Efficient, Near‐Infrared Light‐Induced Photoclick Reaction Enabled by Upconversion Nanoparticles

Abstract

Photoclick reactions combine the selectivity of classical click chemistry with the high precision and spatiotemporal control afforded by light, finding diverse utility in surface customization, polymer conjugation, photocross‐linking, protein labeling, and bioimaging. Nonetheless, UV light, pivotal in prevailing photoclick reactions, poses issues, especially in biological contexts, due to its limited tissue penetration and cell‐toxic nature. Herein, a reliable and versatile strategy of activating the photoclick reactions of 9,10‐phenanthrenequinones (PQs) with electron‐rich alkenes (ERAs) with near infrared (NIR) light transduced by spectrally and structurally customized upconversion nanoparticles (UCNPs) is introduced. Under NIR irradiation, the UCNPs become UV/blue nanoemitters uniformly distributed in the reaction system. Enabled by the customized UCNPs, 800 or 980 nm light effectively activates the photocycloaddition reactions via radiative energy transfer in both general and triplet–triplet energy transfer (TTET)‐mediated PQ‐ERA systems. In particular, the novel sandwich structure UCNPs achieve the click reaction with up to 76% production yield in 10 min under NIR light irradiation. Meanwhile, the tricky side effect of photoclick product absorption‐induced quenching is successfully circumvented from the fine‐tuning of the upconversion spectrum. Moreover, through‐tissue irradiation experiments, the authors show that the UCNP‐PQ‐ERA reaction unlocks the full potential of photoclick reactions for in vivo applications.

The relevance of sustainable laboratory practices

“…114,144,161,162 Crucially, these aspects should also nd their way into the curriculum of Bachelors, Masters and High School programs. 155 There are several examples to improve chemistry education and to stimulate a systematic thinking approach into the minds of early researchers and students. [164][165][166][167][168][169] We cannot expect future scientists to create sustainable products if they are not taught how to think sustainable.…”

“…- Achieving full atom economy ( e.g. , click chemistry) 155 presents the most efficient reaction with practically no waste. 156,157 Here sustainable feedstocks such as biomass, plastic waste and CO 2 should be valorised.…”

“…113,115,153 Prevent waste by designing and executing the experiments with high technical standards. 154 -Achieving full atom economy (e.g., click chemistry) 155 presents the most efficient reaction with practically no waste. 156,157 Here sustainable feedstocks such as biomass, plastic waste and CO 2 should be valorised.…”

With or without a co-solvent? highly efficient ultrafast phenanthrenequinone-electron rich alkene (PQ-ERA) photoclick reactions

“…17 Taking advantage of ERAs (vinyl ethers, enamines) in PQ-ERA photocycloadditions, our group discovered that in this photoclick system, which simultaneously introduces a fluorescent moiety, the reaction rates, photoreaction quantum yields ( Φ P up to 65%) and fluorescence quantum yields ( Φ F up to 97%) can be drastically increased. 14,18–20…”