Xinjiang Cui  Wu Li  Kathrin Junge  Zhaofu Fei  Matthias Beller  Paul J. Dyson 《Angewandte Chemie (International ed. in English)》2020,59(19):7501-7507

Core–shell nanocatalysts are attractive due to their versatility and stability. Here, we describe cobalt nanoparticles encapsulated within graphitic shells prepared via the pyrolysis of a cationic poly‐ionic liquid (PIL) with a cobalt(II) chloride anion. The resulting material has a core–shell structure that displays excellent activity and selectivity in the self‐dehydrogenation and hetero‐dehydrogenation of primary amines to their corresponding imines. Furthermore, the catalyst exhibits excellent activity in the synthesis of secondary imines from substrates with various reducible functional groups (C=C, C≡C and C≡N) and amino acid derivatives.  相似文献   

    

Dr. Reiko Ueoka  Dr. Roy A. Meoded  Alejandro Gran‐Scheuch  Dr. Agneya Bhushan  Prof. Dr. Marco W. Fraaije  Prof. Dr. Jörn Piel 《Angewandte Chemie (International ed. in English)》2020,59(20):7761-7765

Bacterial trans‐acyltransferase polyketide synthases (trans‐AT PKSs) are multimodular megaenzymes that biosynthesize many bioactive natural products. They contain a remarkable range of domains and module types that introduce different substituents into growing polyketide chains. As one such modification, we recently reported Baeyer–Villiger‐type oxygen insertion into nascent polyketide backbones, thereby generating malonyl thioester intermediates. In this work, genome mining focusing on architecturally diverse oxidation modules in trans‐AT PKSs led us to the culturable plant symbiont Gynuella sunshinyii, which harbors two distinct modules in one orphan PKS. The PKS product was revealed to be lobatamide A, a potent cytotoxin previously only known from a marine tunicate. Biochemical studies show that one module generates glycolyl thioester intermediates, while the other is proposed to be involved in oxime formation. The data suggest varied roles of oxygenation modules in the biosynthesis of polyketide scaffolds and support the importance of trans‐AT PKSs in the specialized metabolism of symbiotic bacteria.  相似文献   

    

D. Thao Nguyen  Matthias Freitag  Christian Gutheil  Kai Sotthewes  Bonnie J. Tyler  Marcus Bckmann  Mowpriya Das  Friederike Schlüter  Nikos L. Doltsinis  Heinrich F. Arlinghaus  Bart Jan Ravoo  Frank Glorius 《Angewandte Chemie (International ed. in English)》2020,59(32):13651-13656

A novel photoresponsive and fully conjugated N‐heterocyclic carbene (NHC) has been synthesized that combines the excellent photophysical properties of arylazopyrazoles (AAPs) with an NHC that acts as a robust surface anchor (AAP‐BIMe). The formation of self‐assembled monolayers (SAMs) on gold was proven by ToF‐SIMS and XPS, and the organic film displayed a very high stability at elevated temperatures. This stability was also reflected in a high desorption energy, which was determined by temperature‐programmed SIMS measurements. E‐/Z‐AAP‐BIMe@Au photoisomerization resulted in reversible alterations of the surface energy (i.e. wettability), the surface potential (i.e. work function), and the conductance (i.e. resistance). The effects could be explained by the difference in the dipole moment of the isomers. Furthermore, sequential application of a dummy ligand by microcontact printing and subsequent backfilling with AAP‐BIMe allowed its patterning on gold. To the best of our knowledge, this is the first example of a photoswitchable NHC on a gold surface. These properties of AAP‐BIMe@Au illustrate its suitability as a molecular switch for electronic devices.  相似文献   

    

Brylee David B. Tiu  Peyman Delparastan  Max R. Ney  Matthias Gerst  Phillip B. Messersmith 《Angewandte Chemie (International ed. in English)》2020,59(38):16616-16624

The outstanding adhesive performance of mussel byssal threads has inspired materials scientists over the past few decades. Exploiting the amino‐catechol synergy, polymeric pressure‐sensitive adhesives (PSAs) have now been synthesized by copolymerizing traditional PSA monomers, butyl acrylate and acrylic acid, with mussel‐inspired lysine‐ and aromatic‐rich monomers. The consequences of decoupling amino and catechol moieties from each other were compared (that is, incorporated as separate monomers) against a monomer architecture in which the catechol and amine were coupled together in a fixed orientation in the monomer side chain. Adhesion assays were used to probe performance at the molecular, microscopic, and macroscopic levels by a combination of AFM‐assisted force spectroscopy, peel and static shear adhesion. Coupling of catechols and amines in the same monomer side chain produced optimal cooperative effects in improving the macroscopic adhesion performance.  相似文献   

    

Sebastian N. Intorp  Manuel Hodecker  Matthias Müller  Olena Tverskoy  Marco Rosenkranz  Evgenia Dmitrieva  Alexey A. Popov  Frank Rominger  Jan Freudenberg  Andreas Dreuw  Uwe H. F. Bunz 《Angewandte Chemie (International ed. in English)》2020,59(30):12542-12542

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Biswarup Chakraborty  Shweta Kalra  Rodrigo Beltrn‐Suito  Chittaranjan Das  Tim Hellmann  Prashanth W. Menezes  Matthias Driess 《化学:亚洲杂志》2020,15(6):852-859

In the urge of designing noble metal‐free and sustainable electrocatalysts for oxygen evolution reaction (OER), herein, a mineral Digenite Cu₉S₅ has been prepared from a molecular copper(I) precursor, [{(PyHS)₂Cu^I(PyHS)}₂](OTf)₂ ( 1 ), and utilized as an anode material in electrocatalytic OER for the first time. A hot injection of 1 yielded a pure phase and highly crystalline Cu₉S₅, which was then electrophoretically deposited (EPD) on a highly conducting nickel foam (NF) substrate. When assessed as an electrode for OER, the Cu₉S₅/NF displayed an overpotential of merely 298±3 mV at a current density of 10 mA cm^?2 in alkaline media. The overpotential recorded here supersedes the value obtained for the best reported Cu‐based as well as the benchmark precious‐metal‐based RuO₂ and IrO₂ electrocatalysts. In addition, the choronoamperometric OER indicated the superior stability of Cu₉S₅/NF, rendering its suitability as the sustainable anode material for practical feasibility. The excellent catalytic activity of Cu₉S₅ can be attributed to the formation of a crystalline CuO overlayer on the conductive Cu₉S₅ that behaves as active species to facilitate OER. This study delivers a distinct molecular precursor approach to produce highly active copper‐based catalysts that could be used as an efficient and durable OER electro(pre)catalysts relying on non‐precious metals.  相似文献   

Stabile Methylenborane hoher Lewis-Acidität     

Ralf Hunold  Monika Pilz  Jürgen Allwohn  Matthias Stadler  Werner Massa  Paul von Ragu Schleyer  Armin Berndt 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1989,101(6):759-761

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Thermal Cleavage and Isomerization of 1,3-Diboretanes to Stable Methyleneboranes     

Monika Pilz  Matthias Stadler  Ralf Hunold  Jürgen Allwohn  Werner Massa  Armin Berndt 《Angewandte Chemie (International ed. in English)》1989,28(6):784-786

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Fragment Deconstruction of Small,Potent Factor Xa Inhibitors: Exploring the Superadditivity Energetics of Fragment Linking in Protein–Ligand Complexes     

Marc Nazar  Hans Matter  David W. Will  Michael Wagner  Matthias Urmann  Jrg Czech  Herman Schreuder  Armin Bauer  Kurt Ritter  Volkmar Wehner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2012,124(4):929-935

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Zirkulardichroismus in den Photoelektronen‐Winkelverteilungen von Campher und Fenchon aus der Multiphotonenionisation mit Femtosekunden‐Laserpulsen     

Christian Lux  Matthias Wollenhaupt  Tom Bolze  Qingqing Liang  Jens Khler  Cristian Sarpe  Thomas Baumert 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2012,124(20):5086-5090

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