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By examining structurally similar halogenated xanthene dyes, this study establishes a guiding principle for resolving structure−property− performance relationships in the photocontrolled PET-RAFT polymerization system (PET-RAFT: photoinduced electron/energy transfer−reversible addition−fragmentation chain transfer). We investigated the effect of the halogen substituents on the photophysical and electrochemical properties of the xanthene dyes acting as photocatalysts and their resultant effect on the performance of PET-RAFT polymerization. Consideration of the structure− property−performance relationships allowed design of a new xanthene photocatalyst, where its photocatalytic activity (oxygen tolerance and polymerization rate) was successfully optimized for PET-RAFT polymerization. We expect that this study will serve as a theoretical framework in broadly guiding the design of high performance photocatalysts for organic photocatalysis.

Highly conjugated three-dimensional covalent organic frameworks (3D COFs) were constructed based on spirobifluorene cores linked via imine bonds (SP-3D-COFs) with novel interlacing conjugation systems. The crystalline structures were confirmed by powder X-ray diffraction and detailed structural simulation. A 6-or 7-fold interpenetration was formed depending on the structure of the linking units. The obtained SP-3D-COFs showed permanent porosity and high thermal stability. In application for solar cells, simple bulk doping of SP-3D-COFs to the perovskite solar cells (PSCs) substantially improved the average power conversion efficiency by 15.9% for SP-3D-COF 1 and 18.0% for SP-3D-COF 2 as compared to the reference undoped PSC, while offering excellent leakage prevention in the meantime. By aid of both experimental and computational studies, a possible photoresponsive perovskite−SP-3D-COFs interaction mechanism was proposed to explain the improvement of PSC performance after SP-3D-COFs doping.

The development of advanced materials based on well-defined polymeric architectures is proving to be a highly prosperous research direction across both industry and academia. Controlled radical polymerization techniques are receiving unprecedented attention, with reversible-deactivation chain growth procedures now routinely leveraged to prepare exquisitely precise polymer products. Reversible addition-fragmentation chain transfer (RAFT) polymerization is a powerful protocol within this domain, where the unique chemistry of thiocarbonylthio (TCT) compounds can be harnessed to control radical chain growth of vinyl polymers. With the intense recent focus on RAFT, new strategies for initiation and external control have emerged that are paving the way for preparing well-defined polymers for demanding applications. In this work, the cutting-edge innovations in RAFT that are opening up this technique to a broader suite of materials researchers are explored. Emerging strategies for activating TCTs are surveyed, which are providing access into traditionally challenging environments for reversible-deactivation radical polymerization. The latest advances and future perspectives in applying RAFT-derived polymers are also shared, with the goal to convey the rich potential of RAFT for an ever-expanding range of high-performance applications.

An iron(III) (FeCl3·6H2O) catalyst was found to be an active catalyst for initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) of methyl methacrylate (MMA), using triphenylphosphine (PPh3) as a ligand and azobis(isobutyronitrile) (AIBN) as a thermal radical initiator, and 1,4-(2-bromo-2-methylpropionato)benzene (BMPB2) as an ATRP initiator. Effects of reaction temperature, catalyst concentration and AIBN concentration on polymerization were investigated. These results showed that the catalyst was highly efficient for the ICAR ATRP of MMA. For example, even if the catalyst concentration decreased to 34 ppm, the polymerization with the molar ratio of [MMA]0/[BMPB2]0/[FeCl3·6H2O]0/[PPh3]0/[AIBN]0 = 500/1/0.03/1.5/0.1 could be carried out at 60 °C with a conversion 70.4% in 32 h. At the same time, the molecular weight of the obtained PMMA with a narrow molecular weight distribution (M w/M n = 1.37) was consistent with the theoretical one.

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We explore the utilization of aromatic diselenides as new low temperature exchangeable monomers for their utilization in thermosets.

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