Cyclodextrin effects on excited-state geometry change and intramolecular charge transfer of 4-biphenylcarboxylic acid

Dae Won Cho, Yong Hee Kim, Seong Gwan Kang, Minjoong Yoon, Dongho Kim

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

The cyclodextrin (CDx) effects on the spectroscopic properties of a pretwisted molecule, 4-biphenylcarboxylic acid (4-BPCA), in aqueous solution have been examined. It is observed that the intramolecular charge transfer (ICT) emission of 4-BPCA is blue-shifted upon addition of α-CDx and β-CDx, manifesting that the excited-state ICT of 4-BPCA is partially inhibited by forming the 1:1 CDx inclusion complex. Particularly in the presence of α-CDx, two isoemissive points and dual fluorescence decays are observed, being consistent with the consecutive formation of 2:1 inclusion complex between α-CDx and 4-BPCA. Temperature effects on the fluorescence spectrum and decay kinetics of the inclusion complex suggest that the excited-state geometry change toward coplanarity of the biphenyl moiety becomes slightly accessible with suppression of the ICT in the 2:1 complex, revealing the internal rotational barrier energy of 6 ± 1 kJ/mol. This can be attributed to the inhibition of the interaction of carboxyl group with the polar and hydrogen-bonding water as well as the reduced polarity inside the CDx cavity.

Original languageEnglish
Pages (from-to)558-562
Number of pages5
JournalJournal of physical chemistry
Volume98
Issue number2
DOIs
Publication statusPublished - 1994 Jan 1

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physical and Theoretical Chemistry

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