Molecular Differentiation and Fingerprinting Based on the Conformational Diversity of Cage

The rapid identification of chemical species of interest, particularly for those are structurally similar, is still very challenging. We report here a new strategy for molecular differentiation and fingerprinting, utilizing the diversity in conformational distribution of hosts upon encapsulating different guests. With a cage as an example, we show that the coefficients of conformational distribution can be used for rapidly differentiating guest molecules with similar structures; furthermore, the coefficients can be used along with the 1H NMR chemical shifts of the complexes to provide a two- or multiple-dimensional parameter to efficiently fingerprint molecules, which can be utilized further for identifying analytes. A distinct feature of this strategy is that it focuses on only the molar ratio of different host stereoisomers, technically ignoring other complexation details thus greatly simplifying the comparisons/identifications to provide a promising tool for rapid species detection/identification in the fields of pharmaceuticals analysis, environmental monitoring, and more.