LH = acetoacetanilide (aaH), o-acetoacetanisidide (o-aansH), o-acetoacetotoluidide (o-aatdH) or ethylacetoacetate (eacacH), have been synthesized by the interaction of MnCl2·4H2O with the said ligands in aqueous-ethanol medium. The complexes so obtained have been characterized on the basis of elemental analyses, molar conductance and magnetic measurements, thermogravimetric analyses, mass, EPR, infrared and electronic spectral studies. Synthesized complexes have shown significantly greater antibacterial activity against Escherichia coli and Vibrio cholera than ligands. The 3D-molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compound [Mn(pa)(aa)(H2O)] (1) to substantiate the proposed structures.