Diaryltriazolium Photoswitch: Reaching a Millisecond Cycloreversion with High Stability and NIR Absorption

• Published in: Angewandte Chemie International Edition Vol. 63; no. 8; pp. e202318015 - n/a
• Main Authors: Kolarski, Dušan, Steinbach, Pit, Bannwarth, Christoph, Klaue, Kristin, Hecht, Stefan
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 19.02.2024; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Absorption; Alkylation; Chemical synthesis; Chemistry; Chemistry, Multidisciplinary; Click Chemistry; Diarylethenes; Diaryltriazolium; Fatigue strength; Isomers; Photochromism; Photoswitches; Physical Sciences; Science & Technology; Thermal stability; Diaryltriazolium; Photoswitches; DESIGN; Photochromism; Click Chemistry; IRREVERSIBLE PHOTOCHROMIC SYSTEMS; Diarylethenes; MOLECULES
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202318015

The exceptional thermal stability of diarylethene closed isomers enabled many applications but also prevented utilization in photochromic systems that require rapid thermal reversibility. Herein, we report the diaryltriazolium (DAT+) photoswitch undergoing thermal cycloreversion within a few milliseconds and absorption of the closed form in the near‐infrared region above 900 nm. Click chemistry followed by alkylation offers modular and fast access to the electron‐deficient DAT+ scaffold. In addition to excellent fatigue resistance, the introduced charge increases water solubility, rendering this photoswitch an ideal candidate for exploring biological applications. Diaryltriazolium photoswitch (DAT+) was prepared by alkyne‐azide cycloaddition followed by alkylation. Due to a charged heterocyclic bridge, the closed isomer of DAT+ exhibits the most bathochromically shifted absorption maximum and the shortest thermal half‐life reported for any diarylethene thus far. The new photoswitch exhibits excellent fatigue resistance and is well water‐soluble.