Photosensitizer-free infrared-light-induced radical reactions
- 1Institute of Science Tokyo
- 2Japan Science and Technology Agency
- 3The University of Tokyo
Abstract
Infrared (IR) light is a source of mild energy that facilitates selective chemical reactions in a deeply penetrative manner. However, harvesting IR light through electronic excitation is challenging, and thus organic photoreactions at wavelengths over 1000 nm are scarce even with specialized photosensitizers. Herein, we report radical reactions driven by IR-A (~1000 nm) or IR-B light (~1500 nm) via vibration-mediated photolysis in the absence of a photosensitizer. The developed method promotes diverse transformations, including iodination, alkylation, and selenation reactions, with wider scope, higher selectivity, and deeper penetration through reaction media, compared with those of conventional irradiation with visible light. Applications include irradiation through obstacles, one-pot sequential transformations, and flow chemistry in opaque tubing. Experimental and spectroscopic studies reveal that the absorption of IR light via vibrational modes promotes photolysis that triggers radical chain reactions.
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BibTeX
@misc{dias2026photosensitizerfree,
title = {{Photosensitizer-free infrared-light-induced radical reactions}},
author = {Antônio Junio Araujo Dias and Yuki Nagashima},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv-2025-6xnhk/v2},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-6xnhk/v2},
note = {CC BY},
}
RIS
TY - UNPB
TI - Photosensitizer-free infrared-light-induced radical reactions
AU - Antônio Junio Araujo Dias
AU - Yuki Nagashima
PY - 2026
DA - 2026/10/06
PB - ChemRxiv
DO - 10.26434/chemrxiv-2025-6xnhk/v2
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-6xnhk/v2
AB - Infrared (IR) light is a source of mild energy that facilitates selective chemical reactions in a deeply penetrative manner. However, harvesting IR light through electronic excitation is challenging, and thus organic photoreactions at wavelengths over 1000 nm are scarce even with specialized photosensitizers. Herein, we report radical reactions driven by IR-A (~1000 nm) or IR-B light (~1500 nm) via vibration-mediated photolysis in the absence of a photosensitizer. The developed method promotes diverse transformations, including iodination, alkylation, and selenation reactions, with wider scope, higher selectivity, and deeper penetration through reaction media, compared with those of conventional irradiation with visible light. Applications include irradiation through obstacles, one-pot sequential transformations, and flow chemistry in opaque tubing. Experimental and spectroscopic studies reveal that the absorption of IR light via vibrational modes promotes photolysis that triggers radical chain reactions.
ER -