Article: Influence of the chloro substituent position on the triplet reactivity of benzophenone derivatives: A time-resolved resonance Raman and density functional theory study

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TitleInfluence of the chloro substituent position on the triplet reactivity of benzophenone derivatives: A time-resolved resonance Raman and density functional theory study
AuthorsLi, W1
Xue, J1
Cheng, SC1
Du, Y2
Phillips, DL1
Keywordschloro-substituted benzophenone
hydrogen abstraction
ketyl radical
time-resolved resonance Raman spectroscopy
triplet state
Issue Date2012
PublisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/3420
CitationJournal Of Raman Spectroscopy, 2012, v. 43 n. 6, p. 774-780 [How to Cite?]
DOI: http://dx.doi.org/10.1002/jrs.3078
AbstractA nanosecond time-resolved resonance Raman (ns-TR 3) spectroscopic investigation of the photoreduction reactions and ability of several chloro-substituted benzophenone (Cl-BP) triplets is described. The TR 3 results show that the 3-chlorobenzophenone (3-Cl-BP), 4-chlorobenzophenone (4-Cl-BP) and 4,4'-dichlorobenzophenone (4,4'-dichloro-BP) triplets exhibit similar hydrogen abstraction ability with the parent BP triplet. In 2-propanol, the 3-Cl-, 4-Cl- and 4,4'-dichloro-diphenylketyl (DPK) radicals were observed and they appear to react with dimethylketyl radicals at the para-position to form a light absorption transient species. These transient species were characterized with TR 3 spectra, and identified with the help of results from density functional theory calculations. In an acetontitrile/water (MeCN:H 2O) 1:1 mixed solvent, these DPK radicals were also observed but with slower formation rates. However, the 2-Cl-DPK radical was observed to form with a lower yield and a significantly slower formation rate than the other chloro-substituted benzophenones examined here in 2-propanol under the same experimental conditions. These results reveal that the 2-chloro substituent reduces the hydrogen abstraction ability of the substituted BP triplet, which was not as expected based on the assumption that the electron-withdrawing group could increase its photoreduction ability. This unusual ortho effect of the chlorine substitution is briefly discussed. Copyright © 2011 John Wiley & Sons, Ltd.
ISSN0377-0486
2011 Impact Factor: 3.087
2011 SCImago Journal Rankings: 0.289
DOIhttp://dx.doi.org/10.1002/jrs.3078
ReferencesReferences in Scopus
DC Field
Value
dc.contributor.authorLi, W
dc.contributor.authorXue, J
dc.contributor.authorCheng, SC
dc.contributor.authorDu, Y
dc.contributor.authorPhillips, DL
dc.date.accessioned2012-08-16T05:48:29Z
dc.date.available2012-08-16T05:48:29Z
dc.date.issued2012
dc.description.abstractA nanosecond time-resolved resonance Raman (ns-TR 3) spectroscopic investigation of the photoreduction reactions and ability of several chloro-substituted benzophenone (Cl-BP) triplets is described. The TR 3 results show that the 3-chlorobenzophenone (3-Cl-BP), 4-chlorobenzophenone (4-Cl-BP) and 4,4'-dichlorobenzophenone (4,4'-dichloro-BP) triplets exhibit similar hydrogen abstraction ability with the parent BP triplet. In 2-propanol, the 3-Cl-, 4-Cl- and 4,4'-dichloro-diphenylketyl (DPK) radicals were observed and they appear to react with dimethylketyl radicals at the para-position to form a light absorption transient species. These transient species were characterized with TR 3 spectra, and identified with the help of results from density functional theory calculations. In an acetontitrile/water (MeCN:H 2O) 1:1 mixed solvent, these DPK radicals were also observed but with slower formation rates. However, the 2-Cl-DPK radical was observed to form with a lower yield and a significantly slower formation rate than the other chloro-substituted benzophenones examined here in 2-propanol under the same experimental conditions. These results reveal that the 2-chloro substituent reduces the hydrogen abstraction ability of the substituted BP triplet, which was not as expected based on the assumption that the electron-withdrawing group could increase its photoreduction ability. This unusual ortho effect of the chlorine substitution is briefly discussed. Copyright © 2011 John Wiley & Sons, Ltd.
dc.description.natureLink_to_subscribed_fulltext
dc.identifier.citationJournal Of Raman Spectroscopy, 2012, v. 43 n. 6, p. 774-780 [How to Cite?]
DOI: http://dx.doi.org/10.1002/jrs.3078
dc.identifier.doihttp://dx.doi.org/10.1002/jrs.3078
dc.identifier.epage780
dc.identifier.hkuros203414
dc.identifier.issn0377-0486
2011 Impact Factor: 3.087
2011 SCImago Journal Rankings: 0.289
dc.identifier.issue6
dc.identifier.scopuseid_2-s2.0-84862566538
dc.identifier.spage774
dc.identifier.urihttp://hdl.handle.net/10722/159298
dc.identifier.volume43
dc.languageeng
dc.publisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/3420
dc.publisher.placeUnited Kingdom
dc.relation.ispartofJournal of Raman Spectroscopy
dc.relation.referencesReferences in Scopus
dc.subjectchloro-substituted benzophenone
dc.subjecthydrogen abstraction
dc.subjectketyl radical
dc.subjecttime-resolved resonance Raman spectroscopy
dc.subjecttriplet state
dc.titleInfluence of the chloro substituent position on the triplet reactivity of benzophenone derivatives: A time-resolved resonance Raman and density functional theory study
dc.typeArticle
Author Affiliations
  1. The University of Hong Kong
  2. China Jiliang University