μ3-Carbonato-κ3 O:O′:O′′-tris­{(η6-ben­zene)[(R)-1-(1-amino­ethyl)naphthyl-κ2 C 2,N]ruthenium(II)} hexa­fluorido­phosphate dichloro­methane solvate

The title compound, [Ru3(C12H12N)3(CO3)(C6H6)3]PF6·CH2Cl2, was obtained unintentionally as the product of an attempted deprotonation of the monomeric parent ruthenium complex [Ru(C12H12N)(C6H6)(C2H3N)]PF6. The carbonate ligand bridges three half-sandwich cyclo­ruthenated fragments, each of them exhibiting a pseudo-tetra­hedral geometry. The configuration of the Ru atoms is S. The naphthyl groups of the enanti­opure cyclo­ruthenated benzylic amine ligands point in the same direction, adopting a propeller shape

Monomeric Ti(IV)-based complexes incorporating luminescent nitrogen ligands: synthesis, structural characterization, emission spectroscopy and cytotoxic activities

This manuscript describes the synthesis of a series of neutral titanium(IV) monomeric complexes constructed around a TiO4N2 core. The two nitrogen atoms that compose the coordination sphere of the metallic center belong to 2,2′-bipyrimidine ligands homo-disubstituted in the 4 and 4′ positions by methyl (2a), phenylvinyl (2b), naphthylvinyl (2c) or anthrylvinyl (2d) groups. The crystal structures of these complexes named [Ti(1)2(2a)], [Ti(1)2(2b)], [Ti(1)2(2c)] and [Ti(1)2(2d)] (where 1 is a 2,2′-biphenolato ligand substituted in the 6 and 6′ positions by phenyl groups) are reported. The hydrolytic stability of the four complexes is evaluated by monitoring the evolution of the free 2a–d signals by 1H NMR spectroscopy. For the conditions tested (6 mM, DMSO-d6/D2O: 8/1), a rather good stability with t1/2 ranging from 180 to 300 min is determined for the complexes. In the presence of an acid (DCl), the hydrolysis of [Ti(1)2(2a)] is faster than without an acid. The cytotoxic activity against gastric cancer cells of the titanium-based compounds and the free disubstituted 2,2′-bipyrimidine ligands is tested, showing IC50 ranging from 6.2 ± 1.2 μM to 274 ± 56 μM. The fluorescence studies of the ligands 2a–d, and the complexes [Ti(1)2(2a–d)] reveal an important fluorescence loss of the ligands 2c and 2d upon coordination with the Ti(1)2 fragment. Frontier orbitals obtained by DFT calculations permit us to explain this fluorescence quenching.Other supports : Centre National pour la Recherche Scientifique (CNRS, France), ARC, Ligue contre le Cancer, European action COST CM1105 (C. G.

Réactions de transformations asymétriques catalysées par des complexes de métaux de transition (formation de liaisons carbone-carbone)

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

From monomeric complexes to double-stranded helicates constructed around trans -TiO 4 N 2 motifs with intramolecular inter-ligand hydrogen-bonding interactions

International audienc

Evaluation of the stereoselectivity for titanium(IV)-based coordination entities induced by the enantiopure diphenylethene-1,2-diamine ligand

International audienceThis article describes the formation of neutral TiO 4 N 2-based coordination entities where the titanium centers are coordinated by oxygenated ligands incorporating one or two biphenolato units, i.e. L 1 and L 2 respectively. In these systems, the sixfold coordination spheres of each metallic center are completed by the enantiopure bi-dentate diphenylethene-1,2-diamine compound, abbreviated as dpeda. A solvent dependent diastereomeric ratio is evaluated by 1 H NMR for the monomeric [Ti(L 1) 2 ((1R,2R)-dpeda)] or [Ti(L 1) 2 ((1S,2S)-dpeda)] (abbreviated as [R-Ti] or [S-Ti] respectively) complexes. The highest diastereomeric ratio for [Ti(L 1) 2 (dpeda)] is obtained in chloroform (2 : 1). Energy calculation and circular dichroism spectra simulation, obtained by DFT, permit to assign the configuration of the stereoisomer formed in excess. The (1R,2R)-(+)-dpeda privileges the Δ form and (1S,2S)-(-)-dpeda the Λ form of the [Ti(L 1) 2 (dpeda)] stereoisomers. The helicates formulated as [Ti 2 (L 2) 2 ((1S,2S)-dpeda) 2 ] and [Ti 2 (L 2) 2 (1R,2R)-dpeda) 2 ] (abbreviated as [S-Ti2] or [R-Ti2] respectively) are obtained by following a multi-component self-assembly approach. In this case, the diastereomeric ratios evaluated by 1 H NMR are much lower compared to those determined for the monomeric species, and a privileged P and M configuration for the [Ti 2 (L 2) 2 (1R,2R)-dpeda) 2 ] helicate and the [Ti 2 (L 2) 2 ((1S,2S)-dpeda) 2 ] helicate respectively is assigned through theoretical calculations. Overall, this article describes a strategy to favour handedness in a helicate system where the chiral control is originated from a ligand that is not inscribed within the helical framework of the architecture

Synthesis, Characterization, and Fluxional Behavior of a 34 Electron Homochiral Dimetallic Complex with an Unsupported Hydride Bridge between Two Ru Atoms

International audienceThe binuclear η6-benzene cycloruthenated complex 2, which bears an unsupported bridging hydride ligand, was synthesized by treating the monomeric cationic cycloruthenated (R)-(+)-1-(1-naphthyl)ethylamine 1 with potassium hydroxide under biphasic conditions and then with an alcoholic solvent. Alternatively, compound 2 was prepared from an equimolar amount of compound 1 and the homologous monomeric hydrido complex 3. The crystal structure of 2 revealed π- stacking interactions between the naphthyl groups of each cyclometalated amine; the hydride ligand is bent, with a Ru−H−Ru angle of 145.3(10)°. Compound 2 is fluxional as shown by variable-temperature NMR analysis. DFT analysis of homochiral 2 and of its hypothetical heterochiral counterpart 2* revealed that dispersion-based π−π interactions between the cyclometalated ring are not the only interactions that must be taken into account to rationalize the conformational preference for 2. Indeed, the overall dispersion-based interactions between all the ligands of the connected metallacycles provide an additional 5 to 6 kcal/mol of stabilization energy for 2 regardless whether the π-stacking interactions between the naphthyl rings exist or not

Membrane proteocomplexome of Campylobacter jejuni using 2-D blue native/SDS-PAGE combined to bioinformatics analysis

International audienc

A robust Ti(IV)-based mesogen constructed around a TiO4N2 core

International audienceStable complexes [Ti(1a)(2)2] and [Ti(1b)(2)2], where 2 is the 6,6′-diphenyl-2,2′-biphenolato ligand and 1a and 1b ligands are 2,2′-bipyrimidine derivatives, are synthesized. The complex [Ti(1b)(2)2] containing a diimine ligand substituted with long alkyl chains (C16) exhibits a liquid crystal behaviour. This property and self-assembling in the crystalline state are explained by the particular molecular conformation of the complexes