Synthesis and cytotoxicity of dinuclear complexes containing ruthenium(ii) bipyridyl units linked by a bis(pyridylimine) ligand

Abstract

Enantiopure dinuclear ruthenium polypyridyl complexes of the form [Ru(2)(LL)(4)L(1)](PF(6))(4) (LL = 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen); L(1)= C(25)H(20)N(4) a bis(pyridylimine) ligand containing a diphenylmethane spacer) have been synthesized using the chiral building blocks cis-[Ru(bpy)(2)(py)(2)](2+) and cis-[Ru(phen)(2)(py)(2)](2+). These dinuclear ruthenium complexes have been characterised using NMR, mass spectrometry, UV-visible absorbance, circular dichroism and linear dichroism. The compounds exhibit good photo and thermal stability. The extinction coefficient for the bpy complex at 478 nm is epsilon(478) = 15,700 mol(-1) cm(-1) dm(3) and for the phen complex is epsilon(478) = 24,900 mol(-1) cm(-1) dm(3). Both complexes have their longest wavelength (metal to ligand charge transfer) transition predominantly x/y (short axis)-polarised while the transitions at shorter wavelength are a mixture of x/y and z-polarisations, similar to both the copper helicate and iron triple helicate studied previously. Cytotoxicity studies reveal that the compounds are dramatically less active against cancer cell lines than the recently reported supramolecular cylinders prepared from the same bis(pyridylimine) ligand.

Synthesis, characterization and molecular structures of Ni(II) complexes derived from Schiff base pyridylimine ligands

“…In a similar manner, metallic complexes based on Schiff pyridyl imine ligands have been carried out related with cytotoxicity8 [7,8] antimicrobial [9] and catalytic properties in either ethylene, olefins polymerization and other potentially relevant catalytic transformations [10][11][12][13][14]. Other reports involve Schiff pyridylimine ligands in supramolecular chemistry to promote the formation of helicates [15] and mesocates [16].…”

Mechanism of Cytotoxicity and Cellular Uptake of Lipophilic Inert Dinuclear Polypyridylruthenium(II) Complexes

“…[10] To date, inert dinuclear polypyridylruthenium(II) complexes have only shown modest anticancer activity. [12][13][14] While there are a variety of possible modes of binding available (e.g., intercalation, groove binding, etc. ), there are indications that the cytotoxicity of dinuclear complexes can be significantly enhanced by the incorporation of labile ligands that allow the formation of covalent adducts with DNA.…”

DNA binding and bending by dinuclear complexes comprising ruthenium polypyridyl centres linked by a bis(pyridylimine) ligand

“…Complexes based on ruthenium are particularly attractive because of their photochemical properties and their high kinetic stability towards racemisation and ligand exchange. However, this stability towards ligand exchange reactions does complicate the synthesis: the ruthenium triple-stranded cylinder can be prepared [6] but not in a high yielding supramolecular self-assembly reaction [30,31,34,35,38] as used to make the di-iron cylinder. The focus herein was the design of alternate ruthenium(II) compounds of type illustrated in Fig.…”