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Photoreduction of perylenediimide (PDI) derivatives has been widely studied for use in photocatalysis, hydrogen evolution, photo‐responsive gels, and organic semiconductors. Upon light irradiation, the radical anion (PDI⋅−) can readily be obtained, whereas further reduction to the dianion (PDI2−) is rare. Here we show that full 2‐electron photoreduction can be achieved using UVC light: 1) in anaerobic conditions by 'direct photoreduction' of PDI aggregates, or 2) by 'indirect photoreduction' in aerobic conditions due to acetone ketyl radicals. The latter strategy is also efficient for other dyes, such as naphthalenediimide (NDI) and methylviologen (MV2+). Efficient photoreduction on the minute time‐scale using simple LED light in aerobic conditions is attractive for use in dissipative light‐driven systems and materials. [ABSTRACT FROM AUTHOR]

Hierarchical organization of self‐assembled structures into superstructures is omnipresent in Nature but has been rarely achieved in synthetic molecular assembly due to the absence of clear structural rules. We herein report on the self‐assembly of scissor‐shaped azobenzene dyads which form discrete nanotoroids that further organize into 2D porous networks. The steric demand of the peripheral aliphatic units diminishes the trend of the azobenzene dyad to constitute stackable nanotoroids in solution, thus affording isolated (unstackable) nanotoroids upon cooling. Upon drying, these nanotoroids organize at graphite surface to form well‐defined 2D porous networks. The photoirradiation with UV and visible light enabled reversible dissociation and reconstruction of nanotoroids through the efficient trans↔cis isomerization of azobenzene moieties in solution. [ABSTRACT FROM AUTHOR]

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., (© 2024 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.)