N-(Methyl)phthalimide para functionalized Ni(ii)–POCOP pincer complexes. Synthesis, characterization and biological activity†

Pincer compounds have stood out for their great stability, and they have been primarily employed as catalysts. In recent years, they have also been studied to evaluate their biological properties. In this work, three new POCOP–Ni(II) pincer complexes functionalized with a methylphthalimide fragment (1-Ni, 2-Ni, and 3-Ni) were synthesized. These complexes were unequivocally characterized by X-ray diffraction (XRD), and supramolecular studies were conducted using Hirshfeld surfaces. The cytotoxic activity of the complexes was evaluated on six cancer cell lines and one healthy monkey kidney cell line (COS-7). In a preliminary study, 1-Ni was determined to be the most active of the series, with IC₅₀ values ranging from 0.64 μM to 1.38 μM. Additionally, ethidium bromide (EB) displacement studies were conducted, where it was observed that complexes 1-Ni and 3-Ni intercalate into the DNA target. Moreover, molecular docking studies revealed that these complexes intercalate with DNA, as was experimentally corroborated. Furthermore, the POCOP–Ni(II) complexes did not demonstrate antioxidant activity, suggesting that the presence of the phthalimide moiety may block radical inhibition processes.