@article{12922, abstract = {The influence of structural modifications on the catalytic activity of carbon materials is poorly understood. A collection of carbonaceous materials with different pore networks and high nitrogen content was characterized and used to catalyze four reactions to deduce structure–activity relationships. The CO2 cycloaddition and Knoevenagel reaction depend on Lewis basic sites (electron-rich nitrogen species). The absence of large conjugated carbon domains resulting from the introduction of large amounts of nitrogen in the carbon network is responsible for poor redox activity, as observed through the catalytic reduction of nitrobenzene with hydrazine and the catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine using hydroperoxide. The material with the highest activity towards Lewis acid catalysis (in the hydrolysis of (dimethoxymethyl)benzene to benzaldehyde) is the most effective for small molecule activation and presents the highest concentration of electron-poor nitrogen species.}, author = {Lepre, Enrico and Rat, Sylvain and Cavedon, Cristian and Seeberger, Peter H. and Pieber, Bartholomäus and Antonietti, Markus and López‐Salas, Nieves}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, number = {2}, publisher = {Wiley}, title = {{Catalytic properties of high nitrogen content carbonaceous materials}}, doi = {10.1002/anie.202211663}, volume = {62}, year = {2023}, } @misc{14861, abstract = {Cover Page}, author = {Becker, Lea Marie and Berbon, Mélanie and Vallet, Alicia and Grelard, Axelle and Morvan, Estelle and Bardiaux, Benjamin and Lichtenecker, Roman and Ernst, Matthias and Loquet, Antoine and Schanda, Paul}, booktitle = {Angewandte Chemie International Edition}, issn = {1521-3773}, keywords = {General Chemistry, Catalysis}, number = {19}, publisher = {Wiley}, title = {{Cover Picture: The rigid core and flexible surface of amyloid fibrils probed by Magic‐Angle‐Spinning NMR spectroscopy of aromatic residues}}, doi = {10.1002/anie.202304138}, volume = {62}, year = {2023}, } @article{14687, abstract = {The short history of research on Li-O2 batteries has seen a remarkable number of mechanistic U-turns over the years. From the initial use of carbonate electrolytes, that were then found to be entirely unsuitable, to the belief that (su)peroxide was solely responsible for degradation, before the more reactive singlet oxygen was found to form, to the hypothesis that capacity depends on a competing surface/solution mechanism before a practically exclusive solution mechanism was identified. Herein, we argue for an ever-fresh look at the reported data without bias towards supposedly established explanations. We explain how the latest findings on rate and capacity limits, as well as the origin of side reactions, are connected via the disproportionation (DISP) step in the (dis)charge mechanism. Therefrom, directions emerge for the design of electrolytes and mediators on how to suppress side reactions and to enable high rate and high reversible capacity.}, author = {Jethwa, Rajesh B and Mondal, Soumyadip and Pant, Bhargavi and Freunberger, Stefan Alexander}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, publisher = {Wiley}, title = {{To DISP or not? The far‐reaching reaction mechanisms underpinning Lithium‐air batteries}}, doi = {10.1002/anie.202316476}, year = {2023}, } @article{12675, abstract = {Aromatic side chains are important reporters of the plasticity of proteins, and often form important contacts in protein--protein interactions. By studying a pair of structurally homologous cross-β amyloid fibrils, HET-s and HELLF, with a specific isotope-labeling approach and magic-angle-spinning (MAS) NMR, we have characterized the dynamic behavior of Phe and Tyr aromatic rings to show that the hydrophobic amyloid core is rigid, without any sign of "breathing motions" over hundreds of milliseconds at least. Aromatic residues exposed at the fibril surface have a rigid ring axis but undergo ring flips, on a variety of time scales from ns to µs. Our approach provides direct insight into hydrophobic-core motions, enabling a better evaluation of the conformational heterogeneity generated from a NMR structural ensemble of such amyloid cross-β architecture.}, author = {Becker, Lea Marie and Berbon, Mélanie and Vallet, Alicia and Grelard, Axelle and Morvan, Estelle and Bardiaux, Benjamin and Lichtenecker, Roman and Ernst, Matthias and Loquet, Antoine and Schanda, Paul}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, number = {19}, publisher = {Wiley}, title = {{The rigid core and flexible surface of amyloid fibrils probed by Magic‐Angle Spinning NMR of aromatic residues}}, doi = {10.1002/anie.202219314}, volume = {62}, year = {2023}, } @article{11955, abstract = {Covalent organic frameworks (COFs) are structurally tuneable, porous and crystalline polymers constructed through the covalent attachment of small organic building blocks as elementary units. Using the myriad of such building blocks, a broad spectrum of functionalities has been applied for COF syntheses for broad applications, including heterogeneous catalysis. Herein, we report the synthesis of a new family of porous and crystalline COFs using a novel acridine linker and benzene-1,3,5-tricarbaldehyde derivatives bearing a variable number of hydroxy groups. With the broad absorption in the visible light region, the COFs were applied as photocatalysts in metallaphotocatalytic C−N cross-coupling. The fully β-ketoenamine linked COF showed the highest activity, due to the increased charge separation upon irradiation. The COF showed good to excellent yields for several aryl bromides, good recyclability and even catalyzed the organic transformation in presence of green light as energy source.}, author = {Traxler, Michael and Gisbertz, Sebastian and Pachfule, Pradip and Schmidt, Johannes and Roeser, Jérôme and Reischauer, Susanne and Rabeah, Jabor and Pieber, Bartholomäus and Thomas, Arne}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, number = {21}, publisher = {Wiley}, title = {{Acridine‐functionalized covalent organic frameworks (COFs) as photocatalysts for metallaphotocatalytic C−N cross‐coupling}}, doi = {10.1002/anie.202117738}, volume = {61}, year = {2022}, } @article{12924, abstract = {We demonstrate that several visible-light-mediated carbon−heteroatom cross-coupling reactions can be carried out using a photoactive NiII precatalyst that forms in situ from a nickel salt and a bipyridine ligand decorated with two carbazole groups (Ni(Czbpy)Cl2). The activation of this precatalyst towards cross-coupling reactions follows a hitherto undisclosed mechanism that is different from previously reported light-responsive nickel complexes that undergo metal-to-ligand charge transfer. Theoretical and spectroscopic investigations revealed that irradiation of Ni(Czbpy)Cl2 with visible light causes an initial intraligand charge transfer event that triggers productive catalysis. Ligand polymerization affords a porous, recyclable organic polymer for heterogeneous nickel catalysis of cross-coupling reactions. The heterogeneous catalyst shows stable performance in a packed-bed flow reactor during a week of continuous operation.}, author = {Cavedon, Cristian and Gisbertz, Sebastian and Reischauer, Susanne and Vogl, Sarah and Sperlich, Eric and Burke, John H. and Wallick, Rachel F. and Schrottke, Stefanie and Hsu, Wei‐Hsin and Anghileri, Lucia and Pfeifer, Yannik and Richter, Noah and Teutloff, Christian and Müller‐Werkmeister, Henrike and Cambié, Dario and Seeberger, Peter H. and Vura‐Weis, Josh and van der Veen, Renske M. and Thomas, Arne and Pieber, Bartholomäus}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, number = {46}, publisher = {Wiley}, title = {{Intraligand charge transfer enables visible‐light‐mediated Nickel‐catalyzed cross-coupling reactions}}, doi = {10.1002/anie.202211433}, volume = {61}, year = {2022}, } @article{11451, abstract = {The precursor conversion chemistry and surface chemistry of Cu3N and Cu3PdN nanocrystals are unknown or contested. Here, we first obtain phase-pure, colloidally stable nanocubes. Second, we elucidate the pathway by which copper(II) nitrate and oleylamine form Cu3N. We find that oleylamine is both a reductant and a nitrogen source. Oleylamine is oxidized by nitrate to a primary aldimine, which reacts further with excess oleylamine to a secondary aldimine, eliminating ammonia. Ammonia reacts with CuI to form Cu3N. Third, we investigated the surface chemistry and find a mixed ligand shell of aliphatic amines and carboxylates (formed in situ). While the carboxylates appear tightly bound, the amines are easily desorbed from the surface. Finally, we show that doping with palladium decreases the band gap and the material becomes semi-metallic. These results bring insight into the chemistry of metal nitrides and might help the development of other metal nitride nanocrystals.}, author = {Parvizian, Mahsa and Duràn Balsa, Alejandra and Pokratath, Rohan and Kalha, Curran and Lee, Seungho and Van Den Eynden, Dietger and Ibáñez, Maria and Regoutz, Anna and De Roo, Jonathan}, issn = {1521-3773}, journal = {Angewandte Chemie - International Edition}, number = {31}, publisher = {Wiley}, title = {{The chemistry of Cu₃N and Cu₃PdN nanocrystals}}, doi = {10.1002/anie.202207013}, volume = {61}, year = {2022}, } @article{11705, abstract = {The broad implementation of thermoelectricity requires high-performance and low-cost materials. One possibility is employing surfactant-free solution synthesis to produce nanopowders. We propose the strategy of functionalizing “naked” particles’ surface by inorganic molecules to control the nanostructure and, consequently, thermoelectric performance. In particular, we use bismuth thiolates to functionalize surfactant-free SnTe particles’ surfaces. Upon thermal processing, bismuth thiolates decomposition renders SnTe-Bi2S3 nanocomposites with synergistic functions: 1) carrier concentration optimization by Bi doping; 2) Seebeck coefficient enhancement and bipolar effect suppression by energy filtering; and 3) lattice thermal conductivity reduction by small grain domains, grain boundaries and nanostructuration. Overall, the SnTe-Bi2S3 nanocomposites exhibit peak z T up to 1.3 at 873 K and an average z T of ≈0.6 at 300–873 K, which is among the highest reported for solution-processed SnTe.}, author = {Chang, Cheng and Liu, Yu and Lee, Seungho and Spadaro, Maria and Koskela, Kristopher M. and Kleinhanns, Tobias and Costanzo, Tommaso and Arbiol, Jordi and Brutchey, Richard L. and Ibáñez, Maria}, issn = {1521-3773}, journal = {Angewandte Chemie - International Edition}, number = {35}, publisher = {Wiley}, title = {{Surface functionalization of surfactant-free particles: A strategy to tailor the properties of nanocomposites for enhanced thermoelectric performance}}, doi = {10.1002/anie.202207002}, volume = {61}, year = {2022}, } @article{12228, abstract = {The question of how RNA, as the principal carrier of genetic information evolved is fundamentally important for our understanding of the origin of life. The RNA molecule is far too complex to have formed in one evolutionary step, suggesting that ancestral proto-RNAs (first ancestor of RNA) may have existed, which evolved over time into the RNA of today. Here we show that isoxazole nucleosides, which are quickly formed from hydroxylamine, cyanoacetylene, urea and ribose, are plausible precursors for RNA. The isoxazole nucleoside can rearrange within an RNA-strand to give cytidine, which leads to an increase of pairing stability. If the proto-RNA contains a canonical seed-nucleoside with defined stereochemistry, the seed-nucleoside can control the configuration of the anomeric center that forms during the in-RNA transformation. The results demonstrate that RNA could have emerged from evolutionarily primitive precursor isoxazole ribosides after strand formation.}, author = {Xu, Felix and Crisp, Antony and Schinkel, Thea and Dubini, Romeo C. A. and Hübner, Sarah and Becker, Sidney and Schelter, Florian and Rovo, Petra and Carell, Thomas}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, number = {45}, publisher = {Wiley}, title = {{Isoxazole nucleosides as building blocks for a plausible proto‐RNA}}, doi = {10.1002/anie.202211945}, volume = {61}, year = {2022}, } @article{11956, abstract = {Controlling the selectivity of a chemical reaction with external stimuli is common in thermal processes, but rare in visible-light photocatalysis. Here we show that the redox potential of a carbon nitride photocatalyst (CN-OA-m) can be tuned by changing the irradiation wavelength to generate electron holes with different oxidation potentials. This tuning was the key to realizing photo-chemo-enzymatic cascades that give either the (S)- or the (R)-enantiomer of phenylethanol. In combination with an unspecific peroxygenase from Agrocybe aegerita, green light irradiation of CN-OA-m led to the enantioselective hydroxylation of ethylbenzene to (R)-1-phenylethanol (99 % ee). In contrast, blue light irradiation triggered the photocatalytic oxidation of ethylbenzene to acetophenone, which in turn was enantioselectively reduced with an alcohol dehydrogenase from Rhodococcus ruber to form (S)-1-phenylethanol (93 % ee).}, author = {Schmermund, Luca and Reischauer, Susanne and Bierbaumer, Sarah and Winkler, Christoph K. and Diaz‐Rodriguez, Alba and Edwards, Lee J. and Kara, Selin and Mielke, Tamara and Cartwright, Jared and Grogan, Gideon and Pieber, Bartholomäus and Kroutil, Wolfgang}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, number = {13}, pages = {6965--6969}, publisher = {Wiley}, title = {{Chromoselective photocatalysis enables stereocomplementary biocatalytic pathways}}, doi = {10.1002/anie.202100164}, volume = {60}, year = {2021}, }