Progress in palladium-based catalytic systems for the sustainable synthesis of annulated heterocycles: a focus on indole backbones

BIOVERT+LDJA survey highlighting the most recent palladium catalytic systems produced and their performances for progress in direct synthesis of indole backbones by heterocarbocyclization of reactive substrates is provided. The discussion is developed in relation with the principles of sustainable chemistry concerning atom and mass economy. In this respect, the general convergent character of the syntheses is of particular interest (one-pot, domino, cascade or tandem reactions), and the substrates accessibility and reactivity, together with the final waste production, are also important. This critical review clearly indicates that the development of ligand chemistry, mainly phosphines and carbenes, in the last few decades gave a significant impetus to powerful functionalization of indoles at virtually all positions of this ubiquitous backbone (118 references)

Palladium–Polypyrrole Nanocomposites Pd@PPy for Direct C–H Functionalization of Pyrroles and Imidazoles with Bromoarenes

International audiencePalladium–polypyrrole nanocomposites (Pd@PPy) with unique combination of high palladium dispersion (nanoparticle size 2.4 nm) and high palladium content (35 wt%) are efficient catalysts for the selective arylation of substituted pyrroles and imidazoles with either activated or deactivated aryl bromides. The performances of the recoverable supported palladium catalyst matches the best performances of homogeneous systems based on Pd(OAc)2 at 0.5–0.2 mol%, and largely overwhelm the classical Pd/C catalyst

Etherification of functionalized phenols with chloroheteroarenes at low palladium loading: Theoretical assessment of the role of triphosphane ligands in C-O reductive elimination

10.1002/adsc.201100481Advanced Synthesis and Catalysis353183403-3414JPCH

Nanostructured ceria based thin films (<= 1 mu m) As cathode/electrolyte interfaces

International audienceGadolinium doped cerium oxide (CGO: Ce0.9Gd0.1O2-delta) films were used as an oxygen anion diffusion layer at the cathode/electrolyte interface of Solid Oxide Fuel Cells (SOFCs), between LSCF (lanthanum strontium cobalt ferrite) and YSZ (yttria-stabilized zirconia). Thin (similar to 100 nm) and thick (similar to 700 nm) mesoporous CGO layers were synthesized through a sol-gel process including organic template coupled with the dip-coating method. Structural and microstructural characterizations were performed, highlighting a well-bonded crystalline CGO nanoparticles network which delineates a 3-D inter-connected mesoporous network. Their electrical behaviors were investigated by impedance spectroscopy analysis of YSZ/mesoporous-CGO/LSCF half-cell. Anode-supported SOFCs, operating at 800 degrees C, with either dense or mesoporous CGO dip-coated interlayers were also fabricated [NiO-YSZ anode/YSZ/CGO/LSCF cathode]. The impact of the mesoporous CGO interlayers on SOFCs performances was investigated by galvanostatic analysis and compared to the behavior of a dense CGO interlayer. The polarization curves revealed an enhancement in the electrical performance of the cell, which is assigned to a decrease of the polarization resistance at the cathode/electrolyte interface. The integrity and connectivity of the CGO nanoparticles bonded network facilitates O2- transport across the interface. (C) 2012 Elsevier Inc. All rights reserved

PE-CVD with organometallic precursors: contribution of aerosol assisted processes

International audiencePE-CVD is widely used to deposit inorganic thin films. For example, a lot of different precursors (TEOS, HMDSO, HMDS, TMS, etc.) has been used for organosilicon or silica-like coatings. In contrast, only few studies are using organometallic precursors. Indeed, such molecules are generally unstable, pyrophoric and highly reactive with air and/or oxygen. Aerosol-assisted processes are able to avoid these problems. Indeed, diluted in organic solvents, it enables to inject droplets of organometallic precursor charged liquids. This contribution aims to report first results obtained with nickel-or zinc-based organometallic precursors. Using a pulsed injection of the liquid solution, it enables to deposit DLC matrices doped with Ni or Zn. Depending on the aerosol composition, the plasma behaviours as well as the film structures and properties will be discussed

Functionalized Tri- and Tetraphosphine Ligands as a General Approach for Controlled Implantation of Phosphorus Donors with a High Local Density in Immobilized Molecular Catalysts

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