Extraordinary Stability of IrO(110) Ultrathin Films Supported on TiO(110) under Cathodic Polarization.

Down to a cathodic potentials of -1.20 V versus the reversible hydrogen electrode, the structure of IrO(110) electrodes supported by TiO(110) is found to be stable by in situ synchrotron-based X-ray diffraction. Such high cathodic potentials should lead to reduction to metallic Ir (Pourbaix diagram).

studies of the cathodic stability of single-crystalline IrO(110) ultrathin films supported on RuO(110)/Ru(0001) in an acidic environment.

We investigate with in situ surface X-ray diffraction (SXRD) and X-ray reflectivity (XRR) experiments the cathodic stability of an ultrathin single-crystalline IrO2(110) film with a regular array of mesoscopic rooflike structures that is supported on a RuO2(110)/Ru(0001) template. It turns out that the planarity of the single-crystalline IrO2(110) film is lost in that IrO2(110) oxide domains delaminate at a cathodic potential of -0.18 V.

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H-Evolving Catalysts.

We previously reported that the [Rh(dmbpy)Cl] (dmbpy = 4,4'-dimethyl-2,2'-bipyridine) complex is an efficient H-evolving catalyst in water when used in a molecular homogeneous photocatalytic system for hydrogen production with [Ru(bpy)] (bpy = 2,2'-bipyridine) as photosensitizer and ascorbic acid as sacrificial electron donor. The catalysis is believed to proceed via a two-electron reduction of the Rh(III) catalyst into the square-planar [Rh(dmbpy)], which reacts with protons to form a Rh(III) hydride intermediate that can, in turn, release H following different pathways. To improve the current knowledge of these key intermediate species for H production, we performed herein a detailed electrochemical investigation of the [Rh(dmbpy)Cl] and [Rh(dtBubpy)Cl] (dtBubpy = 4,4'-di- tert-butyl-2,2'-bipyridine) complexes in CHCN, which is a more appropriate medium than water to obtain reliable electrochemical data.

Enhanced Electrochemiluminescence from a Stoichiometric Ruthenium(II)-Iridium(III) Complex Soft Salt.

Electrochemiluminescence (ECL) and electrochemistry are reported for a heterometallic soft salt, [Ru(dtbubpy)3 ][Ir(ppy)2 (CN)2 ]2 ([Ir][Ru][Ir]), consisting of a 2:1 ratio of complementary charged Ru and Ir complexes possessing two different emission colors. The [Ru](2+) and [Ir](-) moieties in the [Ir][Ru][Ir] greatly reduce the energy required to produce ECL. Though ECL intensity in the annihilation path was enhanced 18× relative to that of [Ru(bpy)3 ](2+) , ECL in the co-reactant path with tri-n-propylamine was enhanced a further 4×.

Formylated chloro-bridged iridium(III) dimers as OLED materials: opening up new possibilities.

In this study, a series of four formyl-substituted chloro-bridged iridium(iii) dimers were prepared. Their absorption, photophysical and electrochemical properties were studied in dichloromethane solution. It was found that as the formyl content increased on the cyclometalating ligands, emission unexpectedly became brighter.

Steric congestion at, and proximity to, a ferrous center leads to hydration of α-nitrile substituents forming coordinated carboxamides.

The question of the conversion of nitrile groups into amides (nitrile hydration) by action of water in mild and eco-compatible conditions and in the presence of iron is addressed in this article. We come back to the only known example of hydration of a nitrile function into carboxamide by a ferrous [Fe(II)] center in particularly mild conditions and very efficiently and demonstrate that these unusual conditions result from the occurrence of steric stress at the reaction site and formation of a more stable end product. Two bis(cyano-substituted) (tris 2-pyridyl methyl amine) ligands have been prepared, and the structures of the corresponding FeCl2 complexes are reported, both in the solid state and in solution.

Exploring energy transfer in luminescent heterometallic ruthenium-iridium ion pairs.

Here, we report the synthesis of a luminescent ion pair with the formula [Ru(dtBubpy)3][Ir(ppy)2(CN)2]2. The crystal structure of this three component, heterometallic assembly is described, along with the luminescence properties of the salt. The modulation of the energy transfer between the blue-green-emitting iridium complex and the red-emitting ruthenium complex is also discussed as a function of both medium and concentration.

Heteroleptic diimine copper(I) complexes with large extinction coefficients: synthesis, quantum chemistry calculations and physico-chemical properties.

Using the HETPHEN approach, five new heteroleptic copper(I) complexes composed of a push-pull 4,4'-styryl-6,6'-dimethyl-2,2'-bipyridine ligand and a bulky bis[(2-diphenylphosphino)phenyl]-ether (DPEphos) or a bis2,9-mesityl phenanthroline (Mes2Phen) were prepared and characterized by electronic absorption spectroscopy, electrochemistry, and TD-DFT calculations. These complexes exhibit very intense absorption bands in the visible region with extinction coefficient in the range of 5-7 × 10(4) M(-1) cm(-1). The analysis of the position, intensity and band shape indicates a strong contribution from an intra-ligand charge-transfer transition centered on the styrylbipyridine ligand along with MLCT transitions.

First application of the HETPHEN concept to new heteroleptic bis(diimine) copper(I) complexes as sensitizers in dye sensitized solar cells.

We report here the synthesis and full chemical and physical characterizations of the first stable heteroleptic copper(I)-bis(diimine) complexes designed for implementation in dye sensitized solar cells (DSC). Thanks to the HETPHEN concept, pure and stable heteroleptic copper(I) complexes were isolated. Anchorage of the sensitizers was provided by 2,2'-biquinoline-4,4'-dicarboxylic acid (dcbqH2), while sterically challenged ligands 2,9-dimesityl-1,10-phenanthroline (L0) and N-hexyl-2,9-dimesityl-1,10-phenanthroline-[a:b]imidazo-(4'-dianisylaminophenyl) (L1) were used to complete the copper(I) coordination sphere.

New heteroleptic bis-phenanthroline copper(I) complexes with dipyridophenazine or imidazole fused phenanthroline ligands: spectral, electrochemical, and quantum chemical studies.

Two new sterically challenged diimine ligands L(1) (2,9-dimesityl-2-(4'-bromophenyl)imidazo[4,5-f][1,10]phenanthroline) and L(2) (3,6-di-n-butyl-11-bromodipyrido[3,2-a:2',3'-c]phenazine) have been synthesized with the aim to build original heteroleptic copper(I) complexes, following the HETPHEN concept developed by Schmittel and co-workers. The structure of L(1) is based on a phen-imidazole molecular core, derivatized by two highly bulky mesityl groups in positions 2 and 9 of the phenanthroline cavity, preventing the formation of a homoleptic species, while L(2) is a dppz derivative, bearing n-butyl chains in α positions of the chelating nitrogen atoms. The unambiguous formation of six novel heteroleptic copper(I) complexes based on L(1), L(2), and complementary matching ligands (2,9-R(2)-1,10-phenanthroline, with R = H, methyl, n-butyl or mesityl) has been evidenced, and the resulting compounds were fully characterized.