TY - JOUR
T1 - Visible-light-mediated Diels-Alder reactions under single-chain polymer confinement
T2 - investigating the role of the crosslinking moiety on catalyst activity
AU - Spicuzza, Michael
AU - Gaikwad, Shweta Prakesh
AU - Huss, Steven
AU - Lee, Annemarie A.
AU - Craescu, Cristina V.
AU - Griggs, Anna
AU - Joseph, Joshmi
AU - Puthenpurayil, Mark
AU - Lin, Wilson
AU - Matarazzo, Christopher
AU - Baldwin, Stanley
AU - Perez, Victoria
AU - Rodriguez-Acevedo, Diego Alejandro
AU - Swierk, John R.
AU - Elacqua, Elizabeth
N1 - Publisher Copyright:
© 2024 The Royal Society of Chemistry.
PY - 2024/4/10
Y1 - 2024/4/10
N2 - Macromolecular scaffolds are rapidly emerging in catalysis owing to the ability to control catalyst placement at precise locations. This spatial proximity allows for enhanced catalyst activity that may not be observed using small molecules. Herein, we describe a triphenylpyrylium (TPT)-based visible-light active single-chain polymer nanoparticle (SCNP) that facilitates the radical cation [4 + 2]-cycloaddition. We find that the catalytic activity is highly dependent on the styrylarene comonomer used, wherein it can act as a redox mediator under confinement, increasing the catalytic turnover (TON) by up to 30 times in comparison to free TPT in solution. Mechanistic studies indicate that TPT excited states are quenched by the acene, with the resultant radical cation formed from naphthalene-based SCNPs able to proceed in oxidizing the dienophile in the elementary step of the reaction, while leading to near quantitative yields of the cycloadduct. The TPT-SCNP demonstrates enhanced photocatalyst efficiency compared to molecular TPT, and is able to be recycled and reused in three iterations of the reaction prior to decreased performance from photobleaching. Our results overall suggest that the confined nature of the SCNP and spatial proximity of acene-based pendants enforces their participation as cocatalytic redox mediators that impart enhanced photoredox catalysis under confinement.
AB - Macromolecular scaffolds are rapidly emerging in catalysis owing to the ability to control catalyst placement at precise locations. This spatial proximity allows for enhanced catalyst activity that may not be observed using small molecules. Herein, we describe a triphenylpyrylium (TPT)-based visible-light active single-chain polymer nanoparticle (SCNP) that facilitates the radical cation [4 + 2]-cycloaddition. We find that the catalytic activity is highly dependent on the styrylarene comonomer used, wherein it can act as a redox mediator under confinement, increasing the catalytic turnover (TON) by up to 30 times in comparison to free TPT in solution. Mechanistic studies indicate that TPT excited states are quenched by the acene, with the resultant radical cation formed from naphthalene-based SCNPs able to proceed in oxidizing the dienophile in the elementary step of the reaction, while leading to near quantitative yields of the cycloadduct. The TPT-SCNP demonstrates enhanced photocatalyst efficiency compared to molecular TPT, and is able to be recycled and reused in three iterations of the reaction prior to decreased performance from photobleaching. Our results overall suggest that the confined nature of the SCNP and spatial proximity of acene-based pendants enforces their participation as cocatalytic redox mediators that impart enhanced photoredox catalysis under confinement.
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U2 - 10.1039/d4py00282b
DO - 10.1039/d4py00282b
M3 - Article
C2 - 38721413
AN - SCOPUS:85190743043
SN - 1759-9954
VL - 15
SP - 1833
EP - 1838
JO - Polymer Chemistry
JF - Polymer Chemistry
IS - 18
ER -