ZnO as the Versatile Co-Catalyst for Oxygen-Tolerant External ATRP

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

ZnO as the Versatile Co-Catalyst for Oxygen-Tolerant External ATRP

Popis výsledku v původním jazyce

Zinc oxide (ZnO) is a remarkable semiconductor with piezoelectric and photocatalytic properties. For this reason, ZnO has often been used in mechanically controlled atom transfer radical polymerization (mechanoATRP), but its potential in photo-induced ATRP (photoATRP) remains underexplored. Previous works reported numerous limitations, including high oxygen sensitivity, tedious deoxygenation, ligands in stoichiometric excess to Cu, long polymerization times, and low yields.Herein, well-defined wurtzite ZnO nanocrystals were synthesized and employed as universal cocatalysts for mechano- and photoATRP of (meth)acrylates. Both techniques yielded polymers with excellent control over the molecular weight, but stimulation by photoirradiation resulted in much faster reactions, as compared to mechano-stimulation (conversion of91 % in 1 h vs. 54% in 5 h). We developed a method that makes ATRPs possible without prior deoxygenation, even in reactors with aerated headspace, since ZnO serves as a strong oxygen scavenger. Simultaneously, ZnO acted as an electron donor, reducing [Br-Cu(II)/Lt deactivators to [Cu(I)/Lt activators even in the absence of an excess ligand ( equimolar ligand to Cu ratio ). Co-catalyzed photoATRP was feasible with very low ZnO loadings (&gt; 0.32 mg/mL), making ZnO one ofthe most potent heterogeneous catalysts for ATRP. The ZnO co-catalyzed photoATRP was tuned for excellent temporal control, and synthesized polymers exhibited high chain-end fidelity, as demonstrated by chain extension experiments. Finally, we present a novel concept for combining ZnO co-catalyzed mechano- and photoATRP techniques for facile ATRP workflow and better practicality.

Název v anglickém jazyce

ZnO as the Versatile Co-Catalyst for Oxygen-Tolerant External ATRP

Popis výsledku anglicky

Zinc oxide (ZnO) is a remarkable semiconductor with piezoelectric and photocatalytic properties. For this reason, ZnO has often been used in mechanically controlled atom transfer radical polymerization (mechanoATRP), but its potential in photo-induced ATRP (photoATRP) remains underexplored. Previous works reported numerous limitations, including high oxygen sensitivity, tedious deoxygenation, ligands in stoichiometric excess to Cu, long polymerization times, and low yields.Herein, well-defined wurtzite ZnO nanocrystals were synthesized and employed as universal cocatalysts for mechano- and photoATRP of (meth)acrylates. Both techniques yielded polymers with excellent control over the molecular weight, but stimulation by photoirradiation resulted in much faster reactions, as compared to mechano-stimulation (conversion of91 % in 1 h vs. 54% in 5 h). We developed a method that makes ATRPs possible without prior deoxygenation, even in reactors with aerated headspace, since ZnO serves as a strong oxygen scavenger. Simultaneously, ZnO acted as an electron donor, reducing [Br-Cu(II)/Lt deactivators to [Cu(I)/Lt activators even in the absence of an excess ligand ( equimolar ligand to Cu ratio ). Co-catalyzed photoATRP was feasible with very low ZnO loadings (&gt; 0.32 mg/mL), making ZnO one ofthe most potent heterogeneous catalysts for ATRP. The ZnO co-catalyzed photoATRP was tuned for excellent temporal control, and synthesized polymers exhibited high chain-end fidelity, as demonstrated by chain extension experiments. Finally, we present a novel concept for combining ZnO co-catalyzed mechano- and photoATRP techniques for facile ATRP workflow and better practicality.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10404 - Polymer science

Projekt

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Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů