Preparation, Characterization, and Biological Study of New Halogenated Azo-Schiff Base Ligands and Their Complexes

Three of new azo-Schiff base ligands were prepared in this work via the preparation of Schiff base ((E)-2-(((2,5-dichlorophenyl)imino)methyl)phenol DCSS) produced from the condensation reaction between salicyaldehyde and (2,5-dichloroaniline), this Schiff base was regarded as a coupling component in azo reactions to form the new azo-Schiff ligands [(2-((E)-((2,5-dichlorophenyl)imino)methyl)-4-((E)-(2,4-difluorophenyl)diazenyl)phenol) L1, (4-((E)-(4-chloro-2-fluorophenyl)diazenyl)-2-((E)-((2,5-dichlorophenyl)imino)methyl)phenol) L2, and (4-((E)-(4-bromo-2-fluorophenyl)diazenyl)-2-((E)-((2,5-dichlorophenyl) imino)methyl) phenol) L3], respectively, via the reaction of the diazonium salts of the (2,5-difluoroaniline, 4-chloro-2-fluoroaniline and 4-bromo-2-fluoroaniline) with the previous Schiff base (DCSS). These new Azo-Schiff ligands were characterized with many spectroscopic techniques such as (FT-IR, 1H-NMR, Mass spectra, UV-Visible, and elementary analysis) to ensure their preparation. Five divalent transition ions (Co, Ni, Cu, Pd, and Pt) complexes were prepared for each ligand and characterized (some of them) with the previous techniques, the mole ratio of the cobalt and copper complexes was (1:2), while the rest (Ni, Pd, and Pt) complexes have a (1:1) ratios. In addition, complementary techniques, such as atomic absorption, molar electrical conductivity, and magnetic susceptibility were performed to deduce their geometries and form the collected data. The square planer geometry was examined. The biological study includes the antibacterial screening against two types of bacterial species gram-negative (E.coli) and gram-positive (S. aureus) using tetracycline as a reference antibiotic. Antioxidant assay of some of the prepared ligands and their complexes as well as an MC7 cell line breast cancer assay for two prepared complexes (PdL1 and PtL2) and as compared, they noticed that the platinum azo-Schiff complex has an IC50 = 56.78 a more active anticancer function than the palladium complex with IC50 = 74.64.