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

Journal Article

2023

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 1
H 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](NO30.5H2O)) 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. Inaccordance 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.