Copper(II) Complexes Derived from Schiff Bases Containing 4-Methylbenzylamine as a Core Unit: Cytotoxicity,pBR322-DNA Studies,Biological Assays,and Quantum Chemical Parameters

Bivalent copper complexes, Cu(SB¹)₂] 1 (SB¹=(2-(4-methylbenzylimino)methyl)-5-methylphenol, Cu(SB²)₂] 2 (SB²=(2-(4-methylbenzylimino)methyl)-4-bromolphenol), and Cu(SB³)₂] 3 (SB³=(2-(4-methylbenzylimino)methyl)-4,6-dibromophenol) were synthesized using the Schiff bases prepared from 4-methylbenzylamine (p-tolylmethanamine). These were characterized using a variety of spectro-analytical methods. For all copper complexes, a square planar geometry was determined through spectral analyses. Utilizing molecular orbital energies, the stability of the copper complexes was calculated from quantum chemical characteristics. The kinetic and thermal degradation parameters were calculated from the thermograms. Studies on DNA binding interactions, such as UV absorption and emission, have shown that the manner of DNA binding is intercalative, and the binding constant (K_b) order is 3 > 2 > 1 . Under oxidative and photolytic techniques, the copper complexes outperform the parent Schiff bases in their ability to cleave double-stranded pBR322 DNA. When tested for cytotoxicity on the KB3 and MCF7 cell lines, complexes displayed greater activity than their parent ligands. Studies on the complexes′ in-vitro antibacterial and antioxidant activity showed that they are significantly more powerful than the parent ligands.