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971.
972.
Bing-Yu Li Lauren Voets Ruben Van Lommel Fien Hoppenbrouwers Mercedes Alonso Steven H. L. Verhelst Wim M. De Borggraeve Joachim Demaerel 《Chemical science》2022,13(14):4180
Correction for ‘SuFEx-enabled, chemoselective synthesis of triflates, triflamides and triflimidates’ by Bing-Yu Li et al., Chem. Sci., 2022, 13, 2270–2279, DOI: 10.1039/D1SC06267K.The authors would like to correct the second sentence in the Acknowledgements section, which should read “For HPLC analyses, we kindly acknowledge Marcus Frings and the support from RWTH Aachen University.”The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. 相似文献
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974.
975.
Selective Hydrogenation of Acrolein Over Pd Model Catalysts: Temperature and Particle‐Size Effects 下载免费PDF全文
Casey P. O'Brien Karl‐Heinz Dostert Swetlana Schauermann Hans‐Joachim Freund 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15856-15863
The selectivity in the hydrogenation of acrolein over Fe3O4‐supported Pd nanoparticles has been investigated as a function of nanoparticle size in the 220–270 K temperature range. While Pd(111) shows nearly 100 % selectivity towards the desired hydrogenation of the C=O bond to produce propenol, Pd nanoparticles were found to be much less selective towards this product. In situ detection of surface species by using IR‐reflection absorption spectroscopy shows that the selectivity towards propenol critically depends on the formation of an oxopropyl spectator species. While an overlayer of oxopropyl species is effectively formed on Pd(111) turning the surface highly selective for propenol formation, this process is strongly hindered on Pd nanoparticles by acrolein decomposition resulting in CO formation. We show that the extent of acrolein decomposition can be tuned by varying the particle size and the reaction temperature. As a result, significant production of propenol is observed over 12 nm Pd nanoparticles at 250 K, while smaller (4 and 7 nm) nanoparticles did not produce propenol at any of the temperatures investigated. The possible origin of particle‐size dependence of propenol formation is discussed. This work demonstrates that the selectivity in the hydrogenation of acrolein is controlled by the relative rates of acrolein partial hydrogenation to oxopropyl surface species and of acrolein decomposition, which has significant implications for rational catalyst design. 相似文献
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Peracetylated glycals were treated with terminal alkyne derivatives under Lewis acid catalysis to result in the formation of the pure α- or β- anomerically substituted hex-2-enopyranosides carrying 2(E)-halogenated olefins. 相似文献
978.
Dr. Tobias Wehner Dr. Joachim Heck Prof. Dr. Claus Feldmann Prof. Dr. Klaus Müller-Buschbaum 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(72):16630-16638
The luminescence of the inorganic–organic hybrid nanoparticles ZrO(MFP) (MFP=methylfluorescein phosphate) and ZrO(RP) (RP=resorufin phosphate) was modified by addition of different rare earth halides LnCl3. The resulting composite materials form dispersible nanoparticles that exhibit modified nanoparticle fluorescence depending on the rare earth ion. The resulting chromaticity of the luminescence is further variable by the employment of different solvents for ZrO(MFP)-based composite systems. The strong solvatochromic effect of the MFP chromophore leads to different luminescence chromaticities of the composite materials between green, yellow, and blue in THF, toluene, and dichloromethane, respectively. The luminescence of ZrO(RP)-based composite particles can be modified between the red and blue spectral regions in dependence on the applied reaction temperature. Beside a luminescence shift that is derived from nanoparticle modification by LnCl3, a strong turn-on effect of ZrO(RP) particles results after contact with different Brønsted acids and bases in combination with a respective chromaticity shift. Both effects enable the potential employment of such particles as highly sensitive optical pH sensors. 相似文献
979.
Eike Kirchner Frauke Thiem Rudolt Dernick Jochen Heukeshoven Joachim Thieina 《Journal of carbohydrate chemistry》2013,32(2):453-486
Abstract Glycal derivatives of N-acetylneuraminic acid were prepared and their N-iodosuccinimide-mediated glycosylation shown to proceed only with most reactive alcohols, Their reduced enol ether reactivity is attributed to the α unsaturated ester reature. Thus several reduced glycal derivatives were synthesized. These couid be glycosyiatec with simple alcohols as well as otner saccnarides as aglycones in averaae to modest yields with the trans-diaxiai additions compounas prevailing. A number or selective and specific prepparation led to both the anomeric phenylthioglycosides or N dcety Ineuraminic acid. These could be used in phenylmercurl triflate-promoted glycosylations to afford several derivatives. 相似文献
980.
Dipl.‐Chem. Matthias Peter Dr. Jose Manuel Flores Camacho Dr. Serguey Adamovski Dr. Luis K. Ono Dipl.‐Chem. Karl‐Heinz Dostert Dr. Casey P. O'Brien Prof. Dr. Beatriz Roldan Cuenya Dr. Swetlana Schauermann Prof. Dr. Hans‐Joachim Freund 《Angewandte Chemie (International ed. in English)》2013,52(19):5175-5179