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261.
Ohne Zusammenfassung 相似文献
262.
We study vibrations of structures composed of beams and plates subjected to moving constant or harmonic loads. Such structures occur in civil engineering, e.g. classical tracks or maglev guideways, highways or tarmacs of airports. We discuss the influence of speed and frequencies as well as parameters describing the construction itself. 相似文献
263.
Christian Slugovc Eva Rüba Roland Schmid Karl Kirchner Kurt Mereiter 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1241-1251
Summary. This article gives an overview of recent chemistry based on the tris-acetonitrile complex [RuCp(CH3CN)3]+. Due to the labile nature of the CH3CN ligands, substitution reactions are a dominant feature of this complex. Important derivatives are the highly reactive complexes
[RuCp(PR
3)(CH3CN)2]+ which are a source of the 14e− fragment [RuCp(PR
3)]+. These species are catalytically active in the redox isomerization of allyl alcohols to give aldehydes and ketones. Furthermore,
the cationic complex [RuCp(κ1(P),η2-PPh2CH2CH2CH*CH2)(CH3CN)]PF6 derived from the reaction of [RuCp(CH3CN)3]+ with PPh2CH2CH2CH*CH2 is a model compound for studying coupling reactions of olefins and acetylenes. In addition, [RuCp(CH3CN)3]+ is a valuable precursor for the synthesis of configurationally stable chiral three-legged piano-stool ruthenium complexes.
These are currently being intensively investigated as Lewis acid catalysts in asymmetric synthesis.
Received May 31, 2000. Accepted June 13, 2000 相似文献
264.
Erich Müller und Kurt Mehlhorn 《Fresenius' Journal of Analytical Chemistry》1934,96(5-6):173-175
Ohne Zusammenfassung 相似文献
265.
Kurt Eger Johannes Georg Pfahl Gerd Folkers Hermann J. Roth 《Journal of heterocyclic chemistry》1987,24(2):425-430
The synthesis of the difficult to obtain pyrrolo[2,3-d]pyrimidine-2,4-diamine (4) is reported. Furthermore, some unexpected reactions on the 2-aminopyrrole-3-carbonitrile system are described 15-17. 相似文献
266.
Kurt Strebel 《Archiv der Mathematik》1987,48(1):77-81
Ohne Zusammenfassung 相似文献
267.
268.
Avcı Davut Altürk Sümeyye Sönmez Fatih Tamer Ömer Başoğlu Adil Atalay Yusuf Zengin Kurt Belma Dege Necmi 《Molecular diversity》2021,25(1):171-189
Molecular Diversity - The World Health Organization (WHO) report shows that diabetes mellitus (DM) will be one of the ten deadly diseases in the near future. The best way to prevent DM is to... 相似文献
269.
The thioether functionalized aminosilanes Me2Si(NH‐C6H4‐2‐SR)2 (R = Ph, Me) were lithiated with nBuLi and subsequently reacted with AgCl in the presence of PMe3 or with [AuCl(PMe3)]. In the case of Me2Si(NH‐C6H4‐2‐SPh)2 the dinuclear complexes [M2{Me2Si(NC6H4‐2‐SPh)2}(PMe3)2] (M = Ag; Au) were isolated. The analogous reactions starting from Me2Si(NH‐C6H4‐SMe)2 afforded the dinuclear gold complex [Au2{Me2Si(NC6H4‐2‐SMe)2}(PMe3)2] and the tetranuclear silver complex [Ag4{Me2Si(NC6H4‐2‐SMe)2}2(PMe3)2]. In the dinuclear compounds of the type [M2{Me2Si(NC6H4‐2‐SR)2}(PMe3)2], each of the silylamide N atoms is connected to a M(PMe3) group to give a nearly linear N–M–P arrangement with Ag–N and Au–N bonds in the range of 212.0(4)–213.3(4) pm and 205.3(3)–208.1(9) pm, respectively. [Ag4{Me2Si(NC6H4‐2‐SMe)2}2(PMe3)2] consists of a central Si2N4Ag2 ring with linearly coordinated Ag atoms (Ag‐N: 223.1(4)–222.1(4) pm) and two peripheral Ag(PMe3) units, which are connected to the amido N atoms in a chelating mode. The relatively short transannular Ag ··· Ag separation (277.6(1) pm) within the Si2N4Ag2 ring hints for argentophilic interactions. The peripheral Ag atoms are three coordinated with Ag–N distances of 233.9(4)–242.8(4) pm. 相似文献
270.
Chuanlei Liu Kurt Ungar Dylan Pierce Ian Hoffman Weihua Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(3):471-478
In assistance of radionuclide measurements at Canada’s Comprehensive Nuclear-Test-Ban Treaty (CTBT) laboratory, a Geant4 Monte Carlo application has been developed in simulating a broad-energy germanium detector and calculating detection efficiencies. The detector model was optimized in a reliable and non-biased manner through simultaneous tuning on gap distance and detector dimension, and was validated over various realistic measurement scenarios. All work is based on a series of experiments which covers the typical energy range of gamma radiation in environmental analysis, and considers the variety of the CTBT sample type, dimension and distance-to-detector. In all cases, the predicted efficiencies are consistent with the empirical ones within 5%, with a typical deviation of 3% in majority. 相似文献