Probing CO Generation through Metal-Assisted Alcohol Dehydrogenation in Metal-2-(arylazo)phenol Complexes Using Isotopic Labeling (Metal = Ru, Ir): Synthesis, Characterization, and Cytotoxicity Studies

Abstract

The reaction of 2-{2-(benzo [1,3]dioxol-5-yl)-diazo}-4-methylphenol (HL) with [Ru(PPh 3 ) 3 Cl 2 ] in ethanol resulted in the carbonylated ruthenium complex [RuL(PPh 3 ) 2 (CO)] (1), wherein metal-assisted decarbonylation via in situ ethanol dehydrogenation is observed. When the reaction was performed in acetonitrile, however, the complex [RuL(PPh 3 ) 2 (CH 3 CN)] (2) was obtained as the main product, probably by trapping of a common intermediate through coordination of CH 3 CN to the Ru(II) center. The analogous reaction of HL with [Ir(PPh 3 ) 3 Cl] in ethanol did not result in ethanol decarbonylation and instead gave the organoiridium hydride complex [IrL(PPh 3 ) 2 (H)] (3). Unambiguous evidence for the generation of CO via rutheniumassisted ethanol oxidation is provided by the synthesis of the 13 C-labeled complex, [Ru(PPh 3 ) 2 L( 13 CO)] (1A) using isotopically labeled ethanol, CH 3 13 CH 2 OH. To summarize all the evidence, a ruthenium-assisted mechanistic pathway for the decarbonylation and generation of alkane via alcohol dehydrogenation is proposed. In addition, the in vitro antiproliferative activity of complexes 1−3 was tested against human cervical (HeLa) and human colorectal adenocarcinoma (HT-29) cell lines. Complexes 1−3 showed impressive cytotoxicity against both HeLa (half-maximal inhibitory concentration (IC 50 ) value of 3.84−4.22 μM) and HT-29 cancer cells (IC 50 values between 3.3 and 4.5 μM). Moreover, the complexes were comparatively less toxic to noncancerous NIH-3T3 cells.

Water-Soluble Dioxidovanadium(V) Complexes of Aroylhydrazones: DNA/BSA Interactions, Hydrophobicity, and Cell-Selective Anticancer Potential

“…From this graph it is evident that an increase in hydrophobicity correlates with a steady increase in cytotoxicity for all three cell lines. These results suggest that hydrophobic character, a property that eases the ability to cross the cellular membrane, leading to better availability of compounds in its target, may be useful to the maximum cellular uptake of oxidovanadium complexes and the associated cytotoxic effects. − The reasons for the complex ability for cell permeation through the lipid layer of the cell membrane may be attributed to the coordination behavior, the polarity of the ligand, and the reduced central metal ion through charge equilibration. ,,,,− …”

Study of DNA Interaction and Cytotoxicity Activity of Oxidovanadium(V) Complexes with ONO Donor Schiff Base Ligands

“…The results were expressed as percentages of the control. % cell viability = [mean OD of the treated cell/mean OD of the control] × 100 IC 50 value of the compounds was calculated from the absorbance concentration plot following standard procedure [51,66].…”

Mo(VI) Potential Metallodrugs: Explaining the Transport and Cytotoxicity by Chemical Transformations

“…In order to determine the cytotoxic effect of the Mo complexes, MTT cell viability assay was carried out. ,,, In the present investigation, the complexes with a different number of metal centers and substituents in their ligand backbone were tested for their toxicity on three different cell lines: human cervical cancer (HeLa), human colon cancer (HT-29), and noncancerous mouse embryonic fibroblast (NIH-3T3) cell lines.…”

“…In continuation of our research on the pharmacological properties of various transition metal complexes, ,,− herein the synthesis of two monomeric, [MoO 2 (L 1 )­(MeOH)] ( 1 ) and [MoO 2 (L 2 )­(EtOH)] ( 2 ), and two mixed-ligand dimeric, [{MoO 2 (L 1–2 )} 2 (μ-4,4′-bipy)] ( 3 and 4 ), dioxidomolybdenum­(VI) complexes from two aroylhydrazone ligands (H 2 L 1–2 ) is reported. The complexes revealed a distorted octahedral geometry with the sixth labile coordination site occupied by the solvent molecule (MeOH/EtOH) in case of the monomeric complexes and the coligand 4,4′-bipyridine in case of the dimeric complexes. − Hydrazones are important set of ligands, as they manifests a vast range of pharmaceutical activities. − It has been demonstrated that their biological properties are considerably enhanced upon complexation to metal ions .…”