Synthesis, structural characterisation, thermal properties and bacterial activity of bimetallic bis(dithiocarbamate)-based macrocyclic complexes

Author(s): Enaam I.Yousif, Hasan A.Hasan, Riyadh M.Ahmed, Mohamad J.Al-Jeboori

A range of new binuclear metal(II) dithiocarbamate-based macrocyclic complexes is reported. The formation of complexes was achieved either by the reaction of the free ligand with ametal ion or via a one-pot reaction. The preparation of the bis-amine precursors (A and B) was achieved through several synthetic routes. The reaction of bis-amine precursor with CS2 in presence ofKOHyielded in the formation of free ligand namely; potassium 2,2'-(biphenyl-4,4'-diylbis(azanediyl)) bis(1-chloro-2-oxoethane-2,1-diyl) bis(cyclohexylcarbamodithioate) (L1) and potassium 2,2'-(biphenyl-4,4'- diylbis(azanediyl)) bis(1-chloro-2-oxoethane-2,1-diyl) bis(isopropylcarbamodithioate) (L2). Physico-chemical techniques were used to characterised ligands and their complexes. These include; elemental analysis, thermal properties, FTIR,UV-Vis,mass spectroscopy, magnetic susceptibility, conductance, melting points, and 1H, 13C-NMR spectroscopy. These studies indicated the preparation of binuclear macrocyclic complexes of the general formulae [M(Ln)]2 (M= MnII, CoII, NiII, CuII, ZnII and CdII; n = 1 or 2) with tetrahedral arrangement for MnII, CoII, ZnII and CdII, and square planar geometries with NiII and CuII complexes. Bacterial activity of the ligands and their metal complexes were tested against four bacterial species (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus stubtilis), which indicated that the complexes are potentiallymore active against these bacterial strains, compared with the free ligands.

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