Cross-Fitting of Residual Dipolar Couplings

ABSTRACT

Residual dipolar couplings (RDCs) are important NMR-parameters for the structure determination of organic molecules. In this article we describe how RDCs can be used to effectively transfer structural information by cross-fitting the anisotropic parameters of molecules with similar overall structure. Using the example of 5-α-cholestan-3-one and cholesterol, it is possible to distinguish diastereomers of the compounds by cross-fitting with transferred alignment tensors, even when strongly reduced subsets of RDCs are used. It is also demonstrated that RDCs can be used for direct crossfitting even in flexible parts of the molecules that are sufficiently similar in structure and dynamic behavior. The crossfitting approach as a general tool is discussed in details.