Photocatalyzed organic reactions in aqueous media present significant challenges, primarily due to the poor solubility of substrates and catalyst deactivation. In this study, we introduce a novel approach to overcoming these limitations by developing single-chain nanoparticles (SCNPs) [1,2] capable of efficiently catalyzing a variety of organic reactions in water using visible light as the sole energy source. These artificial photosynthases (APS) [3,4] are constructed by decorating a high-molecular-weight copolymer, poly(oligo(ethylene glycol) methyl ether methacrylate-co-2-acetoacetoxyethyl methacrylate) (poly(OEGMA-coAEMA)), with iridium(III) cyclometalated complex pendants. The resulting functionalized copolymers self-assemble into noncovalent, amphiphilic SCNPs in water, enabling efficient visible-light photocatalysis.
The APS demonstrate remarkable photocatalytic activity for four distinct organic transformations in aqueous media, including the unprecedented [2+2] photocycloaddition of vinyl arenes and the α-arylation of N-arylamines. Additionally, the aerobic oxidation of 9-substituted anthracenes and the β-sulfonylation of α-methylstyrene were successfully performed. The amphiphilic nature of the SCNPs, combined with their high molecular weight and finely tuned composition, facilitates the formation of stable, self-assembled structures that enhance photocatalytic efficiency.
Herein, we will present the design, synthesis, and
characterization of these APS, highlighting their ability to perform challenging organic transformations in water under mild conditions. By merging metal-mediated photocatalysis with the protein-mimetic architecture of SCNPs, this work opens new avenues for the development of sustainable and efficient photocatalytic systems. The results demonstrate the potential of APS to broaden the scope of visible-light photocatalysis, offering a promising platform for future applications in green chemistry and organic synthesis.

Οver the past decade, extensive research on surface-initiated atom transfer radical polymerization (SI-ATRP) has demonstrated the potential of photochemically induced reactions, offering financial and ecological benefits¹. Specifically, SI-photoATRP reactions, which have been successfully employed for the formation of well-defined polymethacrylate brushes, offer significant advantages, such as minimization of the metal catalyst concentration and considerable oxygen tolerance.
In the present work, SI-photoATRP is employed to obtain well-defined PIPOx brushes on silicon substrates. Since similar studies have highlighted the sensitivity of the polymerization rate and control to the catalyst system, here various metal salts, including CuBr₂ and CuCl₂, were studied at concentrations ranging from 50 to 1600 ppm relative to the monomer² ³. Additionally, the influence of ligands with varying reactivities and different solvents was investigated. Furthermore, post-polymerization reactions with conventional drug molecules denoted the potential use of the novel substrates as biosensors. Finally, the antibiofouling properties were evaluated by examining the adhesion of 3T3 fibroblast model cells.

Over the last years itaconic acid has drawn considerable attention as novel renewable building block for bio-based polymers. It is produced via a biotechnological process in large quantities (>80.000 t/a) and at competitive prices (~2 €/kg), which makes it a very attractive monomer also from an industrial point of view. It has been used as (co )monomer in radical polymerization reactions, as well as polycondensation reactions with a wide range of applications. [1,2]
Herein we present our most recent work on itaconic acid-based polymeric materials. First, UV-curing materials with a focus on additive manufacturing as alternative to standard (meth)acrylic acid-based materials will be shown. [3,4] Depending on the composition of the poly(ester itaconates) a wide range of thermal and mechanical properties of the cured materials can be obtained.
Subsequently, the synthesis of structurally different itaconic esters and their application in radical polymerization will be reported. Here a significant influence of the different ester groups on the reactivity of the radical polymerization reaction was observed, which could help to further improve the radical polymerization of itaconic acid-based materials.