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41.
M. Regitz U. Annen E. P. O. Fuchs 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract 1,3-Butadienes 1 and 6-Methyl-2H-pyran-2-ones 6 react with two equivalents of phosphaalkynes 2 in a domino-reaction to the diphosphiranes 5 and 9 respectively. Diels-Alder-reaction of 1 with 2 leads to 3 which cannot be isolated. An Ene-reaction of the phosphacyclohexa-1,4-diene 3 with additional 2 gives 4 followed by an intramolecular Diels-Alder-reaction yielding the stable diphosphatricyclooctenes 5. 相似文献
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Aldol/elimination reactions of ß-ketoamides with methyl glyoxylate result in highly selective production of Z-α,ß-unsaturated amides. An intramolecular Diels-Alder reaction of a triply activated dienophile derived from chiral dienylamine 7ZE stereospecifically affords chiral bicyclic lactam 11 at room temperature. 相似文献
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The core-shell structure of a range of acrylic-acrylic latexes has been investigated by combining different specimen preparation methods with transmission electron microscopy (TEM), dark-field scanning transmission electron microscopy (DSTEM) and low-voltage scanning electron microscopy (LV-SEM), including the first reported use of LV-SEM to observe composite latex particles at ambient and subambient temperatures. Spin-coating of liquid latex dispersions directly onto TEM grids or SEM stubs is shown to be a relatively straightforward mean of avoiding film formation during specimen preparation. In conjunction with double staining techniques, it has been found to be particularly convenient for characterizing the fine structure of particles with diameters down to below 100 nm. 相似文献
46.
Dr. Anna Pakhomova Birgit Fuchs Prof. Dr. Leonid S. Dubrovinsky Prof. Dr. Natalia Dubrovinskaia Prof. Dr. Hubert Huppertz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(19):6007-6014
Based on the results from previous high-pressure experiments on the gadolinite-type mineral datolite, CaBSiO4(OH), the behavior of the isostructural borates β-HfB2O5 and β-ZrB2O5 have been studied by synchrotron-based in situ high-pressure single-crystal X-ray diffraction experiments. On compression to 120 GPa, both borate layer-structures are preserved. Additionally, at ≈114 GPa, the formation of a second phase can be observed in both compounds. The new high-pressure modification γ-ZrB2O5 features a rearrangement of the corner-sharing BO4 tetrahedra, while still maintaining the four- and eight-membered rings. The new phase γ-HfB2O5 contains ten-membered rings including the rare structural motif of edge-sharing BO4 tetrahedra with exceptionally short B−O and B⋅⋅⋅B distances. For both structures, unusually high coordination numbers are found for the transition metal cations, with ninefold coordinated Hf4+, and tenfold coordinated Zr4+, respectively. These findings remarkably show the potential of cold compression as a low-energy pathway to discover metastable structures that exhibit new coordinations and structural motifs. 相似文献
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Marcel Scheepstra Dr. Lidia Nieto Dr. Anna K. H. Hirsch Dr. Sascha Fuchs Dr. Seppe Leysen Chan Vinh Lam Leslie in het Panhuis Prof. Dr. Constant A. A. van Boeckel Dr. Hans Wienk Prof. Dr. Rolf Boelens Dr. Christian Ottmann Dr. Lech‐Gustav Milroy Prof. Dr. Luc Brunsveld 《Angewandte Chemie (International ed. in English)》2014,53(25):6443-6448
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The MOCVD of ZnO layers, at a reduced reactor pressure and using DMZ.2THF and tertiary butanol as zinc and oxygen sources, resp., presents a number of advantages compared with the deposition at normal pressure. This also applies to the copper incorporation by means of cyclopentadienyl-copper(I)-triethyl phosphine. For the copper concentration in the ZnO layers, which linearly increases with the flow rate of the organocopper compound, values > 1020 cm−3 can be achieved. Even in case of high concentrations, the desired compensating effect of the copper is, for the time being, comparatively little, but increases considerably after a thermal retreatment of the layers. Some chemical-defect aspects of ZnO will be discussed for the purpose of interpretation. 相似文献
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The reaction of trifold protected cyclen with fluorinated dinitroarenes yields aryl‐substituted or aryl‐bridged cyclen derivatives in good yield. The two arene nitro groups, necessary for the nucleophilic aromatic substitution, are subsequently selectively reduced to amines and further functionalized by amide formation. As an example, a cyclen derivative bearing a heterocyclic oligoamide with potential DNA binding ability was prepared. 相似文献