Kinetics and Mechanism of the Sensitized Photodegradation of Uracil-Modeling the Fate of Related Herbicides in Aqueous Environments†
2007; Wiley; Volume: 83; Issue: 3 Linguagem: Inglês
10.1562/2006-07-25-ra-982
ISSN1751-1097
AutoresErnesto Haggi, Néstor Blasich, José Luis Díaz, Marta Díaz, Walter A. Massad, F. Amat‐Guerri, Norman A. Garcı́a,
Tópico(s)Photochemistry and Electron Transfer Studies
ResumoPhotochemistry and PhotobiologyVolume 83, Issue 3 p. 520-525 Kinetics and Mechanism of the Sensitized Photodegradation of Uracil—Modeling the Fate of Related Herbicides in Aqueous Environments† Ernesto Haggi, Ernesto Haggi Universidad Nacional de la Patagonia Austral, UARG, Río Gallegos, ArgentinaSearch for more papers by this authorNéstor Blasich, Néstor Blasich Universidad Nacional de la Patagonia Austral, UARG, Río Gallegos, ArgentinaSearch for more papers by this authorJosé Díaz, José Díaz Universidad Nacional de la Patagonia Austral, UARG, Río Gallegos, ArgentinaSearch for more papers by this authorMarta Díaz, Marta Díaz Departamento de Química, FCN, Universidad Nacional de la Patagonia SJB, C. Rivadavia, ArgentinaSearch for more papers by this authorWalter A. Massad, Walter A. Massad Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, ArgentinaSearch for more papers by this authorFrancisco Amat-Guerri, Corresponding Author Francisco Amat-Guerri Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, Madrid, Spain *email: [email protected] (Norman A. García)Search for more papers by this authorNorman A. García, Corresponding Author Norman A. García Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina *email: [email protected] (Norman A. García)Search for more papers by this author Ernesto Haggi, Ernesto Haggi Universidad Nacional de la Patagonia Austral, UARG, Río Gallegos, ArgentinaSearch for more papers by this authorNéstor Blasich, Néstor Blasich Universidad Nacional de la Patagonia Austral, UARG, Río Gallegos, ArgentinaSearch for more papers by this authorJosé Díaz, José Díaz Universidad Nacional de la Patagonia Austral, UARG, Río Gallegos, ArgentinaSearch for more papers by this authorMarta Díaz, Marta Díaz Departamento de Química, FCN, Universidad Nacional de la Patagonia SJB, C. Rivadavia, ArgentinaSearch for more papers by this authorWalter A. Massad, Walter A. Massad Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, ArgentinaSearch for more papers by this authorFrancisco Amat-Guerri, Corresponding Author Francisco Amat-Guerri Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, Madrid, Spain *email: [email protected] (Norman A. García)Search for more papers by this authorNorman A. García, Corresponding Author Norman A. García Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina *email: [email protected] (Norman A. García)Search for more papers by this author First published: 09 May 2007 https://doi.org/10.1562/2006-07-25-RA-982Citations: 2 † This paper is part of a symposium-in print dedicated to Professor Eduardo A. Lissi on the occasion of his 70th birthday. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract The dye-sensitized photodegradation of uracil (UR), the parent compound of several profusely employed herbicides, has been studied as a model of their environmental fate. In order to mimic conditions frequently found in nature, aqueous solutions of UR have been irradiated with visible light in the presence of the natural sensitizer riboflavin (Rf). The results indicate that UR is photostable in acid media, but is quickly degraded in pH 7 or pH 9 solutions, where singlet molecular oxygen [O2(1Δg)] and, to a lesser extent, superoxide radical anion (O2•−)—both species photogenerated from triplet excited Rf, 3Rf*—participate in the photodegradation. At pH 7, UR is slowly degraded through an O2•−-mediated mechanism, whereas Rf disappears through its reaction with O2(1Δg) and, in the form of 3Rf*, with UR. 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