Transition Metal Complexes with Flufenamic Acid for Pharmaceutical Applications—A Novel Three-Centered Coordination Polymer of Mn(II) Flufenamate

Abstract

Five complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with non-steroidal anti-inflammatory drug, flufenamic acid were synthesized: (1) [Mn3(fluf)6EtOH)(H2O)]·3EtOH; (2) [Co(fluf)2(EtOH)(H2O)]·H2O; (3) [Ni(fluf)2(EtOH)(H2O)]·H2O; (4) [Cu(fluf)2·H2O]; (5) [Zn(fluf)2·H2O]. All complexes were characterized by elemental analysis (EA), flame atomic absorption spectrometry (FAAS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The crystal structure of 1 was determined by the single crystal X-ray diffraction technique. It crystallizes in the triclinic space group P1¯ with three independent Mn(II) cations, six coordinated flufenamato ligands augmented with water and ethanol molecules in the inner coordination sphere. In this crystal, manganese atoms are multiplied by symmetry and form infinite, polymeric chains which extend along the [001] dimension. The Hirshfeld Surface analysis revealed changes in interaction assemblies around all metal centers. The antioxidant and antimicrobial activities were established for all complexes and free ligand for comparison. All compounds exhibit good or moderate bioactivity against Gram-positive bacteria and yeasts.