Controlling thermal reactivity with different colors of light

Abstract

The ability to switch between thermally and photochemically activated reaction channels with an external stimulus constitutes a key frontier within the realm of chemical reaction control. Here, we demonstrate that the reactivity of triazolinediones, powerful coupling agents in biomedical and polymer research, can be effectively modulated by an external photonic field. Specifically, we show that their visible light-induced photopolymerization leads to a quantitative photodeactivation, thereby providing a well-defined off-switch of their thermal reactivity. Based on this photodeactivation, we pioneer a reaction manifold using light as a gate to switch between a UV-induced Diels–Alder reaction with photocaged dienes and a thermal addition reaction with alkenes. Critically, the modulation of the reactivity by light is reversible and the individually addressable reaction pathways can be repeatedly accessed. Our approach thus enables a step change in photochemically controlled reactivity, not only in small molecule ligations, yet importantly in controlled surface and photoresist design.

Seeing the Light: Advancing Materials Chemistry through Photopolymerization

“…Using different irradiation wavelengths to simultaneously or sequentially activate distinct reaction pathways allows the possibility to perform complex synthetic protocols that would be tedious or impossible using conventional chemistry (Figure ) . Using chromic orthogonal reaction manifolds to synthesize and modify polymers also allows simplification of multistep processes, which can decrease production time and associated costs.…”

Expanding the Material Space of Biosustainable Poly(sophorolipids) by Modular Functionalization

“…ROMP of LSL leads to a polymer backbone exhibiting one 1,2‐disubstituted double bond per repeat unit ( Scheme ). This structural element lends itself to the triazolinedione–ene (TAD–ene) reaction, which has shown all characteristics of a click‐type reaction . The TAD–ene chemistry has already been utilized in a wide range of coupling reactions to modify biologically active compounds, while not interfering with their activity or reducing the biocompatibility .…”

Lichtinduzierte orthogonale Bildung kovalenter Bindungen durch zwei Wellenlängen

“…[10] Im Allgemeinen ist reihenfolgenabhängige l-Orthogonalitätm çglich, wenn ein lichtaktivierbares Substrat langwelliges Licht absorbiert, das von der anderen Substanz nicht absorbiert wird (langwelliges Licht induziert die erste Reaktion). [11] Vone iner orthogonalen Markierung von Biomolekülen mit 9,10-Phenanthrenchinonen und Te trazolen wurde berichtet, auch wenn die Studie keine ausgiebige Untersuchung der Selektivitätmittels NMR-Spektroskopie und Massenspektrometrie enthält. Bei Bestrahlung der ursprünglichen Mischung mit 420-nm-Licht wurde die letztgenannte Substanz zu 93 %u mgesetzt, während die erste zu 92 %e rhalten blieb.D iese Selektivität ist bemerkenswert füre ine lichtinduzierte Entschützung, allerdings sind die Reaktionen bei weitem nicht quantitativ,und es werden Bindungen gebrochen statt neu gebildet.…”