共查询到20条相似文献,搜索用时 31 毫秒
1.
Wen‐Guang Wang Feng Wang Hong‐Yan Wang Gang Si Dr. Chen‐Ho Tung Prof. Li‐Zhu Wu Prof. 《化学:亚洲杂志》2010,5(8):1796-1803
To mimic [FeFe] hydrogenases (H2ases) in nature, molecular photocatalysts 1a , 1b , and 1c anchoring rhenium(I) complex S to one of the iron cores of [FeFe]‐H2ases model complex C , have been constructed for H2 generation by visible light in homogeneous solution. The time‐dependence of H2 evolution and a spectroscopic study demonstrate that the orientation of S and the specific bridge in 1a , 1b , and 1c are important both for the electron‐transfer step from the excited S* to the catalytic C , and the formation of unprecedented long‐lived charge separation for 1a (780 μs), 1b , and 1c (>2 ms) in [FeFe]‐H2ases mimics. The fast forward electron‐transfer step from the excited S* to the catalytic C but the slow back electron‐transfer step of the charge‐recombination in the designed photocatalysts 1a , 1b , and 1c are reminiscent of the behavior of [FeFe]‐H2ases in nature. 相似文献
2.
[FeFe]‐Hydrogenase Mimetic Metallopolymers with Enhanced Catalytic Activity for Hydrogen Production in Water 下载免费PDF全文
William P. Brezinski Metin Karayilan Kayla E. Clary Nicholas G. Pavlopoulos Sipei Li Liye Fu Prof. Krzysztof Matyjaszewski Prof. Dennis H. Evans Prof. Richard S. Glass Prof. Dennis L. Lichtenberger Prof. Jeffrey Pyun 《Angewandte Chemie (International ed. in English)》2018,57(37):11898-11902
Electrocatalytic [FeFe]‐hydrogenase mimics for the hydrogen evolution reaction (HER) generally suffer from low activity, high overpotential, aggregation, oxygen sensitivity, and low solubility in water. By using atom‐transfer radical polymerization (ATRP), a new class of [FeFe]‐metallopolymers with precise molar mass, defined composition, and low polydispersity, has been prepared. The synthetic methodology introduced here allows facile variation of polymer composition to optimize the [FeFe] solubility, activity, and long‐term chemical and aerobic stability. Water soluble functional metallopolymers facilitate electrocatalytic hydrogen production in neutral water with loadings as low as 2 ppm and operate at rates an order of magnitude faster than hydrogenases (2.5×105 s?1), and with low overpotential requirement. Furthermore, unlike the hydrogenases, these systems are insensitive to oxygen during catalysis, with turnover numbers on the order of 40 000 under both anaerobic and aerobic conditions. 相似文献
3.
Patricia Rodríguez‐Maci Lisa M. Galle Ragnar Bjornsson Christian Lorent Ingo Zebger Yoshitaka Yoda Stephen P. Cramer Serena DeBeer Ingrid Span James A. Birrell 《Angewandte Chemie (International ed. in English)》2020,59(38):16786-16794
[FeFe] hydrogenases are the most active H2 converting catalysts in nature, but their extreme oxygen sensitivity limits their use in technological applications. The [FeFe] hydrogenases from sulfate reducing bacteria can be purified in an O2‐stable state called Hinact. To date, the structure and mechanism of formation of Hinact remain unknown. Our 1.65 Å crystal structure of this state reveals a sulfur ligand bound to the open coordination site. Furthermore, in‐depth spectroscopic characterization by X‐ray absorption spectroscopy (XAS), nuclear resonance vibrational spectroscopy (NRVS), resonance Raman (RR) spectroscopy and infrared (IR) spectroscopy, together with hybrid quantum mechanical and molecular mechanical (QM/MM) calculations, provide detailed chemical insight into the Hinact state and its mechanism of formation. This may facilitate the design of O2‐stable hydrogenases and molecular catalysts. 相似文献
4.
A [RuRu] Analogue of an [FeFe]‐Hydrogenase Traps the Key Hydride Intermediate of the Catalytic Cycle 下载免费PDF全文
Constanze Sommer Dr. Casseday P. Richers Prof. Dr. Wolfgang Lubitz Prof. Dr. Thomas B. Rauchfuss Dr. Edward J. Reijerse 《Angewandte Chemie (International ed. in English)》2018,57(19):5429-5432
The active site of the [FeFe]‐hydrogenases features a binuclear [2Fe]H sub‐cluster that contains a unique bridging amine moiety close to an exposed iron center. Heterolytic splitting of H2 results in the formation of a transient terminal hydride at this iron site, which, however is difficult to stabilize. We show that the hydride intermediate forms immediately when [2Fe]H is replaced with [2Ru]H analogues through artificial maturation. Outside the protein, the [2Ru]H analogues form bridging hydrides, which rearrange to terminal hydrides after insertion into the apo‐protein. H/D exchange of the hydride only occurs for [2Ru]H analogues containing the bridging amine moiety. 相似文献
5.
Photocatalytic hydrogen evolution by two comparable [FeFe]‐hydrogenase mimics assembled to the surface of ZnS 下载免费PDF全文
Xiao‐Wei Song Hui‐Min Wen Cheng‐Bing Ma Ming‐Qiang Hu Hui Chen Hong‐Hua Cui Chang‐Neng Chen 《应用有机金属化学》2014,28(4):267-273
Two photocatalytic hydrogen evolution systems were constructed by assembling [FeFe]‐hydrogenase mimics, either carboxyl group‐containing ( C1 ) or not ( C2 ), on to the surface of ZnS using triethanolamine as electron donor in DMF‐H2O (9/1, v/v) solution. Upon irradiation for 30 h, the turnover numbers of hydrogen evolution were 3400 and 4950 for the hybrid system C1 /ZnS and C2 /ZnS, respectively. The photocatalytic activity of the C2 /ZnS system was five times higher than the activity of the pristine ZnS, suggesting that the [FeFe]‐hydrogenase mimics are crucial toward improving the activity of ZnS. On the basis of the spectroscopic studies and analyses, the photogenerated electron transfer from ZnS to the mimics is probably responsible for the activity enhancement of ZnS. The time dependence of hydrogen generation shows that the mimic C2 is more active than C1 . The different hydrogen evolution activity can be attributed to the different adsorption modes of the two [FeFe]‐hydrogenase mimics on the surface of ZnS. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
6.
Metin Karayilan William P. Brezinski Kayla E. Clary Dennis L. Lichtenberger Richard S. Glass Jeffrey Pyun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7617-7630
Reviewed herein is the development of novel polymer‐supported [2Fe‐2S] catalyst systems for electrocatalytic and photocatalytic hydrogen evolution reactions. [FeFe] hydrogenases are the best known naturally occurring metalloenzymes for hydrogen generation, and small‐molecule, [2Fe‐2S]‐containing mimetics of the active site (H‐cluster) of these metalloenzymes have been synthesized for years. These small [2Fe‐2S] complexes have not yet reached the same capacity as that of enzymes for hydrogen production. Recently, modern polymer chemistry has been utilized to construct an outer coordination sphere around the [2Fe‐2S] clusters to provide site isolation, water solubility, and improved catalytic activity. In this review, the various macromolecular motifs and the catalytic properties of these polymer‐supported [2Fe‐2S] materials are surveyed. The most recent catalysts that incorporate a single [2Fe‐2S] complex, termed single‐site [2Fe‐2S] metallopolymers, exhibit superior activity for H2 production. 相似文献
7.
Julian Szczesny James A. Birrell Felipe Conzuelo Wolfgang Lubitz Adrian Ruff Wolfgang Schuhmann 《Angewandte Chemie (International ed. in English)》2020,59(38):16506-16510
The incorporation of highly active but also highly sensitive catalysts (e.g. the [FeFe] hydrogenase from Desulfovibrio desulfuricans) in biofuel cells is still one of the major challenges in sustainable energy conversion. We report the fabrication of a dual‐gas diffusion electrode H2/O2 biofuel cell equipped with a [FeFe] hydrogenase/redox polymer‐based high‐current‐density H2‐oxidation bioanode. The bioanodes show benchmark current densities of around 14 mA cm?2 and the corresponding fuel cell tests exhibit a benchmark for a hydrogenase/redox polymer‐based biofuel cell with outstanding power densities of 5.4 mW cm?2 at 0.7 V cell voltage. Furthermore, the highly sensitive [FeFe] hydrogenase is protected against oxygen damage by the redox polymer and can function under 5 % O2. 相似文献
8.
Dr. Lívia S. Mészáros Brigitta Németh Dr. Charlène Esmieu Dr. Pierre Ceccaldi Dr. Gustav Berggren 《Angewandte Chemie (International ed. in English)》2018,57(10):2596-2599
EPR spectroscopy reveals the formation of two different semi‐synthetic hydrogenases in vivo. [FeFe] hydrogenases are metalloenzymes that catalyze the interconversion of molecular hydrogen and protons. The reaction is catalyzed by the H‐cluster, consisting of a canonical iron–sulfur cluster and an organometallic [2Fe] subsite. It was recently shown that the enzyme can be reconstituted with synthetic cofactors mimicking the composition of the [2Fe] subsite, resulting in semi‐synthetic hydrogenases. Herein, we employ EPR spectroscopy to monitor the formation of two such semi‐synthetic enzymes in whole cells. The study provides the first spectroscopic characterization of semi‐synthetic hydrogenases in vivo, and the observation of two different oxidized states of the H‐cluster under intracellular conditions. Moreover, these findings underscore how synthetic chemistry can be a powerful tool for manipulation and examination of the hydrogenase enzyme under in vivo conditions. 相似文献
9.
Hui‐Min Lin Jian‐Rong Li Chao Mu Ao Li Xu‐Feng Liu Pei‐Hua Zhao Yu‐Long Li Zhong‐Qing Jiang Hong‐Ke Wu 《应用有机金属化学》2019,33(11)
Five monophosphine‐substituted diiron propane‐1,2‐dithiolate complexes as the active site models of [FeFe]‐hydrogenases have been synthesized and characterized. Reactions of complex [Fe2(CO)6{μ‐SCH2CH(CH3)S}] ( 1 ) with a monophosphine ligand tris(4‐methylphenyl)phosphine, diphenyl‐2‐pyridylphosphine, tris(4‐chlorophenyl)phosphine, triphenylphosphine, or tris(4‐fluorophenyl)phosphine in the presence of the oxidative agent Me3NO·2H2O gave the monophosphine‐substituted diiron complexes [Fe2(CO)5(L){μ‐SCH2CH(CH3)S}] [L = P(4‐C6H4CH3)3, 2 ; Ph2P(2‐C5H4N), 3 ; P(4‐C6H4Cl)3, 4 ; PPh3, 5 ; P(4‐C6H4F)3, 6 ] in 81%–94% yields. Complexes 2 – 6 have been characterized by elemental analysis, spectroscopy, and X‐ray crystallography. In addition, electrochemical studies revealed that these complexes can catalyze the reduction of protons to H2 in the presence of HOAc. 相似文献
10.
Aerobic Damage to [FeFe]‐Hydrogenases: Activation Barriers for the Chemical Attachment of O2 下载免费PDF全文
Dr. Adam Kubas Dr. David De Sancho Dr. Robert B. Best Dr. Jochen Blumberger 《Angewandte Chemie (International ed. in English)》2014,53(16):4081-4084
[FeFe]‐hydrogenases are the best natural hydrogen‐producing enzymes but their biotechnological exploitation is hampered by their extreme oxygen sensitivity. The free energy profile for the chemical attachment of O2 to the enzyme active site was investigated by using a range‐separated density functional re‐parametrized to reproduce high‐level ab initio data. An activation free‐energy barrier of 13 kcal mol?1 was obtained for chemical bond formation between the di‐iron active site and O2, a value in good agreement with experimental inactivation rates. The oxygen binding can be viewed as an inner‐sphere electron‐transfer process that is strongly influenced by Coulombic interactions with the proximal cubane cluster and the protein environment. The implications of these results for future mutation studies with the aim of increasing the oxygen tolerance of this enzyme are discussed. 相似文献
11.
Diversity in Gold‐Catalyzed Formal Cycloadditions of Ynamides with Azidoalkenes or 2H‐Azirines: [3+2] versus [4+3] Cycloadditions 下载免费PDF全文
Samir Kundlik Pawar Rajkumar Lalji Sahani Prof. Dr. Rai‐Shung Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10843-10850
Gold‐catalyzed cycloadditions of ynamides with azidoalkenes or 2H‐azirines give [3+2] or [4+3] formal cycloadducts of three classes. Cycloadditions of ynamides with 2H‐azirine species afford pyrrole products with two regioselectivities when the Cβ‐substituted 2H‐azirine is replaced from an alkyl (or hydrogen) with an ester group. For ynamides substituted with an electron‐rich phenyl group, their reactions with azidoalkenes proceed through novel [4+3] cycloadditions to deliver 1H‐benzo[d]azepine products instead. 相似文献
12.
Branched Polyethylenimine Improves Hydrogen Photoproduction from a CdSe Quantum Dot/[FeFe]‐Hydrogenase Mimic System in Neutral Aqueous Solutions 下载免费PDF全文
Wen‐Jing Liang Dr. Feng Wang Min Wen Jing‐Xin Jian Xu‐Zhe Wang Dr. Bin Chen Prof. Dr. Chen‐Ho Tung Prof. Dr. Li‐Zhu Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3187-3192
Nature uses hydrogenase enzyme to catalyze proton reduction at pH 7 with overpotentials and catalytic efficiencies that rival platinum electrodes. Over the past several years, [FeFe]‐hydrogenase ([FeFe]‐H2ase) mimics have been demonstrated to be effective catalysts for light‐driven H2 evolution. However, it remains a significant challenge to realize H2 production by such an artificial photosynthetic system in neutral aqueous solution. Herein, we report a new system for photocatalytic H2 evolution working in a broad pH range, especially under neutral conditions. This unique system is consisted of branched polyethylenimine (PEI)‐grafted [FeFe]‐H2ase mimic (PEI‐g‐Fe2S2 ), MPA‐CdSe quantum dots (MPA=mercaptopropionic acid), and ascorbic acid (H2A) in water. Due to the secondary coordination sphere of PEI, which has high buffering capacity and stabilizing ability, the system is able to produce H2 under visible‐light irradiation with turnover number of 10 600 based on the Fe2S2 active site in PEI‐g‐Fe2S2 . The stability and activity are much better than that of the same system under acidic or basic conditions and they are, to the best of our knowledge, the highest known to date for photocatalytic H2 evolution from a [FeFe]‐H2ase mimic in neutral aqueous solution. 相似文献
13.
[FeFe]‐Hydrogenase with Chalcogenide Substitutions at the H‐Cluster Maintains Full H2 Evolution Activity 下载免费PDF全文
Dr. Jens Noth Dr. Julian Esselborn Dr. Jörn Güldenhaupt Annika Brünje Dr. Anne Sawyer Dr. Ulf‐Peter Apfel Prof. Klaus Gerwert Prof. Eckhard Hofmann Dr. Martin Winkler Prof. Thomas Happe 《Angewandte Chemie (International ed. in English)》2016,55(29):8396-8400
The [FeFe]‐hydrogenase HYDA1 from Chlamydomonas reinhardtii is particularly amenable to biochemical and biophysical characterization because the H‐cluster in the active site is the only inorganic cofactor present. Herein, we present the complete chemical incorporation of the H‐cluster into the HYDA1‐apoprotein scaffold and, furthermore, the successful replacement of sulfur in the native [4FeH] cluster with selenium. The crystal structure of the reconstituted pre‐mature HYDA1[4Fe4Se]H protein was determined, and a catalytically intact artificial H‐cluster variant was generated upon in vitro maturation. Full hydrogen evolution activity as well as native‐like composition and behavior of the redesigned enzyme were verified through kinetic assays, FTIR spectroscopy, and X‐ray structure analysis. These findings reveal that even a bioinorganic active site with exceptional complexity can exhibit a surprising level of compositional plasticity. 相似文献
14.
Henry Insuasty Paola Mier Gina Suarez John N. Low Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(1):o27-o30
The molecular dimensions of 2‐ethylsulfanyl‐7‐(4‐methylphenyl)‐4‐phenylpyrazolo[1,5‐a][1,3,5]triazine, C20H18N4S, (I), 7‐(4‐chlorophenyl)‐2‐ethylsulfanyl‐4‐phenylpyrazolo[1,5‐a][1,3,5]triazine, C19H15ClN4S, (II), and 4,7‐bis(4‐chlorophenyl)‐2‐(ethylsulfanyl)pyrazolo[1,5‐a][1,3,5]triazine, C19H14Cl2N4S, (III), show evidence for some aromatic delocalization in the pyrazole rings. The conformations adopted by the ethylsulfanyl substituents are different in all three compounds. There are no hydrogen bonds in any of the crystal structures, but pairs of molecules in (II) and (III) are linked into centrosymmetric dimers by π‐stacking interactions. 相似文献
15.
Henrik Land Alina Sekretareva Ping Huang Holly J. Redman Brigitta Nmeth Nakia Polidori Lívia S. Mszros Moritz Senger Sven T. Stripp Gustav Berggren 《Chemical science》2020,11(47):12789
[FeFe]-hydrogenases are known for their high rates of hydrogen turnover, and are intensively studied in the context of biotechnological applications. Evolution has generated a plethora of different subclasses with widely different characteristics. The M2e subclass is phylogenetically distinct from previously characterized members of this enzyme family and its biological role is unknown. It features significant differences in domain- and active site architecture, and is most closely related to the putative sensory [FeFe]-hydrogenases. Here we report the first comprehensive biochemical and spectroscopical characterization of an M2e enzyme, derived from Thermoanaerobacter mathranii. As compared to other [FeFe]-hydrogenases characterized to-date, this enzyme displays an increased H2 affinity, higher activation enthalpies for H+/H2 interconversion, and unusual reactivity towards known hydrogenase inhibitors. These properties are related to differences in active site architecture between the M2e [FeFe]-hydrogenase and “prototypical” [FeFe]-hydrogenases. Thus, this study provides new insight into the role of this subclass in hydrogen metabolism and the influence of the active site pocket on the chemistry of the H-cluster.Characterization of a group D putative sensory [FeFe]-hydrogenase reveals how the active site can be tuned to decrease CO inhibition and increase stability of a reduced H-cluster while retaining the ability to catalyze H+/H2 interconversion. 相似文献
16.
Prof. Dr. Yutaka Matsuo Hiromi Oyama Dr. Iwao Soga Dr. Toshihiro Okamoto Dr. Hideyuki Tanaka Dr. Akinori Saeki Prof. Dr. Shu Seki Prof. Dr. Eiichi Nakamura 《化学:亚洲杂志》2013,8(1):121-128
The efficient nucleophilic addition of aryl Grignard reagents (aryl=4‐MeOC6H4, 4‐Me2NC6H4, Ph, 4‐CF3C6H4, and thienyl) to C60 in the presence of DMSO produced 1,2‐arylhydro[60]fullerenes after acid treatment. The reactions of the anions of these arylhydro[60]fullerenes with either dimethylphenylsilylmethyl iodide or dimethyl(2‐isopropoxyphenyl)silylmethyl iodide yielded the target compounds, 1‐aryl‐4‐silylmethyl[60]fullerenes. The properties and structures of these 1‐aryl‐4‐silylmethyl[60]fullerenes (aryl=4‐MeOC6H4, thienyl) were examined by electrochemical studies, X‐ray crystallography, flash‐photolysis time‐resolved microwave‐conductivity (FP‐TRMC) measurements, and electron‐mobility measurements by using a space‐charge‐limited current (SCLC) model. Organic photovoltaic devices with a polymer‐based bulk heterojunction structure and small‐molecule‐based p–n and p–i–n heterojunction configurations were fabricated by using 1‐aryl‐4‐silylmethyl[60]fullerenes as an electron acceptor. The most efficient device exhibited a power‐conversion efficiency of 3.4 % (short‐circuit current density: 8.1 mA/ cm2, open‐circuit voltage: 0.69 V, fill factor: 0.59). 相似文献
17.
Greco C Bruschi M Fantucci P Ryde U De Gioia L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(6):1954-1965
The presence of Fe‐bound cyanide ligands in the active site of the proton‐reducing enzymes [FeFe]‐hydrogenases has led to the hypothesis that such Brønsted–Lowry bases could be protonated during the catalytic cycle, thus implying that hydrogen isocyanide (HNC) might have a relevant role in such crucial microbial metabolic paths. We present a hybrid quantum mechanical/molecular mechanical (QM/MM) study of the energetics of CN? protonation in the enzyme, and of the effects that cyanide protonation can have on [FeFe]‐hydrogenase active sites. A detailed analysis of the electronic properties of the models and of the energy profile associated with H2 evolution clearly shows that such protonation is dysfunctional for the catalytic process. However, the inclusion of the protein matrix surrounding the active site in our QM/MM models allowed us to demonstrate that the amino acid environment was finely selected through evolution, specifically to lower the Brønsted–Lowry basicity of the cyanide ligands. In fact, the conserved hydrogen‐bonding network formed by these ligands and the neighboring amino acid residues is able to impede CN? protonation, as shown by the fact that the isocyanide forms of [FeFe]‐hydrogenases do not correspond to stationary points on the enzyme QM/MM potential‐energy surface. 相似文献
18.
《Angewandte Chemie (International ed. in English)》2017,56(8):2208-2211
To understand the molecular details of O2‐tolerant hydrogen cycling by a soluble NAD+‐reducing [NiFe] hydrogenase, we herein present the first bioinspired heterobimetallic S‐oxygenated [NiFe] complex as a structural and vibrational spectroscopic model for the oxygen‐inhibited [NiFe] active site. This compound and its non‐S‐oxygenated congener were fully characterized, and their electronic structures were elucidated in a combined experimental and theoretical study with emphasis on the bridging sulfenato moiety. Based on the vibrational spectroscopic properties of these complexes, we also propose novel strategies for exploring S‐oxygenated intermediates in hydrogenases and similar enzymes. 相似文献
19.
Oleg Kasyan Iris Thondorf Michael Bolte Vitaly Kalchenko Volker Bhmer 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(5):o289-o294
The structures of three syn‐1,3‐dialkoxythiacalix[4]arenes with unusual conformations in the solid state are reported. The pinched cone conformation of syn‐22,42‐dihydroxy‐12,32‐bis(prop‐2‐enyloxy)thiacalix[4]arene, C30H24O4S4, (3a), is stabilized by two intramolecular hydrogen bonds, remarkably formed from both OH groups to the same ether O atom. In syn‐22,42‐dihydroxy‐15,25,35,45‐tetranitro‐12,32‐bis(prop‐2‐enyloxy)thiacalix[4]arene acetone disolvate, C30H20N4O12S4·2C3H6O, (3b1), the molecule is found in the 1,3‐alternate conformation. The crystallographic C2 symmetry is due to a twofold rotation axis running through the centre of the calixarene ring. The hydroxy groups cannot form intramolecular hydrogen bonds as in (3a) and both are bonded to an acetone solvent molecule. The molecule of the pseudo‐polymorph of (3b1) in which the same compound crystallized without any solvent, viz. (3b2), is located on a crystallographic mirror plane. Only one of the two hydroxy groups forms a hydrogen bond, and this is with a nitro group of a neighbouring molecule as acceptor. Molecular mechanics calculations for syn‐1,3‐diethers suggest a preference of the 1,3‐alternate over the usual cone conformation for thiacalix[4]arene versus calix[4]arene and for para‐nitro versus para‐H derivatives. 相似文献
20.
The zinc(II) center in the molecule of [(C23H36N4O3)ZnCl]Cl·H2O is coordinated by four nitrogen atoms of HL (1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol) and one chloro anion. The coordination moieties are connected by hydrogen bonds to form a one‐dimensional structure. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献