Ruthenium(II) bipyridine complexes: from synthesis and crystal structures to electrochemical and cytotoxicity investigation

Abstract

Complexes 1-4, [Ru(L)(bpy) 2 ]PF 6 , where bpy = 2,2′-bipyridine; L = 3-methylpyridine-2carboxylic acid (L1), 6-methylpyridine-2-carboxylic acid (L2), 5-bromopyridine-2-carboxylic acid (L3) and 6-bromopyridine-2-carboxylic acid (L4), were synthesized and characterized. The electrochemical character of the complexes was investigated by cyclic voltammetry revealing two reversible reduction waves in the negative range of potentials, most likely due to a reduction of the bipyridine moiety. Cytotoxicity studies by MTT assay for 72 h of drug action revealed that 2-4 exhibited moderate activity in cervical human tumor cells (HeLa). Complex 2 exhibited low activity in colon cancer LS-174 cells (180 ± 10), while all complexes were devoid of activity in lung cancer A549 and non-tumor MRC-5 cells, up to 200 μM. Combinational studies of the most active complex 2, with pharmacological modulators of cell redox status, L-buthioninesulfoximine (L-BSO) or N-acetyl-L-cysteine (NAC), showed that when L-BSO potentiated, 2 induced a sub-G1 peak of the cell cycle in the HeLa cell line. UV-vis and cyclic voltammetry were performed in order to investigate the binding mode of 2 to DNA and suggested intercalation for the complex-DNA interaction.

Co(III), Ni(II) and Cu(II) complexes with a tetradentate Schiff base ligand: synthesis, characterization, electrochemical behavior, binding assessment andin vitrocytotoxicity

“…Moreover, the azomethine oxime stretching band appeared in the spectra of newly synthesized complexes in the region from 1520 cm -1 to 1510 cm -1 pointing out the involvement of oxime nitrogens. The proposed binding mode is further supported by obvious intensity increasing of N -O band and minor negative shifts of 1-3 in comparison to the LH 2 [30]. Finally, in the area below 550 cm -1 , a novel set of three bands was observed for all three complexes, which were attributed to M -N, and M -O vibrations [39].…”

“…The interactions between metal complexes and DNA or HSA have been widely investigated using various spectroscopic [29,30], calorimetric [31], and electrochemical methods [32,33]. Electrochemical studies of these interactions are increasingly represented due to their low cost and the use of simpler and smaller devices in comparison to the spectroscopic methods.…”

The crystal structure of 5-bromopicolinic acid monohydrate, C6H6BrNO3

“…5-Bromopicolinic acid, one of the derivatives of picolinic acid, attracted attention over a long period of time and acted as organic ligand to form metal-organic complexes [5][6][7][8][9][10][11]. One of the derivatives, the methyl-5-bromo-6-methylpicolinate, has been reported as single crystal structure elsewhere [12].…”

Solubility Determination and Thermodynamic Properties of 5-Bromo-2-pyridinecarboxylic Acid in 10 Monosolvents and 3 Binary Solvents at T = (278.15–323.15) K

“…As modern medicine imposes more stringent standards on the final clinical use, the concept of the entire metal drug is also undergoing major changes. Every research conducted needs to go through a rigorous process, including synthetic routes, structure and electrochemical characterization, in vitro and DNA targeting test, and protein inhibition test . Studies have shown that the ligand can be responsible for redox activity and anticancer activity. , It can also improve the solubility of the complex, reduce toxicity, and enhance specificity .…”