Distinctive effects on fluorescence quantum yields of 4-substituted N-methylphthalimides by inclusion complexation with β-cyclodextrins

Yoshimi Sueishi, Yuki Matsumoto, Junko Sohama, Yoshihiro Osawa, Hideki Okamoto

Research output: Contribution to journalArticle

Abstract

The inclusion constants K for the complexation of 4-substituted N-methylphthalimides with β-cyclodextrins [β-CD and 2,6-di-O-methylated β-CD (DM-β-CD)] were determined from the fluorescence spectra that were enhanced by the inclusion. The structures of the 1:1 inclusion complexes were characterized using 2D ROESY NMR measurements. 4-Substituted N-methylphthalimides showed higher stability for the inclusion complexes formed with the methylated β-CD compared with those with native β-CD (K DM-β-CD /K β-CD = 1.2–2.1); this is attributed to the enhanced hydrophobic interaction due to the methylation of the rim OH groups. 4-Substituted N-methylphthalimides having donor–acceptor (D–A) characteristics showed large blue shifts of the fluorescence maxima. In addition, we determined the fluorescence quantum yields (Φ values) for the inclusion complexes using quantum measurement apparatus equipped with a half-moon unit. The Φ values of the D–A N-methylphthalimides were significantly enhanced by the inclusion of β-CDs. The results suggested that the hydrogen-bonding interaction of the OH groups of the β-CD rim with N-methylphthalimides is not operative and that the enhancement of the quantum yield upon inclusion is attributable to the local polarity around the phthalimides inside the hydrophobic CD cavity.

Original languageEnglish
Pages (from-to)275-281
Number of pages7
JournalJournal of Inclusion Phenomena and Macrocyclic Chemistry
Volume93
Issue number3-4
DOIs
Publication statusPublished - Apr 15 2019

Fingerprint

cyclodextrins
Cyclodextrins
Quantum yield
Complexation
Fluorescence
inclusions
fluorescence
Phthalimides
phthalimide
hydrogen bonding
hydrophobic bonding
Hydrogen Bonding
Hydrophobic and Hydrophilic Interactions
methylation
Methylation
rims
phthalimides
Moon
natural satellites
blue shift

Keywords

  • Inclusion complexation
  • N-Methylphthalimide
  • Quantum yield
  • Substituent effect
  • β-Cyclodextrin

ASJC Scopus subject areas

  • Food Science
  • Chemistry(all)
  • Condensed Matter Physics

Cite this

Distinctive effects on fluorescence quantum yields of 4-substituted N-methylphthalimides by inclusion complexation with β-cyclodextrins. / Sueishi, Yoshimi; Matsumoto, Yuki; Sohama, Junko; Osawa, Yoshihiro; Okamoto, Hideki.

In: Journal of Inclusion Phenomena and Macrocyclic Chemistry, Vol. 93, No. 3-4, 15.04.2019, p. 275-281.

Research output: Contribution to journalArticle

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