Ru Bpy Research Articles

Synthesis, characterization, and anticancer activity of Ru(p-cymene) complexes bearing pyrazolyl–pyridine type ligands

The appended aromatic ring system of the Ru–bpy complex influences cytotoxicity and apoptosis-inducing activity and could be developed as a selective chemotherapeutic drug for breast cancer treatment.

Inverting the Swelling Trends in Modular Self‐Oscillating Gels Crosslinked by Redox‐Active Metal Bipyridine Complexes

AbstractThe developing field of active, stimuli‐responsive materials is in need for new dynamic architectures that may offer unprecedented chemomechanical switching mechanisms. Toward this goal, syntheses of polymerizable bipyridine ligands, bis(4‐vinylbenzyl)[2,2′‐bipyridine]‐4,4′‐dicarboxylate and N4,N4′‐bis(4‐vinylphenyl)‐2,2′‐bipyridine‐4,4′‐dicarboxamide, and a number of redox‐active Ruthenium(II) and Iron(II) complexes with them are reported. Detailed characterizations by NMR, Fourier transform infrared spectroscopy, high‐resolution mass‐spectrometry, X‐ray, and cyclic voltammetry show that the topology of these molecules allows them to serve as both comonomers and crosslinkers in polymerization reactions. Electronic properties of the ligands are tunable by choosing carboxylate‐ or carboxamido‐linkages between the core and the vinylaryl moieties, leading to a library of Ru and Fe complexes with the M(III)/M(II) standard redox potentials suitable for catalyzing self‐oscillating Belousov–Zhabotinskii (BZ) reaction. New poly(N‐isopropylacrylamide)‐based redox‐responsive functional gels containing hydrophilic comonomers, which have been prepared using representative Ru bpy complexes as both a crosslinker and redox‐active catalyst, exhibit a unique feature: their swelling/contraction mode switches its dependence on the oxidation state of the Ru center, upon changing the ratio of comonomers in the hybrid gel network. The BZ self‐oscillations of such crosslinked hydrogels have been observed and quantified for both supported film and free‐standing gel samples, demonstrating their potential as chemomechanically active modules for new functional materials.

Electrochemiluminescence of dichlorotris (1,10-phenanthroline) ruthenium (II) with peroxydisulfate in purely aqueous solution at carbon paste electrode

The electrochemiluminescence (ECL) of dichlorotris (1,10-phenanthroline) ruthenium (II) [Ru phen 3 2+ ] with peroxydisulfate (S 2O 8 2−) was first described. The use of carbon paste electrodes, organic solvent modified electrodes, allowed obtaining ECL in purely aqueous solution. The ECL produced by the reaction of electrogenerated Ru phen 3 + with the strongly oxidizing intermediate SO 4 −·, was observed only when the applied potential was negative enough to reduce Ru phen 3 2+ . In comparison with Ru bpy 3 2+ /S 2O 8 2− ECL, the Ru(phen) 3 2+/O 8 2−/S 2O 8 2− ECL was more stable in aqueous solution. It was not affected by the storage of the carbon paste electrodes, and it quenched only at quite high S 2O 8 2− concentrations. The ECL intensity was a function of S 2O 8 2− concentration, increasing linearly with the S 2O 8 2− concentration from 5×10 −6 to 2×10 −3 mol l −1, and dropping off sharply at S 2O 8 2− concentration higher than 20 mmol l −1. The proposed ECL method with Ru phen 3 2+ was sensitive and selective for the determination of S 2O 8 2−.

Chemistry of Electronically Excited Ruthenium Polypyridine Complexes: III.1 Electronic Structure of Complexes cis-[Ru(2,2'-bpy)2(4,4'-bipy)(X)

The results of ab initio quantum-chemical calculations of isolated ruthenium(II) complexes cis- [Ru(bpy)2(bipy)(X)]44q (bpy is 2,2'-bipyridyl, bipy is 4,4'-bipyridyl; X = NH3, Cl-, Br-, CN-, NO-2, ONO-, MeCN, and NO+) are presented. Analysis of the charge distributions and the orbital structures of the complex ions points to absence of strong π-acceptor bonds Ru-bpy, Ru-bipy, and Ru-X (X = NO+), to delocalization of π-electron density under the action of strong donors X, to localized nature of lowest unoccupied molecular orbitals, and to special position of the nitrosyl complexes in this series.

Supramolecular dendrimers with a [Ru(bpy)3]2+ core and naphthyl peripheral units

We report the synthesis and the photophysical properties of first and second generation dendrimers built around a [Ru(bpy)3]2+ core (bpy=2,2′-bipyridine) and bearing 12 and 24 naphthyl units, respectively, in the periphery. The metallodendrimers were obtained by complexation of ruthenium trichloride with bipyridine ligands carrying dendritic wedges in the 4,4′-positions. Since the chromophoric groups present in the dendritic complexes are separated by aliphatic connections, interchromophoric interactions are weak and the absorption spectra of the metallodendrimers are essentially equal to the summation of the spectra of the chromophoric groups which are present in their structures. The ‘free’ wedges show an intense emission band in the region of the naphthyl-type units. Such a band, however, is almost completely absent in the emission spectra of the metallodendrimers, which exhibit the visible emission band characteristic of their [Ru(bpy)3]2+-type unit, regardless of the excitation wavelength. These results show that a very efficient energy-transfer process takes place from the potentially fluorescent excited states of the aromatic units of the wedges to the metal-based dendritic core (antenna effect). We have also found that the dendrimer branches protect the Ru–bpy based core from dioxygen quenching.