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Article: Unraveling the mechanism of the photodeprotection reaction of 8-bromo- and 8-chloro-7-hydroxyquinoline caged acetates

TitleUnraveling the mechanism of the photodeprotection reaction of 8-bromo- and 8-chloro-7-hydroxyquinoline caged acetates
Authors
Keywordscage compounds
photodeprotection
proton transfer
quinoline
time-resolved spectroscopy
Issue Date2012
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, 2012, v. 18 n. 22, p. 6854-6865 How to Cite?
Abstract
Photoremovable protecting groups (PPGs) when conjugated to biological effectors forming "caged compounds" are a powerful means to regulate the action of physiologically active messengers in vivo through 1-photon excitation (1PE) and 2-photon excitation (2PE). Understanding the photodeprotection mechanism is important for their physiological use. We compared the quantum efficiencies and product outcomes in different solvent and pH conditions for the photolysis reactions of (8-chloro-7-hydroxyquinolin-2-yl) methyl acetate (CHQ-OAc) and (8-bromo-7-hydroxyquinolin-2-yl)methyl acetate (BHQ-OAc), representatives of the quinoline class of phototriggers for biological use, and conducted nanosecond time-resolved spectroscopic studies using transient emission (ns-EM), transient absorption (ns-TA), transient resonance Raman (ns-TR 2), and time-resolved resonance Raman (ns-TR 3) spectroscopies. The results indicate differences in the photochemical mechanisms and product outcomes, and reveal that the triplet excited state is most likely on the pathway to the product and that dehalogenation competes with release of acetate from BHQ-OAc, but not CHQ-OAc. A high fluorescence quantum yield and a more efficient excited-state proton transfer (ESPT) in CHQ-OAc compared to BHQ-OAc explain the lower quantum efficiency of CHQ-OAc relative to BHQ-OAc. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Persistent Identifierhttp://hdl.handle.net/10722/159300
ISSN
2013 Impact Factor: 5.696
PubMed Central ID
ISI Accession Number ID
References

 

Author Affiliations
  1. The University of Georgia
  2. The University of Hong Kong
DC FieldValueLanguage
dc.contributor.authorMa, Jen_HK
dc.contributor.authorRea, ACen_HK
dc.contributor.authorAn, Hen_HK
dc.contributor.authorMa, Cen_HK
dc.contributor.authorGuan, Xen_HK
dc.contributor.authorLi, MDen_HK
dc.contributor.authorSu, Ten_HK
dc.contributor.authorYeung, CSen_HK
dc.contributor.authorHarris, KTen_HK
dc.contributor.authorZhu, Yen_HK
dc.contributor.authorNganga, JLen_HK
dc.contributor.authorFedoryak, ODen_HK
dc.contributor.authorDore, TMen_HK
dc.contributor.authorPhillips, DLen_HK
dc.date.accessioned2012-08-16T05:48:30Z-
dc.date.available2012-08-16T05:48:30Z-
dc.date.issued2012en_HK
dc.identifier.citationChemistry - A European Journal, 2012, v. 18 n. 22, p. 6854-6865en_HK
dc.identifier.issn0947-6539en_HK
dc.identifier.urihttp://hdl.handle.net/10722/159300-
dc.description.abstractPhotoremovable protecting groups (PPGs) when conjugated to biological effectors forming "caged compounds" are a powerful means to regulate the action of physiologically active messengers in vivo through 1-photon excitation (1PE) and 2-photon excitation (2PE). Understanding the photodeprotection mechanism is important for their physiological use. We compared the quantum efficiencies and product outcomes in different solvent and pH conditions for the photolysis reactions of (8-chloro-7-hydroxyquinolin-2-yl) methyl acetate (CHQ-OAc) and (8-bromo-7-hydroxyquinolin-2-yl)methyl acetate (BHQ-OAc), representatives of the quinoline class of phototriggers for biological use, and conducted nanosecond time-resolved spectroscopic studies using transient emission (ns-EM), transient absorption (ns-TA), transient resonance Raman (ns-TR 2), and time-resolved resonance Raman (ns-TR 3) spectroscopies. The results indicate differences in the photochemical mechanisms and product outcomes, and reveal that the triplet excited state is most likely on the pathway to the product and that dehalogenation competes with release of acetate from BHQ-OAc, but not CHQ-OAc. A high fluorescence quantum yield and a more efficient excited-state proton transfer (ESPT) in CHQ-OAc compared to BHQ-OAc explain the lower quantum efficiency of CHQ-OAc relative to BHQ-OAc. Copyright © 2012 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.subjectcage compoundsen_HK
dc.subjectphotodeprotectionen_HK
dc.subjectproton transferen_HK
dc.subjectquinolineen_HK
dc.subjecttime-resolved spectroscopyen_HK
dc.titleUnraveling the mechanism of the photodeprotection reaction of 8-bromo- and 8-chloro-7-hydroxyquinoline caged acetatesen_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_OA_fulltext-
dc.identifier.doi10.1002/chem.201200366en_HK
dc.identifier.pmid22511356-
dc.identifier.pmcidPMC3531613-
dc.identifier.scopuseid_2-s2.0-84861558058en_HK
dc.identifier.hkuros203418en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-84861558058&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume18en_HK
dc.identifier.issue22en_HK
dc.identifier.spage6854en_HK
dc.identifier.epage6865en_HK
dc.identifier.eissn1521-3765-
dc.identifier.isiWOS:000304347600022-
dc.publisher.placeGermanyen_HK
dc.identifier.scopusauthoridMa, J=39161647600en_HK
dc.identifier.scopusauthoridRea, AC=37034766600en_HK
dc.identifier.scopusauthoridAn, H=54411879800en_HK
dc.identifier.scopusauthoridMa, C=7402924979en_HK
dc.identifier.scopusauthoridGuan, X=55232314100en_HK
dc.identifier.scopusauthoridLi, MD=35173063700en_HK
dc.identifier.scopusauthoridSu, T=54685079100en_HK
dc.identifier.scopusauthoridYeung, CS=35173915800en_HK
dc.identifier.scopusauthoridHarris, KT=15837099400en_HK
dc.identifier.scopusauthoridZhu, Y=36560602200en_HK
dc.identifier.scopusauthoridNganga, JL=26429870200en_HK
dc.identifier.scopusauthoridFedoryak, OD=8927250000en_HK
dc.identifier.scopusauthoridDore, TM=6603830858en_HK
dc.identifier.scopusauthoridPhillips, DL=7404519365en_HK

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