Fluorescence sensing of anions based on inhibition of excited-state intramolecular proton transfer

Yunkou Wu, Xiaojun Peng, Jiangli Fan, Shang Gao, Maozhong Tian, Jianzhang Zhao, Shiguo Sun

Research output: Contribution to journalArticlepeer-review

315 Scopus citations


Condensation of 2-(2′-aminophenyl)benzoxazole with p-toluenesulfonyl chloride and phenyl isocyanate yields two new anion sensors (TABO and PUBO), which can undergo excited-state intramolecular proton transfer (ESIPT) upon excitation. For the acid receptor TABO, the ESIPT process can be readily disturbed by basic anions such as F-, CH3COO-, and H2PO4- by deprotonating the sulfonamide unit, whereas in the case of PUBO, a good hydrogen-bonding donor, the ESIPT process is inhibited either by the fluoride-induced deprotonation of the urea unit or by the formation of a strong CH3COO--urea intermolecular hydrogen bond complex, and these two types of inhibition mechanisms consequently result in different ratiometric responses. But other anions with less hydrogen-bonding acceptor abilities cannot inhibit the ESIPT, Interestingly, the different inhibition abilities of F-, CH 3COO-, and H2PO4- produce different spectral behaviors in PUBO, so this new sensor successfully distinguishes the subtle difference in these three anionic substrates of similar basicity and surface charge density.

Original languageEnglish (US)
Pages (from-to)62-70
Number of pages9
JournalJournal of Organic Chemistry
Issue number1
StatePublished - Jan 5 2007
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry


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