Synthesis, spectral elucidation, antibacterial, antioxidant and DNA studies of ONNO tetradentate Schiff base metal(II) complexes derived from Benzene-1,4-dicarboxaldehyde

Abstract

The new dibasic tetradentate (ONNO) Schiff base ligands (L₁and L₂) have been synthesized by the reaction of terephthalaldehyde with 2-amino 4-chlorophenol and X (where, X=2-amino 4-methylphenol, 2-aminophenol) in 1:1:1 molar ratio. The macrocyclic binuclear Co(II), Ni(II) and Cu((II) metal complexes are prepared in ligand to metal ratio 2:2. The elements, metal structure and binding sites of Schiff bases and its complexes are established by diverse studies like elemental, molar conductance, UV, magnetic moment, FT-IR, H¹ and C¹³ NMR, ESI-mass, ESR, thermal and powder-XRD. The spectral studies reveal that the ligands are tetradentate and its metal complexes possess a square planar geometry. All the compounds are screened for antibacterial, antioxidant and DNA cleavage and the results show high activity for metal complexes than the ligand. The DNA binding studies of Cu(II) complexes were measured by electronic absorption method. <em>In vitro</em> cytotoxicity assay of Cu(II) complexes have been tested for their tumour inhibiting potential against MCF-7 human breast cancer cell by using MTT method.