A non-singlet oxygen mediated reaction photoinduced by phenalenone, a universal reference for singlet oxygen sensitization

Photosensitized oxidations involve the generation of radicals (type I mechanism) and/or the production of singlet molecular oxygen (1O2) (type II mechanism). Phenalenone (PN) is one of the well-known type II photosensitizers and is widely used as a 1O2 reference sensitizer. In this work, we have stu...

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Bibliographic Details
Authors: Lorente, Carolina, Arzoumanian, Emmanuel, Castaño Espinal, Diana Carolina, Oliveros, Esther, Thomas, Andrés Héctor
Format: article
Status:Published version
Publication Date:2014
Country:Argentina
Institution:Consejo Nacional de Investigaciones Científicas y Técnicas
Repository:CONICET Digital (CONICET)
Language:English
OAI Identifier:oai:ri.conicet.gov.ar:11336/5171
Online Access:http://hdl.handle.net/11336/5171
Access Level:Open access
Keyword:Singlet Oxygen
Electron Transfer
Phenalenone
Tryptophan
https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
Description
Summary:Photosensitized oxidations involve the generation of radicals (type I mechanism) and/or the production of singlet molecular oxygen (1O2) (type II mechanism). Phenalenone (PN) is one of the well-known type II photosensitizers and is widely used as a 1O2 reference sensitizer. In this work, we have studied the interaction of tryptophan (Trp) with the excited states of PN, the production of 1O2 in the presence of Trp, the formation of radicals and the kinetics of the photodegradation of Trp under different experimental conditions. In contrast to what is usually assumed, we have proven that PN is also able to act as a type I photosensitizer. Moreover, we have demonstrated that the predominant mechanism of the photosensitization of Trp by PN involves an electron transfer initiated-process.