Syntheses, structures and anti-cancer activities of CuII and ZnII complexes containing 1,1'-[(3-fluoro-phen-yl)methyl-ene]bis-[3-(3-fluoro-phen-yl)imidazo[1,5-a]pyridine].

Abstract

Two novel complexes, [Cu(T4)Cl₂] and [Zn(T4)Cl₂], were synthesized from 1,1'-[(3-fluoro-phen-yl)methyl-ene]bis-[3-(3-fluoro-phen-yl)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: di-chlorido-{1,1'-[(3-fluoro-phen-yl)methyl-ene]bis-[3-(3-fluoro-phen-yl)imidazo[1,5-a]pyridine]-κ² N,N'}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 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.