1795-15-9Relevant academic research and scientific papers
Fabricating nickel phyllosilicate-like nanosheets to prepare a defect-rich catalyst for the one-pot conversion of lignin into hydrocarbons under mild conditions
Cao, Meifang,Chen, Bo,He, Chengzhi,Ouyang, Xinping,Qian, Yong,Qiu, Xueqing
supporting information, p. 846 - 857 (2022/02/09)
The one-pot conversion of lignin biomass into high-grade hydrocarbon biofuels via catalytic hydrodeoxygenation (HDO) holds significant promise for renewable energy. A great challenge for this route involves developing efficient non-noble metal catalysts to obtain a high yield of hydrocarbons under relatively mild conditions. Herein, a high-performance catalyst has been prepared via the in situ reduction of Ni phyllosilicate-like nanosheets (Ni-PS) synthesized by a reduction-oxidation strategy at room temperature. The Ni-PS precursors are partly converted into Ni0 nanoparticles by in situ reduction and the rest remain as supports. The Si-containing supports are found to have strong interactions with the nickel species, hindering the aggregation of Ni0 particles and minimizing the Ni0 particle size. The catalyst contains abundant surface defects, weak Lewis acid sites and highly dispersed Ni0 particles. The catalyst exhibits excellent catalytic activity towards the depolymerization and HDO of the lignin model compound, 2-phenylethyl phenyl ether (PPE), and the enzymatic hydrolysis of lignin under mild conditions, with 98.3% cycloalkane yield for the HDO of PPE under 3 MPa H2 pressure at 160 °C and 40.4% hydrocarbon yield for that of lignin under 3 MPa H2 pressure at 240 °C, and its catalytic activity can compete with reported noble metal catalysts.
Polysilane-Immobilized Rh-Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism
Miyamura, Hiroyuki,Suzuki, Aya,Yasukawa, Tomohiro,Kobayashi, Shu
supporting information, p. 11325 - 11334 (2018/09/06)
Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.
Synthesis of quinolinyl-based pincer copper(ii) complexes: an efficient catalyst system for Kumada coupling of alkyl chlorides and bromides with alkyl Grignard reagents
Pandiri, Hanumanprasad,Gonnade, Rajesh G.,Punji, Benudhar
, p. 16747 - 16754 (2018/12/05)
Quinolinamide-based pincer copper(ii) complexes, κN,κN,κN-{C9H6N-(μ-N)-C(O)CH2NEt2}CuX [(QNNNEt2)CuX (X = Cl, 2; X = Br, 3; X = OAc, 4)], were synthesized by the reaction of ligand (QNNNEt2)-H (1) with CuX2 (X = Cl, Br or OAc) in the presence of Et3N. The reaction of (QNNNEt2)-H with CuX (X = Cl, Br or OAc) also afforded the Cu(ii) complexes 2, 3 and 4, respectively, instead of the expected Cu(i) pincer complexes. The formation of Cu(ii) complexes from Cu(i) precursors most likely occurred via the disproportionation reaction of Cu(i) into Cu(0) and Cu(ii). A cationic complex [(QNNNEt2)Cu(CH3CN)]OTf (5) was synthesized by the treatment of neutral complex 2 with AgOTf. On the other hand, the reaction of (QNNNEt2)-H (1) with [Cu(MeCN)4]ClO4 produced cationic Cu(i) complex, [(QNN(H)NEt2)Cu(CH3CN)]ClO4 (6), in good yield. All complexes 2-5 were characterized by elemental analysis and HRMS measurements. Furthermore, the molecular structures of 2, 3 and 4 were elucidated by X-ray crystallography. Complex 4 crystallizes in a dimeric and catemeric pattern. The cationic complex 5 was found to be an efficient catalyst for the Kumada coupling reaction of diverse nonactivated alkyl chlorides and bromides with alkyl magnesium chloride under mild reaction conditions.
Co-Catalyzed Cross-Coupling Reaction of Alkyl Fluorides with Alkyl Grignard Reagents
Iwasaki, Takanori,Yamashita, Koji,Kuniyasu, Hitoshi,Kambe, Nobuaki
supporting information, p. 3691 - 3694 (2017/07/26)
The cross-coupling reaction of unactivated alkyl fluorides with alkyl Grignard reagents by a CoCl2/LiI/1,3-pentadiene catalytic system is described. The present reaction smoothly cleaved C-F bonds under mild conditions and achieved alkyl-alkyl cross-coupling even when sterically hindered tertiary alkyl Grignard reagents were employed. Since alkyl fluorides are inert toward many reagents and catalytic intermediates, the use of the present reaction enables a new multistep synthetic route to construct carbon frameworks by combining conventional transformations.
Synthesis and reactivity of new aminophenolate complexes of nickel
Yu, Siqi,Wang, Huan,Sledziewski, Jill E.,Madhira, Venkata N.,Takahashi, Cyrus G.,Leon, Michelle K.,Dudkina, Yulia B.,Budnikova, Yulia H.,Vicic, David A.
, p. 13603 - 13613 (2015/02/19)
New well-defined, paramagnetic nickel complexes have been prepared and characterized by X-ray crystallography. The complexes were found to be active for the cross-coupling of alkyl electrophiles (especially ethyl 2-bromobutyrate) with alkyl Grignard reagents. The ligand architecture in these new complexes could potentially be rendered chiral, opening up future possibilities for performing asymmetric cross-coupling reactions.
Cyclooctane metathesis catalyzed by silica-supported tungsten pentamethyl [(ΞSiO)W(Me)5]: Distribution of macrocyclic alkanes
Riache, Nassima,Callens, Emmanuel,Samantaray, Manoja K.,Kharbatia, Najeh M.,Atiqullah, Muhammad,Basset, Jean-Marie
supporting information, p. 15089 - 15094 (2015/02/19)
Metathesis of cyclic alkanes catalyzed by the new surface complex [(ΞSiO)W(Me)5] affords a wide distribution of cyclic and macrocyclic alkanes. The major products with the formula CnH2n are the result of either a ring contraction or ring expans
Effect of ligand modification on the reactivity of phosphinoamide-bridged heterobimetallic Zr/Co complexes
Zhou, Wen,Saper, Noam I.,Krogman, Jeremy P.,Foxman, Bruce M.,Thomas, Christine M.
, p. 1984 - 1989 (2014/01/17)
The effect of modifying the N-aryl substituent (aryl = mesityl vs. m-xylyl) of the phosphinoamide ligands linking Zr and Co in tris(phosphinoamide)-linked heterobimetallic complexes has been investigated. Treatment of the metalloligand (iPr2PNXyl)3ZrCl (2) (Xyl = m-xylyl) with CoI2 affords the iodide-bridged product ICo(iPr 2PNXyl)2(μ-I)Zr(η2-iPr2PNXyl) (3) rather than the C3-symmetric isomer observed using the N-mesityl derivative, ICo(iPr2PNMes)3ZrCl. Upon two-electron reduction of complex 3, ligand rearrangement occurs to generate the three-fold symmetric reduced complex N2Co(iPr 2PNXyl)3Zr(THF) (4). Comparison of 4 with the previously reported mesityl-substituted complex N2Co(iPr 2PNMes)3Zr(THF) (1) reveals similar structural features but with a less sterically hindered Zr apical site in complex 4. An obvious electronic difference between these two complexes is also present based on the drastically different infrared N2 stretching frequencies of 1 and 4. These notable differences lend themselves to different reactivity in both stoichiometric and catalytic reactions. Alkyl halide addition to complex 4 results in homo-coupling products resulting from alkyl radicals rather than the alkyl-bridged or intramolecular C-H activation products formed upon addition of RX to 1. This difference in reactivity with alkyl halides renders complex 3 a less effective catalyst for the Kumada cross-coupling of alkyl halides with n-octylMgBr than ICo(iPr2PNMes)3ZrCl, as a greater proportion of homocoupling products are formed under catalytic conditions.
A catalytic application of Co/Zr heterobimetallic complexes: Kumada coupling of unactivated alkyl halides with alkyl grignard reagents
Zhou, Wen,Napoline, Jonathan Wesley,Thomas, Christine M.
scheme or table, p. 2029 - 2033 (2011/06/25)
Tris(phosphanylamide) early/late heterobimetallic Zr/Co complexes, ClZr(R′NPR2)3CoI [R′ = iPr, R = Ph (1), R′ = 2,4,6-trimethylphenyl, R = iPr (2), R′ = R = iPr (3)], have been utilized as catalysts for the cross-coupling of alkyl halides with n-octylmagnesium bromide. While yields are consistently higher for alkyl bromide substrates, it is found that these unusual heterobimetallic complexes are also active towards more challenging alkyl chloride substrates. This is particularly interesting in light of the fact that monometallic cobalt complexes are inert towards these substrates, suggesting that Zr also plays a role in catalysis. Radical trapping studies suggest that a one-electron transfer radical oxidative addition pathway is operative.
Cobalt-catalyzed cross-coupling reaction between functionalized primary and secondary alkyl halides and aliphatic Grignard reagents
Cahiez, Gerard,Chaboche, Christophe,Duplais, Christophe,Giulliani, Arianna,Moyeux, Alban
supporting information; experimental part, p. 1484 - 1488 (2009/07/01)
The coupling of primary and secondary unactivated alkyl bromides with alkyl-Grignard reagents was performed in good yields under mild conditions by using a new catalytic system: consisting of cobalt chloride and tetramethylethylenediamine (CoCl2·2 LiI, 4TMEDA). The reaction is very chemoselective since ketone, ester and nitrile functions are tolerated.
Thermal Addition of Alkanes to Alkenes. V. Addition of Cyclohexane to 1-Octene in a Free Radical Chain reaction at Supercritical Fluid Conditions
Metzger, Juergen O.
, p. 767 - 781 (2007/10/02)
Alkanes can be added to alkenes in a thermally initiated free radical chain reaction ("ane reaction").Kinetic and mechanistic studies on the addition of cyclohexane (1) to 1-octene (2) (molar ratio = 100:1) at 330-450 deg C and pressures of up to 300 bar
