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Integrated Computational Protocol for the Analysis of Quadrupolar Splittings from Natural‐Abundance Deuterium NMR Spectra in (Chiral) Oriented Media
Author(s) -
NavarroVázquez Armando,
Berdagué Philippe,
Lesot Philippe
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201601423
Subject(s) - deuterium , chemistry , deuterium nmr , liquid crystal , residual dipolar coupling , nuclear magnetic resonance spectroscopy , nmr spectra database , chemical physics , molecule , fluorine 19 nmr , computational chemistry , nuclear magnetic resonance crystallography , anisotropy , dipole , spectral line , stereochemistry , materials science , organic chemistry , physics , atomic physics , optoelectronics , astronomy , quantum mechanics
Despite its low natural abundance, deuterium NMR spectroscopy in weakly oriented (chiral) solvents gives easy access to deuterium residual quadrupolar couplings ( 2 H‐RQCs). These are formally equivalent to one‐bond residual dipolar couplings (( 13 C– 1 H)‐RDCs) for calculation of the Saupe tensor, and provide similar information for the study of molecular structure and orientational behavior. Because the quadrupolar interaction is one order of magnitude larger than the dipolar one, 2 H‐RQC analysis is a much more sensitive tool for the detection of subtle structural differences and also tiny differences in molecular alignment, such as those observed for different enantiomers in chirally aligned media. To promote the analytical advantages of anisotropic, natural‐abundance deuterium NMR (NAD NMR) spectroscopy in the organic chemistry community, we describe a 2 H‐RQC/DFT‐based integrated computational protocol for the evaluation of the order parameters of aligned solutes by using singular‐value decomposition. Several examples of 2 H‐RQC‐assisted analysis of chiral and prochiral molecules dissolved in various polypeptide lyotropic chiral liquid crystals are reported. The role of the molecular shape in the ordering mechanism was investigated through the determination of intertensor angles between alignment tensors and inertia tensors by using the proposed protocol.