In situ photochemical transformations of monomers of 2-methoxy-4-(prop-1-enyl)phenol (isoeugenol) and 2-methoxy-4-(prop-2-enyl)phenol (eugenol) isolated in low temperature matrices were induced by tunable UV laser light, and the progress of the reactions was followed by FTIR spectroscopy. Conformer-selective E ↔ Z geometrical isomerizations could be successfully induced by irradiation at different wavelengths from the 310-298 nm range in the isoeugenol molecule, contains an asymmetrically substituted exocyclic C═C bond. Photolysis of both studied compounds was also observed, with H-atom shift from the OH group and formation of two types of long-chain conjugated ketenes. The photoproduced ketenes were found to undergo subsequent photodecarbonylation. Interpretation of the observed photoprocesses was supported by quantum chemical calculations undertaken at different levels of theory (DFT, MP2, QCISD).
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http://dx.doi.org/10.1021/jp306339g | DOI Listing |
J Chem Phys
March 2014
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
A matrix isolation study of the infrared spectra and structure of anethole (1-methoxy-4-(1-propenyl)benzene) has been carried out, showing the presence of two E conformers (AE1, AE2) of the molecule in the as-deposited matrices. Irradiation using ultraviolet-tunable laser light at 308-307 nm induced conformationally selective phototransformations of these forms into two less stable Z conformers (AZ1, AZ2). The back reactions were also detected upon irradiation at 301 nm.
View Article and Find Full Text PDFJ Phys Chem B
September 2012
Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland.
In situ photochemical transformations of monomers of 2-methoxy-4-(prop-1-enyl)phenol (isoeugenol) and 2-methoxy-4-(prop-2-enyl)phenol (eugenol) isolated in low temperature matrices were induced by tunable UV laser light, and the progress of the reactions was followed by FTIR spectroscopy. Conformer-selective E ↔ Z geometrical isomerizations could be successfully induced by irradiation at different wavelengths from the 310-298 nm range in the isoeugenol molecule, contains an asymmetrically substituted exocyclic C═C bond. Photolysis of both studied compounds was also observed, with H-atom shift from the OH group and formation of two types of long-chain conjugated ketenes.
View Article and Find Full Text PDFJ Chem Phys
January 2012
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
Monomers of phenol and its ring-perdeuterated isotopologue phenol-d(5) were isolated in argon matrices at 15 K. The infrared (IR) spectra of these species were recorded and analyzed. In situ photochemical transformations of phenol and phenol-d(5) were induced by tunable UV laser light.
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