Coordination complexes of lanthanide(III) derived from 2-(pyridin-2-yl)-1H-benzo[d]imidazole (bimpy) and 2,2′-bipyridine (bpy): Spectroscopic analysis and cytotoxic evaluation

Seven novel coordination complexes (1–7) derived from trivalent lanthanides (La, Nd, Sm, Eu, Gd, Tb, Dy) and bidentate ligands 2,2′-bipyridine (bpy) and 2-(pyridin-2-yl)-1H-benzo[d]imidazole (bimpy) were synthesised. A series of analytical and spectroscopic techniques, including high-resolution mass spectrometry, unambiguously characterised all complexes. Using ligand mixtures to obtain coordination complexes with anticancer activity has shown promising results. Therefore, additional experiments were performed to evaluate the cytotoxic activity in non-transformed cells (NIH/3 T3 and J774A.1) and transformed cells (HeLa, Caco-2 and MCF-7), as well as erythrocyte lysis experiments in human red blood cells. The results revealed moderate but selective cytotoxicity against the studied cell lines. Additional PBE0/def2-SVP computational studies were carried out to elucidate the coordination number, geometry and structural organisation in agreement with the experimental data.