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981.
Eric Sperlich Jonas Knig Daniel Holger Weiß Florian Schrder Martin Kckerling 《无机化学与普通化学杂志》2019,645(3):233-241
Six new hexanuclear niobium cluster compounds of the general formula [Nb6Cl14L4] · x(solvent molecule) [L = neutral O or N donor ligand, x = 0–2.5; pyrimidine ( 1 ), 1‐methyl imidazole ( 2 ), isobutyronitrile ( 3 ), isopropyl alcohol ( 4 ), triphenylphosphine oxide ( 5 ), dimethyl sulfoxide ( 6 )] were prepared. The syntheses were carried out by dehydration of the precursor [Nb6Cl14(H2O)4] · 4H2O with different water scavangers, like acetic anhydride, trimethyl acetic anhydride and diethylcarbonate in the presence of the corresponding neutral ligand. The structures are determined by single‐crystal X‐ray diffraction. The specific bonding situations of the ligands to the [Nb6Cl12]2+ cluster cores are compared and discussed. The phenomenon of the observed M6 distortion is explained and interpreted based on the matrix effect and the terminal ligand effect. In addition, other interactions between the cluster units, such as hydrogen bonding and π–π stacking are discussed. 相似文献
982.
Jonas Strh Laura Ruiz Arana Philipp Polzin Irma Vania Eliani Patric Lindenberg Niclas Heidenreich Csar dos Santos Cunha Sebastian Leubner Huayna Terraschke 《无机化学与普通化学杂志》2019,645(5):537-543
Despite the strong technological importance of lanthanide complexes, their formation processes are rarely investigated. This work is dedicated to determining the influence of synthesis parameters on the formation of [Ce(bipy)2(NO3)3] as well as Ce3+‐ and Tb3+‐substituted [La(bipy)2(NO3)3] (bipy = 2,2′‐bipyridine) complexes. To this end, we performed in situ luminescence measurements, synchrotron‐based X‐ray diffraction (XRD) analysis, infrared spectroscopy (IR), and measured pH value and/or ion conductivity during their synthesis process under real reaction conditions. For the [Ce(bipy)2(NO3)3] complex, the in situ luminescence measurements initially presented a broad emission band at 490 nm, assigned to the 5d→4f Ce3+ ions within the ethanolic solvation shell. Upon the addition of bipy, a red shift to 700 nm was observed. This shift was attributed to the changes in the environment of the Ce3+ ions, indicating their desolvation and incorporation into the [Ce(bipy)2(NO3)3] complex. The induction time was reduced from 8 to 3.5 min, by increasing the reactant concentration by threefold. In contrast, [La(bipy)2(NO3)3] crystallized within days instead of minutes, unless influenced by high Ce3+ and Tb3+ concentrations. Monitoring and controlling the influence of the reaction parameters on the structure of emissive complexes is important for the development of rational synthesis approaches and optimization of their structure‐related properties like luminescence. 相似文献
983.
984.
Robert Stepi Christian R. Wick Vinzent Strobel Daniel Berger Nataa Vu
emilovi‐Alagi Marco Haumann Peter Wasserscheid Ana‐Sun
ana Smith David M. Smith 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(3):751-755
Supported ionic liquid phase (SILP) catalysis enables a highly efficient, Ru‐based, homogeneously catalyzed water‐gas shift reaction (WGSR) between 100 °C and 150 °C. The active Ru‐complexes have been found to exist in imidazolium chloride melts under operating conditions in a dynamic equilibrium, which is dominated by the [Ru(CO)3Cl3]? complex. Herein we present state‐of‐the‐art theoretical calculations to elucidate the reaction mechanism in more detail. We show that the mechanism includes the intermediate formation and degradation of hydrogen chloride, which effectively reduces the high barrier for the formation of the requisite dihydrogen complex. The hypothesis that the rate‐limiting step involves water is supported by using D2O in continuous catalytic WGSR experiments. The resulting mechanism constitutes a highly competitive alternative to earlier reported generic routes involving nucleophilic addition of hydroxide in the gas phase and in solution. 相似文献
985.
986.
Patricia J. Nance Niklas B. Thompson Paul H. Oyala Jonas C. Peters 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6286-6290
Species with 2‐center, 3‐electron (2c/3e?) σ bonds are of interest owing to their fascinating electronic structures and potential for interesting reactivity patterns. Report here is the synthesis and characterization of a pair of zerovalent (d9) trigonal pyramidal Rh and Ir complexes that feature 2c/3e? σ bonds to the Si atom of a tripodal tris(phosphine)silatrane ligand. X‐ray diffraction, continuous wave and pulse electron paramagnetic resonance, density‐functional theory calculations, and reactivity studies have been used to characterize these electronically distinctive compounds. The data available highlight a 2c/3e? bonding framework with a σ*‐SOMO of metal 4‐ or 5dz2 parentage that is partially stabilized by significant mixing with Si (3pz) and metal (5‐ or 6pz) orbitals. Metal‐ligand covalency thus buffers the expected destabilization of transition‐metal (TM)‐silyl σ*‐orbitals by d–p mixing, affording well‐characterized examples of TM–main group, and hence polar, 2c/3e? σ “half‐bonds”. 相似文献
987.
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
988.
Edward L. Briggs Arianna Tota Marco Colella Leonardo Degennaro Renzo Luisi James A. Bull 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(40):14441-14448
Sulfonimidamides are intriguing new motifs for medicinal and agrochemistry, and provide attractive bioisosteres for sulfonamides. However, there remain few operationally simple methods for their preparation. Here, the synthesis of NH‐sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in one step from amines and disulfides. A highly chemoselective and one‐pot NH and O transfer is developed, mediated by PhIO in iPrOH, using ammonium carbamate as the NH source, and in the presence of 1 equivalent of acetic acid. A wide range of functional groups are tolerated under the developed reaction conditions, which also enables the functionalization of the antidepressants desipramine and fluoxetine and the preparation of an aza analogue of the drug probenecid. The reaction is shown to proceed via different and concurrent mechanistic pathways, including the formation of novel S≡N sulfanenitrile species as intermediates. Several alkoxy‐amino‐λ6‐sulfanenitriles are prepared with different alcohols, and shown to be alkylating agents to a range of nucleophiles. 相似文献
989.
Fei Ye Florian Berger Hao Jia Joseph Ford Alan Wortman Jonas Brgel Christophe Genicot Tobias Ritter 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14757-14761
Incorporation of the CF3 group into arenes has found increasing importance in drug discovery. Herein, we report the first photoredox‐catalyzed cross‐coupling of aryl thianthrenium salts with a copper‐based trifluoromethyl reagent, which enables a site‐selective late‐stage trifluoromethylation of arenes. The reaction proceeds with broad functional group tolerance, even for complex small molecules on gram scale. The method was further extended to produce pentafluoroethylated derivatives. 相似文献
990.
Marco Carini Mauro Marongiu Karol Strutyski Akinori Saeki Manuel Melle‐Franco Aurelio Mateo‐Alonso 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15935-15939
Supramolecular polymers show great potential in the development of new materials because of their inherent recyclability and their self‐healing and stimuli‐responsive properties. Supramolecular conductive polymers are generally obtained by the assembly of individual aromatic molecules into columnar arrays that provide an optimal channel for electronic transport. A new approach is reported to prepare supramolecular polymers by hooking together sigmoidal monomers into 1D arrays of π‐stacked anthracene and acridine units, which gives rise to micrometer‐sized fibrils that show pseudoconductivities in line with other conducting materials. This approach paves the way for the design of new supramolecular polymers constituted by acene derivatives with enhanced excitonic and electronic transporting properties. 相似文献