نتایج جستجو برای: proton shift
تعداد نتایج: 201000 فیلتر نتایج به سال:
A reaction between (E)-trimethyl(3,3,3-trifluoroprop-1-en-1-yl)silane (1) and arylaldehydes 2 was triggered by fluoride anions to afford aryl 3,3,3-trifluoropropyl ketones 3 in moderate to good yield. A mechanistic study of this reaction indicated that it occurred via an allyl alkoxide (4). A subsequent 1,3-proton shift of the benzylic proton of 4 forms 3. This reaction involves oxidative 3,3,3...
The PoP(Proof of Principle) FFAG accelerator, which was the world first FFAG proton synchrotron, was constructed at KEK. After the first proton beam acceleration of FFAG, we studied various aspects of the PoP FFAG. The observed beam orbit shift during the acceleration was consistent with the simulation result. It was confirmed that the beam intensity increased about five times with multi-bunch ...
The kinetics of water exchange across the membrane of class II chloroplasts has been studied by two NMR methods. Both methods utilize Dy(en)3+ (en = ethylenediamine) to induce a transmembranal chemical shift the order of 40 Hz in the water proton resonance. The shift reagent is impermeant to the chloroplast membrane, inert as a redox reagent, soluble at millimolar concentrations at neutral pH, ...
A four-dimensional 13C/13C-edited NOESY experiment is described which dramatically improves the resolution of protein NMR spectra and enables the straightforward assignment of nuclear Overhauser effects involving aliphatic and/or aromatic protons in larger proteins. The experiment is demonstrated for uniformly (greater than 95%) 13C-labeled interleukin 1 beta, a protein of 153 residues and 17.4...
This communication describes a chiral base-catalyzed asymmetric [1,3]-proton shift of trifluoromethyl ketimines, giving a wide variety of trifluoromethyl aldimines containing various functional groups with up to 94% ee.
The proton-polarizability contribution to the muonic-hydrogen Lamb shift is a major source of theoretical uncertainty in extraction proton charge radius. An empirical evaluation this effect, based on structure functions, requires systematically improvable calculation "subtraction function", possibly using lattice QCD. We consider different subtraction point, with aim accessing function directly...
It has been shown that the acetamido methyl protons of N-acetyl-D-glucosamine undergo a chemical shift to higher fields in their proton magnetic resonance spectrum when the inhibitor is bound to lysozyme. The observed chemical shift in the presence of the enzyme is different for the CP and /3-anomeric forms of Z-acetamido-Z-deoxy-D-glucopyranose indicating either a difference in the afhnity of ...
The displacement of the excess charge of the proton in acid solutions is caused by a structure migration of groupings H 5 0 2 + or H 9 0 4 + . The processes which take place during structure migration are discussed on the basis of results gained in IR-investigations. In an electrical field the structure migration is given a preferred direction. The hydrogen bond with the tunneling proton in H 5...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید