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71.
72.
Heiko Lange 《Tetrahedron》2008,64(38):9123-9135
Enantioenriched α-stannylated benzyl carbamates were used in highly stereospecific coupling reactions employing Cu(I) as catalyzing transition metal. Acid chlorides and allyl bromide derivatives were used as electrophilic coupling partners. The reaction was applied in the synthesis of two highly enantioenriched indanoles and one enantioenriched tetraline via intramolecular cyclization reactions. 相似文献
73.
74.
The mechanism of the photoreaction of tetramethylene sulfone (TMSO2) was investigated by the semiempirical molecular orbital (MO) method SINDO1. The relevant low-lying potential energy surfaces, which were calculated with limited configuration interaction (CI), were studied by optimizing intermediates and transition structures and by introducing linear interpolations between these stationary points. The main initial reaction step for all important products is an α cleavage of one C? S bond. This leads to an intermediate that can be classified as an excited singlet diradical. Its electronic structure is described with a two-electron, three-orbital model. Starting from this initially generated intermediate, the reaction branches into several pathways leading to various products. Feasible reaction pathways were established for all important products consistent with experiments. © 1995 by John Wiley & Sons, Inc. 相似文献
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76.
Heiko Harborth 《Archiv der Mathematik》1976,27(1):290-294
Ohne ZusammenfassungHerrn Professor Dr.Theodor Schneider zum 65. Geburtstag 相似文献
77.
Jianbei An Heiko Dietrich Shih-Chang Huang 《Journal of Pure and Applied Algebra》2018,222(12):4020-4039
We consider the finite exceptional group of Lie type (universal version) with , where and . We classify, up to conjugacy, all maximal-proper 3-local subgroups of G, that is, all 3-local which are maximal with respect to inclusion among all proper subgroups of G which are 3-local. To this end, we also determine, up to conjugacy, all elementary-abelian 3-subgroups containing , all extraspecial subgroups containing , and all cyclic groups of order 9 containing . These classifications are an important first step towards a classification of the 3-radical subgroups of G, which play a crucial role in many open conjectures in modular representation theory. 相似文献
78.
We consider repulsive potential energies $\mathcal {E}_{q}(\Sigma)$ , whose integrand measures tangent-point interactions, on a large class of non-smooth m-dimensional sets Σ in ? n . Finiteness of the energy $\mathcal {E}_{q}(\Sigma)$ has three sorts of effects for the set Σ: topological effects excluding all kinds of (a priori admissible) self-intersections, geometric and measure-theoretic effects, providing large projections of Σ onto suitable m-planes and therefore large m-dimensional Hausdorff measure of Σ within small balls up to a uniformly controlled scale, and finally, regularizing effects culminating in a geometric variant of the Morrey–Sobolev embedding theorem: Any admissible set Σ with finite $\mathcal {E}_{q}$ -energy, for any exponent q>2m, is, in fact, a C 1-manifold whose tangent planes vary in a Hölder continuous manner with the optimal Hölder exponent μ=1?(2m)/q. Moreover, the patch size of the local C 1,μ -graph representations is uniformly controlled from below only in terms of the energy value $\mathcal {E}_{q}(\Sigma)$ . 相似文献
79.
Darbandi Masih Laurent Sophie Busch Martin Li Zi-An Yuan Ying Krüger Michael Farle Michael Winterer Markus Vander Elst Luce Muller Robert N. Wende Heiko 《Journal of nanoparticle research》2013,15(5):1-9
Quasi-critical fluctuations occur close to critical points or close to continuous phase transitions. In three-dimensional systems, precision tuning is required to access the fluctuation regime. Lowering the dimensionality enhances the parameter space for quasi-critical fluctuations considerably. This enables one to make use of novel properties emerging in fluctuating systems, such as giant susceptibilities, Casimir forces or novel quasi-particle interactions. Examples are discussed ranging from simple metal–adsorbate systems to unconventional superconductivity in iron-based superconductors. 相似文献
80.
Phil M. Pithan Christopher Kuhlmann Prof. Dr. Carsten Engelhard Prof. Dr. Heiko Ihmels 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(70):16088-16098
A series of new 5-mono- and 5,5′-bisamino-substituted azothiazole derivatives was synthesized from the readily available diethyl azothiazole-4,4′-dicarboxylate. This reaction most likely comprises an initial Michael-type addition by the respective primary alkyl and aromatic amines at the carbon atom C5 of the substrate. Subsequently, the resulting intermediates are readily oxidized by molecular oxygen to afford the amino-substituted azothiazole derivatives. The latter exhibit remarkably red-shifted absorption bands (λabs=507–661 nm) with high molar extinction coefficients and show a strong positive solvatochromism. As revealed by spectrometric titrations and circular and linear dichroism studies, the water-soluble, bis-(dimethylaminopropylamino)-substituted azo dye associates with duplex DNA by formation of aggregates along the phosphate backbone at high ligand–DNA ratios (LDR) and by intercalation at low LDR, which also leads to a significant increase of the otherwise low emission intensity at 671 nm. 相似文献