Organic photochemistry from 1 to 4 eV

Published on September 28, 2012

Organic photochemistry utilizes electronic excitation with electromagnetic radiation in the region between 1 electron volt (eV) and 8 eV, corresponding formally to a wavelength region between 1240 nanometers (nm) and 155 nm.

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Organic photochemistry utilizes electronic excitation with electromagnetic radiation in the region between 1 electron volt (eV) and 8 eV, corresponding formally to a wavelength region between 1240 nanometers (nm) and 155 nm. Short-wavelength excitation can lead to direct electron detachment or to photoinduced electron transfer if substrates are excited in the presence of appropriate electron donors or acceptors. This property is demonstrated experimentally by a 308 nm excitation of an aqueous solution of an electron acceptor-donor pair by a xenon chloride (XeCl) excimer radiation source in a falling-film reactor. On the other hand, in the case of the long-wavelength excitation region, direct excitation is unlikely and sensitization by energy-transfer sensitizers is often used. This effect is demonstrated experimentally by excitation of a solution of an organic dye in the presence of oxygen by means of visible light, which leads to the formation of singlet oxygen with an excitation energy of less than 1 eV. Singlet oxygen shows high reactivity with unsaturated organic substrates and is used to produce organic peroxides.

Griesbeck Group | University of Cologne, Germany

Axel Griesbeck studied chemistry in Munich and learned how to teach chemistry and photochemistry from Klaus Gollnick, Waldemar Adam, Dieter Seebach, and the late Howard Zimmerman in Munich, Würzburg, Zürich and Madison. He has been a professor of organic chemistry and photochemistry at the University of Cologne, Germany since 1994 and spent several research semesters in Japan, Korea, and Taiwan. His research interest is organic and mechanistic photochemistry, especially photocatalysis, photooxygenation and photocycloadditions.

Nestor Nazarov is a 3rd year PhD student in the Griesbeck photochemistry group funded by the RheinEnergie Stiftung and working on the photodegradation (VUV radiation, 172 nm and 308 nm) of organic pollutants, especially polyfluorinated hydrocarbons and perfluorinated tensides.

Sarah Sillner is a 3rd year PhD student in the Griesbeck photochemistry group working on the synthesis of artemisinin conjugates and the synthesis of other endoperoxides as well as on the pharmaceutical activities of these compounds.

Maria Bräutigam is a 1st year PhD student in the Griesbeck photochemistry group funded by the Bayer-Cologne graduate program in Pharmacology and Experimental Therapeutics, working on the development of novel Glutathione S-transferase P1 inhibitors as anticancer agents.

Sources

The original research article is published in the Open Access Beilstein Journal of Organic Chemistry and is part of the Thematic Series Photocycloadditions and photorearrangements.

Griesbeck, A. G., Photocycloadditions and photorearrangements, Beilstein J. Org. Chem. 2011, 7, 111–112. doi:10.3762/bjoc.7.15

The original research article is published in the Open Access Beilstein Journal of Organic Chemistry and is part of the Thematic Series Photocycloadditions and photorearrangements.

Griesbeck, A. G., Photocycloadditions and photorearrangements, Beilstein J. Org. Chem. 2011, 7, 111–112. doi:10.3762/bjoc.7.15

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