Innovation of Fe(III), Ni(II), and Pd(II) complexes derived from benzothiazole imidazolidin‐4‐ol ligand: Geometrical elucidation, theoretical calculation, and pharmaceutical studies

Abstract

The synthesis of a simple, highly tunable, and effective BSI ligand, 2‐(benzothiazol‐2‐ylimino)‐2,3‐dihydro‐1H‐imidazol‐4‐ol, was presented. Three new coordinating substances of BSI ligand were synthesized. Various spectroscopic and analytical methods, including 1H NMR and 13C NMR, infrared (IR), ultraviolet–visible (UV‐vis), thermal conduction, and measures of magnetism, were used to clarify the structures of these compounds. A further examination of the compounds revealed an octahedral‐coordinating environment surrounding the Fe3+ ion, ([Fe(BSI)2(NO3)2](NO3·0.5H2O)) and Ni2+, ([Ni(BSI)2(NO3)2](H2O)2) cations and distorted square planner surrounding Pd2+, ([Pd(BSI)(COOCH3)2]H2O) cation. The cations under investigation were linked to the BSI ligand through the nitrogen of the thiazole ring and NH of the imidazole ring. The formed BSI complexes' thermal deterioration behavior was investigated. Calculated kinetic data for the examined complexes' various phases of deterioration supported their endothermic character. Using the Gaussian 09 software at the B3LYP/LANL2DZ level, the equilibrium geometry of the ligands and their coordination complex has been studied by calculations using density functional theory (DFT). The suggested structures by DFT calculation are in good agreement with experimental data. The antibacterial effectiveness of the examined molecules against different types of bacteria and fungus reveals that the BSIPd complex (MIC = 2.25–4.75 μg/mL) has the greatest activity and is most comparable to the standard. The newly synthesized compounds were also tested against several cell lines using the MTT assay. The results are given as an IC50 value, where the Pd(II) complex values show the potential anticancer properties of the compound. Moreover, the inspected complexes showed significant cell growth inhibition activity (IC50 = 6.79–9.05 μg/mL), even higher than the standard anticancer drugs; cisplatin (IC50 = 18 μg/mL) versus breast carcinoma cells. This intriguing finding was verified by Swiss‐ADME and pharmacophore query calculations. In accordance with the actual findings, the in silico results showed that the free ligand's low activity increased when it complexed with the inspected metal ions.