title: Quantitative structural constraints for organic powders at natural isotopic abundance using dynamic nuclear polarization solid-state NMR spectroscopy.
abstract: A straightforward method is reported to quantitatively relate structural constraints based on (13)C-(13)C double-quantum build-up curves obtained by dynamic nuclear polarization (DNP) solid-state NMR to the crystal structure of organic powders at natural isotopic abundance. This method relies on the significant gain in NMR sensitivity provided by DNP (approximately 50-fold, lowering the experimental time from a few years to a few days), and is sensitive to the molecular conformation and crystal packing of the studied powder sample (in this case theophylline). This method allows trial crystal structures to be rapidly and effectively discriminated, and paves the way to three-dimensional structure elucidation of powders through combination with powder X-ray diffraction, crystal-structure prediction, and density functional theory computation of NMR chemical shifts.
authors: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397 Marseille cedex 20 (France).
authors: Giulia
authors: G
authors: Mollica
authors: Myriam
authors: M
authors: Dekhil
authors: Fabio
authors: F
authors: Ziarelli
authors: Pierre
authors: P
authors: Thureau
authors: Stéphane
authors: S
authors: Viel
keywords: natural isotopic abundance; solid-state NMR spectroscopy; spin-spin coupling; structure elucidation