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111.
Marcileia Zanatta Dr. Anne‐Lise Girard Nathalia M. Simon Prof. Gunter Ebeling Prof. Hubert K. Stassen Prof. Paolo R. Livotto Prof. Francisco P. dos Santos Prof. Jairton Dupont 《Angewandte Chemie (International ed. in English)》2014,53(47):12817-12821
1‐n‐Butyl‐2,3‐dimethylimidazolium (BMMI) ionic liquids (ILs) associated with different anions undergo H/D exchange preferentially at 2‐Me group of the imidazolium in deuterated solvents. This process is mainly related to the existence of ion pairs rather than the anion basicity. The H/D exchange occurs in solvents (CDCl3 and MeCN for instance) in which intimate contact ion pairs are present and the anion possesses a labile H in its structure, such as hydrogen carbonate and prolinate. In D2O, separated ion pairs are formed and the H/D exchange does not occur. A plausible catalytic cycle is that the IL behaves as a neutral base in the course of all H/D exchange processes. NMR experiments, density functional calculations, and molecular dynamics simulations corroborate these hypotheses. 相似文献
112.
Tetracyanoquinodimethane Reduction by Complexed Guanidinyl‐Functionalized Aromatic Compounds
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Hendrik Herrmann Alexandra Ziesak Ute Wild Simone Leingang David Schrempp Norbert Wagner Prof. Dr. Johannes Beck Dr. Elisabeth Kaifer Prof. Dr. Hubert Wadepohl Prof. Dr. Hans‐Jörg Himmel 《Chemphyschem》2014,15(2):351-365
In this work, we report on the reduction of tetracyanoquinodimethane (TCNQ) with dicationic complexes of guanidinyl‐functionalized aromatic (GFA) electron donors. In contrast to reduction with free GFAs, milder reduction conditions were achieved, and this led to semiconducting materials with extended TCNQ π stacking. The charge on the TCNQ units was estimated from the structural data obtained by single‐crystal X‐ray diffraction analysis and from IR spectroscopic data. The electrical conductivity was studied and the activation energy of the semiconducting materials was estimated from the temperature dependence of the conductivity. 相似文献
113.
Aydin Berenjian Raja Mahanama Andrea Talbot Hubert Regtop John Kavanagh Fariba Dehghani 《Applied biochemistry and biotechnology》2014,172(3):1347-1357
A nutritional food rich in menaquinone-7 has a potential in preventing osteoporosis and cardiovascular diseases. The static fermentation of Bacillus subtilis natto is widely regarded as an optimum process for menaquinone-7 production. The major issues for the bulk production of menaquinone-7 are the low fermentation yield, biofilm formation and the use of organic solvents for the vitamin extraction. In this study, we demonstrate that the dynamic fermentation involving high stirring and aeration rates enhances the yield of fermentation process significantly compared to static system. The menaquinone-7 concentration of 226 mg/L was produced at 1,000 rpm, 5 vvm, 40 °C after 5 days of fermentation. This concentration is 70-fold higher than commercially available food products such as natto. Additionally, it was found that more than 80 % of menaquinone-7 was recovered in situ in the vegetable oil that was gradually added to the system as an anti-foaming agent. The intensification process developed in this study has a capacity to produce an oil rich in menaquinone-7 in one step and eliminate the use of organic solvents for recovery of this compound. This oil can, therefore, be used for the preparation of broad range of supplementary and dietary food products rich in menaquinone-7 to reduce the risk of osteoporotic fractures and cardiovascular diseases. 相似文献
114.
Henrik Eickhoff Christian Sedlmeier Wilhelm Klein Gabriele Raudaschl-Sieber Hubert A. Gasteiger Thomas F. Fässler 《无机化学与普通化学杂志》2020,646(3):95-102
Recently fast lithium ion conductors were discovered in compounds containing tetrahedral SiP48– and GeP48– units. In the context of material development for all solid state batteries the ternary Li/Ge/P phase system has been further investigated and two new lithium phosphidogermanates were discovered on the lithium poor side of the ternary composition diagram. Li2GeP2 crystallizes in space group I41/acd with unit cell parameters of a = 12.3069(1) Å and c = 19.0306(4) Å, consists of a framework of Ge4P10 supratetrahedra, and exhibits an ionic conductivity of 1.5(3)×10–7 S · cm–1 at 27 °C. LiGe3P3 crystallizes in Pbam with a = 9.8459(5) Å, b = 15.7489(7) Å, and c = 3.5995(2) Å. In LiGe3P3 Ge and P atoms form a two dimensional polyanion. The slabs consist of five- and six-membered heteroatomic rings comprising GeP4 and Ge(P3Ge) tetrahedra including homoatomic Ge–Ge bonds. A semiconducting behavior with an electronic conductivity of ∼10–4 S · cm–1 and a remarkable stability vs. air and moisture is observed. 相似文献
115.
Birgit Fuchs Prof. Dr. Gunter Heymann Xuefei Wang Abudukadi Tudi Dr. Lkhamsuren Bayarjargal Dr. Renée Siegel Adrian Schmutzler Prof. Dr. Jürgen Senker Dr. Bastian Joachim-Mrosko Dr. Andreas Saxer Prof. Dr. Zhihua Yang Prof. Dr. Shilie Pan Prof. Dr. Hubert Huppertz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(30):6851-6861
La3B6O13(OH) was obtained by a high-pressure/high-temperature experiment at 6 GPa and 1673 K. The compound crystallizes in the space group P21 (no. 4) with the lattice parameters a=4.785(2), b=12.880(4), c=7.433(3) Å, and β=90.36(10)°, and is built up of corner- as well as edge-sharing BO4 tetrahedra. It represents the first acentric high-pressure borate containing these B2O6 entities. The compound develops borate layers of „sechser“-rings with the La3+ cations positioned between the layers. Single-crystal and powder X-ray diffraction, vibrational and MAS NMR spectroscopy, second-harmonic generation (SHG) and thermoanalytical measurements, as well as computational methods were used to affirm the proposed structure and the B2O6 entities. 相似文献
116.
117.
Grégoire C. Gschwend Astrid Olaya Pekka Peljo Hubert H. Girault 《Current Opinion in Electrochemistry》2020
Charge transfer phenomena at the interface between two immiscible electrolyte solutions (ITIES) are electrochemical reactions taking place in soft media. Owing to their liquid nature, the ITIES shows a large panel of electrochemical reactions including electron transfer reactions, ion transfer reactions, coupled electron–ion transfer reactions or biomimetic redox reactions. Nevertheless, the mechanisms by which these reactions proceed are yet to be fully understood. The goal of this short review is to summarise the work accomplished over the past decades towards the elucidation of the structure and reactivity at the ITIES, highlighting the main questions still to be answered. 相似文献
118.
Adam Ashcraft Kaixuan Liu Arindam Mukhopadhyay Victor Paulino Chuan Liu Brianna Bernard Dalia Husainy Tina Phan Jean‐Hubert Olivier 《Angewandte Chemie (International ed. in English)》2020,59(19):7487-7493
Locking‐in the conformation of supramolecular assemblies provides a new avenue to regulate the (opto)electronic properties of robust nanoscale objects. In the present contribution, we show that the covalent tethering of a perylene bisimide (PBI)‐derived supramolecular polymer with a molecular locker enables the formation of a locked superstructure equipped with emergent structure–function relationships. Experiments that exploit variable‐temperature ground‐state electronic absorption spectroscopy unambiguously demonstrate that the excitonic coupling between nearest neighboring units in the tethered superstructure is preserved at a temperature (371 K) where the pristine, non‐covalent assembly exists exclusively in a molecularly dissolved state. A close examination of the solid‐state morphologies reveals that the locked superstructure engenders the formation of hierarchical 1D materials which are not achievable by unlocked assemblies. To complement these structural attributes, we further demonstrate that covalently tethering a supramolecular polymer built from PBI subunits enables the emergence of electronic properties not evidenced in non‐covalent assemblies. Using cyclic voltammetry experiments, the elucidation of the potentiometric properties of the locked superstructure reveals a 100‐mV stabilization of the conduction band energy when compared to that recorded for the non‐covalent assembly. 相似文献
119.
Islam Alshamleh Nina Krause Christian Richter Nina Kurrle Hubert Serve Ulrich L. Günther Harald Schwalbe 《Angewandte Chemie (International ed. in English)》2020,59(6):2304-2308
Current metabolomics approaches utilize cellular metabolite extracts, are destructive, and require high cell numbers. We introduce here an approach that enables the monitoring of cellular metabolism at lower cell numbers by observing the consumption/production of different metabolites over several kinetic data points of up to 48 hours. Our approach does not influence cellular viability, as we optimized the cellular matrix in comparison to other materials used in a variety of in‐cell NMR spectroscopy experiments. We are able to monitor real‐time metabolism of primary patient cells, which are extremely sensitive to external stress. Measurements are set up in an interleaved manner with short acquisition times (approximately 7 minutes per sample), which allows the monitoring of up to 15 patient samples simultaneously. Further, we implemented our approach for performing tracer‐based assays. Our approach will be important not only in the metabolomics fields, but also in individualized diagnostics. 相似文献
120.
Hubert Schmidbaur Helgard G. Raubenheimer 《Angewandte Chemie (International ed. in English)》2020,59(35):14748-14771
Excimers and exciplexes are defined as assemblies of atoms or molecules A / A ′ where interatomic/intermolecular bonding appears only in excited states such as [ A 2]* (for excimers) and [ AA ′]* (for exciplexes). Their formation has become widely known because of their role in gas‐phase laser technologies, but their significance in general chemistry terms has been given little attention. Recent investigations in gold chemistry have opened up a new field of excimer and exciplex chemistry that relies largely on the preorganization of gold(I) compounds (electronic configuration AuI(5d10)) through aurophilic contacts. In the corresponding excimers, a new type of Au???Au bonding arises, with bond energies and lengths approaching those of ground‐state Au?Au bonds between metal atoms in the Au0(5d106s1) and AuII(5d9) configurations. Excimer formation gives rise to a broad range of photophysical effects, for which some of the relaxation dynamics have recently been clarified. Excimers have also been shown to play an important role in photoredox binuclear gold catalysis. 相似文献