Guest Exchange among Distinct Water-Soluble Supramolecular Nanocages

Area of Science:

• Supramolecular Chemistry
• Chemical Kinetics
• Photocatalysis

Background:

• Supramolecular host-guest systems mimic biological receptor-substrate interactions.
• Studying substrate competition in crowded biological environments is challenging.
• Elucidating substrate exchange dynamics between multiple protein hosts is crucial.

Purpose of the Study:

• To model guest exchange dynamics between two distinct supramolecular cages.
• To quantitatively describe guest exchange rates on the millisecond timescale.
• To demonstrate visible-light-driven catalysis controlled by guest exchange.

Main Methods:

• Biomimetic modeling of guest exchange dynamics.
• Utilizing 1,4-dimethylnaphthalene as the guest molecule.
• Monitoring exchange via 1H NMR spectroscopy and line-shape simulations.

Main Results:

• Guest exchange between octahedral and square-pyramidal cages was observed on an intermediate timescale.
• Quantitative guest exchange rates were determined on the millisecond timescale.
• Visible-light-driven hetero C-C coupling reactions were successfully performed in water.

Conclusions:

• Supramolecular cage guest exchange dynamics can be quantitatively modeled.
• Controlled supramolecular photoredox catalysis is achievable using multiple cages.
• This work provides a framework for multistep organic transformations in aqueous media.