Refernces
10.1002/anie.202007030
The study presents a novel light-driven approach to Grubbs metathesis, facilitated by the gem-hydrogenation of internal alkynes using [(NHC)(cymene)RuCl2] (NHC = N-heterocyclic carbene) complexes. This method results in the formation of discrete Grubbs-type ruthenium carbene species, which can be harnessed for a "hydrogenative metathesis" reaction that converts enyne substrates into cyclic alkenes. The research explores the unique reactivity of these complexes under UV irradiation, leading to the efficient formation of various cycloalkene products. The study also discusses the potential and limitations of this new catalyst system, as well as providing experimental evidence for the formation of Grubbs-type carbenes through alkyne gem-hydrogenation. This innovative method offers a non-canonical entry into the field of metathesis chemistry, expanding the scope of catalytic hydrogenation and Grubbs catalysis.
10.1021/acs.organomet.5b00218
The research primarily investigates the oxidative cyclization of tetrafluoroethylene (TFE) with ethylene using Ni(0) to form a five-membered nickelacycle, which is a key intermediate in nickel-catalyzed carbon-carbon (C?C) bond-forming reactions. The study focuses on the synthesis and characterization of 2,2,3,3-tetrafluoronickelocyclopentanes, which are generated through this cyclization process. The nickelacycle was isolated using PPh3 as an auxiliary ligand, and its structure was confirmed through X-ray analysis. Experiments involved reacting TFE and ethylene with Ni(0) in the presence of PPh3, leading to the formation of the nickelacycle, which was then further reacted with ethylene to produce a cotrimerization product, 5,5,6,6-tetrafluoro-1-hexene. The reactivity of the nickelacycle with various enones was also explored, resulting in cross-trimerization products. The research utilized various analytical techniques, including NMR and X-ray diffraction, to characterize the intermediates and products. The study also attempted to apply these reactions catalytically, achieving selective cotrimerization of TFE with ethylene to form the desired product with a low turnover number.
10.1021/ja00272a035
The research investigates the photochemical reactions of (q5-C5Me5)Fe(CO)2R complexes, where R represents alkyl and silyl groups, specifically focusing on the reversible ethylene insertion into an iron-silicon bond. The study aims to provide insights into the mechanism of transition-metal-catalyzed hydrosilation of alkenes, proposing a mechanism involving olefin insertion into a metal-silicon bond as a key step. The conclusions drawn from the research demonstrate that the photochemistry of these complexes provides a precedent for all the reactions postulated to occur in catalytic hydrosilation of olefins, including the reversible insertion of C2H4 into an M-Si bond and the reductive elimination of R-H following oxidative addition of HSiR'3. The chemicals used in the process include (q5-C5Me5)Fe(CO)2SiMe3, HSiR'3 (where R' = Me, Et), C2H4, and other related organometallic complexes.
10.1021/ol035270b
The research investigates the use of ethylene to promote intermolecular enyne metathesis between functional group-rich alkynes and vinyl ethers. The study found that ethylene not only enhances the reactivity of the process but also protects the catalyst, thereby increasing the applicability of the intermolecular reaction to problematic substrates. Key chemicals involved in the research include ethylene, which acts as a co-added alkene to improve reaction efficiency; vinyl ethers such as ethyl vinyl ether (EVE); and various alkynes, including thiol benzoates and butynyl derivatives. The second-generation Grubbs catalyst was used to facilitate the metathesis reactions. The study also explored different solvents like benzene and dichloromethane, and examined the effects of varying ethylene pressures and reaction conditions on the outcomes. The results showed that ethylene significantly increased the lifetime of the Fischer carbene complex and enabled the reaction to proceed at ambient temperature, even with substrates that were previously unreactive or poorly reactive.
10.1021/ma011959p
The research focuses on the synthesis and gas transport properties of new high glass transition temperature ring-opened polynorbornenes, specifically the polymers and copolymers derived from N-(1-adamantyl)-exo-norbornene-5,6-dicarboximide (AdNDI), N-cyclohexyl-exo-norbornene-5,6-dicarboximide (ChNDI), and N-phenyl-exonorbornene-5,6-dicarboximide (PhNDI). The experiments involved the preparation of membranes from these homopolymers and copolymers, and the subsequent measurement of the transport of various gases (hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ethylene, and ethane) across these membranes at 30°C using permeation techniques. The study aimed to determine the diffusion coefficients and permselectivity coefficients for different gases, which were influenced by the chemical structure of the membranes. The analyses included 1H and 13C NMR spectroscopy, FTIR spectroscopy, glass transition temperature measurements, and molecular weight determinations via GPC. The results indicated that diffusion coefficients correlated with the diameter of diffusant molecules, and the permselectivity coefficients varied depending on the type of membrane, with some membranes showing high permselectivity for certain gas pairs, such as oxygen with respect to nitrogen, and ethylene with respect to ethane.
10.1016/j.jorganchem.2008.02.007
The study focuses on the synthesis, characterization, and evaluation of a series of transition metal complexes, including iron (II), cobalt (II), and nickel (II) complexes, bearing the ligand 2-(1-isopropyl-2-benzimidazolyl)-6-(1-aryliminoethyl)pyridine. These complexes were designed to catalyze ethylene reactivity, specifically oligomerization and polymerization reactions. The purpose of these chemicals was to investigate their catalytic behaviors towards ethylene, with the aim of producing linear α-olefins, which are important in the manufacturing of detergents, synthetic lubricants, and plasticizer alcohol, among other applications. The study explores the influence of various factors, such as the nature of the ligand environment, the type of cocatalyst, the molar ratio of cocatalyst to metal, and reaction temperature, on the catalytic activity and selectivity of these complexes.
F+
F+:Highly flammable;
