dc.creatorBARROS, Teresa C.
dc.creatorTOMA, Sergio H.
dc.creatorTOMA, Henrique E.
dc.creatorBASTOS, Erick L.
dc.creatorBAPTISTA, Mauricio S.
dc.date.accessioned2012-10-20T05:21:04Z
dc.date.accessioned2018-07-04T15:48:14Z
dc.date.available2012-10-20T05:21:04Z
dc.date.available2018-07-04T15:48:14Z
dc.date.created2012-10-20T05:21:04Z
dc.date.issued2010
dc.identifierJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, v.23, n.10, Special Issue, p.893-903, 2010
dc.identifier0894-3230
dc.identifierhttp://producao.usp.br/handle/BDPI/30961
dc.identifier10.1002/poc.1692
dc.identifierhttp://dx.doi.org/10.1002/poc.1692
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1627600
dc.description.abstractAbsorption and fluorescence spectroscopy, electrochemical techniques, and semiempirical calculations were employed to characterize the multiple complexation equilibria between two polymethine cyanine dyes (IR-786 and Indocyanine green-ICG, 5) and beta-cyclodextrin (beta-CD, L), as well as the chemical reactivity of the complexed and uncomplexed species against the oxidizing agents hypochlorite (HC) and hydrogen peroxide (HP). IR-786 dimerization is favored with the increase in beta-CD concentration in the form of (SL)(2) complexes. In the case of ICG, free dimers (D) and SL complexes are favored. Both IR-786 and ICG react and discolor in the presence of HC and HP. For IR-786, the reaction with HP and HC proceeds with observed rate constants of 10(-3) and 0.28 s(-1) and second-order rate constants (k(2)) of similar to 10(-3) and 10(4) M(-1) s(-1), respectively. The intermediate species observed in the bleaching reactions of IR-786 and ICG were shown, by cyclic voltammetry and VIS absorption, to result from one electron oxidation. IR-786 complexed with beta-CD is protected against bleaching in the presence of HP and HC by factors of 20 and 4, respectively. This protection was not observed in ICG complexes. Superdelocalizability profile of both dyes and frontier orbital analysis indicates that beta-CD does not protect ICG from oxidation by HP or HC, whereas the 2:2 IR-786/beta-Cd complex is able to avoid the oxidation of IR-786. We concluded that the decrease in the chemical reactivity of the dyes against oxidant agents in the presence of beta-CD is due to the formation of (SL)(2) complexes. Copyright (C) 2010 John Wiley & Sons, Ltd.
dc.languageeng
dc.publisherJOHN WILEY & SONS LTD
dc.relationJournal of Physical Organic Chemistry
dc.rightsCopyright JOHN WILEY & SONS LTD
dc.rightsrestrictedAccess
dc.subjectchemical oxidation
dc.subjectcyclodextrin
dc.subjectinclusion complex
dc.subjectinclusion complex
dc.subjectnear-infrared dyes
dc.titlePolymethine cyanine dyes in beta-cyclodextrin solution: multiple equilibria and chemical oxidation
dc.typeArtículos de revistas


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