Photochemistry of substituted methyl-α-arylcinnamates: ortho- and para-substitution
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- 作者：Evans ; Christopher H. ; Reynisson ; Jó ; hannes ; Geirsson ; Jó ; n K.F. ; Kvaran ; Á ; gú ; st ; et. al.
- 关键词：Photochemistry ; Methyl-α ; -arylcinnamates ; Ortho- and para-substitution
- 刊名：Journal of Photochemistry and Photobiology A: Chemistry
- 出版年：1998
- 出版时间：May 15, 1998
- 年：1998
- 卷：115
- 期：1
- 页码：57-61
- 全文大小：412 K
文摘
The 308 nm laser photochemistry of a series of substituted methyl-α-arylcinnamates has been studied in deoxygenated hexane and acetonitrile. Methyl-α-phenylcinnamate (1a) and derivatives that are p-substituted with electron withdrawing (chloro, 1b) or electron donating (methoxy, 1c) groups exhibited very similar photochemistry and spectroscopic properties, with the photostationary state (pss) composition ([E]/[Z]) being, on the average, 2.8 for these substances. By contrast the pss value for the o,o-dichloro substituted arylcinnamate (1d) was found to be only 0.5. This difference is discussed in terms of possible influences of the o,o-dichloro substituents on the excited state potential energy surface for arylcinnamate photoisomerization.