Arabian Journal of Chemistry (Feb 2022)
Solvent free synthesis, characterization, DFT, cyclic voltammetry and biological assay of Cu(II), Hg(II) and UO2(II) – Schiff base complexes
Abstract
A series of metal ion complexes was prepared in solid state from Cu(II), Hg(II) and UO2(II) ions with 3-oxo-3-(2-(2-oxoindolin-3-ylidene)hydrazineyl)-N-phenylpropanamide (H3L) ligand through solvent free synthesis methodology. The chemical formulae of the new compounds were estimated according to variable spectral and analytical investigations. The ligand exhibited a neutral or mononegative tetradentate mode of coordination towards the central ions inside the octahedral arrangement that proposed for the three complexes. The DFT/B3LYP method was applied under different basis sets (6-31G*or SDD) to optimize the structures of new compounds except the UO2(II) complex. The computational data were investigated to verify the binding mode that suggested spectrally. Moreover, studies in solution regarding Cu(II) ion via cyclic voltammetry were performed in absence or presence of H3L, to realize the significant effect of complex formation on the electrochemical manners of copper. The shifts in the potential peaks accompanied by the changes in the values of parameters correspond to kinetic and thermodynamic. Also, the solvation and kinetic characteristics for the cathodic and anodic potential of Cu(II) ion in absence or presence of H3L at different scan rates, were estimated. Finally, the ligand and copper ion exhibited high affinity towards complexation in solution. Furthermore, the activity of the new compounds towards inhibiting microbes was studied against Staphylococcus aureus (G+) and Escherichia coli (G-) bacteria as well as Candida albicans (fungus) by determining the inhibition zone diameter. Also, both the antioxidant and cytotoxic activity of the isolated compounds were evaluated. Commonly, a remarkable antimicrobial and anticancer activity was appeared with UO2(II) complex and the ligand. While, the antioxidant activity of all compounds appeared lower.
