Fluorescence response mechanism of D-glucose selectivity for supramolecular probes composed of phenylboronic-acid-modified beta-cyclodextrin and styrylpyridinium dyes.
Supramolecular complex formation of phenylboronic-acid-modified beta-cyclodextrin (1) with 1-methyl-4-(4-dimethylaminostyryl)pyridinium (C1SP) in aqueous solutions containing saccharides was fully clarified to gain an insight into the observed D-glucose (D-glc) selectivity of a supramolecular fluorescent probe composed of 1 and the 1-heptyl analogue of C1SP (Chem. Commun., 2006, 4319). At pH 9.6, where 1 was in its anionic form, both the stability and the fluorescence of the 1/C1SP complex were reduced by the formation of boronate esters of 1 with saccharides. Among the saccharides, D-glc had the smallest effect on destabilization of the 1/C1SP complex, almost completely retaining the fluorescence of the 1/C1SP complex that was reduced by other saccharides by approximately 2/3. Under neutral conditions, D-glc enhanced the fluorescence of the 1/C1SP complex by increasing the fraction of anionic 1 while minimally decreasing the stability and fluorescence of the 1/C1SP complex. Although other saccharides also increased the fraction of the anionic 1, their relatively large effects on the destabilization and reduction of fluorescence of the 1/C1SP complex limited the enhancement of the fluorescence of the 1-C1SP system under neutral conditions.
Suzuki
Iwao
I
Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan. isuzuki@mail.pharm.tohoku.ac.jp
Yamauchi
Akiyo
A
Sakashita
Yoshiko
Y
Hirose
Kazuaki
K
Miura
Takashi
T
Hayashita
Takashi
T
D001897:Boronic Acids / Q000737:chemistry*; D005453:Fluorescence; D005947:Glucose / Q000737:chemistry*; D015394:Molecular Structure; D011726:Pyridinium Compounds / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
C032315:4-(4-dimethylaminostyryl)-1-methylpyridinium; D001897:Boronic Acids; D011726:Pyridinium Compounds; D047392:beta-Cyclodextrins; D005947:Glucose; C031215:betadex; C010686:benzeneboronic acid