Synthesis, Spectral Characterization, Antioxidant, Antimicrobial and Anticancer Activities of New Binuclear Copper and Rhodium Complexes

Two novel binuclear complexes of Cu (II) and Rh (III) with Bis [4-hydroxy-6-methyl-3-{(1E)-N-[2-(ethylamino) ethyl] ethanimidoyl}-2H-pyran-2-one] (L) were prepared and characterized by elemental analysis, electrospray ionization-mass spectrometry (ESI-MS), conductivity, nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrophotometry, fluorescence, thermogravimetric analysis ( TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV). The spectral data indicate that the ligand binds the metal ions via the oxygen atom of the phenolic group, the nitrogen atoms of the azomethine and NH groups. These characterizations suggested the formation of binuclear complexes with octahedral geometry around each metal ion. For a better understanding of the response of complexes to biological activities, the stability constants, potential zeta and size of the complexes were determined. From the results, we can deduce that the complexes have more significant activities than their corresponding ligand. Moderate antioxidant activity recorded with both complexes, superior antibacterial and antifungal activities with Rh (III) complex with MIC value of 0.3125 mg. mL(-1) and interesting anticancer activity towards Hep2 cells (IC50=13.77 mu M) with Rh (III) and towards Hep2 (IC50=28.35 mu M) and K562 cells (IC50=26.34 mu M) with Cu (II) complex.