4‐Methylsulfonylbenzyl Substituted N ‐Heterocyclic Carbene‐Ruthenium (II) Complexes: Design, Synthesis, Characterization, and Anticancer Activities

ABSTRACT In this study, we report the synthesis and anticancer activities of new ruthenium complexes with N ‐heterocyclic carbene (NHC) ligands, which are of great significance for drug delivery research. For this reason, 4‐methylsulfonylbenzyl‐substituted benzimidazole‐functionalized Ru(II)NHC complexes were synthesized in our research. The characterization of these new complexes were performed using appropriate spectroscopic methods ( 1 H NMR, 13 C NMR, and FT‐IR) and elemental analysis techniques. The crystal structure of complex 1c was obtained using single crystal X‐ray diffraction. MTT method was used to understand in vitro anticancer activities of the complexes against MCF‐7 (breast cancer), HCT‐116 (colon cancer), SH‐SY5Y (brain cancer), and HeLa (cervical cancer) cell lines. Based on the IC 50 values determined by MTT assay, the most effective complex was identified as 1 h . DNA binding analyses were carried out using agarose gel electrophoresis, revealing that 1 h weakly interacted with DNA. Additionally, the effects of 1 h on cell cycle progression and apoptosis in the SH‐SY5Y cell line were examined using flow cytometry. The results indicated that 1 h induced G0/G1 phase accumulation and increased apoptotic cell death. These findings suggest that the synthesized complex 1 h has a significant anticancer potential.