Quasi-Isostructural Co(II) and Ni(II) Complexes with Mefenamato Ligand: Synthesis, Characterization, and Biological Activity

Three metal complexes of mefenamato ligand1were synthesized: [Co-2(mef)(4)(EtOH)(2)(H2O)(4)]:2; [Co(mef)(2)(MeOH)(4)]center dot 2MeOH:3; and [Ni(mef)(2)(MeOH)(4)]center dot 2MeOH:4. Their compositions and properties were investigated by elemental analysis (EA), flame atomic absorption spectrometry (FAAS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Crystal structures were determined by the single crystal X-ray diffraction technique. Additionally, their antioxidant and antimicrobial activity were established, thus proving good/moderate bioactivity against Gram-positive bacteria and yeasts. In the crystal structure of2, an apical water molecule is shared between two adjacent cobalt(II) ions, resulting in the formation of a polymeric chain extending along the [100] direction. Meanwhile, structures3and4have strong intermolecular hydrogen bonds with diverse topologies that yield unique quasi-isostructural arrangements. The packing topology is reflected by the Hirshfeld surface analysis of intermolecular contacts.