A major shortcoming in olefin metathesis, a chemical process that is central to research in several branches of chemistry, is the lack of efficient methods that kinetically favor E isomers in the product distribution. Here we show that kinetically E-selective cross-metathesis reactions may be designed to generate thermodynamically disfavored alkenyl chlorides and fluorides in high yield and wit...

This paper presents the evolution of alkyne metathesis since the early discoveries, essentially from the catalyst point of view. It is shown that although well defined carbynes may be useful for this reaction, further work has been made, aimed at the synthesis of new catalysts or catalytic systems, based on molybdenum precursors , associated or not with phenolic cocatalysts. The major objective...

Sonochemical preparation of Co and Ni promoted MoS(2) supported on alumina was achieved by high-intensity ultrasonic irradiation of isodurene solutions containing molybdenum carbonyl, dicobalt octacarbonyl, elemental sulfur, and Al(2)O(3) or Ni-Al(2)O(3) under Ar flow. The sonochemically prepared catalysts were characterized by elemental analysis, XPS, SEM, TEM, and XEDS, and hydrodesulfurizati...

Intensive efforts for the transformation of dinitrogen using transition metal-dinitrogen complexes as catalysts under mild reaction conditions have been made. However, limited systems have succeeded in the catalytic formation of ammonia. Here we show that newly designed and prepared dinitrogen-bridged dimolybdenum complexes bearing N-heterocyclic carbene- and phosphine-based PCP-pincer ligands ...

Molybdenum (Mo), a bcc metal with a melting point of 2,610°C and a density of 10.22 g/cm, is an important refractory metal. The refractory properties of molybdenum reflect the high strength of interatomic bonding resulting from the overlap of the 4d-orbitals and the number of bonding electrons available (1). The melting point of molybdenum is exceeded only by those of tungsten and tantalum, amo...

Molybdenum carbide (Mo2C) has been considered as a promising non-noble-metal hydrogen evolution reaction (HER) electrocatalyst for future clean energy devices. In this work, we report a facile, green, low-cost and scalable method for the synthesis of a Mo2C-based HER electrocatalyst consisting of ultrafine Mo2C nanoparticles embedded within bacterial cellulosederived 3D N-doped carbon nanofiber...

Inorganic solids are an important class of catalysts that often derive their activity from sparse active sites that are structurally distinct from the inactive bulk. Rationally optimizing activity is therefore beholden to the challenges in studying these active sites in molecular detail. Here, we report a molecule that mimics the structure of the proposed triangular active edge site fragments o...

Molybdenum disulfide nanosheets/reduced graphene oxide (MoS2 NSs/rGO) nanohybrid as a highly effective catalyst for hydrogen evolution reaction (HER) have been successfully synthesized by a facile microwave-assisted method. The results clearly reveal that direct grown of MoS2 NSs on rGO have been achieved. Electrochemical tests show that the as-prepared hybrid material exhibited excellent HER a...

For the first time, dioxomolybdenum(VI) complex with the general formula [MoO2L2] containing a N-O bidentate ligands (HL=2-(o-aminophenyl)- benzimidazole) has been used for the oxidation of sulfides. Elemental analyses (carbon, hydrogen, nitrogen), FT-IR and Uv-Visble spectra and 1HNMR analysis agree well with the proposed stoicheiometry of the complex [MoO...

Since the molybdenum and ruthenium carbene complexes 1a and 1b were discovered by Schrock and Grubbs in 1990 and 1992, synthetic organic chemistry has progressed with the use of these complexes as the catalyst for olefin metathesis. It was found that the ruthenium carbene complex was also effective for enyne metathesis, which occurs between an alkene and an alkyne. Intramolecular enyne metathes...