116 results match your criteria Chemcatchem[Journal]


Artificial Metalloenzymes based on TetR Proteins and Cu(II) for Enantioselective Friedel-Crafts Alkylation Reactions.

ChemCatChem 2020 Jun 29;12(12):3190-3194. Epub 2020 Apr 29.

Stratingh Institute for Chemistry University of Groningen Nijenborgh 49747 AG Groningen The Netherlands.

The supramolecular approach is among the most convenient methodologies for creating artificial metalloenzymes (ArMs). Usually this approach involves the binding of a transition metal ion complex to a biomolecular scaffold its ligand, which also modulates the catalytic properties of the metal ion. Herein, we report ArMs based on the proteins CgmR, RamR and QacR from the TetR family of multidrug resistance regulators (MDRs) and Cu ions, assembled without the need of a ligand. Read More

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http://dx.doi.org/10.1002/cctc.202000245DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7319431PMC

Few-layer Black Phosphorous Catalyzes Radical Additions to Alkenes Faster than Low-valence Metals.

ChemCatChem 2020 Apr 25;12(8):2226-2232. Epub 2020 Feb 25.

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

The substitution of catalytic metals by -block main elements has a tremendous impact not only in the fundamentals but also in the economic and ecological fingerprint of organic reactions. Here we show that few-layer black phosphorous (FL-BP), a recently discovered and now readily available 2D material, catalyzes different radical additions to alkenes with an initial turnover frequency (TOF) up to two orders of magnitude higher than representative state-of-the-art metal complex catalysts at room temperature. The corresponding electron-rich BP intercalation compound (BPIC) KP shows a nearly twice TOF increase with respect to FL-BP. Read More

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http://dx.doi.org/10.1002/cctc.201902276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216949PMC

An Ultrasensitive Fluorescence Assay for the Detection of Halides and Enzymatic Dehalogenation.

ChemCatChem 2020 Apr 31;12(7):2032-2039. Epub 2020 Jan 31.

Department of Biotechnology & Enzyme Catalysis Institute of Biochemistry Greifswald University Greifswald 17487 Germany.

Halide assays are important for the study of enzymatic dehalogenation, a topic of great industrial and scientific importance. Here we describe the development of a very sensitive halide assay that can detect less than a picomole of bromide ions, making it very useful for quantifying enzymatic dehalogenation products. Halides are oxidised under mild conditions using the vanadium-dependent chloroperoxidase from , forming hypohalous acids that are detected using aminophenyl fluorescein. Read More

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http://dx.doi.org/10.1002/cctc.201901891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7188320PMC

Benchtop NMR for Online Reaction Monitoring of the Biocatalytic Synthesis of Aromatic Amino Alcohols.

ChemCatChem 2020 Feb 20;12(4):1190-1199. Epub 2020 Jan 20.

Institute of Bio- and Geosciences - Biotechnology (IBG-1) Forschungszentrum Jülich GmbH 52425 Jülich Germany.

Online analytics provides insights into the progress of an ongoing reaction without the need for extensive sampling and offline analysis. In this study, we investigated benchtop NMR as an online reaction monitoring tool for complex enzyme cascade reactions. Online NMR was used to monitor a two-step cascade beginning with an aromatic aldehyde and leading to an aromatic amino alcohol as the final product, applying two different enzymes and a variety of co-substrates and intermediates. Read More

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http://dx.doi.org/10.1002/cctc.201901910DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7074048PMC
February 2020

Coke Formation during Propane Dehydrogenation over Ga-Rh Supported Catalytically Active Liquid Metal Solutions.

ChemCatChem 2020 Feb 7;12(4):1085-1094. Epub 2020 Jan 7.

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

Supported Catalytically Active Liquid Metal Solutions (SCALMS) were recently described as a new class of heterogeneous catalysts, where the catalytic transformation takes place at the highly dynamic interface of a liquid alloy. Their application in alkane dehydrogenation has been claimed to be superior to classical heterogeneous catalysts, because the single atom nature of Rh dissolved in liquid Ga hinders the formation of significant amounts of coke, e. g. Read More

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http://dx.doi.org/10.1002/cctc.201901922DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7074060PMC
February 2020

Operando Modeling of Multicomponent Reactive Solutions in Homogeneous Catalysis: from Non-standard Free Energies to Reaction Network Control.

ChemCatChem 2020 Feb 11;12(3):795-802. Epub 2019 Dec 11.

TheoMAT Group ITMO University Lomonosova 9 St. Petersburg 191002 Russia.

Optimization and execution of chemical reactions are to a large extend based on experience and chemical intuition of a chemist. The chemical intuition is rooted in the phenomenological Le Chatelier's principle that teaches us how to shift equilibrium by manipulating the reaction conditions. To access the underlying thermodynamic parameters and their condition-dependencies from the first principles is a challenge. Read More

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http://dx.doi.org/10.1002/cctc.201901911DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7043346PMC
February 2020

Assessment of the Location of Pt Nanoparticles in Pt/zeolite Y/γ-AlO Composite Catalysts.

ChemCatChem 2020 Jan 30;12(2):615-622. Epub 2019 Oct 30.

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

The location of Pt nanoparticles was studied in Pt/zeolite Y/γ-AlO composite catalysts prepared by HPtCl ⋅ 6HO (CPA) or Pt(NH)(NO) (PTA) as Pt precursors. The aim of this study is to validate findings from Transmission Electron Microscopy (TEM) by using characterization techniques that sample larger amounts of catalyst per measurement. Quantitative X-ray Photoelectron Spectroscopy (XPS) showed that the catalyst prepared with CPA led to a significantly higher Pt/Al atomic ratio than the catalyst prepared with PTA confirming that the 1-2 nm sized Pt nanoparticles in the former catalyst were located on the open and mesoporous γ-AlO component, whereas they were located in the micropores of zeolite Y in the latter. Read More

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http://dx.doi.org/10.1002/cctc.201901617DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006758PMC
January 2020

Methanol-to-Olefins in a Membrane Reactor with in situ Steam Removal - The Decisive Role of Coking.

ChemCatChem 2020 Jan 25;12(1):273-280. Epub 2019 Nov 25.

Institute for Physical Chemistry and Electrochemistry Leibniz University Hannover Callinstraße 3 A Hannover 30167 Germany.

The reaction of methanol to light olefins and water (MTO) was studied in a fixed bed tubular membrane reactor using commercial SAPO-34 catalyst. In the fixed bed reactor without membrane support, the MTO reaction collapsed after 3 h time on stream. However, if the reaction by-product steam is in situ extracted from the reactor through a hydrophilic tubular LTA membrane, the reactor produces long-term stable about 60 % ethene and 10 % propene. Read More

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http://dx.doi.org/10.1002/cctc.201901222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006748PMC
January 2020

Catalytic CO Reduction with Boron- and Aluminum Hydrides.

ChemCatChem 2019 Nov 30;11(21):5275-5281. Epub 2019 Sep 30.

Department of Chemistry Catalysis Research Center and Institute of Silicon Chemistry Technische Universität München Lichtenbergstr. 4 Garching bei München 85748 Germany.

The previously reported dimeric NHI aluminum dihydrides ,, as well as the bis(NHI) aluminum dihydride salt [OTs], the bis(NHI) boron dihydride salt [OTs], and the "free" bis(NHI) ligand were investigated with regard to their activity as a homogenous (pre)catalyst in the hydroboration (i. e. catalytic reduction) of carbon dioxide (CO) in chloroform under mild conditions (i. Read More

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http://dx.doi.org/10.1002/cctc.201901255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919925PMC
November 2019

Efficient and Practical Transfer Hydrogenation of Ketones Catalyzed by a Simple Bidentate Mn-NHC Complex.

ChemCatChem 2019 Nov 8;11(21):5232-5235. Epub 2019 Jul 8.

Inorganic Systems Engineering group, Department of Chemical Engineering Faculty of Applied Sciences Delft University of Technology Van der Maasweg 9 Delft 2629 HZ (The Netherlands.

Catalytic reductions of carbonyl-containing compounds are highly important for the safe, sustainable, and economical production of alcohols. Herein, we report on the efficient transfer hydrogenation of ketones catalyzed by a highly potent Mn(I)-NHC complex. Mn-NHC is practical at metal concentrations as low as 75 ppm, thus approaching loadings more conventionally reserved for noble metal based systems. Read More

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http://dx.doi.org/10.1002/cctc.201900882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919935PMC
November 2019

Frontiers in Halogen and Chalcogen-Bond Donor Organocatalysis.

ChemCatChem 2019 Nov 30;11(21):5198-5211. Epub 2019 Aug 30.

Organic Chemistry Institute Münster University Corrensstraße 40 Münster D-48149 Germany.

Non-covalent molecular interactions on the basis of halogen and chalcogen bonding represent a promising, powerful catalytic activation mode. However, these "unusual" non-covalent interactions are typically employed in the solid state and scarcely exploited in catalysis. In recent years, an increased interest in halogen and chalcogen bonding has been awaken, as they provide profound characteristics that make them an appealing alternative to the well-explored hydrogen bonding. Read More

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http://dx.doi.org/10.1002/cctc.201901215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919929PMC
November 2019

Methanol Synthesis from CO Hydrogenation.

Authors:
Michael Bowker

ChemCatChem 2019 Sep 10;11(17):4238-4246. Epub 2019 Jul 10.

Cardiff Catalysis Institute School of Chemistry Cardiff University Cardiff CF10 3AT UK.

In the future we will be phasing out the use of fossil fuels in favour of more sustainable forms of energy, especially solar derived forms such as hydroelectric, wind and photovoltaic. However, due to the variable nature of the latter sources which depend on time of day, and season of the year, we also need to have a way of storing such energy at peak production times for use in times of low production. One way to do this is to convert such energy into chemical energy, and the principal way considered at present is the production of hydrogen. Read More

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http://dx.doi.org/10.1002/cctc.201900401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919338PMC
September 2019

Kemp Eliminases of the AlleyCat Family Possess High Substrate Promiscuity.

ChemCatChem 2019 Mar 15;11(5):1425-1430. Epub 2019 Jan 15.

Department of Chemistry, Syracuse University, 111 College Place, Syracuse, NY 13244, USA.

Minimalist enzymes designed to catalyze model reactions provide useful starting points for creating catalysts for practically important chemical transformations. We have shown that Kemp eliminases of the AlleyCat family facilitate conversion of leflunomide (an immunosupressor pro-drug) to its active form teriflunomide with outstanding rate enhancement (nearly four orders of magnitude) and catalytic proficiency (more than seven orders of magnitude) without any additional optimization. This remarkable activity is achieved by properly positioning the substrate in close proximity to the catalytic glutamate with very high pK. Read More

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http://dx.doi.org/10.1002/cctc.201801994DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6884320PMC
March 2019
4.556 Impact Factor

Peroxygenase-Catalysed Epoxidation of Styrene Derivatives in Neat Reaction Media.

ChemCatChem 2019 Sep 27;11(18):4519-4523. Epub 2019 Aug 27.

Department of Biotechnology Delft University of Technology Delft 2629HZ The Netherlands.

Biocatalytic oxyfunctionalisation reactions are traditionally conducted in aqueous media limiting their production yield. Here we report the application of a peroxygenase in neat reaction conditions reaching product concentrations of up to 360 mM. Read More

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http://dx.doi.org/10.1002/cctc.201901142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6853256PMC
September 2019

Continuous-Flow Pd-Catalyzed Carbonylation of Aryl Chlorides with Carbon Monoxide at Elevated Temperature and Pressure.

ChemCatChem 2019 Feb 15;11(3):997-1001. Epub 2019 Jan 15.

Center for Continuous Flow Synthesis and Processing (CCFLOW) Research Center Pharmaceutical Engineering GmbH (RCPE) Inffeldgasse 13 Graz 8010 Austria.

The development of a continuous-flow protocol for a palladium-catalyzed methoxycarbonylation of (hetero)aryl chlorides using carbon monoxide gas and methanol is described. (Hetero)aryl chlorides are the least expensive of the aryl halides, but are underutilized in carbonylation reactions due to their very poor reactivity. The described protocol exploits intensified conditions at elevated temperature and pressure, which are readily accessed within a continuous-flow environment, to provide moderate to excellent product yields (11 examples) in a short 16 min residence time. Read More

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http://dx.doi.org/10.1002/cctc.201801974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6813631PMC
February 2019

Characterization of Type IV Carboxylate Reductases (CARs) for Whole Cell-Mediated Preparation of 3-Hydroxytyrosol.

ChemCatChem 2019 Aug 9;11(16):4171-4181. Epub 2019 Apr 9.

acib - Austrian Center of Industrial Biotechnology Petersgasse 14 8010 Graz Austria.

Fragrance and flavor industries could not imagine business without aldehydes. Processes for their commercial production raise environmental and ecological concerns. The chemical reduction of organic acids to aldehydes is challenging. Read More

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http://dx.doi.org/10.1002/cctc.201900333DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6813634PMC

The Origin of Metal Loading Heterogeneities in Pt/Zeolite Y Bifunctional Catalysts.

ChemCatChem 2019 Aug 24;11(16):4081-4088. Epub 2019 May 24.

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

Preparing catalysts with highly dispersed metal nanoparticles and narrow particle size distribution has been in the focus of numerous studies. Besides size and size distribution, the location of metal nanoparticles within and local metal loading of the support can have significant impact on catalytic performance. This study revealed that great variations in Pt loading between individual Pt/zeolite Y crystals occurred irrespective of the metal deposition method, namely ion-exchange (IE) or incipient wetness impregnation (IWI). Read More

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http://dx.doi.org/10.1002/cctc.201900441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774382PMC

Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts.

ChemCatChem 2019 Aug 4;11(15):3474-3489. Epub 2019 Jul 4.

Department of Biosciences University of Exeter Henry Wellcome Building for Biocatalysis Stocker Road Exeter EX4 4QD UK.

Multi-step enzyme reactions offer considerable cost and productivity benefits. Process models offer a route to understanding the complexity of these reactions, and allow for their optimization. Despite the increasing prevalence of multi-step biotransformations, there are few examples of process models for enzyme reactions. Read More

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http://dx.doi.org/10.1002/cctc.201900646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774274PMC

Catalytic Enantioselective Carbonyl Propargylation Beyond Preformed Carbanions: Reductive Coupling and Hydrogen Auto-Transfer.

ChemCatChem 2019 Jan 7;11(1):324-332. Epub 2018 Aug 7.

University of Texas at Austin, Department of Chemistry, Welch Hall (A5300), 105 E 24 St., Austin, TX 78712, USA.

Chiral metal complexes catalyze enantioselective carbonyl propargylation via reductive coupling or as hydrogen auto-transfer processes, in which reactant alcohols serve dually as reductant and carbonyl proelectrophile. Unlike classical propargylation protocols, which rely on allenylmetal reagents or metallic reductants (e.g. Read More

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http://dx.doi.org/10.1002/cctc.201801121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777576PMC
January 2019

Mechanistic Investigation of Biocatalytic Heme Carbenoid Si-H Insertions.

ChemCatChem 2019 Jul 8;11(13):3101-3108. Epub 2019 May 8.

Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030 (USA).

Recent studies reported the development of biocatalytic heme carbenoid Si-H insertions for the selective formation of carbon-silicon bonds, but many mechanistic questions remain unaddressed. To this end, a DFT mechanistic investigation was performed which reveals an Fe-based concerted hydride transfer mechanism with early transition state feature. The results from these computational analyses are consistent with experimental data of radical trapping, kinetic isotope effects, and structure-reactivity data using engineered variants of hemoproteins. Read More

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http://dx.doi.org/10.1002/cctc.201801755DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699785PMC
July 2019
2 Reads

P450 Monooxygenases Enable Rapid Late-Stage Diversification of Natural Products C-H Bond Activation.

Authors:
Nico D Fessner

ChemCatChem 2019 May 15;11(9):2226-2242. Epub 2019 Feb 15.

Institute of Molecular Biotechnology Graz University of Technology, NAWI Graz Petersgasse 14 8010 Graz Austria.

The biological potency of natural products has been exploited for decades. Their inherent structural complexity and natural diversity might hold the key to efficiently address the urgent need for the development of novel pharmaceuticals. At the same time, it is that very complexity, which impedes necessary chemical modifications such as structural diversification, to improve the effectiveness of the drug. Read More

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http://dx.doi.org/10.1002/cctc.201801829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6686969PMC

Thioesters as Acyl Donors in Biocatalytic Friedel-Crafts-type Acylation Catalyzed by Acyltransferase from .

ChemCatChem 2019 Feb 9;11(3):1064-1068. Epub 2019 Jan 9.

Institute of Chemistry University of Graz NAWI Graz, BioTechMed Graz Graz 8010 Austria.

Functionalization of aromatic compounds by acylation has considerable significance in synthetic organic chemistry. As an alternative to chemical Friedel-Crafts acylation, the C-acyltransferase from has been found to catalyze C-C bond formation with non-natural resorcinol substrates. Extending the scope of acyl donors, it is now shown that the enzyme is also able to catalyze C-S bond cleavage prior to C-C bond formation, thus aliphatic and aromatic thioesters can be used as acyl donors. Read More

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http://dx.doi.org/10.1002/cctc.201801856DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6686624PMC
February 2019
1 Read

Gold-catalyzed Cycloisomerization Reactions within Guanidinium ML Nanospheres: the Effect of Local Concentrations.

ChemCatChem 2019 Mar 11;11(5):1458-1464. Epub 2019 Feb 11.

Homogeneous, Supramolecular and Bio-Inspired Catalysis, Van't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands.

Gold-catalyzed cycloisomerization reactions have been explored using guanidinium functionalized ML nanospheres that strongly encapsulate gold complexes functionalized with a sulfonate group through hydrogen bonds. As the ML nanospheres can bind up to 24 gold complexes, the effect of local catalyst concentration on the reaction outcome can be easily evaluated. Also, the guanidinium groups of the sphere can weakly interact with the carboxylic group of the substrates, facilitating the pre-organization of the substrate near to the catalytic active site. Read More

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http://dx.doi.org/10.1002/cctc.201900089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6646873PMC
March 2019
1 Read

Probing the Location and Speciation of Elements in Zeolites with Correlated Atom Probe Tomography and Scanning Transmission X-Ray Microscopy.

ChemCatChem 2019 Jan 31;11(1):488-494. Epub 2018 Oct 31.

Debye Institute for Nanomaterials Science, Faculty of Science Utrecht University Utrecht 3584 CG Netherlands.

Characterizing materials at nanoscale resolution to provide new insights into structure property performance relationships continues to be a challenging research target due to the inherently low signal from small sample volumes, and is even more difficult for nonconductive materials, such as zeolites. Herein, we present the characterization of a single Cu-exchanged zeolite crystal, namely Cu-SSZ-13, used for NO reduction in automotive emissions, that was subject to a simulated 135,000-mile aging. By correlating Atom Probe Tomography (APT), a single atom microscopy method, and Scanning Transmission X-ray Microscopy (STXM), which produces high spatial resolution X-ray Absorption Near Edge Spectroscopy (XANES) maps, we show that a spatially non-uniform proportion of the Al was removed from the zeolite framework. Read More

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http://dx.doi.org/10.1002/cctc.201801378DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6519228PMC
January 2019
1 Read

Application of Threonine Aldolases for the Asymmetric Synthesis of α-Quaternary α-Amino Acids.

ChemCatChem 2018 Aug 4;10(16):3453-3458. Epub 2018 Jul 4.

Institute of Organic Chemistry Graz University of Technology Stremayrgasse 9, A- 8010 Graz Austria.

We report the synthesis of diverse β-hydroxy-α,α-dialkyl-α-amino acids with perfect stereoselectivity for the α-quaternary center through the action of l- and d-specific threonine aldolases. A wide variety of aliphatic and aromatic aldehydes were accepted by the enzymes and conversions up to >80 % were obtained. In the case of d-selective threonine aldolase from sp. Read More

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http://dx.doi.org/10.1002/cctc.201800611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485451PMC
August 2018
1 Read

Nanoscale Chemical Imaging of a Single Catalyst Particle with Tip-Enhanced Fluorescence Microscopy.

ChemCatChem 2019 Jan 31;11(1):417-423. Epub 2018 Jul 31.

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

Determining the active site in real-life solid catalysts remains an intellectual challenge and is crucial for exploring the road towards their rational design. In recent years various micro-spectroscopic methods have revealed valuable structure-activity data at the level of a single catalyst particle, even under reaction conditions. Herein, we introduce Tip-Enhanced FLuorescence (TEFL) microscopy as a novel and versatile characterization tool for catalysis research. Read More

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http://dx.doi.org/10.1002/cctc.201801023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6472685PMC
January 2019
4.556 Impact Factor

X-Ray Absorption Near Edge Structure Spectroscopy of a Solid Catalyst using a Laboratory-Based Set-up.

ChemCatChem 2019 Feb 11;11(3):1039-1044. Epub 2019 Jan 11.

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

An laboratory-based X-ray Absorption Near Edge Structure (XANES) Spectroscopy set-up is presented, which allows performing long-term experiments on a solid catalyst at relevant reaction conditions of temperature and pressure. Complementary to research performed at synchrotron radiation facilities the approach is showcased for a Co/TiO Fischer-Tropsch Synthesis (FTS) catalyst. Supported cobalt metal nanoparticles next to a (very small) fraction of cobalt(II) titanate, which is an inactive phase for FTS, were detected, with no signs of re-oxidation of the supported cobalt metal nanoparticles during FTS at 523 K, 5 bar and 200 h, indicating that cobalt metal is maintained as the main active phase during FTS. Read More

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http://dx.doi.org/10.1002/cctc.201801822DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471006PMC
February 2019
1 Read

A Cp-Based Trioxo-Rhenium Catalyst for the Deoxydehydration of Diols and Polyols.

ChemCatChem 2018 Oct 25;10(20):4755-4760. Epub 2018 Sep 25.

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

Trioxo-rhenium complexes are well known catalysts for the deoxydehydration (DODH) of vicinal diols (glycols). In this work, we report on the DODH of diols and biomass-derived polyols using CpReO as a new catalyst (Cp=1,3-di--butylcyclopentadienyl). The DODH reaction was optimized using 2 mol % of CpReO and 3-octanol as both reductant and solvent. Read More

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http://dx.doi.org/10.1002/cctc.201801151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6472585PMC
October 2018
2 Reads

Electrochemical and Kinetic Insights into Molecular Water Oxidation Catalysts Derived from Cp*Ir(pyridine-alkoxide) Complexes.

ChemCatChem 2018 Oct 30;10(19):4280-4291. Epub 2018 Sep 30.

Centre for Sustainable Chemical Technologies University of Bath Claverton DownBath BA2 7AY United Kingdom.

We report the solution-phase electrochemistry of seven half-sandwich iridium(III) complexes with varying pyridine-alkoxide ligands to quantify electronic ligand effects that translate to their activity in catalytic water oxidation. Our results unify some previously reported electrochemical data of Cp*Ir complexes by showing how the solution speciation determines the electrochemical response: cationic complexes show over 1 V higher redox potentials that their neutral forms in a distinct demonstration of charge accumulation effects relevant to water oxidation. Building on previous work that analysed the activation behaviour of our pyalk-ligated Cp*Ir complexes -, we assess their catalytic oxygen evolution activity with sodium periodate (NaIO) and ceric ammonium nitrate (CAN) in water and aqueous BuOH solution. Read More

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http://dx.doi.org/10.1002/cctc.201800916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470865PMC
October 2018
3 Reads

Understanding the CO Oxidation on Pt Nanoparticles Supported on MOFs by XPS.

ChemCatChem 2018 Oct 13;10(19):4238-4242. Epub 2018 Aug 13.

School of Chemical Engineering and Analytical Science The University of Manchester Oxford Road Manchester M13 9PL UK.

Metal-organic frameworks (MOFs) are playing a key role in developing the next generation of heterogeneous catalysts. In this work, near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) is applied to study in the CO oxidation on Pt@MOFs (UiO-67) and Pt@ZrO catalysts, revealing the same Pt surface dynamics under the stoichiometric CO/O ambient at 3 mbar. Upon the ignition at . Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/cctc.2018010
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http://dx.doi.org/10.1002/cctc.201801067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470863PMC
October 2018
15 Reads

Gold Catalysis in (Supra)Molecular Cages to Control Reactivity and Selectivity.

ChemCatChem 2019 Jan 30;11(1):287-297. Epub 2018 Oct 30.

Homogeneous, Supramolecular and Bio-Inspired Catalysis Van't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 Amsterdam 1098 XH The Netherlands.

Gold catalysis has experienced a tremendous development over the past decades, and is nowadays widely used in organic synthesis to perform chemical transformations of π-bond-containing molecules. Catalyst development has been based mostly on ligand development and counter-ion strategies. More recently, the encapsulation of gold catalysts in (supra)molecular cages was explored as a new way to control selectivity and reactivity of gold catalysts. Read More

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http://dx.doi.org/10.1002/cctc.201801399DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391950PMC
January 2019
1 Read

Ligand Migration from Cluster to Support: A Crucial Factor for Catalysis by Thiolate-protected Gold Clusters.

ChemCatChem 2018 Dec 26;10(23):5372-5376. Epub 2018 Nov 26.

Institute of Materials Chemistry Technische Universität Wien Getreidemarkt 9/BC/01 1060 Vienna Austria.

Thiolate protected metal clusters are valuable precursors for the design of tailored nanosized catalysts. Their performance can be tuned precisely at atomic level, e. g. Read More

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http://dx.doi.org/10.1002/cctc.201801474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6348379PMC
December 2018
4 Reads
4.556 Impact Factor

Conversion of Sugars and Biomass to Furans Using Heterogeneous Catalysts in Biphasic Solvent Systems.

ChemCatChem 2018 Nov 13;10(21):4805-4816. Epub 2018 Sep 13.

Department of Chemical and Biological Engineering Montana State University Bozeman 59717-2220 MT USA.

Within the last decade, interest in using biphasic systems for producing furans from biomass has grown significantly. Biphasic systems continuously extract furans into the organic phase, which prevents degradation reactions and potentially allows for easier separations of the products. Several heterogeneous catalyst types, including zeolites, ion exchange resins, niobium-based, and others, have been used with various organic solvents to increase furan yields from sugar dehydration reactions. Read More

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http://dx.doi.org/10.1002/cctc.201800926DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6283062PMC
November 2018
2 Reads

Transaminase-Catalyzed Racemization with Potential for Dynamic Kinetic Resolutions.

ChemCatChem 2018 Nov 11;10(21):5012-5018. Epub 2018 Oct 11.

Department of Industrial Biotechnology KTH Royal Institute of Technology AlbaNova University Center Stockholm SE-106 91 Sweden.

Dynamic kinetic resolution (DKR) reactions in which a stereoselective enzyme and a racemization step are coupled in one pot would represent powerful tools for the production of enantiopure amines through enantioconvergence of racemates. The exploitation of DKR strategies is currently hampered by the lack of effective, enzyme-compatible and scalable racemization strategies for amines. In the present work, the proof of concept of a fully biocatalytic method for amine racemization is presented. Read More

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http://doi.wiley.com/10.1002/cctc.201801049
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http://dx.doi.org/10.1002/cctc.201801049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6282829PMC
November 2018
19 Reads

Direct Methylation of Benzene with Methane Catalyzed by Co/MFI Zeolite.

ChemCatChem 2018 Sep 11;10(17):3806-3812. Epub 2018 Jul 11.

Center for Research on Green Sustainable Chemistry Tottori University 4-101 Koyama-cho Minami Tottori 680-8552 Japan.

Cobalt-loaded MFI zeolite showed distinct activity for direct methylation of benzene with methane into toluene. High activity was found at around 0.6 of Co/Al molar ratio. Read More

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http://dx.doi.org/10.1002/cctc.201800724DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6282706PMC
September 2018
2 Reads

Bootstrapped Biocatalysis: Biofilm-Derived Materials as Reversibly Functionalizable Multienzyme Surfaces.

ChemCatChem 2017 Dec 2;9(23):4328-4333. Epub 2017 Aug 2.

Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115 (USA).

Cell-free biocatalysis systems offer many benefits for chemical manufacturing, but their widespread applicability is hindered by high costs associated with enzyme purification, modification, and immobilization on solid substrates, in addition to the cost of the material substrates themselves. Herein, we report a "bootstrapped" biocatalysis substrate material that is produced directly in bacterial culture and is derived from biofilm matrix proteins, which self-assemble into a nanofibrous mesh. We demonstrate that this material can simultaneously purify and immobilize multiple enzymes site specifically and directly from crude cell lysates by using a panel of genetically programmed, mutually orthogonal conjugation domains. Read More

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http://dx.doi.org/10.1002/cctc.201701221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6277024PMC
December 2017
3 Reads

Energetic Effects of a Closed System Approach Including Explicit Proton and Electron Acceptors as Demonstrated by a Mononuclear Ruthenium Water Oxidation Catalyst.

ChemCatChem 2018 Oct 28;10(20):4594-4601. Epub 2018 Aug 28.

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

When considering water oxidation catalysis theoretically, accounting for the transfer of protons and electrons from one catalytic intermediate to the next remains challenging: correction factors are usually employed to approximate the energetics of electron and proton transfer. Here these energetics were investigated using a closed system approach, which places the catalytic intermediate in a simulation box including proton and electron acceptors, as well as explicit solvent. As a proof of principle, the first two catalytic steps of the mononuclear ruthenium-based water oxidation catalyst [Ru(cy)(bpy)(HO)] were examined using Car-Parrinello Molecular Dynamics. Read More

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http://dx.doi.org/10.1002/cctc.201801093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221022PMC
October 2018
2 Reads

Selective Hydrogenation of Aldehydes Using a Well-Defined Fe(II) PNP Pincer Complex in Biphasic Medium.

ChemCatChem 2018 Oct 22;10(19):4386-4394. Epub 2018 Aug 22.

Institute of Applied Synthetic Chemistry Vienna University of Technology Getreidemarkt 9/163-AC Wien A-1060 Austria.

A biphasic process for the hydrogenation of aldehydes was developed using a well-defined iron (II) PNP pincer complex as model system to investigate the performance of various ionic liquids. A number of suitable hydrophobic ionic liquids based on the N(Tf) anion were identified, allowing to immobilize the iron (II) catalyst in the ionic liquid layer and to facilitate the separation of the desired alcohols. Further studies showed that targeted Brønsted basic ionic liquids can eliminate the need of an external base to activate the catalyst. Read More

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http://dx.doi.org/10.1002/cctc.201800841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221069PMC
October 2018
27 Reads

Aminotriazole Mn(I) Complexes as Effective Catalysts for Transfer Hydrogenation of Ketones.

ChemCatChem 2018 Oct 11;10(20):4514-4518. Epub 2018 Oct 11.

Max Planck Institute for Chemical Energy Conversion Stiftstr. 34-36 Mülheim an der Ruhr 45470 Germany.

A catalytic system based on complexes comprising abundant and cheap manganese together with readily available aminotriazole ligands is reported. The new Mn(I) complexes are catalytically competent in transfer hydrogenation of ketones with 2-propanol as hydrogen source. The reaction proceeds under mild conditions at 80 °C for 20 h with 3 % of catalyst loading using either KO Bu or NaOH as base. Read More

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http://doi.wiley.com/10.1002/cctc.201800953
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http://dx.doi.org/10.1002/cctc.201800953DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220868PMC
October 2018
53 Reads

Terminal Alkenes from Acrylic Acid Derivatives via Non-Oxidative Enzymatic Decarboxylation by Ferulic Acid Decarboxylases.

ChemCatChem 2018 Sep 17;10(17):3736-3745. Epub 2018 Jul 17.

Manchester Institute of Biotechnology School of Chemistry University of Manchester 131 Princess Street Manchester M1 7DN United Kingdom.

Fungal ferulic acid decarboxylases (FDCs) belong to the UbiD-family of enzymes and catalyse the reversible (de)carboxylation of cinnamic acid derivatives through the use of a prenylated flavin cofactor. The latter is synthesised by the flavin prenyltransferase UbiX. Herein, we demonstrate the applicability of FDC/UbiX expressing cells for both isolated enzyme and whole-cell biocatalysis. Read More

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http://doi.wiley.com/10.1002/cctc.201800643
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http://dx.doi.org/10.1002/cctc.201800643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175315PMC
September 2018
10 Reads

Expansion of the Substrate Specificity of Porcine Kidney D-Amino Acid Oxidase for -Stereoselective Oxidation of 4-Cl-Benzhydrylamine.

ChemCatChem 2018 Aug 13;10(16):3500-3505. Epub 2018 Jul 13.

Biotechnology Research Center and Department of Biotechnology Toyama Prefectural University 5180 Kurokawa Imizu, Toyama 939-0398 Japan.

Discovery and development of enzymes for the synthesis of chiral amines have been a hot topic for basic and applied aspects of biocatalysts. Based on our X-ray crystallographic analyses of porcine kidney D-amino acid oxidase (pkDAO) and its variants, we rationally designed a new variant that catalyzed the oxidation of ()-4-Cl-benzhydrylamine (CBHA) from pkDAO and obtained it by functional high-throughput screening with colorimetric assay. The variant I230A/R283G was constructed from the variant R283G which had completely lost the activity for D-amino acids, further gaining new activity toward ()-chiral amines with the bulky substituents. Read More

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http://doi.wiley.com/10.1002/cctc.201800614
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http://dx.doi.org/10.1002/cctc.201800614DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174955PMC
August 2018
25 Reads

Competitive Adsorption of Nitrite and Hydrogen on Palladium during Nitrite Hydrogenation.

ChemCatChem 2018 Sep 5;10(17):3770-3776. Epub 2018 Jul 5.

Catalytic Processes and Materials group Faculty of Science and Technology MESA+ Institute for Nanotechnology University of Twente PO Box 217 7500 AE Enschede The Netherlands.

Nitrite hydrogenation is studied in steady-state as well as transient operation using a Pd catalyst in a tubular membrane contactor reactor. A negative reaction order in hydrogen in steady state operation proofs that hydrogen and nitrite adsorb competitively. In transient operation, feeding nitrite to the Pd surface fully covered with hydrogen results initially in very low conversion of nitrite, speeding up once hydrogen is removed from part of the Pd surface. Read More

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http://dx.doi.org/10.1002/cctc.201800523DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6146939PMC
September 2018
2 Reads

Smart Nanoparticles for Selective Immobilization of Acid Phosphatases.

ChemCatChem 2018 Aug 17;10(16):3490-3499. Epub 2018 Jul 17.

Department of Organic Chemistry and Technology Budapest University of Technology and Economics Műegyetem rkp. 3 1111 Budapest Hungary.

An easy to use method combining the selectivity of metal chelate affinity binding with strong covalent linking was developed for immobilization of non-specific acid phosphatases bearing a His-tag from crude cell lysate. Silica nanoparticles were grafted with aminopropyl functions which were partially transformed further with EDTA dianhydride to chelators. The heterofunctionalized nanoparticles charged with Ni as the most appropriate metal ion were applied as support. Read More

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http://dx.doi.org/10.1002/cctc.201800405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6146910PMC
August 2018
40 Reads

Oxa-Michael Addition to α,β-Unsaturated Nitriles: An Expedient Route to γ-Amino Alcohols and Derivatives.

ChemCatChem 2018 Jul 8;10(13):2868-2872. Epub 2018 May 8.

Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747AG Groningen The Netherlands.

Water addition to α,β-unsaturated nitriles would give facile access to the β-hydroxy-nitriles, which in turn can be hydrogenated to the γ-amino alcohols. We have previously shown that alcohols readily add in 1,4-fashion to these substrates using Milstein's Ru(PNN) pincer complex as catalyst. However, attempted water addition to α,β-unsaturated nitriles gave the 3-hydroxynitriles in mediocre yields. Read More

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http://dx.doi.org/10.1002/cctc.201800509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6147005PMC
July 2018
13 Reads

Sequence-Based Discovery, Characterisation, and Biocatalytic Application of a Set of Imine Reductases.

ChemCatChem 2018 Aug 17;10(15):3236-3246. Epub 2018 Jul 17.

University of Graz Institute of Chemistry NAWI Graz, BioTechMed Graz Heinrichstrasse 28 8010 Graz Austria.

Imine reductases (IREDs) have recently become a primary focus of research in biocatalysis, complementing other classes of amine-forming enzymes such as transaminases and amine dehydrogenases. Following in the footsteps of other research groups, we have established a set of IRED biocatalysts by sequence-based enzyme discovery. In this study, we present basic characterisation data for these novel IREDs and explore their activity and stereoselectivity using a panel of structurally diverse cyclic imines as substrates. Read More

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http://doi.wiley.com/10.1002/cctc.201800607
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http://dx.doi.org/10.1002/cctc.201800607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6120462PMC
August 2018
2 Reads

Bench-Stable -Heterocyclic Carbene Nickel Precatalysts for C-C and C-N Bond-Forming Reactions.

ChemCatChem 2018 Jul 2;10(13):2873-2877. Epub 2018 May 2.

Department of Chemistry Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139 USA.

Herein, we introduce a new class of bench-stable -heterocyclic carbene (NHC) nickel-precatalysts for homogeneous nickel-catalysis. The nickel(II) complexes are readily activated to Ni in situ under mild conditions, via a proposed Heck-type mechanism. The precatalysts are shown to facilitate carbonyl-ene, hydroalkenylation, and amination reactions. Read More

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http://doi.wiley.com/10.1002/cctc.201800454
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http://dx.doi.org/10.1002/cctc.201800454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6099443PMC
July 2018
35 Reads

Correlative Multiscale 3D Imaging of a Hierarchical Nanoporous Gold Catalyst by Electron, Ion and X-ray Nanotomography.

ChemCatChem 2018 Jul 7;10(13):2858-2867. Epub 2018 May 7.

Institute for Chemical Technology and Polymer Chemistry Karlsruhe Institute of Technology Engesserstraße 20 76131 Karlsruhe Germany.

Tomographic imaging of catalysts allows non-invasive investigation of structural features and chemical properties by combining large fields of view, high spatial resolution, and the ability to probe multiple length scales. Three complementary nanotomography techniques, (i) electron tomography, (ii) focused ion beam-scanning electron microscopy, and (iii) synchrotron ptychographic X-ray computed tomography, were applied to render the 3D structure of monolithic nanoporous gold doped with ceria, a catalytically active material with hierarchical porosity on the nm and μm scale. The resulting tomograms were used to directly measure volume fraction, surface area and pore size distribution, together with 3D pore network mapping. Read More

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http://dx.doi.org/10.1002/cctc.201800230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6055843PMC
July 2018
103 Reads
4.560 Impact Factor

Tailored Mutants of Phenylalanine Ammonia-Lyase from for the Synthesis of Bulky l- and d-Arylalanines.

ChemCatChem 2018 Jun 26;10(12):2627-2633. Epub 2018 Apr 26.

Biocatalysis and Biotransformation Research Centre Faculty of Chemistry and Chemical Engineering Babeş-Bolyai University of Cluj-Napoca Arany János Str. 11 400028 Cluj-Napoca Romania.

Tailored mutants of phenylalanine ammonia-lyase from (PAL) were created and tested in ammonia elimination from various sterically demanding, non-natural analogues of phenylalanine and in ammonia addition reactions into the corresponding ()-arylacrylates. The wild-type PAL was inert or exhibited quite poor conversions in both reactions with all members of the substrate panel. Appropriate single mutations of residue F137 and the highly conserved residue I460 resulted in PAL variants that were active in ammonia elimination but still had a poor activity in ammonia addition onto bulky substrates. Read More

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http://dx.doi.org/10.1002/cctc.201800258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6055856PMC
June 2018
2 Reads

Cooperative Surface-Particle Catalysis: The Role of the "Active Doughnut" in Catalytic Oxidation.

ChemCatChem 2018 May 16;10(10):2119-2124. Epub 2018 Feb 16.

Van't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 Amsterdam 1098 XH The Netherlands.

We consider the factors that govern the activity of bifunctional catalysts comprised of active particles supported on active surfaces. Such catalysts are interesting because the adsorption and diffusion steps, which are often discounted in "conventional" catalytic scenarios, play a key role here. We present an intuitive model, the so-called "active doughnut" concept, defining an active catalytic region around the supported particles. Read More

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http://dx.doi.org/10.1002/cctc.201701819DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6001523PMC
May 2018
2 Reads

Ring-Expanded N-Heterocyclic Carbenes for Copper-Mediated Azide-Alkyne Click Cycloaddition Reactions.

ChemCatChem 2018 May 7;10(9):2041-2045. Epub 2018 Mar 7.

Department of Chemistry Imperial College London Exhibition Road, South Kensington London SW7 2AZ UK.

A series of well-defined copper(I) complexes bearing ring-expanded N-heterocyclic carbene (NHC) ligands has been applied to the azide-alkyne cycloaddition reaction. The obtained results notably showed that the six-membered NHC ligands outperform well-established five-membered ones. [CuI(Mes-6)] displayed a remarkable catalytic activity while respecting the strict criteria for click reactions. Read More

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http://dx.doi.org/10.1002/cctc.201701992DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969269PMC
May 2018
4 Reads