Synthesis of Para‐Acetylated Functionalized Ni(II)‐POCOP Pincer Complexes and Their Cytotoxicity Evaluation Against Human Cancer Cell Lines

A series of three Ni(II)‐POCOP complexes para‐functionalized with an acetoxyl fragment were synthesized. All complexes (2 a–c) were fully characterized through standard analytical techniques. The molecular structure of complex 2 b was unambiguously determined by single‐crystal X‐ray diffraction, revealing that the metal center is situated in a slightly distorted square‐planar environment. Additionally, the acetoxy fragment at the para‐position of the phenyl ring was found to be present. The in vitro cytotoxic activity of all complexes was assessed on six human cancer cell lines. Notably, complex 2 b exhibited selective activity against K‐562 (chronic myelogenous leukemia) and MCF‐7 (mammary adenocarcinoma) with IC50 values of 7.32±0.60 μM and 14.36±0.02 μM, respectively. Furthermore, this compound showed negligible activity on the healthy cell line COS‐7, highlighting the potential therapeutic application of 2 b. The cytotoxic evaluations were further complemented with molecular docking calculations to explore the potential biological targets of complex 2 b, revealing interactions with cluster differentiation protein 1a (CD1 A, PDB: 1xz0) for K‐562 and with the progesterone receptor for MCF‐7.