title: Long-Range Residual Dipolar Couplings: A Tool for Determining the Configuration of Small Molecules.
abstract: Together with NOE and J coupling, one-bond residual dipolar coupling (RDC), which reports on the three-dimensional orientation of an internuclear vector in the molecular frame, plays an important role in the conformation and configuration analysis of small molecules in solution by NMR spectroscopy. When the molecule has few C-H bonds, or too many bonds are in parallel, the available RDCs may not be sufficient to obtain the alignment tensor used for structure elucidation. Long-range RDCs that connect nuclei over multiple bonds are normally not parallel to the single bonds and therefore complement one-bond RDCs. Herein we present a method for extracting the long-range RDC of a chosen proton or group of protons to all remotely connected carbon atoms, including non-protonated carbon atoms. Alignment tensors fitted directly to the total long-range couplings (T=J+D) enabled straightforward analysis of both the long-range and one-bond RDCs for strychnine.
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen (Germany).
authors.forename: Nilamoni
authors.initials: N
authors.lastname: Nath
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen (Germany).
authors.forename: Edward J
authors.initials: EJ
authors.lastname: d'Auvergne
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen (Germany). cigr@nmr.mpibpc.mpg.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Griesinger
mesh_terms: D000465:Algorithms; D003292:Convulsants / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008968:Molecular Conformation; D011522:Protons; D013331:Strychnine / Q000737:chemistry*
chemical_list: D003292:Convulsants; D011522:Protons; D013331:Strychnine
keywords: NMR spectroscopy; configuration determination; conformation analysis; long-range residual dipolar coupling; molecular alignment