Influence of another, ruthenium containing, electroactive component on the apparent heterogeneous electron transfer rate constant of a ferrocene containing molecular wire in a Self-Assembled Monolayer of 11-hydroxyundecanethiol on gold

The co-adsorption of three thiol compounds on gold, two of them being electroactive, yields a Self-Assembled Monolayer (SAM) the behaviour of which was studied by impedance spectroscopy. The two redox active thiols have been chosen to have a good miscibility in a supporting inert component, non-degenerate first-oxidation redox couples, and distinct heterogeneous electron transfer rate constant. However, in the ternary monolayer, the slowest process was found to be concentration dependent on the other redox site. This unexpected behaviour should thus be taken into account when using multi-component SAM as a support for integrated devices.     

Labeling of a self-hardening bone substitute using ruthenium tris-bipyridine complexes, for the analysis of its in vivo metabolism

A self-setting cellulose scaffold, used as a component of an injectable bone substitute, was labeled with ruthenium tris-bipyridine complexes functionalized by triethoxysilane groups. The labeling yield was found to vary according to the number and location of Si(OR)₃ groups present on the ruthenium complex backbone. For label loadings, less than 0.1 wt%, no significant modification of the rheological properties of the gel was observed.     

Screening of a library of hemisalen ligands in asymmetric H-transfer: Reduction of aromatic ketones in water

A library of chiral hemisalen ligands (30) was realized. The ligands were synthesized by the condensation of salicylaldehyde derivatives with amino-alcohols (amino-indanol or substituted amino-ethanol) and characterized. These ligands associated with ruthenium (II) precursors were tested on the asymmetric transfer hydrogenation (ATH) of aromatic ketones by sodium formate in water. The different substituent pattern on the ligand (electronic and hindrance effects on different positions) as well as the ruthenium precursor were investigated. The best compromise in terms of conversion and chiral induction led to the complex [RuCl₂(mesitylene)]₂ coordinated to (1S,2R)-1-((E)-(3-(dimethyl(phenyl)silyl)-2-hydroxy-5-methoxy benzylidene) amino)-2,3-dihydro-1H-inden-2-ol (L25). It reduces acetophenone in 95% yield and 91% ee in 18 h at 30 °C.     

微波消解和氢化物发生--电感耦合等离子体发射光谱法测定煤中痕量硒

基于微波消解和氢化物发生电感耦合等离子体发射光谱法 ,实现了对煤中痕量硒的测定。采用硝酸 盐酸 氢氟酸消解体系 ,氢化物发生在 3mol·L-1盐酸介质中进行 ,以硼氢化钠为还原剂 ,浓度为 1%。考察了微波消解条件、预还原条件和干扰的影响。方法准确、快速 ,用该法测定国家标准参考物质的结果与推荐值一致 ,并与艾氏剂灼烧法测定结果一致。硒的检出限为 0 3μg·L-1,RSD小于 5 %。     

Technetium transmutation and production of artificial stable ruthenium

The recent Russian results on technetium transmutation into ruthenium are summarized, including the first isolation of artificial stable ruthenium from irradiated technetium targets. To cite this article: V. Peretroukhine et al., C. R. Chimie 7 (2004).

Résumé

Transmutation du technétium et production du ruthénium artificiel. Les résultats obtenus en Russie sur la transmutation du technétium en ruthénium artificiel et son isolement des cibles irradiées sont présentés. Pour citer cet article : V. Peretroukhine et al., C. R. Chimie 7 (2004).     

Synthesis and reactivity of new heterodinuclear iron/rhenium Cx complexes of the formula (η-C5Me5)Re(NO)(PPh3)(CC)n(η-dppe)Fe(η-C5Me5) (n = 3, 4): Redox properties and a dicobalt hexacarbonyl adduct

We report in this communication the synthesis and characterization of two Fe/Re heterodinuclear complexes 3_n of formula (η⁵-C₅Me₅)Re(NO)(PPh₃)(CC)_n(η²-dppe)Fe(η⁵-C₅Me₅) (n = 3, 4) as well as the hexacarbonyl dicobalt adduct (4) of the hexatriynediyl complex 3₃. We show by cyclic voltammetry that the “electronic communication” between the organometallic endgroups and thereby the thermodynamic stability of the corresponding mixed-valent (MV) parent 3_n⁺ is strongly influenced by bridge extension or by complexation of the [Co₂(CO)₆] fragment. In the case of the hexatriynediyl complex, the MV complex 3₃⁺ or 4 can be isolated by performing the chemical oxidation of 3₃ at low temperature. Spectroscopic studies of this compound and of other stable oxidized redox congeners should now help us to unravel how bridge extension modifies the electronic communication between the different redox-active endgroups in this family of unsymmetrically-substituted polyynediyl compounds.