共查询到20条相似文献,搜索用时 15 毫秒
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Sarah L. Ackermann Dr. David J. Wolstenholme Chris Frazee Dr. Ghislain Deslongchamps Sandra H. M. Riley Dr. Andreas Decken Dr. G. Sean McGrady 《Angewandte Chemie (International ed. in English)》2015,54(1):164-168
The design of molecular catalysts that mimic the behavior of enzymes is a topical field of activity in emerging technologies, and can lead to an improved understanding of biological systems. Herein, we report how the bulky arms of the cations in [(n C4H9)4N]+[HCO3]‐ give rise to a host scaffold that emulates the substrate binding sites in carbonic anhydrase enzymes, affording a unique glimpse of an arrested intermediate in the base‐mediated binding and activation of CO2. 相似文献
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Comment on “Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2” 下载免费PDF全文
Juha Hurmalainen Michael A. Land Dr. Katherine N. Robertson Christopher J. Roberts Dr. Ian S. Morgan Dr. Heikki M. Tuononen Prof. Jason A. C. Clyburne 《Angewandte Chemie (International ed. in English)》2015,54(26):7484-7487
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Computational Design of New Heterofullerene‐Based Biomimetic α‐Carbonic Anhydrase Analogues 下载免费PDF全文
The biomimetic CO2 hydration activity of Ru/Rh‐doped fullerenes was revealed by using density functional theory calculations. The mechanism of CO2 hydration on the proposed heterofullerenes followed the mechanistic action of α‐carbonic anhydrases, and consisted of the adsorption and deprotonation of H2O, CO2 interaction with hydroxyl groups, CO2 bending, and proton transfer to give the product. Free‐energy landscapes for the reaction showed the catalysts to be active for the reaction. H2O adsorption over the catalysts was exergonic whereas CO2 adsorption over the catalyst–OH complex was observed to be an endergonic process. Intramolecular proton transfer resulting in the final product, , was found to be the rate‐limiting step for the reaction on C56N3M (M=Ru/Rh), whereas H2O dissociation was found to be the rate‐limiting step for the reaction on C59M (M=Ru/Rh). C56N3M catalysts were found to be superior to C59M catalysts for biomimetic CO2 hydration, as indicated by the free‐energy landscapes and energy requirements. 相似文献
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Suguru Motokucho Akito Yamaguchi Yu Nakayama Hiroshi Morikawa Hisayuki Nakatani 《Journal of polymer science. Part A, Polymer chemistry》2017,55(12):2004-2010
We have demonstrated a hydrolysis reaction of polyurethane (PU) under high pressure of carbon dioxide (CO2) in water. We employed the PU sample, poly(methylene bis‐(1,4‐phenylene)hexamethylene dicarbamate), denoted as M‐PU, which was synthesized from 4,4′‐diphenyl methane diisocyanate and 1,4‐butane diol (BD). The optimum hydrolysis reaction condition was 190 °C under CO2 pressures over 4.1 MPa in water medium, and 93% hydrolysis of M‐PU was achieved. After the reaction, the water‐soluble parts were obtained, and isolated by column chromatography. The isolated products were 4,4′‐methylenedianiline (MDA) and 1,4‐butane diol (BD), which were components of repeating unit of M‐PU. In addition, the hydrolysis reaction gave no byproduct. This hydrolysis under high pressure of CO2 with water is a reaction by which M‐PU is selectively hydrolyzed into MDA and BD by cleaving urethane linkage. Moreover, the resulting hydrolyzed products were easily obtained by evaporation of aqueous layer after the reaction, indicating an efficient chemical recycling of PU was achieved. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2004–2010 相似文献
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Iwona Peech Piotr Staciwa Daniel Sibera Robert Peech Konrad S. Sobczuk Gulsen Yagmur Kayalar Urszula Narkiewicz Robert Cormia 《Molecules (Basel, Switzerland)》2022,27(17)
The adsorption properties of microporous spherical carbon materials obtained from the resorcinol-formaldehyde resin, treated in a solvothermal reactor heated with microwaves and then subjected to carbonization, are presented. The potassium-based activation of carbon spheres was carried out in two ways: solution-based and solid-based methods. The effect of various factors, such as chemical agent selection, chemical activating agent content, and the temperature or time of activation, was investigated. The influence of microwave treatment on the adsorption properties was also investigated and described. The adsorption performance of carbon spheres was evaluated in detail by examining CO2 adsorption from the gas phase. 相似文献
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Prof. Dr. Carsten Jenne Marc C. Nierstenhöfer Dr. Valentin van Lessen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(10):3288-3291
The hydride-bridged silylium cation [Et3Si−H−SiEt3]+, stabilized by the weakly coordinating [Me3NB12Cl11]− anion, undergoes, in the presence of excess silane, a series of unexpected consecutive reactions with the valence-isoelectronic molecules CS2 and CO2. The final products of the reaction with CS2 are methane and the previously unknown [(Et3Si)3S]+ cation. To gain insight into the entire reaction cascade, numerous experiments with varying conditions were performed, intermediate products were intercepted, and their structures were determined by X-ray crystallography. Besides the [(Et3Si)3S]+ cation as the final product, crystal structures of [(Et3Si)2SMe]+, [Et3SiS(H)Me]+, and [Et3SiOC(H)OSiEt3]+ were obtained. Experimental results combined with supporting quantum-chemical calculations in the gas phase and solution allow a detailed understanding of the reaction cascade. 相似文献
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Dr. Katia D'Ambrosio Dr. Melissa D'Ascenzio Dr. Simone Carradori Dr. Simona M. Monti Prof. Claudiu T. Supuran Dr. Giuseppina De Simone 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):97-100
Carboxylates are the least investigated class of inhibitors of carbonic anhydrases (CAs). Here we explain the versatility of binding of these molecules to CAs by examining a new adduct of hCA II with N‐carboxymethyl‐saccharin. 相似文献
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Adriana Cabrera-Ramírez Daniel J. Arismendi-Arrieta Álvaro Valdés Dr. Rita Prosmiti 《Chemphyschem》2020,21(23):2618-2628
Through reliable first-principles computations, we have demonstrated the impact of CO2 molecules enclathration on the stability of sI clathrate hydrates. Given the delicate balance between the interaction energy components (van der Waals, hydrogen bonds) present on such systems, we follow a systematic bottom-up approach starting from the individual 512 and 51262 sI cages, up to all existing combinations of two-adjacent sI crystal cages to evaluate how such clathrate-like models perform on the evaluation of the guest-host and first-neighbors inter-cage effects, respectively. Interaction and binding energies of the CO2 occupation of the sI cages were computed using DF-MP2 and different DFT/DFT−D electronic structure methodologies. The performance of selected DFT functionals, together with various semi-classical dispersion corrections schemes, were validated by comparison with reference ab initio DF-MP2 data, as well as experimental data from x-ray and neutron diffraction studies available. Our investigation confirms that the inclusion of the CO2 in the cage/s is an energetically favorable process, with the CO2 molecule preferring to occupy the large 51262 sI cages compared to the 512 ones. Further, the present results conclude on the rigidity of the water cages arrangements, showing the importance of the inter-cage couplings in the cluster models under study. In particular, the guest-cage interaction is the key factor for the preferential orientation of the captured CO2 molecules in the sI cages, while the inter-cage interactions seems to cause minor distortions with the CO2 guest neighbors interactions do not extending beyond the large 51262 sI cages. Such findings on these clathrate-like model systems are in accord with experimental observations, drawing a direct relevance to the structural stability of CO2@sI clathrates. 相似文献
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Toward Functional Type III [Fe]‐Hydrogenase Biomimics for H2 Activation: Insights from Computation 下载免费PDF全文
Kevin A. Murray Dr. Matthew D. Wodrich Prof. Dr. Xile Hu Prof. Dr. Clémence Corminboeuf 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(10):3987-3996
The chemistry of [Fe]‐hydrogenase has attracted significant interest due to its ability to activate molecular hydrogen. The intriguing properties of this enzyme have prompted the synthesis of numerous small molecule mimics aimed at activating H2. Despite considerable effort, a majority of these compounds remain nonfunctional for hydrogenation reactions. By using a recently synthesized model as an entry point, seven biomimetic complexes have been examined through DFT computations to probe the influence of ligand environment on the ability of a mimic to bind and split H2. One mimic, featuring a bidentate diphosphine group incorporating an internal nitrogen base, was found to have particularly attractive energetics, prompting a study of the role played by the proton/hydride acceptor necessary to complete the catalytic cycle. Computations revealed an experimentally accessible energetic pathway involving a benzaldehyde proton/hydride acceptor and the most promising catalyst. 相似文献
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Jose R. Cabrero‐Antonino Rosa Adam Matthias Beller 《Angewandte Chemie (International ed. in English)》2019,58(37):12820-12838
N‐Alkylamines are key intermediates in the synthesis of fine chemicals, dyes, and natural products, and hence are highly valuable building blocks in organic chemistry. Consequently, the development of greener and more efficient procedures for their production continues to attract the interest of both academic and industrial chemists. Reductive procedures such as reductive amination or N‐alkylation through hydrogen autotransfer by employing carbonyl compounds or alcohols as alkylating agents have prevailed for the synthesis of amines. In the last few years, carboxylic/carbonic acid derivatives and CO2 have been introduced as alternative and convenient alkylating sources. The safety, easy accessibility, and high stability of these reagents makes the development of new reductive transformations with them as N‐alkylating agents a useful alternative to existing procedures. In this Review, we summarize reported examples of one‐pot reductive N‐alkylation methods that use carboxylic/carbonic acid derivatives or CO2 as alkylating agents. 相似文献
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Aurélien Adenot Dr. Niklas von Wolff Dr. Guillaume Lefèvre Dr. Jean-Claude Berthet Dr. Pierre Thuéry Dr. Thibault Cantat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(34):8118-8126
The guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and the substituted derivatives [TBD–SiR2]+ and TBD–BR2 reacted with SO2 to give different FLP–SO2 adducts. Molecular structures, elucidated by X-ray diffraction, showed some structural similarities with the analogous CO2 adducts. Thermodynamic stabilities were both experimentally evidenced and computed through DFT calculations. The underlying parameters governing the relative stabilities of the different SO2 and CO2 adducts were discussed from a theoretical standpoint, with a focus on the influence of the Lewis acidic moiety. 相似文献
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Magnesium(I) Dimers Bearing Tripodal Diimine–Enolate Ligands: Proficient Reagents for the Controlled Reductive Activation of CO2 and SO2 下载免费PDF全文
Aaron J. Boutland Dr. Indrek Pernik Dr. Andreas Stasch Prof. Cameron Jones 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15749-15758
The first examples of magnesium(I) dimers bearing tripodal ligands, [(Mg{κ3‐N,N′,O‐(ArNCMe)2(OCCPh2)CH})2] [Ar=2,6‐iPr2C6H3 (Dip) 7 , 2,6‐Et2C6H3 (Dep) 8 , or mesityl (Mes) 9 ] have been prepared by post‐synthetic modification of the β‐diketiminato ligands of previously reported magnesium(I) systems, using diphenylketene, O?C?CPh2. In contrast, related reactions between β‐diketiminato magnesium(I) dimers and the isoelectronic ketenimine, MesN?C?CPh2, resulted in reductive insertion of the substrate into the Mg?Mg bond of the magnesium(I) reactant, and formation of [{(Nacnac)Mg}2{μ‐κ2‐N,C‐(Mes)NCCPh2}] (Nacnac=[(ArNCMe)2CH]?; Ar=Dep 10 or Mes 11 ). Reactions of the four‐coordinate magnesium(I) dimer 8 with excess CO2 are readily controlled, and cleanly give carbonate [(LMg)2(μ‐κ2:κ2‐CO3)] 12 (L=[κ3‐N,N′,O‐(DepNCMe)2(OCCPh2)CH]?; thermodynamic product), or oxalate [(LMg)2(μ‐κ2:κ2‐C2O4)] 13 (kinetic product), depending on the reaction temperature. Compound 12 and CO are formed by reductive disproportionation of CO2, whereas 13 results from reductive coupling of two molecules of the gas. Treatment of 8 with an excess of N2O cleanly gives the μ‐oxo complex [(LMg)2(μ‐O)] 14 , which reacts facilely with CO2 to give 12 . This result presents the possibility that 14 is an intermediate in the formation of 12 from the reaction of 8 and CO2. In contrast to its reactions with CO2, 8 reacts with SO2 over a wide temperature range to give only one product; the first example of a magnesium dithionite complex, [(LMg)2(μ‐κ2:κ2‐S2O4)] 16 , which is formed by reductive coupling of two molecules of SO2, and is closely related to f‐block metal dithionite complexes derived from similar SO2 reductive coupling processes. On the whole, this study strengthens previously proposed analogies between the reactivities of magnesium(I) systems and low‐valent f‐block metal complexes, especially with respect to small molecule activations. 相似文献
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《化学:亚洲杂志》2017,12(17):2271-2277
Development of inexpensive, easily prepared, non‐toxic, and efficient catalysts for the cycloaddition of CO2 with epoxides to synthesize five‐membered cyclic carbonates is a very attractive topic in the field of CO2 transformation. In this work, we conducted the first work on the cycloaddition of CO2 with epoxides to produce cyclic carbonates catalyzed by a binary catalyst system consisting of KI and boron phosphate (BPO4), which are both inexpensive and non‐toxic, and various corresponding cyclic carbonates could be produced with high yields (93–99 %) at 110 °C with a CO2 pressure of 4 MPa under solvent‐free conditions. In the BPO4/KI catalyst system, BPO4, a Brønsted and Lewis acid hybrid, played the role of activating the epoxy ring through the formation of hydrogen bonds with Brønsted acidic sites and the interaction with Lewis acidic sites simultaneously, and thus enhanced the activity of KI for the cycloaddition of CO2 with epoxides significantly. Additionally, the activity of the BPO4/KI catalyst system showed no noticeable decrease after being reused five times, indicating that the BPO4 was stable under the reaction conditions. 相似文献
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Dr. Jens Langer Dr. Andrea Hamza Dr. Imre Pápai 《Angewandte Chemie (International ed. in English)》2018,57(9):2455-2458
The synthesis of a new iridium(I) complex containing an enamido phosphine anion (dbuP?) and its unique reactivity with CO2 is reported. The complex binds two equivalents of CO2 and initiates a highly selective reaction cascade. The reaction leads to the reversible cleavage of CO2 and the enamido ligand as well. Computational analysis points to the existence of a relatively stable Ir‐CO2 complex as a reaction intermediate prior to CO2 cleavage, which was confirmed experimentally. The observed transformation resembles several aspects of enzymatic CO2 fixation by RuBisCO. 相似文献