612-00-0Relevant articles and documents
Mechanistic insight on the hydrogenation of conjugated alkenes with H 2 catalyzed by early main-group metal catalysts
Zeng, Guixiang,Li, Shuhua
, p. 3361 - 3369 (2010)
Density functional theory calculations have been performed to investigate the molecular mechanism of the hydrogenation reactions of 1,1-diphenylethylene and myrcene catalyzed by the actual calcium hydride catalyst, CaH(dipp-nacnac)(thf) (dipp-nacnac = CH{
THE STOICHIOMETRIC HYDROGENATION OF SUBSTITUTED PHENYL ALKENES BY HYDRIDOCOBALT TETRACARBONYL
Roth, Jerome A.,Wiseman, Paul
, p. 231 - 234 (1981)
The relative rates of hydrogenation of a series of styrenes, phenylpropenes, 1,1-diphenylethylenes, and 1,1-diphenylpropenes were measured.Compared to 1,1-diphenylethylene (k2=2.42*10-2 l mol-1 sec-1), 1,1-diphe
Complexes between lithium cation and diphenylalkanes in the gas phase: The pincer effect
Gal, Jean-Francois,Maria, Pierre-Charles,Mo, Otilia,Yanez, Manuel,Kuck, Dietmar
, p. 7676 - 7683 (2006)
The gas-phase lithium cation basicities (LCB values, Gibbs free energies of binding) of α,ω)-diphenylal-kanes Ph-(CH2) n-Ph (n = 2, 3, or 7) and 1,1-diphenylethane Ph-CH(Me)-Ph were investigated by means of Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry. Their structures, and those of the corresponding Li+ complexes were optimized at the B3LYP/6-31G(d) level and their relative stabilities calculated at the B3LYP/6-311+G(3df,2p)//B3LYP/6-31G(d) level. Whereas the most stable conformers of the free diphenylalkanes were found to adopt a completely stretched aliphatic chain connecting the two benzene rings, the most stable Li+ complexes correspond to conformers in which the alkali metal cation interacts simultaneously with both benzene rings through the folding of the aliphatic chain ("pincer effect"). This chelation brings about a significant enhancement of the Li+ binding enthalpies (LBE values), which were calculated to be approximately 75 kJ mor-1 higher than those evaluated for conventional (singly coordinated) π complexes in which the metal cation interacts with only one of the benzene rings. The increase of the corresponding lithium cation basicities, however, (Gibbs free energies of Li+ binding, LCB values) was calculated to be smaller by approximately 15 kJ mol-1 as the pincer effect is entropically disfavored. The good agreement between the calculated LCB values, assuming a statistical distribution of the different conformers present in the gas phase, and the experimental LCB values measured by means of FTICR mass spectrometry are considered indirect evidence of the existence of the pincer effect.
Ga+-catalyzed hydrosilylation? about the surprising system Ga+/HSiR3/olefin, proof of oxidation with subvalent Ga+and silylium catalysis with perfluoroalkoxyaluminate anions
Barthélemy, Antoine,Glootz, Kim,Hanske, Annaleah,Krossing, Ingo,Scherer, Harald
, p. 439 - 453 (2022/01/22)
Already 1 mol% of subvalent [Ga(PhF)2]+[pf]- ([pf]- = [Al(ORF)4]-, RF = C(CF3)3) initiates the hydrosilylation of olefinic double bonds under mild conditions. Reactions with HSiMe3 and HSiEt3 as substrates efficiently yield anti-Markovnikov and anti-addit
H2 Evolution Upon Hydrolysis of Ammonia-Borane Catalyzed by Porphyrin Stabilized Nanocatalysts
Zhang, Nuonuo,Liu, Genjiang,Sun, Yao,Wang, Yanlan,Yan, Jiaying,Liu, Xiang
, p. 2272 - 2278 (2021/01/04)
Abstract: Ammonia-borane (AB) is one of the most promising fuel forms for the hydrogen economy, but the reaction requires a good catalyst to accelerate this hydrolysis reaction under ambient conditions. Here, H2 evolution upon hydrolysis of amm
Hydrolysis of B2pin2 over Pd/C Catalyst: High Efficiency, Mechanism, and in situ Tandem Reaction
Li, Ning,Shen, Jialu,Liu, Xiang
supporting information, p. 2797 - 2800 (2021/02/16)
A facile and effective synthesis of H2 or D2 from Pd/C catalyzed hydrolysis of B2pin2 has first been developed. Among them, B2pin2 is frequently used for borylation reaction, and has rarely been used for hydrogen evolution. The kinetic isotope effects (KIEs) and tandem reaction for diphenylacetylene and norbornene hydrogenation have confirmed both two H atoms of H2 gas are provided from H2O. This is contrary to other boron compounds hydrolysis (including NH3BH3, NaBH4), which generates H2 with only one H atom provided by water and the other one by boron compounds. Note that the hydrolysis of B2pin2 in D2O also provides an easy and useful synthesis of D2.
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.
Acid- and Base-Catalyzed Hydrolytic Hydrogen Evolution from Diboronic Acid
Wang, Yi,Shen, Jialu,Huang, Yu,Liu, Xiang,Zhao, Qiuxia,Astruc, Didier
supporting information, p. 3013 - 3018 (2021/03/26)
The efficient production of H2 from hydrogen-rich sources, particularly from water, is a crucial task and a great challenge, both as a sustainable energy source and on the laboratory scale for hydrogenation reactions. Herein, a facile and effective synthesis of H2 and D2 from only acid- or base-catalyzed metal-free hydrolysis of B2(OH)4, a current borylation reagent, has been developed without any transition metal or ligand. Acid-catalyzed H2 evolution was completed in 4 min, whereas the base-catalyzed process needed 6 min. The large kinetic isotopic effects for this reaction with D2O, deuteration experiments and mechanistic studies have confirmed that both H atoms of H2 originate from water using either of these reactions. This new, metal-free catalytic system holds several advantages, such as high efficiency, simplicity of operation, sustainability, economy, and potential further use.
Indium Tribromide-Catalysed Transfer-Hydrogenation: Expanding the Scope of the Hydrogenation and of the Regiodivergent DH or HD Addition to Alkenes
Li, Luomo,Hilt, Gerhard
supporting information, p. 11221 - 11225 (2021/06/25)
The transfer-hydrogenation as well as the regioselective and regiodivergent addition of H?D from regiospecific deuterated dihydroaromatic compounds to a variety of 1,1-di- and trisubstituted alkenes was realised with InBr3 in dichloro(m)ethane. In comparison with the previously reported BF3?Et2O-catalysed process, electron-deficient aryl-substituents can be applied reliably and thereby several restrictions could be lifted, and new types of substrates could be transformed successfully in hydrodeuterogenation as well as deuterohydrogenation transfer-hydrogenation reactions.
Boosting homogeneous chemoselective hydrogenation of olefins mediated by a bis(silylenyl)terphenyl-nickel(0) pre-catalyst
Lücke, Marcel-Philip,Yao, Shenglai,Driess, Matthias
, p. 2909 - 2915 (2021/03/14)
The isolable chelating bis(N-heterocyclic silylenyl)-substituted terphenyl ligand [SiII(Terp)SiII] as well as its bis(phosphine) analogue [PIII(Terp)PIII] have been synthesised and fully characterised. Their reaction with Ni(cod)2(cod = cycloocta-1,5-diene) affords the corresponding 16 VE nickel(0) complexes with an intramolecularη2-arene coordination of Ni, [E(Terp)E]Ni(η2-arene) (E = PIII, SiII; arene = phenylene spacer). Due to a strong cooperativity of the Si and Ni sites in H2activation and H atom transfer, [SiII(Terp)SiII]Ni(η2-arene) mediates very effectively and chemoselectively the homogeneously catalysed hydrogenation of olefins bearing functional groups at 1 bar H2pressure and room temperature; in contrast, the bis(phosphine) analogous complex shows only poor activity. Catalytic and stoichiometric experiments revealed the important role of the η2-coordination of the Ni(0) site by the intramolecular phenylene with respect to the hydrogenation activity of [SiII(Terp)SiII]Ni(η2-arene). The mechanism has been established by kinetic measurements, including kinetic isotope effect (KIE) and Hammet-plot correlation. With this system, the currently highest performance of a homogeneous nickel-based hydrogenation catalyst of olefins (TON = 9800, TOF = 6800 h?1) could be realised.
