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111.
Niels Lichtenberger Werner Massa Stefanie Dehnen 《Angewandte Chemie (International ed. in English)》2019,58(10):3222-3226
We present the results from a reactivity study of the binary anion (TlBi3)2? towards Group 12 metal compounds MPh2 (M=Zn, Cd, Hg) to gain access to coordination compounds of polycyclic polypnictide molecules such as Bi73? or Bi113?. The coordination chemistry of these polybismuthide cages has been unprecedented to date, while it has been known for a long time for the lighter Group 15 anions Pn73? (Pn=P, As, Sb). The use of (TlBi3)2?, previously shown to release Tl under certain conditions in situ, resulted in the formation of the first heterometallic polyanion in which a nortricyclane‐type polybismuthide coordinates a transition‐metal atom, [(Bi7)Cd(Bi7)]4?. Reactions with the lighter Group 12 metal precursor yielded the uncommon ternary cluster [(Bi6)Zn3(TlBi5)]4?, most likely representing a reaction intermediate, and at the same time hinting at the formation of the nortricyclane‐shaped cage. Quantum‐chemical studies provide deeper insight into the stability trends of the [(E7)M(E7)]4? anion family and reveal a complex bonding situation in [(Bi6)Zn3(TlBi5)]4?, which features both localized and multi‐center bonding. 相似文献
112.
Niels J. Hauwert Tamara A. M. Mocking Daniel DaCostaPereira Ken Lion Yara Huppelschoten Henry F. Vischer Iwan J. P. DeEsch Maikel Wijtmans Rob Leurs 《Angewandte Chemie (International ed. in English)》2019,58(14):4531-4535
Spatiotemporal control over biochemical signaling processes involving G protein‐coupled receptors (GPCRs) is highly desired for dissecting their complex intracellular signaling. We developed sixteen photoswitchable ligands for the human histamine H3 receptor (hH3R). Upon illumination, key compound 65 decreases its affinity for the hH3R by 8.5‐fold and its potency in hH3R‐mediated Gi protein activation by over 20‐fold, with the trans and cis isomer both acting as full agonist. In real‐time two‐electrode voltage clamp experiments in Xenopus oocytes, 65 shows rapid light‐induced modulation of hH3R activity. Ligand 65 shows good binding selectivity amongst the histamine receptor subfamily and has good photolytic stability. In all, 65 (VUF15000) is the first photoswitchable GPCR agonist confirmed to be modulated through its affinity and potency upon photoswitching while maintaining its intrinsic activity, rendering it a new chemical biology tool for spatiotemporal control of GPCR activation. 相似文献
113.
E. S. Zijlstra J. Walkenhorst C. Gilfert C. Sippel W. Töws M. E. Garcia 《Applied physics. B, Lasers and optics》2008,93(4):743-747
Using first principles, all-electron calculations and dynamical simulations we study the behavior of solid InSb immediately
after intense femtosecond excitation. First, we determine the laser-excited potential energy surfaces with high accuracy for
different electronic temperatures (corresponding to different laser fluences). Then, we demonstrate that, although most phonon
modes become only slightly softened even for high electron temperatures, the transverse acoustic modes at the boundary of
the Brillouin zone undergo dramatic changes and become unstable. This is the origin of nonthermal melting. Based on these
results, the dynamics during the first hundreds of femtoseconds after laser excitation can be unambiguously elucidated. Our
results are in agreement with recent experiments and support the predictions made by Stampfli and Bennemann for silicon. 相似文献
114.
An integrated shape morphing and topology optimization approach based on the deformable simplicial complex methodology is developed to address Stokes and Navier‐Stokes flow problems. The optimized geometry is interpreted by a set of piecewise linear curves embedded in a well‐formed triangular mesh, resulting in a physically well‐defined interface between fluid and impermeable regions. The shape evolution is realized by deforming the curves while maintaining a high‐quality mesh through adaption of the mesh near the structural boundary, rather than performing global remeshing. Topological changes are allowed through hole merging or splitting of islands. The finite element discretization used provides smooth and stable optimized boundaries for simple energy dissipation objectives. However, for more advanced problems, boundary oscillations are observed due to conflicts between the objective function and the minimum length scale imposed by the meshing algorithm. A surface regularization scheme is introduced to circumvent this issue, which is specifically tailored for the deformable simplicial complex approach. In contrast to other filter‐based regularization techniques, the scheme does not introduce additional control variables, and at the same time, it is based on a rigorous sensitivity analysis. Several numerical examples are presented to demonstrate the applicability of the approach. 相似文献
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118.
Niels Weidmann Marthe Ketels Prof. Dr. Paul Knochel 《Angewandte Chemie (International ed. in English)》2018,57(33):10748-10751
The first sodiations of (hetero)arenes in continuous flow using NaDA (sodium diisopropylamide) in Me2EtN are reported. This flow procedure enables sodiation of functionalized arenes and heteroarenes that decompose under batch‐sodiation conditions. The resulting sodiated (hetero)arenes react instantly with various electrophiles, such as ketones, aldehydes, isocyanates, alkyl bromides, and disulfides, affording polyfunctionalized (hetero)arenes in high yields. Scale‐up is possible without further optimization. 相似文献
119.
120.
We derive a probabilistic expression for the symbol of the generator of a Feller process. 相似文献