Single-Molecule Stoichiometry of Supramolecular Complexes

Area of Science:

• Supramolecular chemistry
• Photophysics
• Single-molecule spectroscopy

Background:

• Characterizing supramolecular complexes at low concentrations (<1 nM) is challenging.
• Understanding host-guest interactions is crucial for designing functional materials.

Purpose of the Study:

• To introduce single-molecule microscopy for rapid quantification of supramolecular complex photophysics.
• To demonstrate the method's utility with cucurbit[n]uril (CB[n]) host-guest systems.

Main Methods:

• Utilizing single-molecule microscopy to analyze fluorescent host-guest complexes.
• Employing cucurbit[n]uril (CB[n]) macrocycles and a fluorescent guest (Ant910Me).
• Analyzing photon detection thresholds in aqueous media and hydrogels.

Main Results:

• Successfully quantified photophysical properties and stoichiometries of supramolecular complexes at ultra-low concentrations.
• Differentiated host-guest complex behavior in solution and noninvasively within hydrogels.
• Demonstrated the method's applicability in both aqueous and hydrogel environments.

Conclusions:

• Single-molecule microscopy offers a rapid and sensitive approach for supramolecular complex analysis.
• This technique facilitates the design of next-generation materials with tailored properties.
• The method provides new insights into host-guest complexation dynamics.