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Surface photochemistry: diffuse reflectance studies of thioketones included into p-tert-butylcalix[6 and 8]arenes

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dc.contributor.authorFerreira, Luís F. Vieira
dc.contributor.authorMachado, I. Ferreira
dc.contributor.authorOliveira, A. S.
dc.contributor.authorSilva, José P. da
dc.contributor.authorKrawczyk, A.
dc.contributor.authorSikorski, M.
dc.date.accessioned2015-06-22T14:13:49Z
dc.date.available2015-06-22T14:13:49Z
dc.date.issued2007
dc.description.abstractThis paper presents time resolved laser induced luminescence (LIL) and diffuse reflectance laser flash-photolysis (DRLFP) studies of solid powdered samples of xanthione (XT) and 4H-1-benzopyran-4-thione (BPT). These thioketones form inclusion complexes with ptert-butylcalix[6]arene (CLX[6]) and p-tert-butylcalix[8]arene (CLX[8]). Room temperature air equilibrated LIL studies for XT/CLX[8] inclusion complex have shown the existence of both fluorescence and delayed fluorescence emission S-2 -> S-0 emissions in the nanosecond and microsecond time ranges, respectively) peaking at ca. 460 nm while phosphorescence peaks at about 670 nm with a half life of about 4 mu s. For the BPT/CLX[8] inclusion complex, the emissions now peak at ca. 450 and 630 nm, respectively. When these two thioketones are included into the CLX[6] nanocavities similar luminescence spectra were detected. The phosphorescence spectra in all cases present a clear vibrational structure characteristic of non-polar environments, in accordance with the non-polar character of the calixarene's cavities. Diffuse reflectance transient absorption spectra revealed in all cases the presence of the triplet state of the thioketones and also of longer lived species. The use of chromatographic methods (GC-MS) allowed us to identify the formation of xanthone, chromone and hydroxy-thio ketones following laser irradiation at 355 or 337 nm. (c) 2006 Elsevier B.V. All rights reserved.
dc.identifier.doihttps://dx.doi.org/10.1016/j.molstruc.2006.04.049
dc.identifier.issn0022-2860
dc.identifier.urihttp://hdl.handle.net/10400.1/6555
dc.language.isoeng
dc.peerreviewedyes
dc.publisherElsevier
dc.relation.isbasedonP-004-BS7
dc.subjectSurface photochemistry
dc.subjectSuThioketones
dc.subjectCalixarenes
dc.subjectInclusion complexes
dc.subjectDiffuse reflectance
dc.subjectRoom temperature phosphorescence
dc.subjectSTime resolved luminescence
dc.subjectLaser flash photolysis
dc.subjectPhotodegradation products
dc.titleSurface photochemistry: diffuse reflectance studies of thioketones included into p-tert-butylcalix[6 and 8]arenes
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage19
oaire.citation.issue1-3
oaire.citation.startPage11
oaire.citation.titleJournal of Molecular Structure
oaire.citation.volume827
person.familyNameSilva
person.givenNameJosé Paulo da
person.identifier.ciencia-id3413-C4F4-73F7
person.identifier.orcid0000-0002-6458-7328
person.identifier.ridA-4606-2008
person.identifier.scopus-author-id7201733236
rcaap.rightsrestrictedAccess
rcaap.typearticle
relation.isAuthorOfPublicatione2004fa2-a47d-44b0-b11c-fc95fe51cbf9
relation.isAuthorOfPublication.latestForDiscoverye2004fa2-a47d-44b0-b11c-fc95fe51cbf9

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