Synthesis, Spectral Characterization, DFT Calculations, Cell Cycle Arrest, Apoptosis Assay, Cytotoxicity, DNA Binding and Biological Evaluation Study of Novel NO Pincer-Type 2-(5,6-Diflorobenzo[d]thiazol-2-yl)phenol and Its Bis(2-(5,6-diflorobenzo[d]thiazol-2-yl)phenoxy) Dichloro Platinum(IV) Trihydrate

Abstract

A new novel NO pincer-type bezo[d]thiazole ligand, 2-(5,6-diflorobenzo[d]thiazol-2-yl)phenol (H-DFBTP), is synthesized through reacting 2-amino-4,5-diflorobenzenethiol and 2-hydroxybenzoic acid in a 1:1 ratio. A nano-sized tetravalent Pt(IV) complex is created and subsequently characterized using various physical methods. The complex's structural geometry is validated by employing the DFT approach, utilizing DMOL³ determinations. Based on the elemental analysis results, the complexes are inferred to follow the overall formula [Pt(DFBTP)₂Cl₂].3H₂O. Quantum chemical calculations, along with electronic spectra findings, indicate that the Pt(IV) complex exhibits an octahedral configuration. The EDX, XRPD, TEM, and AFM analyses of the studied Pt(IV) complex unveil distinct and strong diffraction peaks, indicating its crystalline nature and providing evidence of its nano-sized particle sizes. Absor ption titration techniques and viscosity measurements were employed to inspect the interaction between CT-DNA and the Pt(IV) complex. The findings showed that the complex's binding to CT-DNA occurred throughout a typical intercalation mechanism. The anticancer properties of isolated compounds were evaluated in vitro using the MTT assay, targeting both normal cell lines (NHDF) and cancer cell lines (HeLa, HepG2, MCF-7, and A549). Findings revealed that the tetravalent platinum complex effectively inhibits the proliferation of cancer cells (HeLa: 24.68 ± 1.29 μg/mL; HepG2: 32.2 ± 1.69 μg/mL; MCF-7: 20.12 ± 1.00 μg/mL; A549: 23.46 ± 1.17 mg/mL) while sparing normal cells (NHDF: 109.26 ± 5.46 μg/mL). Additionally, the isolated compounds demonstrated notable antioxidant and antimicrobial capabilities. Both the ligand and the Pt complex exhibited strong potent antioxidant activity by neutralizing four distinct free radicals, as well as antimicrobial efficacy against C. albicans and E. coli. Moreover, the Pt(IV) complex exhibited the capability for triggering DNA damage in HepG2 cells, resulting in dose-dependent cell apoptosis. Subsequent investigations revealed that the complex triggered cell cycle arrest during the phases S and G2.