Synthesis, Characterization, Antioxidant and Antibacterial Activities of Six Metal Complexes Based Tetradentate Salen Type Bis-Schiff Base

Considering the importance of metal complexes in the development of medicinal chemistry, a series of transition metal complexes of Co(II), Fe(II), Zn(II), Cu(II), and Ni(II) has been synthesized from N,N'-bis(salicylidene)-2,2-dimethyl-1,3-diaminopropane H2L Schiff base ligand. The reaction of the H2L with the selected metal ions led to tetrahedral and octahedral coordinated complexes. The structural features of the obtained metal complexes were determined using analytical techniques such as FT-IR, NMR, UV-Vis, X-ray powder diffraction, mass spectrometry, and Thermogravimetry–differential thermal (TGA/DTA) analysis. The measured conductance for obtained compounds has shown the electrolytic behavior of all obtained complexes. The synthesized ligand and corresponding complexes were screened for their antioxidant and antibacterial activities. Indeed, Co(II) and Fe(II) complexes have shown excellent antioxidant activities for DPPH radical scavenging and FRAP assays, respectively. The results obtained from the disc diffusion assay showed that Co(II), Fe(II), Zn(II), and Cu(II) complexes had displayed promising antibacterial activity against Escherichia coli and Staphylococcus aureus, while no effect has been observed on both strains for ligand H2L and its corresponding Ni(II) complex.