Hydrogen Atom Transfer Induces Photodegradation in Carbonyl‐Based Multi‐Resonance TADF Emitters

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Autori principali: Changfeng Si, Elvie F. P. Beaumont, Jenn Zi Yu Tan, Mitchell J. Demchuk, Zachary M. Hudson
Natura: Artículo Open Access
Pubblicazione: Wiley 2026
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author Changfeng Si
Elvie F. P. Beaumont
Jenn Zi Yu Tan
Mitchell J. Demchuk
Zachary M. Hudson
author_facet Changfeng Si
Elvie F. P. Beaumont
Jenn Zi Yu Tan
Mitchell J. Demchuk
Zachary M. Hudson
Changfeng Si
Elvie F. P. Beaumont
Jenn Zi Yu Tan
Mitchell J. Demchuk
Zachary M. Hudson
collection Wiley Open Access
contents Hydrogen Atom Transfer Induces Photodegradation in Carbonyl‐Based Multi‐Resonance TADF Emitters Changfeng Si Elvie F. P. Beaumont Jenn Zi Yu Tan Mitchell J. Demchuk Zachary M. Hudson Angewandte Chemie International Edition ABSTRACT Nitrogen/carbonyl (N/C═O) based multi‐resonant thermally activated delayed fluorescence (MR‐TADF) emitters are attractive due to their narrowband delayed emission. Here, four MR‐TADF emitters were developed by sterically wrapping a tert ‐butylated DiKTa core. Through modulation of short‐range and through‐space charge transfer, triplet harvesting efficiency was boosted from 1% in tDiKTa to 52% in tDiKTa‐GCz ( k RISC  = 1.37 × 10 6  s −1 ) in degassed toluene. Surprisingly, however, these improvements were accompanied by rapid photodegradation, while that same degradation was not observed in toluene under air. Our studies revealed that triplet excited states trigger hydrogen‐atom transfer (HAT) from the solvent to the carbonyl group of the emitter, leading to fast, irreversible chemical change. Moreover, this phenomenon was found to be general for several previously published MR‐TADF compounds. Using natural population analysis and bond dissociation energies, we show that the electrophilicity of the donor hydrogen atom governs the observed reactivity. This work uncovers a previously unrecognized photochemical vulnerability in N/C═O MR‐TADF systems, and suggests that researchers studying them must be aware of their sensitivity toward HAT‐induced photodegradation. We also call for a careful re‐examination of published data on these compounds, as even brief exposure to light was sufficient to cause observable degradation in certain solvents. 10.1002/anie.2490607 http://creativecommons.org/licenses/by-nc/4.0/
doi_str_mv 10.1002/anie.2490607
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institution Wiley Open Access
license_str_mv http://creativecommons.org/licenses/by-nc/4.0/
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publisher Wiley
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spellingShingle Hydrogen Atom Transfer Induces Photodegradation in Carbonyl‐Based Multi‐Resonance TADF Emitters
Changfeng Si
Elvie F. P. Beaumont
Jenn Zi Yu Tan
Mitchell J. Demchuk
Zachary M. Hudson
Angewandte Chemie International Edition
Hydrogen Atom Transfer Induces Photodegradation in Carbonyl‐Based Multi‐Resonance TADF Emitters Changfeng Si Elvie F. P. Beaumont Jenn Zi Yu Tan Mitchell J. Demchuk Zachary M. Hudson Angewandte Chemie International Edition ABSTRACT Nitrogen/carbonyl (N/C═O) based multi‐resonant thermally activated delayed fluorescence (MR‐TADF) emitters are attractive due to their narrowband delayed emission. Here, four MR‐TADF emitters were developed by sterically wrapping a tert ‐butylated DiKTa core. Through modulation of short‐range and through‐space charge transfer, triplet harvesting efficiency was boosted from 1% in tDiKTa to 52% in tDiKTa‐GCz ( k RISC  = 1.37 × 10 6  s −1 ) in degassed toluene. Surprisingly, however, these improvements were accompanied by rapid photodegradation, while that same degradation was not observed in toluene under air. Our studies revealed that triplet excited states trigger hydrogen‐atom transfer (HAT) from the solvent to the carbonyl group of the emitter, leading to fast, irreversible chemical change. Moreover, this phenomenon was found to be general for several previously published MR‐TADF compounds. Using natural population analysis and bond dissociation energies, we show that the electrophilicity of the donor hydrogen atom governs the observed reactivity. This work uncovers a previously unrecognized photochemical vulnerability in N/C═O MR‐TADF systems, and suggests that researchers studying them must be aware of their sensitivity toward HAT‐induced photodegradation. We also call for a careful re‐examination of published data on these compounds, as even brief exposure to light was sufficient to cause observable degradation in certain solvents. 10.1002/anie.2490607 http://creativecommons.org/licenses/by-nc/4.0/
title Hydrogen Atom Transfer Induces Photodegradation in Carbonyl‐Based Multi‐Resonance TADF Emitters
topic Angewandte Chemie International Edition
url https://onlinelibrary.wiley.com/doi/10.1002/anie.2490607