Synthesis, characterization and anticancer activities of cationic η6-p-cymene ruthenium(II) complexes containing phosphine and nitrogenous ligands
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Date
2022
Authors
Guimaraes, Ivelise D. L.
Marszaukowski, Flávia
Rutka, Priscila B.
Borge, Luis F.
Ribeiro, Renan A. P.
Ricardo de Lazaro, Sergio
Castellen, Patrícia
Sagoe-Wagner, Araba
Golsteyn, Roy M.
Boeré, René T.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Ruthenium-based anticancer agents have created a center of attention in the field of inorganic medicinal chemistry. The first fully characterized cationic ruthenium(II)-arene complexes [Ru(η6-p-cymene) (PAr3)LNCl]+ with highly lipophilic PAr3 ligands where Ar = 3,5-((CH3)3C)2C6H3– (L1), 3,5-(CH3)2C6H3– (L2), 4-CH3O-3,5-(CH3)2C6H2– (L3) and 4-CH3O-C6H4– (L4) with N = 3-methylpyridine (1–4, respectively), or L4 and 4-methylpyridine (5), or L4 and CH3CN (6) were obtained (yields 67–91%) as solids stable to light and air. Electrical conductance indicates that all the complexes are 1:1 electrolytes in solution. Their composition and purity have been unambiguously established by single-crystal X-ray diffraction, NMR spectroscopy and elemental analysis. The coordination geometries are uniform for all six complexes and each structure consist of a unipositive complex cation bearing the phosphine ligands L1-L4 and LN = 3-methylpyridine, 4-methylpyridine or CH3CN attached to the organometallic fragment. The equivalent unit cell volumes per formula unit decrease with 1 > 3 > 2 > 4 > 5 > 6, accurately reflecting the decreasing sizes of the phosphines L1-L4, and a greater occupied volume for 3-methyl- vs. 4-methylpyridine, and the smallest volume contribution from CH3CN. Electrochemical studies showed mixed electrochemical mechanisms (EC/ECE) from partial substitution of p-cymene by CH3CN ligands from the solvent. A large electrochemical stability window (>2.2 V) for Ru(II) was observed extending beyond the physiological E° range. The complexes were cytotoxic against human cancer cell lines in vitro, and some complexes altered cell morphology.
Description
Accepted author manuscript.
Keywords
Cationic ruthenium-arene , Triarylphosphine , Pyridine derivative , Cyclic voltammetry , Cytotoxicity assays , DFT calculations
Citation
Guimaraes, I. D. L., Marszaukowski, F., Rutka, P. B., Borge, L. F., Ribeiro, R. A. P., Ricardo de Lazaro, S., Castellen, P., Sagoe-Wagner, A., Golsteyn, R. M., Boeré, R. T., & Wohnrath, K. (2022).Synthesis, characterization and anticancer activities of cationic η6-p-cymene ruthenium(II) complexes containing phosphine and nitrogenous ligands. Polyhedron, 224, Article 115980. https://doi.org/10.1016/j.poly.2022.115980