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Article: Ultrafast Time Resolved Spectroscopic Studies on the Generation of the Ketyl-Sugar Biradical by Intramolecular Hydrogen Abstraction Among Ketoprofen and Purine Nucleoside Dyads.

TitleUltrafast Time Resolved Spectroscopic Studies on the Generation of the Ketyl-Sugar Biradical by Intramolecular Hydrogen Abstraction Among Ketoprofen and Purine Nucleoside Dyads.
Authors
Issue Date2015
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/joc
Citation
The Journal of Organic Chemistry, 2015, v. 80 n. 7, p. 3462–3470 How to Cite?
AbstractIntramolecular hydrogen abstraction reactions among ketoprofen (KP) and purine nucleoside dyads have been proposed to form ketyl-sugar biradical intermediates in acetonitrile. Femtosecond transient absorption studies on KP and purine nucleoside dyads reveal that the triplet state of the KP moiety of the dyads with cisoid structure decay faster (due to an intramolecular hydrogen abstraction reaction to produce a ketyl-sugar biradical intermediate) than the triplet state of the KP moiety of the dyads with transoid structure detected in acetonitrile solvent. For the cisoid 5-KP-dG dyad, the triplet state of the KP moiety decays too fast to be observed by ns-TR3, only the ketyl-sugar biradical intermediates are detected by ns-TR3 in acetonitrile. For the cisoid 5-KP-dA dyad, the triplet states of the KP moiety could be observed at early nanosecond delay times and then it quickly undergoes intramolecular hydrogen abstraction to produce a ketyl-sugar biradical intermediate. For the cisoid 5-KPGly-dA and transoid 3-KP-dA dyads, the triplet state of the KP moiety had a longer lifetime due to the long distance chain between the KP moiety and the purine nucleoside (5-KPGly-dA) and the transoid structure (3-KP-dA). The experimental and computational results suggest that the ketyl-sugar biradical intermediate is generated with a higher efficiency for the cisoid dyad. However, the transoid dyad exhibits similar photochemistry behaviour as the KP molecule and no ketyl-sugar biradical intermediate was observed in the ns-TR3 experiments for the transoid 3-KP-dA dyad. Ultrafast Time Resolved Spectroscopic Studies on the Generation of the Ketyl-Sugar Biradical by Intra-molecular Hydrogen Abstraction Among Ketoprofen and Purine Nucleoside Dyads.. Available from: http://www.researchgate.net/publication/273152948_Ultrafast_Time_Resolved_Spectroscopic_Studies_on_the_Generation_of_the_Ketyl-Sugar_Biradical_by_Intra-molecular_Hydrogen_Abstraction_Among_Ketoprofen_and_Purine_Nucleoside_Dyads [accessed Jul 2, 2015].
Persistent Identifierhttp://hdl.handle.net/10722/211705
ISSN
2015 Impact Factor: 4.785
2015 SCImago Journal Rankings: 2.095

 

DC FieldValueLanguage
dc.contributor.authorLi, MD-
dc.contributor.authorDang, L-
dc.contributor.authorLiu, M-
dc.contributor.authorDu, L-
dc.contributor.authorZheng, X-
dc.contributor.authorPhillips, DL-
dc.date.accessioned2015-07-21T02:08:29Z-
dc.date.available2015-07-21T02:08:29Z-
dc.date.issued2015-
dc.identifier.citationThe Journal of Organic Chemistry, 2015, v. 80 n. 7, p. 3462–3470-
dc.identifier.issn0022-3263-
dc.identifier.urihttp://hdl.handle.net/10722/211705-
dc.description.abstractIntramolecular hydrogen abstraction reactions among ketoprofen (KP) and purine nucleoside dyads have been proposed to form ketyl-sugar biradical intermediates in acetonitrile. Femtosecond transient absorption studies on KP and purine nucleoside dyads reveal that the triplet state of the KP moiety of the dyads with cisoid structure decay faster (due to an intramolecular hydrogen abstraction reaction to produce a ketyl-sugar biradical intermediate) than the triplet state of the KP moiety of the dyads with transoid structure detected in acetonitrile solvent. For the cisoid 5-KP-dG dyad, the triplet state of the KP moiety decays too fast to be observed by ns-TR3, only the ketyl-sugar biradical intermediates are detected by ns-TR3 in acetonitrile. For the cisoid 5-KP-dA dyad, the triplet states of the KP moiety could be observed at early nanosecond delay times and then it quickly undergoes intramolecular hydrogen abstraction to produce a ketyl-sugar biradical intermediate. For the cisoid 5-KPGly-dA and transoid 3-KP-dA dyads, the triplet state of the KP moiety had a longer lifetime due to the long distance chain between the KP moiety and the purine nucleoside (5-KPGly-dA) and the transoid structure (3-KP-dA). The experimental and computational results suggest that the ketyl-sugar biradical intermediate is generated with a higher efficiency for the cisoid dyad. However, the transoid dyad exhibits similar photochemistry behaviour as the KP molecule and no ketyl-sugar biradical intermediate was observed in the ns-TR3 experiments for the transoid 3-KP-dA dyad. Ultrafast Time Resolved Spectroscopic Studies on the Generation of the Ketyl-Sugar Biradical by Intra-molecular Hydrogen Abstraction Among Ketoprofen and Purine Nucleoside Dyads.. Available from: http://www.researchgate.net/publication/273152948_Ultrafast_Time_Resolved_Spectroscopic_Studies_on_the_Generation_of_the_Ketyl-Sugar_Biradical_by_Intra-molecular_Hydrogen_Abstraction_Among_Ketoprofen_and_Purine_Nucleoside_Dyads [accessed Jul 2, 2015].-
dc.languageeng-
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/joc-
dc.relation.ispartofThe Journal of Organic Chemistry-
dc.titleUltrafast Time Resolved Spectroscopic Studies on the Generation of the Ketyl-Sugar Biradical by Intramolecular Hydrogen Abstraction Among Ketoprofen and Purine Nucleoside Dyads.-
dc.typeArticle-
dc.identifier.emailLi, MD: mdli@hku.hk-
dc.identifier.emailPhillips, DL: phillips@hku.hk-
dc.identifier.authorityPhillips, DL=rp00770-
dc.identifier.doi10.1021/acs.joc.5b00047-
dc.identifier.hkuros244751-
dc.identifier.volume80-
dc.identifier.issue7-
dc.identifier.spage3462-
dc.identifier.epage3470-
dc.publisher.placeUnited States-

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