Photochemistry
DASA photoswitches work in chloroform if N-methyl
Open access · cc by · source: Europe PMC
First-generation donor–acceptor Stenhouse adducts with a small N-methyl substituent switch well in chloroform; kinetics split photoisomerisation from cyclisation.
Study at a glance
- Design
- Other — Synthesis and photoswitching kinetics/fatigue of DASA photochromes 1–14
- N
- Molecular photochrome SAR — no sample N
- Population
- Donor–acceptor Stenhouse adduct photoswitches
- Outcome
- Photoswitching amplitude, kinetics, and fatigue related to substituents
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Most alkyl-amine DASAs share λmax ≈ 567 nm; DASA 1 drops 94% absorbance on irradiation. N-methyl is needed for good switching; ring-closing rates track substituent parameters. Fatigue can exceed 99% recovery per cycle.
Methodology
Authors prepared DASAs 1–14, assigned linear/cyclic isomers by NMR and X-ray, measured photoswitching and 100–1000 cycle fatigue, and fitted a three-species kinetic model.
Limitations
Aqueous switching is not the focus; compound 14 (aniline) behaves differently; air still causes fatigue versus argon.
How this study connects
Role on claims
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This library holds 10 empirical chemistry papers on photochemistry with isolated findings, rates or spectra rather than reviews.
Evidence for the claim as stated.
First-generation donor–acceptor Stenhouse adducts with a small N-methyl substituent switch well in chloroform; kinetics split photoisomerisation from cyclisation.
Evidence for the claim as stated.
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.
Related papers in this topic
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