Synthesis, crystal structures and antimicrobial properties of copper(II)-thiophene-2,5-dicarboxylate complexes with N-donor ligands

Abstract

Eight new copper(II)-thiophene-2,5-dicarboxylate (tdc) complexes with N-methylethylenediamine (nmen), [Cu(H2O)(2)(nmen)(2)](tdc) (1), N,N-dimethylethylenediamine (nnen), [Cu(tdc)(nnen)(2)]center dot H2O (2), N,N'-dimethylethylenediamine (dmen), [Cu(mu-tdc)(H2O)(dmen)](n) (3), N,N,N',N'-tetramethylethylenediamine (tmen), {[Cu(mu-tdc)(tmen)(2)]center dot H2O}(n) (4), N-ethylethylenediamine (neten), trans-[Cu(H2O)(2)(neten)(2)](tdc)center dot 2H(2)O (5), N,N'-diethylethylenediamine (deten), trans-[Cu(H2O)(2)(deten)(2)](tdc) (6), N,N-diethylethylenediamine (eten), [Cu(mu-tdc)(eten)](n), (7), and N-methyl-1,3-propanediamine (nmpen), [Cu(tdc)(nmpen)(2)] (8), have been synthesized and characterized by elemental analyses, magnetic moments, thermal analyses (TG, DTG and DTA), UV-Vis and IR spectra. The crystal structures of 2, 3, 5 and 7 were determined by single crystal X-ray diffraction studies. In 1, 5 and 6, the Cu(II) ions are coordinated by two aqua ligands and four nitrogen atoms of nmen, neten and deten, respectively and thiophene-2,5-dicarboxylate (tdc) acts as a counterion. In 2, 4 and 8, tdc coordinates to the Cu(II) ions through the oxygen atom of the carboxylate group as a monodentate ligand, and the distorted square pyramidal geometries of the Cu(II) ions of 2, 4 and 8 are completed by the nnen, tmen and nmpen ligands, respectively, which act as bidentate ligands. In 3 and 7, the tdc ligand exhibits tridentate-mu(2) and tetradentate-mu(2) bridging modes, being coordinated through three and four carboxylate oxygens atoms, respectively. The crystal packing of the complexes is a composite of intermolecular hydrogen bonding interactions. Furthermore, in vitro antimicrobial activities of these complexes were tested against selected wild type microorganisms using MIC methods