Syntheses, structures and anti­cancer activities of CuII and ZnII complexes containing 1,1′-[(3-fluoro­phen­yl)methyl­ene]bis­[3-(3-fluoro­phen­yl)imidazo[1,5-a]pyridine]

The Cu^II and Zn^II complexes containing 1,1′-[(3-fluoro­phen­yl)methyl­ene]bis­[3-(3-fluoro­phen­yl)imidazo[1,5-a]pyridine] show potential as cancer treatment agents. The crystal-structure determination of the Cu^II complex confirms a distorted tetra­hedral N₂Cl₂ coordination set for the Cu^II atom.

Two novel complexes, [Cu(T4)Cl₂] and [Zn(T4)Cl₂], were synthesized from 1,1′-[(3-fluoro­phen­yl)methyl­ene]bis­[3-(3-fluoro­phen­yl)imidazo[1,5-a]pyridine] (T4), 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 CuT4 complex [systematic name: di­chlorido­{1,1′-[(3-fluoro­phen­yl)methyl­ene]bis­[3-(3-fluoro­phen­yl)imidazo[1,5-a]pyridine]-κ²N,N′}copper(II), [CuCl₂(C₃₃H₂₁F₃N₄)], was confirmed by single-crystal X-ray diffraction. The Cu^II atom adopts a distorted tetra­hedral 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 inter­actions. Biological evaluations demonstrated that both complexes exhibit enhanced anti­cancer activity compared to the free ligand, with IC₅₀ values ranging between 18.93 and 67.06 µM. Notably, the Cu^II complex displays excellent inhibitory activity against the MCF7 breast cancer cell line (IC₅₀ = 27.99 µM), approximately twice as effective as cisplatin. Conversely, the ZnT4 complex shows greater efficacy against Hep-G2 and A549 lung cancer cell lines, with IC₅₀ values between 18.93 and 24.83 µM. The results suggest that Cu^II and Zn^II complexes of T4 show potential as cancer treatment agents.