Photo-Electroswitchable Arylaminoazobenzenes
| Autor: | Connor M. Meyers, Melody D. Kelley, Katie S. Keane, Silas C. Blackstock, David J. Warner, Carl Jacky Saint-Louis |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | The Journal of Organic Chemistry. 86:11341-11353 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/acs.joc.1c00763 |
| Popis: | Azobenzenes appended with a redox-active arylamino group (redox auxiliary, RA) are prepared and shown to undergo fast, complete, and catalytic Z→E azo isomerization upon electron loss from the RA unit of the azobenzene. The RA-azo structures can be reversibly (E→Z→E)n cycled by sequential photo- and electrostimulation. Due to the robust nature of the RA•+-azo radical cation chain carrying species, initiation of electron transfer (ET) catalysis occurs at low levels (1.0-0.04 mol %) of catalytic loading and is effective even at Z-RA-azo concentrations of 10-4-10-5 M, yielding TONs (turnover numbers) of 100-2300 under such dilute conditions. The RA-azo Z→E conversion is demonstrated using chemical oxidation (redox switching), electrochemical oxidation (electro switching), and photochemical oxidation (photoredox switching). The Z→E acceleration is shown to be at least 2 × 109-fold for RA-azo 5. DFT calculations on methyl yellow suggest that a N-centered radical cation of the RA group stabilizes the Z→E N-N twist transition state of the RA•+-azo, yielding a large reduction in the barrier for RA•+-azo compared to neutral RA-azo. The RA-azo structure class has nanomechanical features that can be toggled with photo- and electrostimulation, the latter offering a quick switch for complete Z→E conversion. |
| Databáze: | OpenAIRE |
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