Coupling of vinylic tellurides with alkynes catalyzed by palladium dichloride: Evaluation of synthetic and mechanistic details

Under palladium dichloride catalysis, vinylic tellurides couple efficiently with alkynes with retention of the double-bond geometry. Herein we show that the amount of the PdCl2 catalyst can be reduced from 40 mol % to 10 mol % by using copper(II) chloride as an oxidizing agent. Under these conditions, an inert atmosphere is no longer required and the reaction occurs quite efficiently in the presence of air, leading to the enynes in 40-82% isolated yields. Mass and tandem mass spectrometric experiments using electrospray ionization were performed, and Pd-Te cationic intermediates were, for the first time, intercepted and transferred to the gas phase for structural characterization. An expanded catalytic cycle for this important method for enyne synthesis is proposed.23163990399

Organometallic Ruthenium Nanoparticles and Catalysis

International audienceDue to a high number of possible applications in various domains, metal nanoparticles are nowadays the subject of an extensive development. This interest in metal nanoparticles is related to their electronic properties at the frontier between those of molecular species and bulk compounds which are induced by their nanometric size. Regarding the field of catalysis, the growing attention for metal nanoparticles also results from the high proportion of surface atoms present in the upper layer of the metallic core which gives rise to numerous potential active sites. Thus, nanocatalysis (which involves the use of catalysts with at least one dimension at the nanoscale) has emerged in the field of modern catalysis as a domain on the borderline between homogeneous and heterogeneous catalysis. Present developments aim at multifunctionality which can be achieved by the proper design of complex nanostructures also named nanohybrids. In nanohybrid the term “hybrid” refers to the appropriate association between a metal core and a stabilizing shell such as a polymer, a ligand, an ionic liquid, or even a support (inorganic materials, carbon black, carbon nanotubes, etc.…). This association can be considered as crucial to tune the surface properties of nanostructures and consequently their catalytic performance. The main expectation for the scientific community is that precisely designed nanoparticles (in terms of size, shape, and composition including surface ligands) should offer the benefits of both homogeneous and heterogeneous catalysts, namely high efficiency and better selectivity

Earth-Abundant d-Block Metal Nanocatalysis for Coupling Reactions in Polyols

International audienc

Nano metal fluorides: small particles with great properties

The recently developed fluorolytic sol–gel route to metal fluorides opens a very broad range of both scientific and technical applications of the accessible high surface area metal fluorides, many of which have already been applied or tested. Specific chemical properties such as high Lewis acidity and physical properties such as high surface area, mesoporosity and nanosize as well as the possibility to apply metal fluorides on surfaces via a non-aqueous sol make the fluorolytic synthesis route a very versatile one. The scope of its scientific and technical use and the state of the art are presented.Peer Reviewe