scholarly journals Molecular and Silica-Supported Molybdenum Alkyne Metathesis Catalysts: Influence of Electronics and Dynamics on Activity Revealed by Kinetics, Solid-State NMR, and Chemical Shift Analysis

2017 ◽  
Vol 139 (48) ◽  
pp. 17597-17607 ◽  
Author(s):  
Deven P. Estes ◽  
Christopher P. Gordon ◽  
Alexey Fedorov ◽  
Wei-Chih Liao ◽  
Henrike Ehrhorn ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Alkyne Metathesis ◽  
Shift Analysis ◽  
Metathesis Catalysts ◽  
Chemical Shift Analysis

Structure of an elastin-mimetic polypeptide by solid-state NMR chemical shift analysis

Biopolymers ◽  
2003 ◽  
Vol 70 (2) ◽  
pp. 158-168 ◽  
Author(s):  
M. Hong ◽  
D. Isailovic ◽  
R.A. McMillan ◽  
V.P. Conticello
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Nmr Chemical Shift ◽  
Shift Analysis ◽  
Chemical Shift Analysis

scholarly journals Temperature-Dependent Solid-State NMR Proton Chemical-Shift Values and Hydrogen Bonding

2021 ◽  
Author(s):  
Alexander A. Malär ◽  
Laura A. Völker ◽  
Riccardo Cadalbert ◽  
Lauriane Lecoq ◽  
Matthias Ernst ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Chemical Shift ◽  
Hydrogen Bonds ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Proton Chemical Shift ◽  
Temperature Dependent

Temperature-dependent NMR experiments are often complicated by rather long magnetic-field equilibration times, for example occurring upon a change of sample temperature. We demonstrate that the fast temporal stabilization of the magnetic field can be achieved by actively stabilizing the temperature which allows to quantify the weak temperature dependence of the proton chemical shift which can be diagnostic for the presence of hydrogen bonds. Hydrogen bonding plays a central role in molecular recognition events from both fields, chemistry and biology. Their direct detection by standard structure determination techniques, such as X-ray crystallography or cryo-electron microscopy, remains challenging due to the difficulties of approaching the required resolution, on the order of 1 Å. We herein explore a spectroscopic approach using solid-state NMR to identify protons engaged in hydrogen bonds and explore the measurement of proton chemical-shift temperature coefficients. Using the examples of a phosphorylated amino acid and the protein ubiquitin, we show that fast Magic-Angle Spinning (MAS) experiments at 100 kHz yield sufficient resolution in proton-detected spectra to quantify the rather small chemical-shift changes upon temperature variations.<br>

Probing solid iminobis(diorganophosphine chalcogenide) systems with multinuclear magnetic resonance

2009 ◽  
Vol 87 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Bryan A Demko ◽  
Roderick E Wasylishen
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Magnetic Shielding ◽  
Chemical Shift Tensors ◽  
X Ray ◽  
X Ray Crystallography ◽  
Shielding Tensor ◽  
Nuclear Magnetic Shielding Tensors ◽  
Nuclear Magnetic

A 31P and 77Se solid-state NMR investigation of the iminobis(diorganophosphine chalcogenide) HN(R2PE)2 (R = Ph,iPr; E = O, S, Se) systems is presented. The NMR results are discussed in terms of the known HN(R2PE)2 structures available from X-ray crystallography. The phosphorus chemical shift tensors are found to be sensitive to the nature of the alkyl and chalcogen substituents. The nature of the R group also influences the selenium chemical shift tensors of HN(R2PSe)2 (R = Ph, iPr), which are shown to be sensitive to hydrogen bonding in the dimer structure of HN(Ph2PSe)2 and to the presence of disorder in the case of HN(iPr2PSe)2. Scalar relativistic ZORA DFT nuclear magnetic shielding tensor calculations were performed yielding the orientations of the corresponding chemical shift tensors. A theoretical investigation into the effect of the E-P···P-E “torsion” angle on the phosphorus and selenium chemical shift tensors of a truncated HN(Me2PSe)2 system indicates that the electronic effect of the alkyl group on the respective nuclear magnetic shielding tensors are more important than the steric effect of the E-P···P-E torsion angle.Key words: iminobis(diorganophosphine chalcogenide), solid-state NMR, 31P NMR, 77Se NMR, ZORA DFT.

Acetylenic Carbon-13 Chemical Shift Tensors for Diphenylacetylene and (η2-Diphenylacetylene)Pt(PPh3)2:  A Solid-State NMR and Theoretical Study

2006 ◽  
Vol 45 (6) ◽  
pp. 2461-2473 ◽  
Author(s):  
Kristopher J. Harris ◽  
Guy M. Bernard ◽  
Chris McDonald ◽  
Robert McDonald ◽  
Michael J. Ferguson ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Theoretical Study ◽  
Chemical Shift Tensors

Solid-state NMR chemical shift assignments of aquaporin Z in lipid bilayers

2018 ◽  
Vol 12 (2) ◽  
pp. 323-328
Author(s):  
Huayong Xie ◽  
Yongxiang Zhao ◽  
Jing Wang ◽  
Zhengfeng Zhang ◽  
Jun Yang
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Lipid Bilayers ◽  
Solid State Nmr ◽  
Chemical Shift Assignments ◽  
Nmr Chemical Shift ◽  
Nmr Chemical Shift Assignments ◽  
Aquaporin Z
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