Development of Some Novel Hydrophilic Schiff Base Complexes: Synthesis, Spectroscopic Characterization, and DFT Calculation DNA-Binding and Biomedical Studies Supported by Molecular Docking Approach

Abstract

Several unique transition metal chelates of ESSA = sodium;4-[(3-ethoxy-2-hydroxy-benzylidene)-amino]-benzenesulfonate and its Cu(II), Fe(III), VO(II), and Pd(II) chelates were developed. Various spectral and physicochemical experiments were carried out to ascertain the geometrical form of the compounds under exploration. Spectrum info of the ESSA imine azomethine ligand and its metal compounds was employed for clarification of the alterations to structure triggered by complex formation. The formation of complexes by deploying continuous variation and molar ratio was explored, and the findings coincided with those observed in solid compounds, with a molar ratio of (M:L) being (1:2) for all metal complexes, except for Pd(II) is (1:1) metal-to-ligand ratio. Electronic spectra and magnetic moments can be applied to derive data concerning geometric formations. The activation thermodynamic variables related to the thermal breakdown of ESSA complexes were identified by using the Coats–Redfern approach. The ESSA imine ligand coordinates with Cu(II) and Pd(II) through square planner geometry, Fe(III) into octahedral geometry, and VO(II) in square pyramidal geometry, based on the correlation of all physicochemical techniques used in the inquiry and DFT calculation. The novel compounds were tested for DNA binding using spectroscopy, viscosity, and gel electrophoresis. Intercalation or replacement binding modes were hypothesized for their interaction with CT-DNA. Molecular docking studies were conducted to analyze the protein-generated compounds' binding and affinity. The antibacterial, anticancer, and antioxidant properties of ESSA ligand and its complexes were evaluated in vitro. ESSAPd complex excelled over the free ligand ineffective therapy.