Synthesis and Structural Characterization of a Monomeric Mixed Ligand Copper(II) Complex Involving N,N,N′,N′-Tetramethylethylenediamine and Mefenamate

Abstract

A monomeric ternary complex [Cu(tmen)(mef)₂] (1) (where mef = mefenamate anion (C₁₅H₁₅NO₂¹⁻, tmen = N,N,N′,N′-tetramethylethylenediamine) is prepared by the reaction of CuCl₂·2H₂O, mefenamic acid (mefH = 2-(2,3-dimethylphenyl)aminobenzoic acid), and N,N,N′,N′-tetramethylethylenediamine (tmen) in the presence of sodium hydroxide. Complex 1 is characterized by the elemental combustion analysis, UV-visible and FT–IR spectroscopy, thermal analysis, and single crystal X-ray diffraction. From the crystal structure of complex 1, it is evident that each copper(II) ion is six-coordinate and is bonded to chelating tmen, and four O atoms of two mef anions (mef^1–). In the crystal, the intramolecular hydrogen bonding exists between the H atom of the –NH group of mef and the O atom of one of the coordinated carboxylate O atoms, belonging to the same mef ligand. Complex 1 is tested for antibacterial properties against four strains, including Staphylococcus aureus, Bacillus spizizenii, Escherichia coli, and Klebsiella pneumonia. The complex shows a biological activity against Staphylococcus aureus and Bacillus spizizenii.