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Results from Super-Kamiokande-I’s entire 1496 live days of solar neutrino data are presented, including the absolute flux,
energy spectrum, zenith angle (day/night) and seasonal variation. The possibility of MSW and vacuum oscillations is discussed
in light of these results. Results from the first 1289 days of Super-K-I’s atmospheric neutrino analysis are also presented,
including the evidence for νμ →ν
τ oscillations, against νμ → νsterile oscillations, and the current limits on proton decay. Finally, results based on 56 × 1019 protons on target are given for the K2K long-baseline neutrino oscillation experiment. 相似文献
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Dr. Valerie H. L. Wong Dr. Sai V. C. Vummaleti Prof. Luigi Cavallo Dr. Andrew J. P. White Prof. Steven P. Nolan Dr. King Kuok Hii 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13320-13327
A general synthetic route was used to prepare 15 new N‐heterocyclic carbene (NHC)–AgI complexes bearing anionic carboxylate ligands [Ag(NHC)(O2CR)], including a homologous series of complexes of sterically flexible ITent ligands, which permit a systematic spectroscopic and theoretical study of the structural and electronic features of these compounds. The complexes displayed a significant ligand‐accelerated effect in the intramolecular cyclisation of propargylic amides to oxazolidines. The substrate scope is highly complementary to that previously achieved by NHC–Au and pyridyl–AgI complexes. 相似文献
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Oxidative Addition to Palladium(0) Diphosphine Complexes: Observations of Mechanistic Complexity with Iodobenzene as Reactant
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Dr. Almira Kurbangalieva Dr. Duncan Carmichael Dr. K. K. Hii Dr. Anny Jutand Dr. John M. Brown 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):1116-1125
Using a combination of electrochemical and NMR techniques, the oxidative addition of PhX to three closely related bis‐diphosphine P2Pd0 complexes, where the steric bulk of just one substituent was varied, has been analysed quantitatively. For the complex derived from MetBu2P, a rapid reaction ensued with PhI following an associative mechanism, and data was also obtained by cyclic voltammetry for PhOTs, PhBr and PhCl, revealing distinct relative reactivities from the related (PCx3)2Pd complex (Cx=cyclohexyl) previously studied. The corresponding EttBu2P complex reacted more slowly with PhI and was studied by NMR spectroscopy. The reaction course indicated a mixture of pathways, with contribution from a component that was [PhI] independent. For the CxtBu2P complex, reaction was again monitored by NMR spectroscopy, and was even slower. At high PhI concentrations reaction was predominantly linear in [PhI], but at lower concentrations the [PhI] independent pathway was again observed, and an accelerating influence of the reaction product was observed over the concentration range. The NMR spectra of the EttBu2P and CxtBu2P complexes conducted in C6D6 shows some line broadening that was augmented on addition of PhI. NMR experiments carried out in parallel show that there is rapid ligand exchange between free phosphine and the Pd2Pd complex and also a slow ligand crossover between different P2Pd complexes. DFT calculations were carried out to further test the feasibility of C6D6 involvement in the oxidative addition process, and located Van der Waals complexes for association of the P2Pd0 complexes with either PhI or benzene. PhI or solvent‐assisted pathways for ligand loss are both lower in energy than direct ligand dissociation. Taken all together, these results provide a consistent explanation for the surprising complexity of an apparently simple reaction step. The clear dividing line between reactions that give a di‐ or monophosphine palladium complex after oxidative addition clarifies the participation of the ligand in coupling catalysis. 相似文献
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tert-Butyl perbenzoate is a substitute for benzoquinone for mild (room-temperature) Fujiwara-Moritani reactions between acetanilides and butyl acrylate under homogeneous conditions. The system was enhanced further by including Cu(OAc)(2) as a cocatalyst. Methyl methacrylate can be activated toward coupling under these conditions. 相似文献
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This tutorial review deals with recent advances in the use of phosphine-functionalised polymers in organic synthesis. In the first part of the review, some recent applications of polymer-supported palladium catalysts are reviewed, particularly recyclable catalysts for C-C and C-X bond formation with aryl bromide and chloride substrates. In the second half, novel applications of phosphine-functionalised polymers as reagents, scavengers, organocatalysts and linkers in organic chemistry are presented. Emphasis is placed on the synthesis of biologically active molecules. 相似文献
7.
D. Christopher Braddock King Kuok Hii John M. Brown 《Angewandte Chemie (International ed. in English)》1998,37(12):1720-1723
Different cyclization products are formed with different Lewis acids in the ene cyclization of 5-hexenals (see scheme on the right; a: methylaluminum bisphenoxide, b: Me2AlCl, c: Sc(OSO2CF3)3). This is not surprising, but it is gratifying that these result can be rationalized with an internally consistent model. 相似文献
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A new approach to the simultaneous measurement of refractive index and thickness based on the focus shifts of a convergent beam intercepted by a test plate is proposed. By using ray optics, a defined focus shift can be derived as a function of the refractive index and thickness as well as the angular position of the test plate with respect to the optical axis. From a pair of focus shifts obtained at two different angular positions, it is shown that the desired measurands can be simultaneously determined without prior knowledge of either parameter. A simulation result for the proposed concept based on graphically solving the equations of their respective focus shifts is presented. 相似文献
10.
Qadir M Cobb J Sheldrake PW Whittall N White AJ Hii KK Horton PN Hursthouse MB 《The Journal of organic chemistry》2005,70(5):1552-1557
Partially and fully reduced forms of benzo-fused eight- to ten-membered nitrogen heterocycles (1-benzazecines, 1-benzazonines and 1-benzazecines) have been prepared. Conformational features, transannular distances and dynamic behavior were studied using X-ray crystallography and VT NMR spectroscopy. The amide moiety in the nine-membered benzazonine ring 5b favors N-pyramidization, whereas the ten-membered benzazecine 5c adopts an amide twist. Molecular mechanics calculations reveals a correlation between the amide twist (tau) and ring stability. The dynamic behavior of the heterocycles in solution were also found to be dependent on the extent and nature of the amide distortion. We thus conclude that ring strain of these medium-sized heterocyclic rings is relieved through amide distortion, which leads to a more stable structure. 相似文献