+44 1625708989New copper (II) complexes with ethylenediamine, bipyridine and amino acids: synthesis, characterization, optimization of geometry by theoretical DFT studies, electrochemical properties and biological activities
Author(s): Ahmed Adkhis, Fahima Belhocine-Hocini, Malika Makhloufi-chebli, Tahar Amrouche, Souhila Terrachet-BouazzizThree new copper (II) complexes of the formula (Cu (Trp)2 (en))0.5H2O (1), (Cu (Trp)2 (Bpy))2NO3. 4H2O (2) and (Cu(His)2(Bpy))2NO34H2O(3) (bpy=bipyridine, en=ethylenediamine, His=Histidine, Trp=tryptophan), were synthesized and characterized by elemental analysis, molar conductance measurements and IR, UV-spectral studies Visible. Molar conductance measurements suggest the non-electrolytic nature of metal complex 1 while compounds 2 and 3 are electrolytes. The electron absorption spectral data revealed an octahedral geometry of all the complexes, which is confirmed by the theoretical calculation (DFT). The electrochemical properties of the complexes obtained were studied by cyclic voltammetry. The voltammograms of all the complexes indicate a well-defined redox process corresponding to the formation of the almost quasi-reversible Cu (II)/Cu (I) couple at a scan rate of 50 and 100 mVs-1.
The antibacterial activity of copper complexes against E. coli, Staphylococcus aureus was investigated, the antioxidant properties were determined using the scavenging of the 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH). The results obtained showed a good antibacterial activity of the complexes tested. Furthermore, compounds 1 and 3 exhibited better antioxidant activity than compound 2. Our experiments were focused on the antibacterial activity of both ligands and copper complexes against a (Gram positive bacteria, namely Staphylococcus aureus, versus a Gram negative bacteria, namely Escherichia-coli). The ligands as well as the copper complexes revealed important antibacterial activities against both bacteria tested. Given these results further studies dedicated to biological activity of these compounds are encouraged using other complexes from same family of complexes and more pathogenic bacterial strains. This approach based on investigation of new copper complexes with biological activities may bring new insights for chemistry and food and pharmaceutical industries.
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