title: Integrated Computational Protocol for the Analysis of Quadrupolar Splittings from Natural-Abundance Deuterium NMR Spectra in (Chiral) Oriented Media.
abstract: Despite its low natural abundance, deuterium NMR spectroscopy in weakly oriented (chiral) solvents gives easy access to deuterium residual quadrupolar couplings (2H-RQCs). These are formally equivalent to one-bond residual dipolar couplings ((13C-1H)-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,2H-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 a2H-RQC/DFT-based integrated computational protocol for the evaluation of the order parameters of aligned solutes by using singular-value decomposition. Several examples of2H-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.
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitária, CEP: 50, 740-540, Recife, PE, Brazil.|Institute of Organic Chemistry and Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, German.
authors.forename: Armando
authors.initials: A
authors.lastname: Navarro-Vázquez
authors.affiliation: RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Université Paris-Sud/Université Paris-Saclay, Bât. 410, 91405, Orsay cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Berdagué
authors.affiliation: RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Université Paris-Sud/Université Paris-Saclay, Bât. 410, 91405, Orsay cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lesot
mesh_terms: D003903:Deuterium / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D010455:Peptides; D003903:Deuterium
keywords: NMR spectroscopy; deuterium; hyphenated software; natural abundance; quadrupolar splitting; small molecules