| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1493788 | Optical Materials | 2015 | 5 Pages |
•Stable Z isomers using chromophore solvent interactions were obtained.•The kinetic parameters describing E–Z–E isomerization of azo-derivatives were calculated.•Thermal relaxation was tuned from substitution pattern and solvent polarity.
In this paper, a detailed isomerization study of a series of 2,4-nitro/cyan substituted azobenzenes is conducted by UV–Vis spectroscopy. The experiments, carried out in both toluene and N, N′-dimethylformamide, reveal an intriguing behavior. Interestingly, the disubstituted azo-derivatives display stable Z isomers in DMF, while in toluene they exhibit very fast relaxation. In addition, the azo-derivatives thermally isomerize from the metastable Z form to the thermodynamically stable E isomer through either inversion route or rotational mechanism, depending on the chemical nature of the substituents and on the solvent polarity.
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