The enhancement of fluorescence quantum yields of anilino naphthalene sulfonic acids by inclusion of various cyclodextrins and cucurbit[7]uril.
Spectrochim Acta A Mol Biomol Spectrosc
; 114: 344-9, 2013 Oct.
Article
em En
| MEDLINE
| ID: mdl-23786974
ABSTRACT
The association constants (K) for the inclusion complexation of four kinds of cyclodextrins (CDs (ß- and γ-), 2,6-di-O-methylated ß-CD, and 2,3,6-tri-O-methylated ß-CD) and cucurbit[7]uril (CB[7]) with 1,8- and 2,6-anilinonaphthalene sulfonic acids (ANSs) were determined from fluorescence spectra enhanced by inclusion. Various CDs and CB[7] form stable 11 inclusion complexes with 1,8- and 2,6-ANSs K=80-11700 M(-1) for 2,6-ANS and 50-195 M(-1) for 1,8-ANS. The high stability of the inclusion complexes of 2,6-ANS with CB[7] and 2,6-di-O-methylated ß-CD is shown. Further, we determined the fluorescence quantum yields (Φ values) for the inclusion complexes of ANSs by using a fluorescence spectrophotometer equipped with a half-moon unit. The Φ values of 1,8- and 2,6-ANSs were largely enhanced by the inclusion of methylated ß-CDs and did not correlate with the degree of stability (K) of the inclusion complexes. We characterized the structures of the inclusion complexes by 2D ROESY-NMR measurements. In addition, the microenvironmental polarity inside the hydrophobic CD and CB[7] cavities was evaluated using the fluorescence probe 2,6-ANS. Based on the emission mechanism and the aspect of inclusion in a hydrophobic cavity, we have suggested that the microenvironmental polarity and viscosity for the excited state of ANS plays an important role for the Φ values of inclusion complexes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hidrocarbonetos Aromáticos com Pontes
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Ciclodextrinas
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Corantes Fluorescentes
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Imidazóis
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Naftalenossulfonato de Anilina
Idioma:
En
Revista:
Spectrochim Acta A Mol Biomol Spectrosc
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Japão