Stabilization of excited states by association: Emissive and reactive exciplexes from a non-emissive precursor
✍ Scribed by Yuan L. Chow; Carl I. Johansson
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 530 KB
- Volume
- 231
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
Acetylacetonatoboron
difluoride and benzene derivatives photolytically add to form aromatic ketone products, presumably through 2 + 2 photocycloaddition.
In dioxane, acetylacetonatoboron difluoride does not show detectable emission but fluoresces in the presence of added toluene, xylenes or mesitylene within a narrow excitation window of 300-320 nm. These broad emissions (A,, of 4 15-435 nm) were assigned to an exciplex that had lifetimes of 1.1-4.2 ns and fluorescence quantum yields of (3-7) X 10m3. These exciplexes were found to be precursors of the cycloaddition products through competitive quenching experiments. From kinetic evaluations, *AABF* was identified to be the reactive state with a lifetime of zz 1 ps.