Stabilizing water-sensitive reaction intermediates is challenging but desirable for guiding reactions to desired products in water. Herein, we report that labile imine and hemiaminal functional groups can be stabilized inside a synthetic container compound, a watersoluble naphthotube. The naphthotube features a primary amine group anchored in a cavity with both hydrogen bonding sites and hydrophobic surfaces. Aldehydes in bulk aqueous solution are trapped in the cavity by the amine to form hemiaminals stabilized through hydrogen bonding and hydrophobic effects. Dehydration of the hemiaminal to the imine is favored by the release of water from the hydrophobic microenvironment. Both the hemiaminals and imines can be detected at room temperature by NMR spectroscopy and mass spectrometry.

We found the binding affinities of amide naphthotube to neutral organic molecules in water are not influenced by most of small biomolecules, inorganic salts, and PBS and Tris buffers but are reduced in HEPES buffer through competitive binding. Nevertheless, salts do change the binding affinities of amide naphthotube to charged molecules through a screening effect.

Molecular recognition and spectral tuning of 13 organic dyes were achieved in water by amide naphthotubes. The association affinity to a styryl derivative is up to 4.5×107 M-1, which is...

Stabilizing water-sensitive reaction intermediates is challenging but desirable for guiding reactions to desired products in water. Herein, we report that labile imine and hemiaminal functional groups can be stabilized inside a synthetic container compound, a watersoluble naphthotube. The naphthotube features a primary amine group anchored in a cavity with both hydrogen bonding sites and hydrophobic surfaces. Aldehydes in bulk aqueous solution are trapped in the cavity by the amine to form hemiaminals stabilized through hydrogen bonding and hydrophobic effects. Dehydration of the hemiaminal to the imine is favored by the release of water from the hydrophobic microenvironment. Both the hemiaminals and imines can be detected at room temperature by NMR spectroscopy and mass spectrometry.