Effect of NaCl Salts on the Activation Energy of Excited-State Proton Transfer Reaction of Coumarin 183

Joonyoung F. Joung, Sangin Kim, Sungnam Park

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Coumarin 183 (C183) was used as a photoacid to study excited-state proton transfer (ESPT) reactions. Here, we studied the effect of ions on the ESPT of C183 in aqueous NaCl solutions using a steady-state fluorescence spectroscopy and time-correlated single photon counting (TCSPC) method. The acid dissociation equilibrium of excited-state C183 and the activation energy for the ESPT of C183 were determined as a function of NaCl concentration. The change in the equilibrium constant was found to be correlated with the solvation energy of deprotonated C183. Frequency-resolved TCSPC signals measured at several temperatures were analyzed by using a global fitting analysis method which enabled us to extract all the rate constants involving the ESPT reaction and the spectra of individual species. The activation energy for the ESPT reaction of C183 was highly dependent on NaCl concentration. Quantum chemical calculations were used to calculate the local hydrogen-bond (H-bond) configurations around C183 in aqueous NaCl solutions. It was found that the activation energy for the ESPT was determined by the local H-bond configurations around C183 which were significantly influenced by the dissolved ions.

Original languageEnglish
Pages (from-to)15514-15515
Number of pages2
JournalJournal of Physical Chemistry B
Volume119
Issue number50
DOIs
Publication statusPublished - 2015 Dec 17

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Fingerprint Dive into the research topics of 'Effect of NaCl Salts on the Activation Energy of Excited-State Proton Transfer Reaction of Coumarin 183'. Together they form a unique fingerprint.

  • Cite this