939-27-5Relevant articles and documents
Preparation and use of tritiated Schwartz' reagent (ZrCp2Cl3H)
Zippi,Andres,Morimoto,Williams
, p. 1037 - 1044 (1994)
Treatment of Li3H with ZrCp2Cl2 in THF affords ZrCp2Cl3H. By the action of ZrCp2Cl3H on an acetylene, it is possible to stereo- and regioselectively introduce tritium into the vinylic position, a site which has often proved to be metabolically stable in complex molecules. In addition, ZrCp2Cl3H may be used to regioselectively label olefins with tritium.
Thermodynamics and kinetics of formation of intramolecular naphthalene dimer radical cation studied by near-IR transient absorption spectroscopy
Fushimi, Toshiki,Fujita, Yusuke,Ohkita, Hideo,Ito, Shinzaburo
, p. 1443 - 1448 (2004)
Thermodynamics and kinetics for formation of an intramolecular dimer radical cation of a series of α,ω-di(2-naphthyl)alkanes in solutions were quantitatively investigated by near-IR transient absorption spectroscopy, which allows one to observe dimer radical cations directly. The standard enthalpy (-ΔH°) for the formation of the intramolecular dimer radical cation increased as the chain length between the two naphthyl moieties increased, and was smaller than that of the intermolecular dimer radical cation of 2-ethylnaphthalene. This shows that -ΔH° depends on the strain required for the chain to form the ring-closure configuration. Destabilization due to repulsion between the two naphthyl moieties in the intramolecular dimer radical cation was evaluated to be ca. 20 kJ mol-1. This value is smaller than that of the naphthalene excimer, indicating that the separation distance and/or the overlap between the two naphthyl moieties are not as restricted as those of the excimer. The activation energy for the formation of the intramolecular dimer radical cation was comparable to the energy for local motions of a few methylene units linking the two naphthalene moieties.
Expanding the useful range of ionic liquids: Melting point depression of organic salts with carbon dioxide for biphasic catalytic reactions
Scurto, Aaron M.,Leitner, Walter
, p. 3681 - 3683 (2006)
Large and previously unreported melting point depressions (even exceeding ΔTm of 100°C) were observed for simple ammonium and phosphonium salts in the presence of compressed CO2, bringing them well within the range of typical ionic liquids; possible applications include biphasic catalysis in IL/scCO2 systems as demonstrated for rhodium complex catalyzed hydrogenation, hydroformylation, and hydroboration of 2-vinyl-naphthalene using a CO2-induced molten sample of [NBu 4][BF4] as a catalyst phase at temperatures in the range of 55-75°C, i.e. 100°C below the normal melting point of the organic salt. The Royal Society of Chemistry 2006.
Attenuation of Ni(0) Decomposition: Mechanistic Insights into AgF-Assisted Nickel-Mediated Silylation
Balakrishnan, Venkadesh,Chindan, Bincy,Murugesan, Vetrivelan,Rasappan, Ramesh
, p. 1438 - 1446 (2022/01/27)
In nickel-mediated Kumada cross-coupling reactions, low valent active nickel complexes are often generated in situ and the ligands usually govern the reactivity or stability of these complexes. However, the decomposition of active nickel complexes is inev
Sustainable System for Hydrogenation Exploiting Energy Derived from Solar Light
Ishida, Naoki,Kamae, Yoshiki,Ishizu, Keigo,Kamino, Yuka,Naruse, Hiroshi,Murakami, Masahiro
supporting information, p. 2217 - 2220 (2021/02/16)
Herein described is a sustainable system for hydrogenation that uses solar light as the ultimate source of energy. The system consists of two steps. Solar energy is captured and chemically stored in the first step; exposure of a solution of azaxanthone in ethanol to solar light causes an energy storing dimerization of the ketone to produce a sterically strained 1,2-diol. In the second step, the chemical energy stored in the vicinal diol is released and used for hydrogenation; the diol offers hydrogen onto alkenes and splits back to azaxanthone, which is easily recovered and reused repeatedly for capturing solar energy.
Ligand-enabled and magnesium-activated hydrogenation with earth-abundant cobalt catalysts
Han, Bo,Jiao, Hongmei,Ma, Haojie,Wang, Jijiang,Zhang, Miaomiao,Zhang, Yuqi
, p. 39934 - 39939 (2021/12/31)
Replacing expensive noble metals like Pt, Pd, Ir, Ru, and Rh with inexpensive earth-abundant metals like cobalt (Co) is attracting wider research interest in catalysis. Cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. Herein, we describe a hydrogenation method for polycyclic aromatic hydrocarbons (PAHs) and olefins with a magnesium-activated earth-abundant Co catalyst. When diketimine was used as a ligand, simple and inexpensive metal salts of CoBr2in combination with magnesium showed high catalytic activity in the site-selective hydrogenation of challenging PAHs under mild conditions. Co-catalyzed hydrogenation enabled the reduction of two side aromatics of PAHs. A wide range of PAHs can be hydrogenated in a site-selective manner, which provides a cost-effective, clean, and selective strategy to prepare partially reduced polycyclic hydrocarbon motifs that are otherwise difficult to prepare by common methods. The use of well-defined diketimine-ligated Co complexes as precatalysts for selective hydrogenation of PAHs and olefins is also demonstrated.
Efficient synthesis of quinazolines by the iron-catalyzed acceptorless dehydrogenative coupling of (2-aminophenyl)methanols and benzamides
Zhang, Shi-Qi,Cui, Yao,Guo, Bin,Young, David J.,Xu, Ze,Li, Hong-Xi
, (2020/12/13)
The acceptorless dehydrogenation coupling (ADC) of (2-aminophenyl)methanols with benzamides was achieved with catalytic FeCl2·4H2O in an efficient synthesis of quinazolines. This simple catalytic system is atom-economical, environmentally benign and suited to a variety of substrates.
Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
supporting information, p. 2157 - 2161 (2021/05/21)
The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
supporting information, p. 18591 - 18598 (2021/06/28)
A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
, p. 3843 - 3853 (2021/11/18)
Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
