scholarly journals Origins of Small Proton Chemical Shift Differences in Monodeuterated Methyl Groups

2017 ◽  
Vol 82 (17) ◽  
pp. 8943-8949 ◽  
Author(s):  
O. Maduka Ogba ◽  
Stuart J. Elliott ◽  
David A. Kolin ◽  
Lynda J. Brown ◽  
Sebastian Cevallos ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Methyl Groups ◽  
Proton Chemical Shift

scholarly journals An Examination of Factors Influencing Small Proton Chemical Shift Differences in Nitrogen-Substituted Monodeuterated Methyl Groups

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1610
Author(s):  
Stuart Elliott ◽  
O. Ogba ◽  
Lynda Brown ◽  
Daniel O’Leary
Keyword(s):  
Chemical Shift ◽  
Local Environment ◽  
Computational Approach ◽  
Methyl Groups ◽  
Proton Chemical Shift ◽  
Isotropic Chemical Shift ◽  
Spin States ◽  
Chemical Shift Difference ◽  
Factors Influencing ◽  
Different Populations

Monodeuterated methyl groups have previously been demonstrated to provide access to long-lived nuclear spin states. This is possible when the CH2D rotamers have sufficiently different populations and the local environment is chiral, which foments a non-negligible isotropic chemical shift difference between the two CH2D protons. In this article, the focus is on the N-CH2D group of N-CH2D-2-methylpiperidine and other suitable CH2D-piperidine derivatives. We used a combined experimental and computational approach to investigate how rotameric symmetry breaking leads to a 1H CH2D chemical shift difference that can subsequently be tuned by a variety of factors such as temperature, acidity and 2-substituted molecular groups.

Comprehensive Strategy for Proton Chemical Shift Prediction: Linear Prediction with Nonlinear Corrections

2014 ◽  
Vol 54 (2) ◽  
pp. 419-430 ◽  
Author(s):  
Reino Laatikainen ◽  
Tommi Hassinen ◽  
Juuso Lehtivarjo ◽  
Mika Tiainen ◽  
Juha Jungman ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Linear Prediction ◽  
Proton Chemical Shift ◽  
Comprehensive Strategy ◽  
Chemical Shift Prediction

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>

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