652 results match your criteria ACS Catalysis[Journal]

-Boryl Organometallic Reagents in Catalytic Asymmetric Synthesis.

ACS Catal 2021 Aug 12;11(16):10660-10680. Epub 2021 Aug 12.

Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.

Recent years have witnessed an increase in the popularity of -boryl organometallic reagents as versatile nucleophiles in asymmetric synthesis. These compounds have been adopted in chemo- and stereoselective coupling reactions with a number of different electrophiles. The resulting enantioenriched boronic esters can be applied in stereospecific carbon-carbon or carbon-heteroatom bond construction reactions, enabling a two-step strategy for the construction of complex structures with high efficiency and functional group compatibility. Read More

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How Photoactivation Triggers Protochlorophyllide Reduction: Computational Evidence of a Stepwise Hydride Transfer during Chlorophyll Biosynthesis.

ACS Catal 2022 Apr 21;12(7):4141-4148. Epub 2022 Mar 21.

Manchester Institute of Biotechnology and Department of Chemistry, The University of Manchester, Manchester M1 7DN, U.K.

The photochemical reaction catalyzed by enzyme protochlorophyllide oxidoreductase (POR), a rare example of a photoactivated enzyme, is a crucial step during chlorophyll biosynthesis and involves the fastest known biological hydride transfer. Structures of the enzyme with bound substrate protochlorophyllide (PChlide) and coenzyme nicotinamide adenine dinucleotide phosphate (NADPH) have recently been published, opening up the possibility of using computational approaches to provide a comprehensive understanding of the excited state chemistry. Herein, we propose a complete mechanism for the photochemistry between PChlide and NADPH based on density functional theory (DFT) and time-dependent DFT calculations that is consistent with recent experimental data. Read More

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Elucidating Film Loss and the Role of Hydrogen Bonding of Adsorbed Redox Enzymes by Electrochemical Quartz Crystal Microbalance Analysis.

ACS Catal 2022 Feb 20;12(3):1886-1897. Epub 2022 Jan 20.

Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.

The immobilization of redox enzymes on electrodes enables the efficient and selective electrocatalysis of useful reactions such as the reversible interconversion of dihydrogen (H) to protons (H) and formate to carbon dioxide (CO) with hydrogenase (Hase) and formate dehydrogenase (FDH), respectively. However, their immobilization on electrodes to produce electroactive protein films for direct electron transfer (DET) at the protein-electrode interface is not well understood, and the reasons for their activity loss remain vague, limiting their performance often to hour timescales. Here, we report the immobilization of [NiFeSe]-Hase and [W]-FDH from Hildenborough on a range of charged and neutral self-assembled monolayer (SAM)-modified gold electrodes with varying hydrogen bond (H-bond) donor capabilities. Read More

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February 2022

Catalytic Net Oxidative C-C Activation and Silylation of Cyclopropanols with a Traceless Acetal Directing Group.

ACS Catal 2022 Feb 18;12(3):1764-1774. Epub 2022 Jan 18.

Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States.

Redox-neutral carbon-carbon (C-C) bond activation and functionalization strategies of cyclopropanols that give metallo homoenolate have offered merits to construct a range of useful -functionalized ketones in an inverse-polarity fashion. Discovery and identification of oxidative C-C activation reactions of cyclopropanols that generate metallo enolate-homoenolate would provide an opportunity to afford ,-difunctionalized ketones. We report catalytic, net oxidative C-C activation, and silylation of cyclopropanols with traceless acetal directing groups under consecutive Ir and Rh catalysis in regio-, stereo-, and chemo-selective fashion. Read More

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February 2022

Mechanistic study of enantioselective Pd-catalyzed C(sp)-H activation of thioethers involving two distinct stereomodels.

ACS Catal 2021 Aug 19;11(15):9738-9753. Epub 2021 Jul 19.

Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037.

Enantioselective C(sp)-H activation has gained considerable attention from the synthetic chemistry community. Despite the intense interest in these reactions, the mechanisms responsible for enantioselection are still vague. In the course of the development of aryl thioether-directed C(sp)-H arylation, we noticed extreme variation in sensitivity of two substrate classes to substituent effects of ligands and directing groups: whereas 3-pentyl sulfides (prochiral α-center) responded positively to substitution on ligands and directing groups, isobutyl sulfides (prochiral β-center) were entirely insensitive. Read More

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Improving the Performance of Supported Ionic Liquid Phase Catalysts for the Ultra-Low-Temperature Water Gas Shift Reaction Using Organic Salt Additives.

ACS Catal 2022 May 27;12(9):5661-5672. Epub 2022 Apr 27.

Lehrstuhl für Chemische Reaktionstechnik (CRT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany.

The water gas shift reaction (WGSR) is catalyzed by supported ionic liquid phase (SILP) systems containing homogeneous Ru complexes dissolved in ionic liquids (ILs). These systems work at very low temperatures, that is, between 120 and 160 °C, as compared to >200 °C in the conventional process. To improve the performance of this ultra-low-temperature catalysis, we investigated the influence of various additives on the catalytic activity of these SILP systems. Read More

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Multiscale Simulations Identify Origins of Differential Carbapenem Hydrolysis by the OXA-48 β-Lactamase.

ACS Catal 2022 Apr 4;12(8):4534-4544. Epub 2022 Apr 4.

School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, U.K.

OXA-48 β-lactamases are frequently encountered in bacterial infections caused by carbapenem-resistant Gram-negative bacteria. Due to the importance of carbapenems in the treatment of healthcare-associated infections and the increasingly wide dissemination of OXA-48-like enzymes on plasmids, these β-lactamases are of high clinical significance. Notably, OXA-48 hydrolyzes imipenem more efficiently than other commonly used carbapenems, such as meropenem. Read More

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Elucidating the Formation and Structural Evolution of Platinum Single-Site Catalysts for the Hydrogen Evolution Reaction.

ACS Catal 2022 Mar 23;12(5):3173-3180. Epub 2022 Feb 23.

Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom.

Platinum single-site catalysts (SSCs) are a promising technology for the production of hydrogen from clean energy sources. They have high activity and maximal platinum-atom utilization. However, the bonding environment of platinum during operation is poorly understood. Read More

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The Critical Role of βPdZn Alloy in Pd/ZnO Catalysts for the Hydrogenation of Carbon Dioxide to Methanol.

ACS Catal 2022 May 20;12(9):5371-5379. Epub 2022 Apr 20.

Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, United Kingdom.

The rise in atmospheric CO concentration and the concomitant rise in global surface temperature have prompted massive research effort in designing catalytic routes to utilize CO as a feedstock. Prime among these is the hydrogenation of CO to make methanol, which is a key commodity chemical intermediate, a hydrogen storage molecule, and a possible future fuel for transport sectors that cannot be electrified. Pd/ZnO has been identified as an effective candidate as a catalyst for this reaction, yet there has been no attempt to gain a fundamental understanding of how this catalyst works and more importantly to establish specific design criteria for CO hydrogenation catalysts. Read More

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Favoring the Methane Oxychlorination Reaction over EuOCl by Synergistic Effects with Lanthanum.

ACS Catal 2022 May 28;12(9):5698-5710. Epub 2022 Apr 28.

Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.

The direct conversion of CH into fuels and chemicals produces less waste, requires smaller capital investments, and has improved energy efficiency compared to multistep processes. While the methane oxychlorination (MOC) reaction has been given little attention, it offers the potential to achieve high CH conversion levels at high selectivities. In a continuing effort to design commercially interesting MOC catalysts, we have improved the catalyst design of EuOCl by the partial replacement of Eu by La. Read More

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Visible and NIR Light Assistance of the N Reduction to NH Catalyzed by Cs-promoted Ru Nanoparticles Supported on Strontium Titanate.

ACS Catal 2022 May 12;12(9):4938-4946. Epub 2022 Apr 12.

Instituto Universitario de Tecnología Química CSIC-UPV, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Universitat Politecnica de Valencia, Avda. de los Naranjos s/n, 46022 Valencia, Spain.

NH production accounts for more than 1% of the total CO emissions and is considered one of the most energy-intensive industrial processes currently ( > 400 °C and > 80 bars). The development of atmospheric-pressure N fixation to NH under mild conditions is attracting much attention, especially using additional renewable energy sources. Herein, efficient photothermal NH evolution in continuous flow upon visible and NIR light irradiation at near 1 Sun power using Cs-decorated strontium titanate-supported Ru nanoparticles is reported. Read More

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Amine Organocatalysis of Remote, Chemoselective C(sp)-H Hydroxylation.

ACS Catal 2022 Apr 28;12(8):4302-4309. Epub 2022 Mar 28.

Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, United States.

We introduce an organocatalytic approach for oxaziridinium-mediated C-H hydroxylation that employs secondary amines as catalysts. We also demonstrate the advantages of this operationally simple catalytic strategy for achieving high yielding and highly selective remote hydroxylation of compounds bearing oxidation-sensitive functional groups such as alcohols, ethers, carbamates, and amides. By employing hexafluoroisopropanol as the solvent in the absence of water, a proposed hydrogen bonding effect leads to, among other advantages, as high as ≥99:1 chemoselectivity for remote aliphatic hydroxylation of 2° alcohols, an otherwise unsolved synthetic challenge normally complicated by substantial amounts of alcohol oxidation. Read More

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Site-Selective Catalytic Epoxidation of Alkene with Tunable, Atomic Precision by Molecularly Imprinted Artificial Epoxidases.

ACS Catal 2022 Mar 2;12(6):3444-3451. Epub 2022 Mar 2.

Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111.

Distinction of chemical functionality by their local chemical environment is a skill mastered by enzymes, evident from the selective synthesis, cleavage, and transformation of peptides, nucleic acids, and polysaccharides that abound with the same type of functional groups. In contrast, synthetic catalysts are generally better at differentiating functional groups based on their electronic and steric properties. Here we report artificial epoxidases prepared through molecular imprinting of surface-core doubly cross-linked micelles, followed by efficient functionalization of the imprinted site in the micellar core via photoaffinity labeling. Read More

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Radical Aza-Heck Cyclization of Imidates via Energy Transfer, Electron Transfer, and Cobalt Catalysis.

ACS Catal 2022 Apr 28;12(8):4327-4332. Epub 2022 Mar 28.

Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States.

A radical aza-Heck cyclization has been developed to afford functionally rich products with four contiguous C-heteroatom bonds. This multi-catalytic strategy provides rapid syntheses of dense, medicinally relevant motifs by enabling the conversion of alcohol-derived imidates to heteroatom-rich fragments containing vinyl oxazolines/oxazoles, allyl amines, β-amino alcohols/halides, and combinations thereof. Mechanistic insights of this process show how three distinct photocatalytic cycles cooperate to enable: (1) imidate radical generation by energy transfer, (2) dehydrogenation by Co catalysis, and (3) catalyst turnover by electron transfer. Read More

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On the Homogeneity of a Cobalt-Based Water Oxidation Catalyst.

ACS Catal 2022 Apr 4;12(8):4597-4607. Epub 2022 Apr 4.

Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, RA, Leiden 2300, The Netherlands.

The homogeneity of molecular Co-based water oxidation catalysts (WOCs) has been a subject of debate over the last 10 years as assumed various homogeneous Co-based WOCs were found to actually form CoO under operating conditions. The homogeneity of the Co(H) (H = ,-bis(2,2'-bipyrid-6-yl)amine) system was investigated with cyclic voltammetry, electrochemical quartz crystal microbalance, and X-ray photoelectron spectroscopy. The obtained experimental results were compared with heterogeneous CoO . Read More

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Impact of the Experimental Parameters on Catalytic Activity When Preparing Polymer Protected Bimetallic Nanoparticle Catalysts on Activated Carbon.

ACS Catal 2022 Apr 30;12(8):4440-4454. Epub 2022 Mar 30.

Cardiff Catalysis Institute (CCI), School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.

Sol immobilization is used to produce bimetallic catalysts with higher activity to monometallic counterparts for a wide range of environmental and commercial catalytic transformations. Analysis of complementary surface characterization (XPS, Boehm's titration, and zeta potential measurements) was used to elucidate alterations in the surface functionality of two activated carbon supports during acid exposure. When considered in parallel to the experimentally determined electrostatic and conformational changes of the polymer surrounding the nanoparticles, an electrostatic model is proposed describing polymer protected nanoparticle deposition with several polymer-carbon support examples described. Read More

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Impact of Intrinsic Density Functional Theory Errors on the Predictive Power of Nitrogen Cycle Electrocatalysis Models.

ACS Catal 2022 Apr 6;12(8):4784-4791. Epub 2022 Apr 6.

Department of Materials Science and Chemical Physics & Institute of Theoretical and Computational Chemistry (IQTCUB), University of Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain.

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Enzymatic Hydrolysis of Human Milk Oligosaccharides. The Molecular Mechanism of Lacto--biosidase.

ACS Catal 2022 Apr 6;12(8):4737-4743. Epub 2022 Apr 6.

Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.

lacto--biosidase (LnbB) is a critical enzyme for the degradation of human milk oligosaccharides in the gut microbiota of breast-fed infants. Guided by recent crystal structures, we unveil its molecular mechanism of catalysis using QM/MM metadynamics. We show that the oligosaccharide substrate follows / → [ ] → / and / → [ / ] → conformational itineraries for the two successive reaction steps, with reaction free energy barriers in agreement with experiments. Read More

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Chemoenzymatic Hunsdiecker-Type Decarboxylative Bromination of Cinnamic Acids.

ACS Catal 2022 Apr 4;12(8):4554-4559. Epub 2022 Apr 4.

Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft 2629HZ, The Netherlands.

In this contribution, we report chemoenzymatic bromodecarboxylation (Hunsdiecker-type) of α,ß-unsaturated carboxylic acids. The extraordinarily robust chloroperoxidase from (VCPO) generated hypobromite from HO and bromide, which then spontaneously reacted with a broad range of unsaturated carboxylic acids and yielded the corresponding vinyl bromide products. Selectivity issues arising from the (here undesired) addition of water to the intermediate bromonium ion could be solved by reaction medium engineering. Read More

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Catalytic Arylboration of Spirocyclic Cyclobutenes: Rapid Access to Highly Substituted Spiro[3.n]alkanes.

ACS Catal 2021 Oct 6;11(20):12815-12820. Epub 2021 Oct 6.

Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.

A method to achieve the synthesis of highly substituted spirocyclic cyclobutanes is disclosed. The reaction involves the catalytic arylboration of cyclobutenes. Depending on the substitution pattern of the cyclobutene, either a Cu/Pd- or a Ni-catalyzed reaction was utilized. Read More

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October 2021

Three-Component Visible-Light-Induced Palladium-Catalyzed 1,2-Alkyl Carbamoylation/Cyanation of Alkenes.

ACS Catal 2021 Nov 15;11(21):13217-13222. Epub 2021 Oct 15.

Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080-3021, United States.

A mild visible-light-induced Pd-catalyzed one-pot three-component alkyl-carbamoylation and cyanation of alkenes was developed. This general transformation, which proceeds via the in situ formation of a reactive ketenimine intermediate, allows for a rapid construction of a broad range of valuable amides and nitriles from readily available alkenes, alkyl iodides, and isocyanides. An efficient synthesis of tetrazole and amidine via this approach was also demonstrated. Read More

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November 2021

Au(I) Catalyzed HF Transfer: Tandem Alkyne Hydrofluorination and Perfluoroarene Functionalization.

ACS Catal 2022 Mar 1;12(6):3411-3419. Epub 2022 Mar 1.

Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London W12 0BZ, U.K.

HF transfer reactions between organic substrates are potentially useful transformations. Such reactions require the development of catalytic systems that can promote both defluorination and fluorination steps in a single reaction sequence. Herein, we report a catalytic protocol in which an equivalent of HF is generated from a perfluoroarene | nucleophile pair and transferred directly to an alkyne. Read More

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ACS Catal 2022 Mar 18;12(5):2979-2985. Epub 2022 Feb 18.

Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K.

A synthetic study into the catalytic hydrogen/deuterium (H/D) exchange of 1° silanes, 2° silanes, and 3° siloxanes is presented, facilitated by iron-β-diketiminato complexes ( and ). Near-complete H/D exchange is observed for a variety of aryl- and alkyl-containing hydrosilanes and hydrosiloxanes. The reaction tolerates alternative hydride source pinacolborane (HBpin), with quantitative H/D exchange. Read More

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Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines.

ACS Catal 2021 Oct 23;11(20):12417-12422. Epub 2021 Sep 23.

Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.

The development and study of a simple copper-catalyzed reaction of nitroarenes with aryl boronic acids to form diarylamines that uses phenyl silane as the stoichiometric terminal reductant is described. This cross-coupling reaction requires as little as 2 mol % of CuX and 4 mol% of diphosphine for success and tolerates a broad range of functional groups on either the nitroarene or the aryl boronic acid with to afford the amine in good yield. Mechanistic investigations established that the cross-coupling reaction proceeds via a nitrosoarene intermediate and that copper is required to catalyze both the deoxygenation of the nitroarene to afford the nitrosoarene and C-NAr bond formation of the nitrosoarene with the aryl boronic acid. Read More

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October 2021

Dicoordinate Au(I)-Ethylene Complexes as Hydroamination Catalysts.

ACS Catal 2022 Apr 23;12(7):4227-4241. Epub 2022 Mar 23.

Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Instituto de Investigaciones Químicas (IIQ), Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla, Sevilla 41092, Spain.

A series of gold(I)-ethylene π-complexes containing a family of bulky phosphine ligands has been prepared. The use of these sterically congested ligands is crucial to stabilize the gold(I)-ethylene bond and prevent decomposition, boosting up their catalytic performance in the highly underexplored hydroamination of ethylene. The precatalysts bearing the most sterically demanding phosphines showed the best results reaching full conversion to the hydroaminated products under notably mild conditions (1 bar of ethylene pressure at 60 °C). Read More

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Reversible On/Off Switching of Lactide Cyclopolymerization with a Redox-Active Formazanate Ligand.

ACS Catal 2022 Apr 21;12(7):4125-4130. Epub 2022 Mar 21.

Stratingh Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands.

Redox-switching of a formazanate zinc catalyst in ring-opening polymerization (ROP) of lactide is described. Using a redox-active ligand bound to an inert metal ion (Zn) allows modulation of the catalytic activity by reversible reduction/oxidation chemistry at a purely organic fragment. A combination of kinetic and spectroscopic studies, together with mass spectrometry of the catalysis mixture, provides insight in the nature of the active species and the initiation of lactide ring-opening polymerization. Read More

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In-Situ Bromination Enables Formal Cross-Electrophile Coupling of Alcohols with Aryl and Alkenyl Halides.

ACS Catal 2022 Jan 21;12(1):580-586. Epub 2021 Dec 21.

University of Wisconsin-Madison, Department of Chemistry, Madison, WI 53706.

Although alcohols are one of the largest pools of alkyl substrates, approaches to utilize them in cross-coupling and cross-electrophile coupling are limited. We report the use of 1° and 2° alcohols in cross-electrophile coupling with aryl and vinyl halides to form C(sp)-C(sp) bonds in a one-pot strategy utilizing a very fast (<1 min) bromination. The reaction's simple benchtop setup and broad scope (42 examples, 56% ± 15% ave yield) facilitates use at all scales. Read More

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January 2022

Mechanism-Based Design of Efficient PET Hydrolases.

ACS Catal 2022 Mar 28;12(6):3382-3396. Epub 2022 Feb 28.

Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, University of Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany.

Polyethylene terephthalate (PET) is the most widespread synthetic polyester, having been utilized in textile fibers and packaging materials for beverages and food, contributing considerably to the global solid waste stream and environmental plastic pollution. While enzymatic PET recycling and upcycling have recently emerged as viable disposal methods for a circular plastic economy, only a handful of benchmark enzymes have been thoroughly described and subjected to protein engineering for improved properties over the last 16 years. By analyzing the specific material properties of PET and the reaction mechanisms in the context of interfacial biocatalysis, this Perspective identifies several limitations in current enzymatic PET degradation approaches. Read More

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Identification of the Reversible Skin Layer on CoO as a Three-Dimensional Reaction Zone for Oxygen Evolution.

ACS Catal 2022 Mar 24;12(6):3256-3268. Epub 2022 Feb 24.

Institute of Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany.

Co oxides and oxyhydroxides have been studied extensively in the past as promising electrocatalysts for the oxygen evolution reaction (OER) in neutral to alkaline media. Earlier studies showed the formation of an ultrathin CoO (OH) skin layer on CoO at potentials above 1.15 V vs reversible hydrogen electrode (RHE), but the precise influence of this skin layer on the OER reactivity is still under debate. Read More

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Planar Chiral 1,3-Disubstituted Ferrocenyl Phosphine Gold(I) Catalysts.

ACS Catal 2022 Mar 25;12(6):3317-3322. Epub 2022 Feb 25.

Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.

Planar chiral monodentate 1,3-disubstituted ferrocene phosphines inspired on JohnPhos-type ligands have been synthesized and applied to the enantioselective gold(I) catalyzed [4 + 2] cycloaddition of 1,6-arylenynes. Computational studies rationalized the working mode of the catalyst on the folding of the substrate in the chiral environment of the ligand involving attractive noncovalent interactions. Read More

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