19F NMR Fingerprints: Identification of Neutral Organic Compounds in a Molecular Container

Improved methods for quickly identifying neutral organic compounds and differentiation of analytes with similar chemical structures are widely needed. We report a new approach to effectively “fingerprint” neutral organic molecules by using 19F NMR and molecular containers. The encapsulation of analytes induces characteristic up- or downfield shifts of 19F resonances that can be used as multidimensional parameters to fingerprint each analyte. The strategy can be achieved either with an array of fluorinated receptors or by incorporating multiple nonequivalent fluorine atoms in a single receptor. Spatial proximity of the analyte to the 19F is important to induce the most pronounced NMR shifts and is crucial in the differentiation of analytes with similar structures. This new scheme allows for the precise and simultaneous identification of multiple analytes in a complex mixture.