Luminescent Ruthenium(II) Polypyridyl Functionalized Gold Nanoparticles; Their DNA Binding Abilities and Application As Cellular Imaging Agents

The synthesis and photophysical and biological investigation of Ru(II)-polypyridyl stabilized watersoluble, luminescent gold nanoparticles (AuNPs) are described. These structures bind to DNA and undergo rapid cellular uptake, being localized within the cell cytoplasm and nucleus within 4 h

Rhodium(III) and ruthenium(II) complexes of redox-active, chelating N-heterocyclic carbene/thioether ligands

International audienceHalf-sandwich rhodium(III) and ruthenium(II) complexes bearing a new redox-active ferrocenyl NHC–thioether ligand have been prepared. The synthesis of ferrocenyl thioether-imidazolium salts 3a and 3b was carried out via intermediate 2 using an improved procedure. Rhodium(III) complex 4 and ruthenium(II) complex 5 were obtained in good yields and were fully characterised by NMR spectroscopy, X-ray diffraction analysis and electrochemistry. Complex 4 shows a complex ABCD system by 1H NMR, which denotes conformational rigidity due to the presence of several bulky groups. Electrochemical analysis by cyclic voltammetry reveals reversible redox behaviour about the iron centre in 4 and 5, and indicates electronic communication between iron and rhodium or ruthenium

A rhodium(I) dicarbonyl complex with a redox-active ferrocenyl phosphine-NHC ligand: Enhanced reactivity of the metal centre through ferrocene oxidation

International audienceA rhodium(I) dicarbonyl complex bearing a bidentate ferrocenyl phosphine-NHC ligand has been synthesized and characterized by NMR, IR spectroscopy, mass spectrometry and X-ray diffraction methods. Its behaviour towards oxidation was investigated and revealed that changing the oxidation state of ferrocene can significantly modify the electron density at rhodium. Oxidation of the rhodium(I) dicarbonyl complex in acetonitrile furnished an air-stable rhodium(III) complex, stabilized by acetonitrile molecules and with an interesting C–H bond activation at ferrocene. This new rhodium(III) complex is active for the hydrosilylation of acetophenone and its derivatives

Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals

International audienceAxially chiral biaryl structures are unique systems encountered in various synthetic compounds such as BINAP and BINOL, polymers, but also in natural products presenting a pharmaceutical interest such as Vancomycin, Steganacin or Korupensamine. The axial chirality of these products, so-called atropisomerism, is induced by the restricted rotation around the aryl–aryl bond. This review will summarize the different strategies imagined by chemists to control such chirality, focusing on asymmetric catalytic processes with transition metals. Only transition metal complexes bearing chiral ligands will be considered and the core of this review will consist of the enantioselective coupling of two achiral substrates

Bifunctional N-heterocyclic carbene ferrocenyl ligands - synthesis and palladium(II) complexes

International audienceTwo ferrocenylimidazolium tetrafluoroborate salts [R = Me, 7 and R = (2,4,6-trimethylphenyl), 8], precursors of new ferrocenylimidazol-2-ylidene bifunctional ligands, have been prepared for the first time. The free 1-(2-dimethylaminomethyl)ferrocenyl-3-methylimidazol-2-ylidene (12) was isolated and characterised by H-1 and C-13 NMR spectroscopy and represents the second example of an isolated and characterised imidazol-2-ylidene directly linked to ferrocene. Neutral (compound 13) and cationic (compound 14) palladium(II) complexes were obtained in moderate yields and characterised by H-1 and C-13 NMR spectroscopy and mass spectrometry

Synthesis and characterization of half-sandwich ruthenium complexes containing aromatic sulfonamides bearing pyridinyl rings: catalysts for transfer hydrogenation of acetophenone derivatives

1099-0682N-(Quinoline-8-yl-aryl)benzenesulfonamides 1-6 were successfully synthesized by the reaction of 8-aminoquinoline and various benzenesulfonyl chlorides. Then, half-sandwich ruthenium complexes 7-12 were prepared from the reactions of 1-6 with [RuCl2(p-cymene)]2. The synthesized compounds were characterized by NMR and FTIR spectroscopy and elemental analysis, and compounds 8 and 9 were further analyzed by X-ray diffraction. The complexes were screened for their efficiency as catalysts in the transfer hydrogenation of acetophenone derivatives to phenylethanols in the presence of KOH with 2-propanol (as hydrogen source) at 82 °C, and they all showed good activity. Complexes 10 and 12 were the most active (turnover frequency values: 703 and 734 h-1, respectively)

Palladium(ii) complexes with planar chiral ferrocenyl phosphane-(benz)imidazol-2-ylidene ligands

International audienceWe describe here the first examples of planar chiral ferrocenyl phosphane-benzimidazol-2-ylidene ligands and their coordination chemistry with palladium(ii). All ligand precursors, namely enantiopure ferrocenyl phosphane-(benz)imidazolium salts, and all enantiopure palladium complexes have been fully characterised by 1H, 31P and 13C NMR, mass spectrometry and X-ray diffraction methods for seven examples. The potential of these very bulky bidentate ligands in catalysis was evaluated and compared to their imidazol-2-ylidene analogues. The influence of sterics was shown to be non-negligible as the bulkiest ligand gave the lowest activities in the asymmetric Suzuki-Miyaura reaction

Palladium(ii) complexes with planar chiral ferrocenyl phosphane-(benz) imidazol-2-ylidene ligands

We describe here the first examples of planar chiral ferrocenyl phosphane-benzimidazol-2-ylidene ligands and their coordination chemistry with palladium(ii). All ligand precursors, namely enantiopure ferrocenyl phosphane-(benz)imidazolium salts, and all enantiopure palladium complexes have been fully characterised by 1H, 31P and 13C NMR, mass spectrometry and X-ray diffraction methods for seven examples. The potential of these very bulky bidentate ligands in catalysis was evaluated and compared to their imidazol-2-ylidene analogues. The influence of sterics was shown to be non-negligible as the bulkiest ligand gave the lowest activities in the asymmetric Suzuki-Miyaura reaction. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2014

Catalytic enantioselective intermolecular cycloadditions of 2-diazo-3,6-diketoester-derived carbonyl ylides with alkene dipolarophiles

Catalyzed cascade reactions that generate molecular complexity rapidly and in an enantioselective manner are attractive methods for asymmetric synthesis. In the present article, chiral rhodium catalysts are shown to effect such a transformation by using a range of 2-diazo-3,6-diketoesters with bicyclo[2.2.1]alkenes and styrenes as reaction partners. The reactions are likely to proceed by formation of a catalyst-complexed carbonyl ylide from the diazo compound, followed by intermolecular cycloaddition with the alkene dipolarophile. It was possible to obtain high levels of asymmetric induction [up to 89% enantiomeric excess (ee) and 92% ee for the two chiral catalysts investigated]. Enantioselectivity is not highly sensitive to substituent variation at the ketone that forms the ylide; however, branching does improve ee. Observations of dipolarophile-dependent enantiofacial selectivity in the cycloadditions indicate that the dipolarophile can be intimately involved in the enantiodiscrimination process