Visible-Light Photoswitching by Azobenzazoles
| Autor: | Isolde Sandler, Junming Ho, Jonathon E. Beves, Aaron D. W. Kennedy, Joakim Andréasson |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Absorption spectroscopy
Photoswitch 010405 organic chemistry Organic Chemistry Protonation General Chemistry Benzoxazole 010402 general chemistry Photochemistry 01 natural sciences Catalysis 0104 chemical sciences 3. Good health Photochromism chemistry.chemical_compound chemistry Benzothiazole Isomerization Visible spectrum |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany). 26(5) |
| ISSN: | 1521-3765 |
| Popis: | Three visible-light responsive photoswitches are reported, azobis(1-methyl-benzimidazole) (1), azobis(benzoxazole) (2) and azobis(benzothiazole) (3). Photostationary distributions are obtained upon irradiation with visible light comprising approximately 80 % of the thermally unstable isomer, with thermal half-lives up to 8 min and are mostly invariant to solvent. On protonation, compound 1H+ has absorption extending beyond 600 nm, allowing switching with yellow light, and a thermal half-life just under 5 minutes. The two isomers have significantly different pKa values, offering potential as a pH switch. The absorption spectra of 2 and 3 are insensitive to acid, although changes in the thermal half-life of 3 indicate more basic intermediates that significantly influence the thermal barrier to isomerization. These findings are supported by high-level ab initio calculations, which validate that protonation occurs on the ring nitrogen and that the Z isomer is more basic in all cases. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text