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921.
Pierre Mathey Frédéric Lirette Prof. Dr. Israel Fernández Lukas Renn Prof. Dr. R. Thomas Weitz Prof. Dr. Jean-François Morin 《Angewandte Chemie (International ed. in English)》2023,62(11):e202216281
Non-alternant non-benzenoid hydrocarbons exhibit very different optical and electronic properties than their well-studied benzenoid analogues. However, preparing such structures with extended conjugation length, remains challenging. Herein, we report the synthesis and properties of azuleno[2,1,8-ija]azulene derivatives using a two-step sequence involving a four-fold aldol condensation between aromatic dialdehydes and readily available tetrahydropentalene-2,5-(1H,3H)-dione. Molecules with band gap values ranging from 1.69 to 2.14 eV and molar extinction coefficients (ϵ) of nearly 3×105 M−1 cm−1 have been prepared. These annulene-like structures exhibit significant diatropic ring currents (aromatic), as supported by 1H NMR spectroscopy and DFT calculations. Field-effect transistors (OFETs) using azuleno[2,1,8-ija]azulene derivatives as semiconductors exhibit charge mobility values of up to 0.05 cm2 V−1 s−1. 相似文献
922.
Giulia Bertoli Ángel Manu Martínez Jonas F. Goebel Debora Belmonte Nardana Sivendran Lukas J. Gooßen 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215920
Redox-active N-(fluoromethoxy)benzotriazoles were made accessible from fluoroacetic acid and hydroxybenzotriazoles via electrodecarboxylative coupling. After alkylation, they become effective monofluoromethoxylation reagents, enabling the photocatalytic C−H functionalization of arenes. Thus, irradiation of 1-(OCH2F)-3-Me-6-(CF3)benzotriazolium triflate with blue LED light in the presence of [Ru(bpy)3(PF6)2] promotes the synthesis of diversely functionalized aryl monofluoromethyl ethers. This method allows the late-stage functionalization of biologically relevant structures without relying on ecologically problematic halofluorocarbons. 相似文献
923.
Philipp J. Kohlpaintner Lucas Marquart Prof. Dr. Lukas J. Gooßen Prof. Dr. Siegfried R. Waldvogel 《European journal of organic chemistry》2023,26(17):e202300220
Peroxodicarbonate represents a green and largely underexplored oxidizer generated electrochemically from aqueous carbonate solutions. Through state-of-the-art electrolyzer technology, highly concentrated solutions have now become accessible. These were successfully employed as green oxidizer in deborolative hydroxylations. A plethora of phenols and alcohols have thus been synthesized in up to 99 % from organoboron compounds using only green and non-toxic solvents. This transformation was successfully scaled-up to multi-gram batch sizes. 相似文献
924.
Moritz Bernhardt Lukas Lätsch Boris Le Guennic Christophe Copéret 《Helvetica chimica acta》2023,106(11):e202300130
Industrial data storage application based on single-molecule magnets (SMMs) necessitates not only strong magnetic remanence at high temperatures but also requires the implementation of SMMs into a solid material to increase their durability and addressability. While the understanding of the relationship between the local structure of the metal and the resulting magnetic behavior is well understood in molecular systems, it remains challenging to establish a similar understanding for magnetic materials, especially for isolated lanthanide sites on surfaces. For instance, dispersed Dy(III) ions on silica prepared via surface organometallic chemistry exhibit slow magnetic relaxation at low temperatures, but the origin of these properties remains unclear. In this work, we modelled ten neutral complexes with coordination numbers (CN) between three and six ([Dy(OSiF3)3(O(SiF3)2)CN-3]) representing possible surface sites for dispersed Dy(III) ions and investigated their SMM potential via ab initio CASSCF/RASSI-SO calculations. Detailed analysis of the data shows the strong influence of the spatial position of the anionic ligands while the neutral ligands only play a minor role for the magnetic properties. In particular, a T-shape like orientation of the anionic ligands is predicted to exhibit good SMM properties making it a promising targeted coordination environment for molecular and surface-based SMMs. 相似文献
925.
Ansgar Stratmann Thomas Schupp Christiane Toupet Wolfgang Schilling Lukas Oberer Rene Traber 《ChemInform》2002,33(41):222-222
926.
Lukas Kogler Philip L. Lederer Joachim Schöberl 《Numerical Linear Algebra with Applications》2023,30(5):e2503
We are studying the efficient solution of the system of linear equations stemming from the mass conserving stress-yielding (MCS) discretization of the Stokes equations. We perform static condensation to arrive at a system for the pressure and velocity unknowns. An auxiliary space preconditioner for the positive definite velocity block makes use of efficient and scalable solvers for conforming Finite Element spaces of low order and is analyzed with emphasis placed on robustness in the polynomial degree of the discretization. Numerical experiments demonstrate the potential of this approach and the efficiency of the implementation. 相似文献
927.
Dr. Andreas Hermann Rana Seymen Dr. Lukas Brieger Johannes Kleinheider Dr. Bastian Grabe Prof. Dr. Wolf Hiller Prof. Dr. Carsten Strohmann 《Angewandte Chemie (International ed. in English)》2023,62(25):e202302489
Since its introduction in 2004, Knochel's so called Turbo-Grignard reagents revolutionized the usage of Grignard reagents. Through the simple addition of LiCl to a magnesium alkyl an outstanding increase in reactivity can be achieved. Though the exact composition of the reactive species remained mysterious, the reactive mixture itself is readily used not only in synthesis but also found its way into more distant fields like material science. To unravel this mystery, we combined single-crystal X-ray diffraction with in-solution NMR-spectroscopy and closed our investigations with quantum chemical calculations. Using such a variety of methods, we have gained insight into and an explanation for the extraordinary reactivity of this extremely convenient reagent by determining the structure of the first bimetallic reactive species [t-Bu2Mg ⋅ LiCl ⋅ 4 thf] with two tert-butyl anions at the magnesium center and incorporated lithium chloride. 相似文献
928.
Dr. Leonid Komissarov Lukas Krep Felix Schmalz Dr. Wassja A. Kopp Prof. Dr. Kai Leonhard Prof. Dr. Toon Verstraelen 《Chemphyschem》2023,24(8):e202200786
This work presents a novel parametrization for the ReaxFF formalism as a means to investigate reaction processes of chlorinated organic compounds. Force field parameters cover the chemical elements C, H, O, Cl and were obtained using a novel optimization approach involving relaxed potential energy surface scans as training targets. The resulting ReaxFF parametrization shows good transferability, as demonstrated on two independent ab initio validation sets. While this first part of our two-paper series focuses on force field parametrization, we apply our parameters to the simulation of chlorinated dibenzofuran formation and decomposition processes in Part II. 相似文献
929.
Dajana Durach Lukas Neudert Peter J. Schmidt Oliver Oeckler Wolfgang Schnick 《ChemInform》2015,46(39):no-no
Agglomerates of a few μm of the yellow phosphor La3BaSi5N9O2:Ce3+ are obtained by heating a mixture of LaF3, La(NH2)3, BaH2, Si(NH)2, and CeF3 in a radio frequency furnace under N2 (1600 °C, 10 h; cooling to 900 °C within 44 h). 相似文献
930.
Jonas F. Goebel Julian Löffler Zhongyi Zeng Jens Handelmann Albert Hermann Ilja Rodstein Dr. Tobias Gensch Prof. Dr. Viktoria H. Gessner Prof. Dr. Lukas J. Gooßen 《Angewandte Chemie (International ed. in English)》2023,62(9):e202216160
Palladium-catalyzed couplings of silicon enolates with aryl electrophiles are of great synthetic utility, but often limited to expensive bromide substrates. A comparative experimental study confirmed that none of the established ligand systems allows to couple inexpensive aryl chlorides with α-trimethylsilyl alkylnitriles. In contrast, ylide functionalized phosphines (YPhos) led to encouraging results. A statistical model was developed that correlates the reaction yields with ligand features. It was employed to predict catalyst structures with superior performance. With this cheminformatics approach, YPhos ligands were tailored specifically to the demands of Hiyama couplings. The newly synthesized ligands displayed record-setting activities, enabling the elusive coupling of aryl chlorides with α-trimethylsilyl alkyl nitriles. The preparative utility of the catalyst system was demonstrated by the synthesis of pharmaceutically meaningful α-aryl alkylnitriles, α-arylcarbonyls and biaryls. 相似文献