Synthesis, Characterization, and Biological Studies of a New Schiff Base Ligand Derived from 5-Amino-2-hydroxybenzoic Acid and Benzaldehyde and its Metal Complexes.

A Schiff base (E)-5-(benzylideneamino)-2-hydroxybenzoic acid ligand is formed when benzaldehyde and 5-amino salicylic acid combine in a 1:1 ratio. The ligand has been studied using various spectroscopic techniques, including FT-IR, UV-visible spectroscopy, ¹H and ¹³C NMR, mass spectrometry, TLC, XRD powder analysis, and DFT calculations. The metal ions (Co²⁺, Ni²⁺, Mn²⁺), resulting in complexes using the generic equations[L(M)Cl. H₂O], in which M represents Co²⁺, Ni²⁺, or Mn²⁺, as seen in the Graphical Abstract Scheme 1. The complexes have been studied using spectroscopic techniques, including FT-IR, UV-visible spectroscopy, melting point determination, conductivity measurement, and magnetic susceptibility analysis. Biological activity encompasses the beneficial or detrimental impacts that a drug or molecule can have on living organisms, highlighting its potential to prevent cell death, reduce inflammation, stimulate nerve growth, and deliver essential nutrients. The DFT method was used to optimize the suggested structures of the ligand and the complexes, and the optimized structures were used to calculate the energies of the molecular orbitals and the energy gap. Based on the measurements obtained, this study suggests that the geometrical configuration of all the complexes is tetrahedral (sp³) surrounding the metal ions.