To use all functions of this page, please activate cookies in your browser.
my.chemeurope.com
With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
Photochemical reactionA photochemical reaction is a chemical reaction which is induced by light. Examples of photochemical organic reactions are electrocyclic reactions, photoisomerization and Norrish reactions. Additional recommended knowledgeThe basic requirements for photochemical reactions are:
Photoexcitation is the first step in a photochemical process where the reactant is elevated to an excited state of higher energy. Photosensitizers absorb radiation and transfer energy to the reactant. The opposite process is called quenching when a photoexited state is deactivated by a chemical reagent. The first ever photochemical reaction was described by Trommsdorf in 1834.[1] He observed that crystals of the compound α-santonin when exposed to sunlight turned yellow and burst. In a 2007 study the reaction was described as a succession of three steps taking place within a single crystal.[2] The first step is a rearrangement reaction to a cyclopentadienone intermediate 2, the second one a dimerization in a Diels-Alder reaction (3) and the third one a intramolecular [2+2]cycloaddition (4). The bursting effect is attributed to a large change in crystal volume on dimerization.
References
Categories: Photochemistry | Organic reactions |
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Photochemical_reaction". A list of authors is available in Wikipedia. |