Photoinitiated Transient Self‐Assembly in a Catalytically Driven Chemical Reaction Cycle.

Chemically fueled chemical reaction networks (CRNs) are essential in controlling dissipative self‐assembly. A key challenge in the field is to store chemical fuel‐precursors or "pre‐fuels" in the system that are converted into activating or deactivating fuels in a catalytically controlled CRN. In addition, real‐time control over catalysis in a CRN by light is highly desirable, but so far not yet achieved. Here we show a catalytically driven CRN that is photoinitiated with 450 nm light, producing activated monomers that go on to perform transient self‐assembly. Monomer activation proceeds via photoredox catalysis, converting the monomer alcohol groups into the corresponding aldehydes that self‐assemble into large supramolecular fibers. Monomer deactivation is achieved by organometallic catalysis that relies on pre‐fuel hydrolysis to release formate (i.e. the deactivating fuel). Additionally, irradiation with 305 nm light accelerates the release of formate by photo‐uncaging the pre‐fuel, leading to a factor of ca. 2 faster deactivation of the monomer. Overall, we show transient self‐assembly upon visible light photoactivation, and tunable life‐times by ultraviolet light. [ABSTRACT FROM AUTHOR]