title: Excited-state proton transfer from quinone-cyanine 9 to protic polar-solvent mixtures.
abstract: Steady-state and time-resolved emission techniques were used to study the excited-state proton-transfer (ESPT) process of quinone cyanine 9 (QCy9) in solvent mixtures. We found that the ESPT rate from QCy9 in water/methanol mixtures is independent of the mixture composition and the rate constant is k(PT) ∼ 10(13) s(-1). In ethanol/trifluoroethanol (TFE) mixtures the ESPT rate strongly depends on the solvent-mixture composition. We observe two ESPT rates rather than one over a wide range of solvent-mixture compositions. The average ESPT rate decreases as the mole fraction of TFE increases.
authors: Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University , Tel Aviv 69978, Israel.
authors: Ron
authors: R
authors: Simkovitch
authors: Shay
authors: S
authors: Shomer
authors: Rinat
authors: R
authors: Gepshtein
authors: Doron
authors: D
authors: Shabat
authors: Dan
authors: D
authors: Huppert