Surface photoreactions of 2-benzoylcyclopentanones: Silica gel surface as a possible field bringing out the latent reactivity of dispersed molecules
✍ Scribed by Tadashi Hasegawa; Yoshihiro Imase; Manabu Imada; Kazushige Kumakura; Michikazu Yoshioka
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 480 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0894-3230
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✦ Synopsis
Irradiation of 2-benzoyl-and 2-(p-methylbenzoyl)cyclopentanone (la and lb), which have the lowest n,z* excited states and showed no photoreactivities in inert solvents, neat or in the solid state, gave two types of products on a silica gel surface; one arose from the cleavage of the C-C bond a to the benzoyl group and the other arose from the cyclopentanone C-1-C-2 bond cleavage. Analysis of Langmuir adsorption isotherm of l a by a non-linear least-squares method revealed that 7 . 9 ~ mol of la was spread as a monomolecular layer over 1 g of silica gel. The photoreactivity of la on the surface was very sensitive to the coverage; the efficiency of disappearance of l a decreased monotonically from 100% at low coverages to zero at nearly 100% coverage. Close packing of molecules of 1 on the surface diminished the photoreactivity. A silica gel surface provided a possible dispersion field for bringing out the latent photoreactivity of 1.