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Schlagwörter:
configuration determination;conformation analysis;long-range residual dipolar coupling;molecular alignment;NMR spectroscopy
Zusammenfassung:
Together with the NOE and the J-coupling, the one-bond Residual Dipolar Coupling (RDC) that reports on the three dimensional orientation of an internuclear vector in the moleculear frame plays an important role in the conformation and configuration analysis of small molecules in solution by NMR. When the molecule has few C-H bonds or too many bonds are in parallel, the available RDCs may not suffice for obtaining 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 the 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 carbons, including non-protonated carbons, to complement the other NMR parameters. Using alignment tensors fitted directly to the total long range couplings (T=J+D), an easy and straightforward analysis of both the long range and one-bond RDCs has been performed on the natural product strychnine.
Long Range Residual Dipolar Couplings: A tool for determining the Configuration of Small Molecules (PDF Download Available). Available from: http://www.researchgate.net/publication/279850590_Long_Range_Residual_Dipolar_Couplings_A_tool_for_determining_the_Configuration_of_Small_Molecules [accessed Aug 31, 2015].
