Binuclear dichlorido(η⁶‐p‐cymene)ruthenium(II) complexes with bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol ester ligands

Abstract

-p-cym)((3-py)COO(CH 2 CH 2 OCH 3 )-κN)], complex 9, were synthesized and characterized using elemental analysis and electrospray ionization high-resolution mass spectrometry, infrared, 1 H NMR and 13 C NMR spectroscopies. Stability of the binuclear complexes in the presence of dimethylsulfoxide was studied. Furthermore, formation of a cationic complex containing bridging pyridine-based bidentate ligand was monitored using 1 H NMR spectroscopy. Ligand precursors, polyethylene glycol esters of nicotinic (L1 · 2HCl-L4 · 2HCl and L9 · HCl) and isonicotinic acid dihydrochlorides (L5 · 2HCl-L8 · 2HCl), binuclear ruthenium(II) complexes 1-8 and mononuclear complex 9 were tested for in vitro cytotoxicity against 518A2 (melanoma), 8505C (anaplastic thyroid cancer), A253 (head and neck tumour), MCF-7 (breast tumour) and SW480 (colon carcinoma) cell lines.

Influence of the Linker Length on the Cytotoxicity of Homobinuclear Ruthenium(II) and Gold(I) Complexes

“…The complexes containing the mono­(ethylene glycol) linker ( 1b and 1d ) are considerably less cytotoxic than the complexes with longer linkers ( 2b – 7b and 2d – 7d ). In contrast, in a series of diruthenium­(II) p -cymene complexes with bridging bis­(nicotinate)/bis­(isonicotinate) ligands, only the complex with the shortest mono­(ethylene glycol) linker possessed moderate activity against a range of cell lines including the human melanoma (518A2) cell line (IC 50 = 53 ± 1 μM) …”

“…Flexible alkyl spacers used in acylpyrazolonato-bridged ruthenium­(II) complexes led to complexes with a higher cytotoxicity than those of related compounds with rigid phenyl spacers . Attempts were made to investigate poly­(ethylene glycol) (PEG) linkers; however, the bis­(nicotinate)/bis­(isonicotinate) ligands were unstable in solution . Homobinuclear ruthenium­(II) complexes linked by different stereochemically configured 1,2-diphenylethylenediamine spacers exhibit open and closed conformations.…”

Antiproliferative activity of ruthenium(ii) arene complexes with mono- and bidentate pyridine-based ligands

“…The ruthenium complex [{RuCl 2 ( p-cym)} 2 ] is an excellent starting material for synthesis of novel Ru II complexes with monoor bidentate amine or phosphine ligands. 57,58 Complex 1 was prepared according to a literature procedure and the identity and purity were verified by 1 H and 13 C NMR spectroscopy; 46 complexes 2-5 were synthesised accordingly by treating [{RuCl 2 ( p-cym)} 2 ] with the corresponding amine ligand B-E under inert atmosphere (Scheme 1). Complexes 2 and 3 form orange solids within several minutes even at room temperature, underlining the reactivity of the ruthenium complex [{RuCl 2 ( p-cym)} 2 ] toward Lewis bases such as amines.…”

“…The spectroscopic data are as expected. 57,58 Stock solutions of the compounds in DMSO were stored at 4 °C to ensure the stabilities of the investigated solutions. Furthermore, the stock solutions were checked by timeresolved UV/VIS measurements before use.…”

Locked and Loaded: Ruthenium(II)-Capped Cucurbit[n]uril-Based Rotaxanes with Antimetastatic Properties

“…Organoruthenium “piano stool” complexes with a Ru­(II) center have been developed as robust and potent antimetastatic drug candidates with RAPTA-C as a model representative. ,− These half-sandwich complexes possess two key components, η 6 -arene rings and phosphine ligands, the first enhancing the affinity of the complex for cells and the second increasing the solubility in water. Moreover, potent dinuclear Ru­(II) complexes (like the multinuclear Pt anticancer agents, e.g., BBR3464 and CT-3610 , ) have been developed (e.g., see Figure C). − The antimicrobial activity of a dinuclear Ru­(II) complex with CB[10] (Figure D) has been reported, showing the improved pharmacokinetic profile of the Ru drug after supramolecular coupling with the CB macrocycle . The biological properties of similar supramolecular Ru assemblies with CB carriers have been investigated only recently. , …”