Photoinitiated Transient Self-Assembly in a Catalytically Driven Chemical Reaction Cycle

Area of Science:

• Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Chemically fueled chemical reaction networks (CRNs) are crucial for controlling dissipative self-assembly processes.
• A significant challenge involves storing chemical fuel-precursors ('pre-fuels') for controlled activation and deactivation within CRNs.
• Real-time light-based control over CRN catalysis remains an unachieved goal.

Purpose of the Study:

• To develop a photoinitiated CRN for transient self-assembly.
• To achieve real-time control over monomer activation and deactivation using light.
• To demonstrate tunable lifetimes of self-assembled structures.

Main Methods:

• Photoinitiation of a CRN using 450 nm visible light to activate monomers via photoredox catalysis.
• Conversion of monomer alcohol groups to aldehydes, inducing self-assembly into supramolecular fibers.
• Organometallic catalysis for monomer deactivation, triggered by pre-fuel hydrolysis releasing formate.
• Photo-uncaging of pre-fuel using 305 nm UV light to accelerate formate release and deactivation.

Main Results:

• Successful photoinitiation of self-assembly using visible light.
• Demonstration of transient supramolecular fiber formation.
• Achieved tunable deactivation rates by controlling formate release with UV light.
• Observed a twofold increase in deactivation speed upon UV irradiation.

Conclusions:

• A novel catalytically driven CRN is presented, controlled by visible and UV light.
• Transient self-assembly is achieved through photoactivated monomer formation.
• The system allows for tunable lifetimes of self-assembled structures via light-induced deactivation.