Modification of the Photochemical Behaviour of Organic Molecules by Cyclodextrin: Geometric Isomerization of Stilbenes and Alkyl Cinnamates

Syamala, MS and Devanathan, S and Ramamurthy, V (1986) Modification of the Photochemical Behaviour of Organic Molecules by Cyclodextrin: Geometric Isomerization of Stilbenes and Alkyl Cinnamates. In: Journal of Photochemistry, 34 (2). pp. 219-229.

PDF sdarticle.pdf Restricted to Registered users only Download (850kB) | Request a copy

Abstract

The photochemical behaviour of stilbenes and alkyl cinnamates complexed to cyclodextrin has been investigated in aqueous media. In benzene, on direct excitation, the photostationary state of stilbene, p-methylstilbene, p-methoxystilbene and p-fluorostilbene contains predominantly the cis isomer (greater than 85%); excitation of cyclodextrin complexes of either cis- or trans-stilbene in aqueous media resulted in a photostationary state enriched in trans isomers. Furthermore, the cyclization product of cis-stilbene, i.e. phenanthrene, which is formed in detectable amounts in benzene solution was found to be absent during aqueous $\beta$-cyclodextrin irradiation. However, for cinnamate esters the behaviours in solution and in cyclodextrin are identical. Irradiation in organic solvents such as benzene and methanol and irradiation in aqueous $\beta$-cyclodextrin solution result in the same 1:1 mixture of cis and trans isomers. The above results have been rationalized on the basis of the influence of the cyclodextrin cavity on the decay ratio of the twisted olefins.

Item Type:	Journal Article
Publication:	Journal of Photochemistry
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	13 Apr 2008
Last Modified:	19 Sep 2010 04:44
URI:	http://eprints.iisc.ac.in/id/eprint/13730

Actions (login required)

View Item