Nagao Masanori, Mundsinger Kai, Barner-Kowollik Christopher
Department of Chemical Engineering, Kyushu University, 744 Motooka Nishi-ku, Fukuoka, Japan.
School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.
Angew Chem Int Ed Engl. 2025 Feb 10;64(7):e202419205. doi: 10.1002/anie.202419205. Epub 2025 Jan 15.
We demonstrate that single-chain nanoparticles (SCNPs) - compact covalently folded single polymer chains - can increase photocatalytic performance of an embedded catalytic center, compared to the comparable catalytic system in free solution. In particular, we demonstrate that the degree of compaction allows to finely tailor the catalytic activity, thus evidencing that molecular confinement is a key factor in controlling photocatalysis. Specifically, we decorate a linear parent polymer with both photoreactive chalcone moieties as well as Ru(bpy) catalytic centers. We initially construct a SCNP via a photosensitized [2+2] cycloaddition at 510 nm and demonstrate that the SCNP formation is substantially more efficient when the Ru(bpy) units are part of the polymer chain instead of as free molecules in solution. Subsequently, we employ the same Ru(bpy) units as photocatalysts in a model reaction employing pyrene units as charge transfer moieties. We establish that the photocatalytic activity increases as the polymer becomes more compact, reaching peak efficiency, followed by a subsequent decline as the SCNP becomes too compact. Thus, we identify a goldilocks regime of catalyst confinement via SCNP compaction for use in photocatalysis.
我们证明，与游离溶液中的可比催化体系相比，单链纳米颗粒（SCNPs）——紧密共价折叠的单聚合物链——可以提高嵌入催化中心的光催化性能。特别是，我们证明了紧密程度能够精细地调节催化活性，从而证明分子限域是控制光催化的关键因素。具体而言，我们用光反应性查耳酮部分以及Ru(bpy)催化中心修饰线性母体聚合物。我们最初通过在510 nm处进行光敏[2+2]环加成反应构建了一个SCNP，并证明当Ru(bpy)单元是聚合物链的一部分而非溶液中的游离分子时，SCNP的形成效率显著更高。随后，我们在以芘单元作为电荷转移部分的模型反应中，将相同的Ru(bpy)单元用作光催化剂。我们发现，随着聚合物变得更加紧密，光催化活性增加，达到峰值效率，随后随着SCNP变得过于紧密而下降。因此，我们确定了通过SCNP紧密程度实现的用于光催化的催化剂限域的适度状态。
