The Intermolecular NOE Depends on Isotope Selection: Short Range vs Long Range Behavior
Philipp Honegger, Maria Enrica Di Pietro, Franca Castiglione, Chiara Vaccarini, Alea Quant, Othmar Steinhauser, Christian Schröder, Andrea Mele
Abstract
The nuclear Overhauser effect (NOE) is a powerful tool in molecular structure elucidation, combining the subtle chemical shift of NMR and three-dimensional information independent of chemical connectivity. Its usage for intermolecular studies, however, is fundamentally limited by an unspecific long-ranged interaction behavior. This joint experimental and computational work shows that proper selection of interacting isotopes can overcome these limitations: Isotopes with strongly differing gyromagnetic ratios give rise to short-ranged intermolecular NOEs. In this light, existing NOE experiments need to be re-evaluated and future ones can be designed accordingly. Thus, a new chapter on intermolecular structure elucidation is opened.