A novel adenine-based diruthenium(III) complex: Synthesis, crystal structure, electrochemical properties and evaluation of the anticancer activity

Abstract

Metal complexes based on purine nucleobases can be a very useful tool in the diagnosis and treatment of some diseases as well as in other biomedical applications. We have prepared and characterized a novel dinuclear ruthenium(III) complex based on the nucleobase adenine of formula [{Ru(μ-Cl)(μ-Hade)}₂Cl₄]Cl₂·2H₂O (1) [Hade = protonated adenine]. Complex 1 was characterized through Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX), magnetometer (SQUID) and cyclic voltammetry (CV) techniques. The crystal structure of 1 was determined by single-crystal X-ray diffraction. 1 crystallizes in the monoclinic system with space group P2₁/n. Each ruthenium(III) ion is six-coordinate and bonded to four Cl atoms [the average value of the Ru^III-Cl bonds lengths is ca. 2.329(1) Å] and two N atoms (N3 and N9) from two adenine molecules, the N1 atom being protonated in both of them. The anticancer activity was evaluated through cell viability assays performed on a colon cancer (HCT116) and a gastric cancer cell lines (AGS), 1 showing an incipient anticancer effect on the AGS cell line at the highest concentration used in the study.

Keywords: Adenine; Cancer cell lines; Cell viability; Crystal structure; Cyclic voltammetry; Ruthenium(III).