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The asymmetric imidazolium salt [Ru[(dmbpy).sub.2][(bpip)]([PF.sub.6]).sub.3] (bpip = 1-benzyl-3-isopropyl-1H-imidazo[4,5-f][1,10]phenanthrolinium) was prepared by a four-step synthetic route. The isotopomer labelled with [.sup.13]C at the C2 position of bpip was prepared from 1,10-phenanthroline-5,6-diamine and triethyl orthoformate-(formyl-[.sup.13]C). Deprotonation at low temperatures in acetonitrile using [KO.sup.t]Bu and KHMDS were monitored by NMR to investigate the formation of the free N-heterocyclic carbene. Key words: ruthenium, polypyridyl, [.sup.13]C labelling, N-heterocyclic carbene, photocatalyst. Nous avons prepare le sel d'imidazolium asymetrique, le [Ru[(dmbpy).sub.2][(bpip)]([PF.sub.6]).sub.3] (bpip = 1-benzyl-3-isopropyl-1Himidazo [4,5f][1,10]phenanthrolinium), par une voie de synthese en quatre etapes. L'isotopomere marque au [.sup.13]C a la position C2 du ligand bpip a ete prepare a partir de la 1,10-phenanthroline-5,6-diamine et de l'orthoformiate d'ethyle-(formiate-[.sup.13]C). Nous avons suivi par RMN la deprotonation a basse temperature dans l'acetonitrile effectuee a l'aide du [KO.sup.t]Bu et du KHMDS afin d'etudier la formation du carbene N-heterocyclique libre. [Traduit par la Redaction] Mots-cles : ruthenium, polypyridyl, marquage au [.sup.13]C, carbene N-heterocyclique, photocatalyseur., Introduction A highly investigated method to store solar energy is artificial photosynthesis. (1,2) Water and sunlight are converted into [H.sub.2] and [O.sub.2], or water, sunlight, and [CO.sub.2] are converted into [...]

Proton ([super 1]H) NMR microscopy is used to examine the distribution of water throughout a self-humidifying proton-exchange membrane fuel cell (PEMFC) operating at ambient temperature and pressure on dry [H.sub.2](g) and [O.sub.2](g). ([super 1]H) NMR microscopy would help in revealing critical information regarding the distribution of water inside operating PEMFCs and is a powerful tool for diagnosing, understanding and optimizing the effects of fuel cell materials, components and designs.

The chiral bis(phosphine) ligand P,P'-1,2-phenylenebis[(1R,2S,4R,5S)-2,5-dimethyl-7-phosphabicyclo[2.2.1] heptane], [(R,S,R,S)-Me-PennPhos] (1) reacts with trans-Ru[Cl.sub.2)(NBD) [Py.sub.2] (NBD = norbornadiene, Py = pyridine) (2) in C[H.sub.2][Cl.sub.2] at 45[degrees]C to form two diastereomers of the triply chloride bridged cation [[{(1)Ru[Py}.sub.2]([micro]-[Cl).sub.3])][Cl.sup.-]] (3) in the ratio 1:3. The isomers were studied by NMR spectroscopy and separated by crystallization from [CD.sub.2][Cl.sub.2]-hexanes mixture. The major diastereomer is one of the anti-diastereomers and contains face-sharing bioctahedral diruthenium (Ru(II, II)) molecules with a Ru--Ru distance of 3.289 [Angstrom]. This diastereomer crystallizes in the monoclinic space group C2 (No. 5) with the cell dimensions a([Angstrom]) = 28.102(2), b([Angstrom]) = 20.5344(15), c([Angstrom]) = 12.7692(10), [beta]([degrees]) = 95.7411(16), V([[Angstrom].sup.3]) = 7331.6(9), and Z = 4. The Me-PennPhos ligand adopts an unexpected bent, non-C2 symmetric conformation upon coordination to ruthenium. Key words: PennPhos crystal structure, diruthenium complexes, triply bridged complexes, bisphosphine ruthenium complexes.

Results indicate that in diastereomeric substrate-catalyst systems, the ketone-hydride insertion is rapid and exergonic. The rate of hydrolysis is higher than the rate of reversion to catalyst and ketone. Further, the catalytic hydrogenations operate via the diastereomeric catalyst that is present in highest concentration to form major enantiomer product.

Reaction of [Ru((R)-BINAP)(H)[(MeCN).sub.n][(aCetone).sub.3-n] (B[F.sub.4]) (where n = 0-3) (2) with 1 equiv of the olefin substrate methyl [alpha]-acetamidoacrylate (MAA) in acetone at room temperature immediately generated a mixture (72:28) of two diastereomers of the complex [Ru((R)-BINAP)(MeCN)(MAA(H))](B[F.sub.4]) (3). The olefin-hydride insertion reaction between 2 and MAA to generate 3 was regioselective, with transfer of the hydride to the [beta]-olefinic carbon and transfer of ruthenium to the [alpha]-carbon in both diastereomers of 3. The two diastereomers of 3 differ by the absolute configuration at the [alpha]-carbon of MAA(H) (([S.sub.c[alpha]])-3 and ([R.sub.c[alpha]]-3). The absolute configuration of the major (([S.sub.c[alpha]]-3) diastereomer was determined by X-ray diffraction in conjunction with NMR spectroscopic data. Protonolysis of the ruthenium-carbon bond in 3 and in the methyl [alpha]-acetamidocinnamate (MAC) analog ([Ru((R)-BINAP)(MeCN)((S)-MAC(H))](B[F.sub.4]) (([S.sub.c[alpha]])-4)) by addition of 2 equiv HB[F.sub.4]*[Et.sub.2]O in [CH.sub.2][Cl.sub.2] at room temperature was not stereospecific and did not occur with [beta]-hydride elimination from the methyl or benzyl groups. Key words: ruthenium, BINAP, enantioselective, hydrogenation, catalysis.

Experiments were performed to investigate the adsorption of ruthenium (Ru) adatoms on synthesized black platinum (Pt) surfaces through hydrogenation. The catalytic function of the Pt surfaces in the oxidation of MeOH and adsorbed carbon monoxide in sulfuric acid electrolytes was examined. Hydrogenation produced rough Pt-Ru adatoms surfaces with known specific surface areas and with acceptable control over surface stoichiometry. Moreover, the Pt-Ru adatom surfaces exhibited stable electrochemical properties.

The black platinum-catalyzed hydrogenation of Ru(COD)(eta3-C3H5)2 (COD = 1,5-cyclooctadiene) by dihydrogen gas led to the adsorption of Ru adatoms by the surface of Pt. The hydrogenation of the ruthenium complex by dihydrogen gas over Pt led to the generation of a prototypic kinetic bimetallic surface. The reaction was also characterized by the low-temperature deposition of the submonolayer equivalents of adatoms under reaction-rate control.

Chiral rhodium diphosphines catalyze hydroacylation of 4-substituted 4-pentenals, yielding related 3-substituted cyclo-pentanones. The binap catalyst yields almost total enantioselectivity for 4-pentenals with tertiary substituents. Ketonic substituents give good enantioselectivity.

Enantioselective catalytic intramolecular hydrosilation of olefins using rhodium(I) chiral diphosphine catalysts was observed for various silyl and olefin substituents. The process provided highly efficient asymmetric hydrosilation generating high enantiomeric excesses (ee's) except for terminal alkyl olefin substituents which generally hindered catalysis. Contrastingly, terminal aryl olefin substituents easily underwent hydrosilation with relatively good ee's.

A study on the asymmetric catalytic hydrosilation mechanism of olefins with (Rh diphosphine) catalysts was presented. Silyl olefin insertion initiated the process and served as both turnover-limiting and enantioselective step. Moreover, a fast and reversible reaction was observed on both the silicon hydrogen oxidative addition and 5- and 6-membered metallacycle catalysis. However, the 6-membered compound quickly dissociated due to rapid beta-hydride elimination.

1,10-Phenanthroline (phen) was grafted to either indium tin oxide (ITO), fluorine-doped tin oxide (FTO), or titanium dioxide (TiO2) semiconductors (SC's) by electrochemical reduction of 5-diazo-phen. The phen ligand is bonded to the semiconductor at C5, and it can be handled in air. The semiconductor-phen (SC-phen) complexes displace both CH3CN ligands from either cis-[Ru(Mebipy)2(CH3CN)2]2+ (Mebipy = 4,4′-methyl-2,2′-bipyridine), cis-[Ru(tBubipy)2(CH3CN)2]2+ (tBubipy = 4,4′-tert-butyl-2,2′-bipyridine), or cis-[Ru(pheno)(bipy)(CH3CN)2]2+ (bipy = 2,2′-bipyridine; pheno = 1,10-phenanthroline-5,6-dione) dissolved in DCM/THF (4 h, 70 °C) to form the corresponding surface-bound SC-[(phen)Ru(bipyridyl)2]2+ chromophores. The identities of the SC-[(phen)Ru(Mebipy)2]2+, SC-[(phen)Ru(tBubipy)2]2+, and SC-[(phen)Ru(pheno)(bipy)]2+ (SC = ITO, FTO or TiO2) chromophores were confirmed by X-ray photoelectron spectroscopy (XPS); inductively coupled plasma mass spectrometry (ICP-MS); UV-vis and reflectance infrared spectroscopies; and cyclic voltammetry (CV). The data were compared to analogous Ru-polypyridyl control compounds dissolved in solution. A facile ketone-amine condensation solid-phase synthesis reaction between SC-[(phen)Ru(pheno)(bipy)]2+ and [Ru(1,10-phenthroline-5,6-diamine)(bipy)2]2+ in ethanol (80 °C, 1 h) formed the dinuclear, bound chromophore SC-[(phen)(bipy)Ru(tpphz)Ru(bipy)2]4+ (tpphz = tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine). Photoelectrochemical oxidation of hydroquinone and triethylamine under acidic, neutral, or basic conditions showed that the SC-chromophore photoanodes are active, and that TiO2-[(phen)Ru(Mebipy)2]2+ is the most active and stable under basic- and neutral conditions. The dinuclear chromophore SC-[(phen)(bipy)Ru(tpphz)Ru(bipy)2]4+ was most active and stable under potentiostatic conditions in acid. [ABSTRACT FROM AUTHOR]

Trans-[Ru((R)-BINAP)[(H).sub.2]((R,R)-dpen)] and related compounds as catalysts with base in THF is used to generate the corresponding hydroxy lactams in 88-97% ee from monohydrogenated meso-Cyclic imides. Conversion of a hydroxy lactam into the corresponding iminium ion followed by addition of indene is found to extend the number of stereogenic centers from 5 to 7.

A study details the first low-temperature syntheses and conclusive characterizations of several illusive intermediates and a new intermediate, an analogous compound. Results show that any amide formed during a catalytic hydrogenation will quickly react with the 2-PrOH solvent to form a 2-propoxide compound.

The study of a cationic, ruthenium-dihydrogen-hydride compound as a putative intermediate in an asymmetric ketone hydrogenation is described. The catalyst systems comprised of trans-(bisphosphine)RuCl2(diamine) and a base, which are the most active and selective catalysts for the asymmetric hydrogenation of aryl-alkyl and related ketones.