Limits...
¹⁹F NMR fingerprints: identification of neutral organic compounds in a molecular container.

Zhao Y, Markopoulos G, Swager TM - J. Am. Chem. Soc. (2014)

Bottom Line: We report a new approach to effectively "fingerprint" neutral organic molecules by using (19)F NMR and molecular containers.Spatial proximity of the analyte to the (19)F 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.

ABSTRACT
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 (19)F NMR and molecular containers. The encapsulation of analytes induces characteristic up- or downfield shifts of (19)F 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 (19)F 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.

Show MeSH

Related in: MedlinePlus

2D scatter of analytes based on the shiftsof 19F resonancesupon bonding: x axis, 2-OCHF3 fluorine(1) (−Δδ × 1000); y axis, 3,5-CF3 fluorine (4) (−Δδ× 1000).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4120996&req=5

fig6: 2D scatter of analytes based on the shiftsof 19F resonancesupon bonding: x axis, 2-OCHF3 fluorine(1) (−Δδ × 1000); y axis, 3,5-CF3 fluorine (4) (−Δδ× 1000).

Mentions: Multiple sensors with orthogonaldiscriminatory properties allowfor higher analyte resolution through a combined analysis of signalsfrom multiple receptors. Figure 6 is a plotusing the 19F NMR differences observed with 1 and 4. As a result of the orthogonal selectivity impartedby the spatial distribution variance, this combination provides betterresolution than that shown in Figure 3 wherein 1 and 2 were employed. Moreover, the resolutioncan be further enhanced by using signals collected by a third receptor.The use of 1, 2, and 4 enablesan interpretable 3D differentiation of all the analytes. As shownin Figure 7, all aromatic nitriles appear belowthe xy plane, benzyl nitriles give pronounced x values, and alkyl nitriles give smaller x values. Simple inspection of these figures reveals utility for thefacile classification of analytes.


¹⁹F NMR fingerprints: identification of neutral organic compounds in a molecular container.

Zhao Y, Markopoulos G, Swager TM - J. Am. Chem. Soc. (2014)

2D scatter of analytes based on the shiftsof 19F resonancesupon bonding: x axis, 2-OCHF3 fluorine(1) (−Δδ × 1000); y axis, 3,5-CF3 fluorine (4) (−Δδ× 1000).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120996&req=5

fig6: 2D scatter of analytes based on the shiftsof 19F resonancesupon bonding: x axis, 2-OCHF3 fluorine(1) (−Δδ × 1000); y axis, 3,5-CF3 fluorine (4) (−Δδ× 1000).
Mentions: Multiple sensors with orthogonaldiscriminatory properties allowfor higher analyte resolution through a combined analysis of signalsfrom multiple receptors. Figure 6 is a plotusing the 19F NMR differences observed with 1 and 4. As a result of the orthogonal selectivity impartedby the spatial distribution variance, this combination provides betterresolution than that shown in Figure 3 wherein 1 and 2 were employed. Moreover, the resolutioncan be further enhanced by using signals collected by a third receptor.The use of 1, 2, and 4 enablesan interpretable 3D differentiation of all the analytes. As shownin Figure 7, all aromatic nitriles appear belowthe xy plane, benzyl nitriles give pronounced x values, and alkyl nitriles give smaller x values. Simple inspection of these figures reveals utility for thefacile classification of analytes.

Bottom Line: We report a new approach to effectively "fingerprint" neutral organic molecules by using (19)F NMR and molecular containers.Spatial proximity of the analyte to the (19)F 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.

ABSTRACT
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 (19)F NMR and molecular containers. The encapsulation of analytes induces characteristic up- or downfield shifts of (19)F 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 (19)F 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.

Show MeSH
Related in: MedlinePlus