Weitzel, Naomi and Tsutskiridze, Armaz and Bramowski, Julia and Koenig, Burkhard and Hirsch, Thomas (2025) Fully Sensitized Upconversion Nanoparticles as Efficient Catalysts for NIR-Driven UV Photochemistry. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 64 (46). ISSN 1433-7851, 1521-3773
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Biological photosynthesis harnesses energy from multiple photons to drive complex chemical transformations. In contrast, chemical photocatalysis typically relies on single-photon excitation, limiting its applicability in high-energy-demanding reactions. Upconversion nanoparticles (UCNPs), which can convert multiple low-energy near-infrared (NIR) photons into a single higher-energy photon, offer a promising solution. We synthesized and systematically improved NaYbF4:Tm@NaYF4 nanoparticles, focusing on sensitizer concentration, dopant spacing, and shell thickness to enhance ultraviolet (UV) and blue emission. Compared to low doped NaYF4:Yb, Tm systems, our nanoparticles exhibited significantly improved brightness, with a 210-fold enhancement in UV emission at 345 nm. Using these UCNPs as heterogeneous photocatalysts, we achieved efficient [2 + 2] photocycloadditions and Patern & ograve;-B & uuml;chi reactions under 980 nm excitation, with turnover numbers (TON) exceeding 290,000 and turnover frequencies (TOF) up to 8.52 s-1. Additionally, the UCNP catalysts were readily recoverable. Our results provide a rational framework for tailoring UCNPs for energy-demanding photochemical reactions and establish their potential in synthetic and biomedical applications that require deep-tissue, low-phototoxicity excitation.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOTOREDOX CATALYSIS; INFRARED LIGHT; LUMINESCENCE ENHANCEMENT; 2+2 PHOTOCYCLOADDITIONS; TRANSITION-METAL; IN-VITRO; SURFACE; ORIGINS; DESIGN; SHELL; Cycloaddition; Doping; Luminescence; Nanoparticles; Photocatalysis |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik Chemistry and Pharmacy > Institut für Organische Chemie > Lehrstuhl Prof. Dr. Burkhard König |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 28 Jul 2026 06:02 |
| Last Modified: | 28 Jul 2026 06:02 |
| URI: | https://pred.uni-regensburg.de/id/eprint/66038 |
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