Syntheses, structures and anticancer activities of Cu^II and Zn^II complexes containing 1,1′-[(3-fluorophenyl)methylene]bis[3-(3-fluorophenyl)imidazo[1,5-<i>a</i>]pyridine]

Two novel complexes, [Cu(<b>T4</b>)Cl₂] and [Zn(<b>T4</b>)Cl₂], were synthesized from 1,1'-[(3-fluoro-phen-yl)methyl-ene]bis-[3-(3-fluoro-phen-yl)imidazo[1,5-<i>a</i>]pyridine] (<b>T4</b>), and copper(II) and zinc(II) chloride, respectively. The structures of these complexes were confirmed using ESI-MS, IR and ¹H NMR spectra. The results reveal mononuclear structures in which the central metal atoms are coordinated by two N atoms from the imidazole rings and two Cl ligands. The structure of the <b>CuT4</b> complex [systematic name: di-chlorido-{1,1'-[(3-fluoro-phen-yl)methyl-ene]bis-[3-(3-fluoro-phen-yl)imidazo[1,5-<i>a</i>]pyridine]-κ² <i>N</i>,<i>N</i>'}copper(II), [CuCl₂(C₃₃H₂₁F₃N₄)], was confirmed by single-crystal X-ray diffraction. The Cu^II atom adopts a distorted tetra-hedral coordination environment with an N₂Cl₂ coordination set. The predominant features of the crystal packing are C-H⋯F, C-H⋯π and C-F⋯π inter-actions. Biological evaluations demonstrated that both complexes exhibit enhanced anti-cancer activity compared to the free ligand, with IC₅₀ values ranging between 18.93 and 67.06 µ<i>M</i>. Notably, the Cu^II complex displays excellent inhibitory activity against the MCF7 breast cancer cell line (IC₅₀ = 27.99 µ<i>M</i>), approximately twice as effective as cisplatin. Conversely, the <b>ZnT4</b> complex shows greater efficacy against Hep-G2 and A549 lung cancer cell lines, with IC₅₀ values between 18.93 and 24.83 µ<i>M</i>. The results suggest that Cu^II and Zn^II complexes of <b>T4</b> show potential as cancer treatment agents.