Solvent dependent femtosecond E-Z photoisomerization dynamics of hemiindigo derivatives
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Summary
This summary is machine-generated.Photochromic dye hemiindigo
Area Of Science
- Photochemistry
- Dye Chemistry
- Spectroscopy
Background
- Hemiindigo is a photochromic dye combining indigo and stilbene structures.
- Photochromic dyes undergo reversible color changes upon light exposure.
- Understanding solvent effects is crucial for tuning dye properties.
Purpose Of The Study
- Investigate the solvent dependence of E-Z isomerization dynamics in hemiindigo dyes.
- Determine the excited state lifetimes of E- and Z- isomers.
- Elucidate the role of solvent polarity and hydrogen bonding on photoisomerization.
Main Methods
- Femtosecond transient absorption spectroscopy was employed.
- Two hemiindigo derivatives, DABI and its N-propyl analog, were studied.
- Solvent properties like polarity and hydrogen bonding ability were varied.
Main Results
- Excited (S1) state lifetimes were less than 100 picoseconds.
- Lifetimes showed significant dependence on solvent polarity and H-bonding.
- Z-DABI lifetime decreased from 76 ps in toluene to 9.3 ps in methanol.
Conclusions
- Stronger solvent H-bonds in the S1 state accelerate nonradiative decay.
- Increased H-bonding reduces the quantum yield of photoisomerization.
- Similar solvent-mediated processes are proposed for indigo carmine.
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