Light-driven molecular trap enables bidirectional manipulation of dynamic covalent systems

Area of Science:

• Organic Chemistry
• Photochemistry
• Supramolecular Chemistry

Background:

• Chemical reactions in closed systems favor thermodynamically stable products.
• Microscopic reversibility governs bond formation and dictates reaction direction.
• Controlling reactions against thermodynamic favorability is a significant challenge.

Purpose of the Study:

• To demonstrate light-driven control over reversible bimolecular reactions.
• To bypass the principle of microscopic reversibility using light.
• To regulate dynamic covalent systems via external stimuli.

Main Methods:

• Utilizing photoswitchable carbonyl electrophiles and N-nucleophiles.
• Employing light-driven tautomerization cycles to reverse electrophile reactivity ('umpolung').
• Applying specific wavelengths of light (red or blue) to control reaction direction.

Main Results:

• Achieved selective and nearly quantitative intermolecular bond formation and scission.
• Demonstrated control over thermodynamically disfavored condensation/hydrolysis equilibria.
• Showcased light-induced C=N exchange for dynamic system regulation.

Conclusions:

• Light can override thermodynamic control in chemical reactions.
• Wavelength-dependent photochemistry enables precise control over bond dynamics.
• This approach offers a molecular, bidirectional alternative to macroscopic separation techniques like the Dean-Stark trap.