Approximation of random microstructures by periodic statistically similar representative volume elements based on lineal-path functions     

Jörg Schröder  Daniel Balzani  Dominik Brands 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(7):975-997

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Raphaël Robidas  Dominik L. Reinhard  Prof. Stefan M. Huber  Prof. Claude Y. Legault 《Chemphyschem》2023,24(1):e202200634

Cyclic diaryliodonium compounds like iodolium derivatives have increasingly found use as noncovalent Lewis acids in the last years. They are more stable toward nucleophilic substitution than acyclic systems and are markedly more Lewis acidic. Herein, this higher Lewis acidity is analyzed and explained via quantum-chemical calculations and energy decomposition analyses. Its key origin is the change in energy levels and hybridization of iodine's orbitals, leading to both more favorable electrostatic interaction and better charge transfer. Both of the latter seem to contribute in similar fashion, while hydrogen bonding as well as steric repulsion with the phenyl rings play at best a minor role. In comparison to iodolium, bromolium and chlorolium are less Lewis acidic the lighter the halogen, which is predominantly based on less favorable charge-transfer interactions.  相似文献   

    

Dominik Müller 《Chemie in Unserer Zeit》2020,54(3):151-151

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Gbor N. Boross  Dominik Schauenburg  Jeffrey W. Bode 《Helvetica chimica acta》2019,102(2)

Synthetic folded insulin variants containing an ornithine‐hydroxylamine residue are readily modified in aqueous buffers by amide‐forming ligations with potassium acyltrifluoroborates (KATs). The synthetic insulin analogs were prepared by Fmoc‐SPPS, α‐ketoacid‐hydroxylamine (KAHA) ligation, and a prosthetic C‐peptide that delivers the correct disulfide pattern and allows facile incorporation at the B0 position of Glargine M2 of a new ornithine hydroxylamine protected with a photolabile group. The folded insulin is readily modified by photo‐deprotection followed by amide‐forming KAT ligation to give insulin variants labeled with dyes, lipids, and PEGs, as well as the formation of a covalent dimer.  相似文献   

    

Saeed Amirjalayer  Harald Fuchs  Dominik Marx 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5286-5289

On the way to establishing biomass as a renewable and environmentally friendly source to cover the ever‐increasing global demand on energy and chemicals, one great challenge is the efficient depolymerization of cellulose. Enhanced conversion rates have been discovered in ball‐milling experiments, thus opening a mechanocatalytic approach. However, an understanding of the impact of mechanical forces on the acid‐catalyzed cleavage of glycosidic bonds at the molecular level is still missing. Herein, we contribute such fundamental insight based on atomistic modeling. Mechanically stressing the macromolecular backbone radically changes the depolymerization pathway from a complex high‐barrier reaction upon thermal activation to a low‐energy single‐step mechanocatalytic process. In addition to revealing a regioselective increase in basicity under a mechanical force, our results provide molecular‐level explanations of the experimental findings and might therefore guide rational ways to improve such mechanocatalytic processes.  相似文献   

    

Pia Vervoorts  Claire L. Hobday  Michael G. Ehrenreich  Dominik Daisenberger  Gregor Kieslich 《无机化学与普通化学杂志》2019,645(15):969-969

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Mihael Erakovi&#x;  Dominik Cin i&#x;  Kre&#x;imir Mol anov  Vladimir Stilinovi&#x; 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15849-15853

The covalent nature of strong N?Br???N halogen bonds in a cocrystal ( 2 ) of N‐bromosuccinimide ( NBS ) with 3,5‐dimethylpyridine ( lut ) was determined from X‐ray charge density studies and compared to a weak N?Br???O halogen bond in pure crystalline NBS ( 1 ) and a covalent bond in bis(3‐methylpyridine)bromonium cation (in its perchlorate salt ( 3 ). In 2 , the donor N?Br bond is elongated by 0.0954 Å, while the Br???acceptor distance of 2.3194(4) is 1.08 Å shorter than the sum of the van der Waals radii. A maximum electron density of 0.38 e Å^?3 along the Br???N halogen bond indicates a considerable covalent contribution to the total interaction. This value is intermediate to 0.067 e Å^?3 for the Br???O contact in 1 , and approximately 0.7 e Å^?3 in both N?Br bonds of the bromonium cation in 3 . A calculation of the natural bond order charges of the contact atoms, and the σ*(N1?Br) population of NBS as a function of distance between NBS and lut , have shown that charge transfer becomes significant at a Br???N distance below about 3 Å.  相似文献   

    

Mahmoud Khademi  Dominik P. J. Barz 《Electrophoresis》2019,40(5):710-719

The complex permittivities of aqueous SDS solutions, with and without the addition of sodium chloride (NaCl), are measured in the frequency range from 200 MHz to 14 GHz. The SDS concentrations are chosen such that the SDS molecules aggregate to micelles. In this frequency range, the measured spectra allow for the identification of two different relaxation processes. That is, the relaxation of the water molecules at frequencies above 1 GHz and the micellar relaxation at frequencies lower than 1 GHz. It is found that the addition of NaCl to the system mostly affects the micellar relaxation process. In detail, the time constant as well as the amplitude of the relaxation decrease by adding NaCl. These effects are attributed to the change in the solution conductivity that changes the properties of the micelle's electrical double layer. We also extract the Dukhin number of the micelles as a function of surfactant and electrolyte content from the measurements. The Dukhin number is a dimensionless group that describes the influence of the surface conductivity on a phenomena. A regression between Dukhin numbers and free sodium ions is found so that all data collapses on a single curve independent of the surfactant concentration. The surface conductivity is a manifestation of the electrical double layer and we use the Bikerman equation to infer the zeta potential of the micelles. Comparison to literature data shows very good agreement and proves that dielectric relaxation spectroscopy can be engaged to infer the zeta potential of micelles. Abbreviations: CMC critical micelle concentration, DRS dielectric relaxation spectroscopy, EDL electrical double layer  相似文献   

    

Marc‐Andr Kasper  Andreas Stengl  Philipp Ochtrop  Marcus Gerlach  Tina Stoschek  Dominik Schumacher  Jonas Helma  Martin Penkert  Eberhard Krause  Heinrich Leonhardt  Christian P. R. Hackenberger 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11757-11762

Requirements for novel bioconjugation reactions for the synthesis of antibody–drug conjugates (ADCs) are exceptionally high, since conjugation selectivity as well as the stability and hydrophobicity of linkers and payloads drastically influence the performance and safety profile of the final product. We report Cys‐selective ethynylphosphonamidates as new reagents for the rapid generation of efficacious ADCs from native non‐engineered monoclonal antibodies through a simple one‐pot reduction and alkylation. Ethynylphosphonamidates can be easily substituted with hydrophilic residues, giving rise to electrophilic labeling reagents with tunable solubility properties. We demonstrate that ethynylphosphonamidate‐linked ADCs have excellent properties for next‐generation antibody therapeutics in terms of serum stability and in vivo antitumor activity.  相似文献   

    

Dominik Jacob  Kathrin Thüring  Aurellia Galliot  Virginie Marchand  Adeline Galvanin  Akif Ciftci  Karin Scharmann  Michael Stock  Jean‐Yves Roignant  Sebastian A. Leidel  Yuri Motorin  Raffael Schaffrath  Roland Klassen  Mark Helm 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9666-9670

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