Author(s):
Reva, I. D. 
; Nowak, M. J. ; Lapinski, L. ; Fausto, R.
Date: 2006
Persistent ID: http://hdl.handle.net/10316/5071
Origin: Estudo Geral - Universidade de Coimbra
Document details
UV-induced photochemistry of methyl coumalate (methyl 2-pyrone-5-carboxylate) i...
Description
Photochemical transformations of methyl coumalate have been studied by matrix-isolation technique. Two photoreactions were induced by UV ([lambda] > 295 nm) light: isomerisation to the Dewar form and [alpha]-bond cleavage leading to the open-ring aldehyde-ketene. The first photoprocess was found to be strongly dominating. Experimental evidence of photoreversibility of both photoisomerisation processes has been provided. Upon [lambda] > 200 nm irradiation, the photochemically formed monomeric Dewar species underwent decarboxylation, with production of methoxycarbonyl-substituted cyclobutadiene. This antiaromatic photoproduct was experimentally observed for the first time. All the photoproduced species were identified by comparison of their IR spectra with the spectra calculated at the DFT(B3LYP)/6-311++G(d,p) level. http://www.sciencedirect.com/science/article/B6TFN-4KNM6J9-C/1/0d0e18c865aa8f1c05481a9479a09329
Photochemical transformations of methyl coumalate have been studied by matrix-isolation technique. Two photoreactions were induced by UV ([lambda] > 295 nm) light: isomerisation to the Dewar form and [alpha]-bond cleavage leading to the open-ring aldehyde-ketene. The first photoprocess was found to be strongly dominating. Experimental evidence of photoreversibility of both photoisomerisation processes has been provided. Upon [lambda] > 200 nm irradiation, the photochemically formed monomeric Dewar species underwent decarboxylation, with production of methoxycarbonyl-substituted cyclobutadiene. This antiaromatic photoproduct was experimentally observed for the first time. All the photoproduced species were identified by comparison of their IR spectra with the spectra calculated at the DFT(B3LYP)/6-311++G(d,p) level. http://www.sciencedirect.com/science/article/B6TFN-4KNM6J9-C/1/0d0e18c865aa8f1c05481a9479a09329
Document Type
Article
Language English
Language English
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