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

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.