Characterization and Cytotoxic Assessment of Bis(2-hydroxy-3-carboxyphenyl)methane and Its Nickel(II) Complex

Abstract

A condensation reaction of salicylic acid with formaldehyde in the presence of sulfuric acid led to the synthesization of the bis(2-hydroxy-3-carboxyphenyl)methane (BHCM) ligand, which was subsequently allowed to bind with nickel (II) ions. In light of the information obtained from the elemental analyses (C, H, and M), spectral (IR, MS, ¹H-NMR, and UV-Vis) and thermal and magnetic measurements, the most likely structures of the ligand and complex have been identified. It has been suggested that the BHCM coordinates in a tetradentate manner with two Ni(II) ions to produce an octahedral binuclear complex. The SEM and TEM morphology of the compounds showed spherical shapes. An X-ray diffraction analysis indicated a considerable difference in the diffraction patterns between BHCM (crystalline) and Ni-BHCM (amorphous), and the Scherrer equation was used to calculate the crystallite size. Some optical characteristics were estimated from UV-Vis spectra. The ligand and its nickel(II) complex underlie the range of semiconductors. It was verified that for human lung (A-549) cancer, the BHCM compound displayed a significant barrier to the proliferation test in noncancerous cells (human lung fibroblasts, WI-38), which was also undertaken. To demonstrate the binding affinities of the chosen compounds (BHCM and Ni-BHCM) in the receptor protein's active site [PDB ID: 5CAO], a molecular docking (MD) study was carried out.