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61.
P. Winter M. Wolke H.-H. Adam A. Budzanowski R. Czyżykiewicz D. Grzonka M. Janusz L. Jarczyk B. Kamys A. Khoukaz K. Kilian P. Klaja P. Moskal W. Oelert C. Piskor-Ignatowicz J. Przerwa J. Ritman T. Rożek T. Sefzick M. Siemaszko J. Smyrski A. Täschner P. Wüstner Z. Zhang W. Zipper 《Physics letters. [Part B]》2006
The total cross section of the reaction pp→ppK+K− has been measured at excess energies Q=10 MeV and 28 MeV with the magnetic spectrometer COSY-11. The new data show a significant enhancement of the total cross section compared to pure phase space expectations or calculations within a one boson exchange model. In addition, we present invariant mass spectra of two particle subsystems. While the K+K− system is rather constant for different invariant masses, there is an enhancement in the pK− system towards lower masses which could at least be partially connected to the influence of the Λ(1405) resonance. 相似文献
62.
M. Abdel-Bary K. -Th. Brinkmann H. Clement E. Doroshkevich S. Dshemuchadse A. Erhardt W. Eyrich H. Freiesleben A. Gillitzer R. Jäkel L. Karsch K. Kilian E. Kuhlmann K. Möller H. P. Morsch L. Naumann N. Paul C. Pizzolotto J. Ritman E. Roderburg P. Schönmeier W. Schroeder M. Schulte-Wissermann G. Y. Sun A. Teufel A. Ucar G. J. Wagner M. Wagner P. Wintz P. Wüstner P. Zupranski 《The European Physical Journal A - Hadrons and Nuclei》2006,29(3):353-361
The reaction
has been studied in a kinematically complete experiment at a single beam momentum
GeV/c (T = 759MeV). All four ejectiles have been detected in the large-acceptance time-of-flight spectrometer COSY-TOF. We analyzed
the data along the lines of the spectator model as a means to isolate the quasi-free
reaction. The spectator proton was identified by its momentum and flight direction thus yielding access to the associated
Fermi motion of the bound neutron. A comparison is carried out with Monte Carlo simulations based on two different parameterizations
of the deuteron wave function. Up to a Fermi momentum of roughly 150MeV/c no significant deviations between experimental and simulated data of various observables were found from which we conclude
that the deuteron can indeed be taken as a valid substitute for the neutron. 相似文献
63.
64.
Scalable Synthesis of Piperazines Enabled by Visible‐Light Irradiation and Aluminum Organometallics 下载免费PDF全文
Dr. Samuel Suárez‐Pantiga Kilian Colas Dr. Magnus J. Johansson Dr. Abraham Mendoza 《Angewandte Chemie (International ed. in English)》2015,54(47):14094-14098
The development of more active C? H oxidation catalysts has inspired a rapid, scalable, and stereoselective assembly of multifunctional piperazines through a [3+3] coupling of azomethine ylides. A combination of visible‐light irradiation and aluminum organometallics is essential to promote this transformation, which introduces visible‐light photochemistry of main‐group organometallics and sets the basis for new and promising catalysts. 相似文献
65.
Kilian Muñiz Prof. Dr. Claas H. Hövelmann Esther Campos‐Gómez José Barluenga Prof. Dr. José M. González Prof. Dr. Jan Streuff Martin Nieger Dr. 《化学:亚洲杂志》2008,3(4):776-788
The oxidative intramolecular diamination of alkenes with tethered ureas and related groups as the nitrogen source has been investigated both with the iodonium reagent IPy2BF4 (Py=pyridine) and under palladium catalysis in the presence of copper(II) bromide as a reoxidant. For terminal alkenes, the two procedures enable selective and high‐yielding transformations. Studies with deuterated material led to the conclusion that the reactions proceed through different stereochemical pathways. An advanced protocol for palladium‐catalyzed diamination through six‐membered‐ring annulation was also developed, and the first examples of the intramolecular diamination of internal alkenes are described. In this case, the same stereochemical outcome was observed for the iodonium‐promoted and palladium‐catalyzed transformations. On this basis, it was possible to determine the importance of aminohalogenated intermediates in both diamination reactions. Overall, the disclosed procedures broaden significantly the synthetic applicability of the oxidative intramolecular diamination of alkenes. 相似文献
66.
Hövelmann CH Streuff J Brelot L Muñiz K 《Chemical communications (Cambridge, England)》2008,(20):2334-2336
Palladium catalysed intramolecular guanidine transfer to alkenes can be accomplished with copper chloride as the oxidant to give bicyclic guanidines with complete selectivity and in high yields. 相似文献
67.
Philip M. Keil Ademola Soyemi Kilian Weisser Prof. Tibor Szilvási Prof. Christian Limberg Dr. Terrance J. Hadlington 《Angewandte Chemie (International ed. in English)》2023,62(19):e202381961
The open-shell cationic stannylene-iron(0) complex 4 ( 4 =[PhiPDippSn⋅Fe⋅IPr]+; PhiPDipp={[Ph2PCH2Si(iPr)2](Dipp)N}; Dipp=2,6-iPr2C6H3; IPr=[(Dipp)NC(H)]2C:) cooperatively and reversibly cleaves dihydrogen at the Sn−Fe interface under mild conditions (1.5 bar, 298 K), in forming bridging hydrido-complex 6 . The One-electron oreduction of the related GeII−Fe0 complex 3 leads to oxidative addition of one C−P linkage of the PhiPDipp ligand in an intermediary Fe−I complex, leading to FeI phosphide species 7 . One-electron reduction reaction of 4 gives access to the iron(−I) ferrato-stannylene, 8 , giving evidence for the transient formation of such a species in the reduction of 3 . The covalently bound tin(II)-iron(−I) compound 8 has been characterised through EPR spectroscopy, SQUID magnetometry, and supporting computational analysis, which strongly indicate a high localization of electron spin density at Fe−I in this unique d9-iron complex. 相似文献
68.
Kilian A. Müller Carolin H. Nagel Prof. Dr. Alexander Breder 《European journal of organic chemistry》2023,26(2):e202201180
An expedient method for the synthesis of cyclic carbonates from homoallylic carbonic acid esters by means of photo-aerobic selenium-π-acid multicatalysis is reported. Until now, conceptually related methods commonly relied either on the stoichiometric addition of electrophiles onto the substrate's alkene moiety or the presence of pre-installed leaving groups in allylic position of said alkene to – in part, catalytically – initiate an intramolecular attack by an adjacent carbonic acid ester group. In sharp contrast, the current study shows that the C−C double bond of homoallylic carbonic acid esters can be directly activated by the catalytic interplay of a pyrylium dye and a diselane using ambient air as the sole oxidant and visible light as an energy source. 相似文献
69.
Solution Layer Deposition: A Technique for the Growth of Ultra‐Pure Manganese Oxides on Silica at Room Temperature 下载免费PDF全文
Dr. Jérémy Cure Dr. Kilian Piettre Dr. Yannick Coppel Dr. Eric Beche Dr. Jérôme Esvan Vincent Collière Dr. Bruno Chaudret Dr. Pierre Fau 《Angewandte Chemie (International ed. in English)》2016,55(9):3027-3030
With the ever increasing miniaturization in microelectronic devices, new deposition techniques are required to form high‐purity metal oxide layers. Herein, we report a liquid route to specifically produce thin and conformal amorphous manganese oxide layers on silicon substrate, which can be transformed into a manganese silicate layer. The undesired insertion of carbon into the functional layers is avoided through a solution metal–organic chemistry approach named Solution Layer Deposition (SLD). The growth of a pure manganese oxide film by SLD takes place through the decoordination of ligands from a metal–organic complex in mild conditions, and coordination of the resulting metal atoms on a silica surface. The mechanism of this chemical liquid route has been elucidated by solid‐state 29Si MAS NMR, XPS, SIMS, and HRTEM. 相似文献
70.
F. Kuchler E. Babcock M. Burghoff T. Chupp S. Degenkolb I. Fan P. Fierlinger F. Gong E. Kraegeloh W. Kilian S. Knappe-Grüneberg T. Lins M. Marino J. Meinel B. Niessen N. Sachdeva Z. Salhi A. Schnabel F. Seifert J. Singh S. Stuiber L. Trahms J. Voigt 《Hyperfine Interactions》2016,237(1):95
Permanent electric dipole moments (EDMs) arise due to the breaking of time-reversal or, equivalently, CP-symmetry. Although EDM searches have so far only set upper limits, which are many orders of magnitude larger than Standard Model (SM) predictions, the motivation for more sensitive searches is stronger than ever. A new effort at FRM-II incorporating 129Xe and 3He as a co-magnetometer can potentially improve the current limit. The noble gas mixture of 129Xe and 3He is simultanously polarized by spin-exchange optical pumping and then transferred into a high-performance magnetically shielded room. Inside, both species can freely precess in the presence of applied magnetic and electric fields. The precession signals are detected by LTc SQUID sensors. In EDM cells with silicon electrodes we observed spin lifetimes in excess of 2500 s without and with high-voltage applied. This meets one requirement to achieve our goal of improving the EDM limit on 129Xe by several orders of magnitude. 相似文献