5683-31-8Relevant academic research and scientific papers
Design and Remarkable Efficiency of the Robust Sandwich Cluster Composite Nanocatalysts ZIF-8@Au25@ZIF-67
Yun, Yapei,Sheng, Hongting,Bao, Kang,Xu, Li,Zhang, Yu,Astruc, Didier,Zhu, Manzhou
supporting information, p. 4126 - 4130 (2020/03/05)
Heterogeneous catalysts with precise surface and interface structures are of great interest to decipher the structure-property relationships and maintain remarkable stability while achieving high activity. Here, we report the design and fabrication of the new sandwich composites ZIF-8@Au25@ZIF-67[tkn] and ZIF-8@Au25@ZIF-8[tkn] [tkn = thickness of shell] by coordination-assisted self-assembly with well-defined structures and interfaces. The composites ZIF-8@Au25@ZIF-67 efficiently catalyzed both 4-nitrophenol reduction and terminal alkyne carboxylation with CO2 under ambient conditions with remarkably improved activity and stability, compared to the simple components Au25/ZIF-8 and Au25@ZIF-8, highlighting the highly useful function of the ultrathin shell. In addition, the performances of these composite sandwich catalysts are conveniently regulated by the shell thickness. This concept and achievements should open a new avenue to the targeted design of well-defined nanocatalysts with enhanced activities and stabilities for challenging reactions.
Synthesis of carboxy-polyethylene glycol-amine (CA (PEG)n) and [1-14C]-CA (PEG)n via oxa-Michael addition of amino-polyethylene glycols to propiolates vs to acrylates
Song, Fengbin,Chen, Lu,Lin, Ronghui,Salter, Rhys
, p. 15 - 24 (2019/12/30)
Synthesis of carboxy-polyethylene glycol-amine (CA (PEG)n) via oxa-Michael addition of amino-polyethylene glycols to either acrylates or propiolates was investigated. Compared with the oxa-Michael addition to acrylates, the corresponding addition to propiolates was found to proceed under mild reaction conditions and afford the adducts in high yields from a broad scope of substrates. A two-step efficient and convenient synthesis of benzyl [1-14C]-propiolate from 14CO2 was therefore developed and utilized as a common synthon to afford practical and high yielding access to [1-14C]-CA (PEG)n.
Carboxylation of terminal alkynes promoted by silver carbamate at ambient pressure
Bresciani, Giulio,Marchetti, Fabio,Pampaloni, Guido
, p. 10821 - 10825 (2019/07/15)
Transition metal carbamates constitute a class of compounds with unique properties, however their catalytic potential has been sparingly explored so far. The easily available silver N,N-dimethylcarbamate, Ag(O2CNMe2), worked as a catalyst in the carboxylation reaction of terminal alkynes with CO2 at atmospheric pressure. Different reaction parameters (solvent, base, temperature, time and the amount of catalyst) were investigated in order to establish the optimal conditions.
Cis -1,2-Bis(diphenylphosphino)ethylene copper(i) catalyzed C-H activation and carboxylation of terminal alkynes
Trivedi, Manoj,Smreker, Jacob R.,Singh, Gurmeet,Kumar, Abhinav,Rath, Nigam P.
, p. 14145 - 14151 (2017/11/28)
The reaction of cis-1,2-bis(diphenylphosphino)ethylene (dppet) with CuX (X = CN, SCN) in 1:1 M molar ratio in DCM-MeOH (50:50 V/V) under refluxing conditions gave two dimeric Cu(i) complexes, viz. [Cu2(μ-CN)2(κ2-P,P-dppet)2] (1) and [Cu2(μ2-SCN)2(κ2-P,P-dppet)2] (2). These complexes have been characterized by elemental analyses, IR, 1H and 31P NMR, and electronic absorption spectroscopies, and ESI-MS. The molecular structure of 2 was confirmed by single crystal X-ray diffraction, which indicated that 2 exists as a centrosymmetric dimer in which the two copper centers are bonded to two dppet ligands and two bridging thiocyanate groups in a μ2-manner. The electrochemical properties of 1 and 2 were studied by cyclic voltammetry. Both the complexes exhibited strong luminescence properties in the solution state at ambient temperature. Both the complexes were found to be efficient catalysts for the conversion of terminal alkynes into propiolic acids with CO2. Owing to their excellent catalytic activity, the reactions proceed at atmospheric pressure and ambient temperature (25 °C). The catalytic products were obtained in excellent yields (90-97%) by using the complex loading of 1 mol%.
Method for preparing acid through oxidating alcohols or aldehydes by oxygen
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Paragraph 0051; 0052; 0053; 0054; 0091; 0092; 0093, (2017/09/29)
The invention provides a method for preparing acid through oxidating alcohols or aldehydes by using oxygen or oxygen in air as an oxidant. The method comprises the steps: oxidating the alcohols or aldehydes to produce the acid at room temperature in an organic solvent in a manner of taking ferric nitrate (Fe(NO3)3.9H2O), 2,2,6,6-tetramethylpiperidyl nitrogen oxide (TEMPO) and an inorganic halide as catalysts and taking the oxygen or air as an oxidant, and oxidating diols to produce lactone; or, carrying out a reaction on the aldehydes, which serve as a raw material, under neutral conditions by taking ferric nitrate as a catalyst, and oxidating the aldehydes to produce the acid and peroxy acid. The method has the advantages that the method is environmentally friendly, the cost is low, the yield is high, the atomic economical efficiency is high, the compatibility of substrate functional groups is good, the reaction conditions are mild, a reaction scale can be enlarged, and the like, so that the method is suitable for being applied to industrial production.
Iron Catalysis for Room-Temperature Aerobic Oxidation of Alcohols to Carboxylic Acids
Jiang, Xingguo,Zhang, Jiasheng,Ma, Shengming
supporting information, p. 8344 - 8347 (2016/07/26)
Oxidation from alcohols to carboxylic acids, a class of essential chemicals in daily life, academic laboratories, and industry, is a fundamental reaction, usually using at least a stoichiometric amount of an expensive and toxic oxidant. Here, an efficient and practical sustainable oxidation technology of alcohols to carboxylic acids using pure O2 or even O2 in air as the oxidant has been developed: utilizing a catalytic amount each of Fe(NO3)3·9H2O/TEMPO/MCl, a series of carboxylic acids were obtained from alcohols (also aldehydes) in high yields at room temperature. A 55 g-scale reaction was demonstrated using air. As a synthetic application, the first total synthesis of a naturally occurring allene, i.e., phlomic acid, was accomplished.
Iron-catalyzed selective oxidation of α,β-unsaturated aldehydes to α,β-unsaturated carboxylic acids by molecular oxygen
Tanaka, Shinji,Kon, Yoshihiro,Uesaka, Yumiko,Morioka, Ryo,Tamura, Masanori,Sato, Kazuhiko
supporting information, p. 188 - 190 (2016/03/01)
Selective oxidation of α,β-unsaturated aldehydes to α,β-unsaturated carboxylic acids was performed using O2 as the oxidant in the presence of a simple iron catalyst. The addition of an alkali metal carboxylate as a cocatalyst enhanced the selectivity for the desired product. Redox tuning of the iron catalyst via association with the alkali metal led to a controlled radical generation during the catalytic O2 oxidation.
1,1′-Bis(di-tert-butylphosphino)ferrocene copper(i) complex catalyzed C-H activation and carboxylation of terminal alkynes
Trivedi, Manoj,Singh, Gurmeet,Kumar, Abhinav,Rath, Nigam P.
, p. 20874 - 20882 (2015/12/11)
Four copper(i) complexes, [CuBr(dtbpf)] (1), [CuI(dtbpf)] (2), [Cu4(μ2-I)2(μ3-I)2(μ-dtbpf)2] (3) and [Cu6(μ3-I)6(μ-dtbpf)2]·2CH3CN (4), were prepared using CuX (X = Br, I) and 1,1′-bis(di-tert-butylphosphino)ferrocene (dtbpf). These complexes have been characterized by elemental analyses, IR, 1H and 31P NMR, ESI-MS and electronic absorption spectroscopy. Molecular structures of the complexes 2 and 4 were determined crystallographically. Complex 2 is the first monomeric isolated Cu(i) complex of dtbpf with the largest P-Cu-P bite angle (120.070(19)°) to date. Complex 4 shows a centrosymmetrical dimeric unit with two [Cu3(μ3-I)3] motifs bridged by two bidentate dtbpf ligands in the κ1-manner. Each [Cu3(μ3-I)3] motif unites to form a pyramid with one copper atom at the apex and one of the triangular faces capped by an iodine atom. All the complexes were found to be efficient catalysts for the conversion of terminal alkynes into propiolic acids with CO2. Owing to the excellent catalytic activity, the reactions proceeded at atmospheric pressure and ambient temperature (25 °C). The catalytic products were obtained in moderate to good yields (80-96%) by using complex loading to 2 mol%. To the best of our knowledge, this is the first example of an active ferrocenyl diphosphine Cu(i) catalyst for the carboxylation of terminal alkynes with CO2.
Asymmetric synthesis of N-stereogenic molecules: Diastereoselective double aza-Michael reaction
Lauber, Alex,Zelenay, Benjamin,Cvengros, Jan
supporting information, p. 1195 - 1197 (2014/02/14)
A novel approach towards the asymmetric synthesis of N-stereogenic molecules via double aza-Michael addition was developed. The diastereomeric ratio can be increased by a thermodynamically controlled isomerization mechanism. Simple separation and functionalization of the products afford N-stereogenic compounds in high enantiomeric purity.
Highly regioselective synthesis of substituted isoindolinones via ruthenium-catalyzed alkyne cyclotrimerizations
Foster, Robert W.,Tame, Christopher J.,Hailes, Helen C.,Sheppard, Tom D.
supporting information, p. 2353 - 2360 (2013/10/01)
(Cyclooctadiene)(pentamethylcyclopentadiene) ruthenium chloride [Cp*RuCl (cod)] has been used to catalyze the regioselective cyclization of amide-tethered diynes with monosubstituted alkynes to give polysubstituted isoindolinones. Notably, the presence of a trimethylsilyl group on the diyne generally led to complete control over the regioselectivity of the alkyne cyclotrimerization. The cyclization reaction worked well in a sustainable non-chlorinated solvent and was tolerant of moisture. The optimized conditions were effective with a diverse range of alkynes and diynes. The 7-silylisoindolinone products could be halogenated, protodesilylated or ring opened to access a range of usefully functionalized products.
