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Article: Water- and acid-mediated excited-state intramolecular proton transfer and decarboxylation reactions of ketoprofen in water-rich and acidic aqueous solutions

TitleWater- and acid-mediated excited-state intramolecular proton transfer and decarboxylation reactions of ketoprofen in water-rich and acidic aqueous solutions
Authors
Issue Date2011
PublisherWiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistry
Citation
Chemistry - A European Journal, 2011, v. 17 n. 39, p. 10935-10950 How to Cite?
AbstractWe present an investigation of the decarboxylation reaction of ketoprofen (KP) induced by triplet excited-state intramolecular proton transfer in water-rich and acidic solutions. Nanosecond time-resolved resonance Raman spectroscopy results show that the decarboxylation reaction is facile in aqueous solutions with high water ratios (water/acetonitrile≥50 %) or acidic solutions with moderate and strong acid concentration. These experimental results are consistent with results from density functional theory calculations in which 1) the activation energy barriers for the triplet-state intramolecular proton transfer and associated decarboxylation process become lower when more water molecules (from one up to four molecules) are involved in the reaction system and 2) perchloric acid, sulfuric acid, and hydrochloric acid can shuttle a proton from the carboxyl to carbonyl group through an initial intramolecular proton transfer of the triplet excited state, which facilitates the cleavage of the C-C bond, thus leading to the decarboxylation reaction of triplet state KP. During the decarboxylation process, the water molecules and acid molecules may act as bridges to mediate intramolecular proton transfer for the triplet state KP when KP is irradiated by ultraviolet light in water-rich or acidic aqueous solutions and subsequently it generates a triplet-protonated carbanion biradical species. The faster generation of triplet-protonated carbanion biradical in acidic solutions than in water-rich solutions with a high water ratio is also supported by the lower activation energy barrier calculated for the acid-mediated reactions versus those of water-molecule-assisted reactions. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Persistent Identifierhttp://hdl.handle.net/10722/159295
ISSN
2014 Impact Factor: 5.731
2014 SCImago Journal Rankings: 2.234
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLi, MDen_HK
dc.contributor.authorYeung, CSen_HK
dc.contributor.authorGuan, Xen_HK
dc.contributor.authorMa, Jen_HK
dc.contributor.authorLi, Wen_HK
dc.contributor.authorMa, Cen_HK
dc.contributor.authorPhillips, DLen_HK
dc.date.accessioned2012-08-16T05:48:28Z-
dc.date.available2012-08-16T05:48:28Z-
dc.date.issued2011en_HK
dc.identifier.citationChemistry - A European Journal, 2011, v. 17 n. 39, p. 10935-10950en_HK
dc.identifier.issn0947-6539en_HK
dc.identifier.urihttp://hdl.handle.net/10722/159295-
dc.description.abstractWe present an investigation of the decarboxylation reaction of ketoprofen (KP) induced by triplet excited-state intramolecular proton transfer in water-rich and acidic solutions. Nanosecond time-resolved resonance Raman spectroscopy results show that the decarboxylation reaction is facile in aqueous solutions with high water ratios (water/acetonitrile≥50 %) or acidic solutions with moderate and strong acid concentration. These experimental results are consistent with results from density functional theory calculations in which 1) the activation energy barriers for the triplet-state intramolecular proton transfer and associated decarboxylation process become lower when more water molecules (from one up to four molecules) are involved in the reaction system and 2) perchloric acid, sulfuric acid, and hydrochloric acid can shuttle a proton from the carboxyl to carbonyl group through an initial intramolecular proton transfer of the triplet excited state, which facilitates the cleavage of the C-C bond, thus leading to the decarboxylation reaction of triplet state KP. During the decarboxylation process, the water molecules and acid molecules may act as bridges to mediate intramolecular proton transfer for the triplet state KP when KP is irradiated by ultraviolet light in water-rich or acidic aqueous solutions and subsequently it generates a triplet-protonated carbanion biradical species. The faster generation of triplet-protonated carbanion biradical in acidic solutions than in water-rich solutions with a high water ratio is also supported by the lower activation energy barrier calculated for the acid-mediated reactions versus those of water-molecule-assisted reactions. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.en_HK
dc.languageengen_US
dc.publisherWiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistryen_HK
dc.relation.ispartofChemistry - A European Journalen_HK
dc.subject.meshAcids - chemistryen_HK
dc.subject.meshAnti-Inflammatory Agents, Non-Steroidal - chemistryen_HK
dc.subject.meshDecarboxylationen_HK
dc.subject.meshKetoprofen - chemistryen_HK
dc.subject.meshProtonsen_HK
dc.subject.meshSpectrum Analysis, Ramanen_HK
dc.subject.meshWater - chemistryen_HK
dc.titleWater- and acid-mediated excited-state intramolecular proton transfer and decarboxylation reactions of ketoprofen in water-rich and acidic aqueous solutionsen_HK
dc.typeArticleen_HK
dc.identifier.emailMa, C:macs@hkucc.hku.hken_HK
dc.identifier.emailPhillips, DL:phillips@hku.hken_HK
dc.identifier.authorityMa, C=rp00758en_HK
dc.identifier.authorityPhillips, DL=rp00770en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1002/chem.201003297en_HK
dc.identifier.pmid21850720-
dc.identifier.scopuseid_2-s2.0-80052849918en_HK
dc.identifier.hkuros203396en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-80052849918&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume17en_HK
dc.identifier.issue39en_HK
dc.identifier.spage10935en_HK
dc.identifier.epage10950en_HK
dc.identifier.eissn1521-3765-
dc.identifier.isiWOS:000296262400020-
dc.publisher.placeGermanyen_HK
dc.identifier.scopusauthoridLi, MD=35173063700en_HK
dc.identifier.scopusauthoridYeung, CS=35173915800en_HK
dc.identifier.scopusauthoridGuan, X=8313149700en_HK
dc.identifier.scopusauthoridMa, J=39161647600en_HK
dc.identifier.scopusauthoridLi, W=36068145000en_HK
dc.identifier.scopusauthoridMa, C=7402924979en_HK
dc.identifier.scopusauthoridPhillips, DL=7404519365en_HK

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