Fluorescence ratiometry of monomer/excimer emissions in a space-through PET system

Sun Hyun Lee, Su Ho Kim, Sung Kuk Kim, Jong Hwa Jung, Jong Seung Kim

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)

Abstract

Fluorogenic calix[4]arenes (1 and 2) bearing a pendent ethyleneamine on their triazacrown rings, respectively, were synthesized in the cone conformation. Compared with 4, free 1 and 2 display a relatively weak emission, reflecting that a PET process from the pendent amine group (-CH 2CH2NH2) to the fluorogenic pyrenes is mainly operated. Addition of various metal ions or anions to the solution of 1 or 2 reduces the PET because the pendent alkylamine takes part in the complexation, causing their fluorescence spectra to be changed. When Pb2+, a quenching metal ion, is added to 1 or 2, their pyrene monomer emission is enhanced with their excimer emission quenched, which is due to conformational changes of the facing carbonyl groups as well as to the participation of the ethyleneamine into the three-dimensional Pb2+ ion encapsulation. In contrast, upon addition of alkali metal ions to the 1 and 2, both monomer and excimer emissions are observed to increase, which is attributable to the CHEF effect and the retained conformations. For anion sensing, both 1 and 2 show a high selectivity for F- ions over other anions tested. When the F- ion is bound to 1 or 2 by hydrogen bonding between the amide NH of the triazacrown ring and F-, both their monomer and excimer emissions are weakened due to PET from the bound F- to the pyrene units.

Original languageEnglish
Pages (from-to)9288-9295
Number of pages8
JournalJournal of Organic Chemistry
Volume70
Issue number23
DOIs
Publication statusPublished - 2005 Nov 11
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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