title: Correlation between excited-state intramolecular proton-transfer and singlet-oxygen quenching activities in 1-(acylamino)anthraquinones.
abstract: Excited-state intramolecular proton-transfer (ESIPT) and singlet-oxygen ((1)O2) quenching activities of intramolecularly hydrogen-bonded 1-(acylamino)anthraquinones have been studied by means of static and laser spectroscopies. The ESIPT shows a substituent effect, which can be explained in terms of the nodal-plane model. The ESIPT activity positively and linearly correlates with their (1)O2 quenching activity. The reason for this correlation can be understood by considering ESIPT-induced distortion of their ground-state potential surface and their encounter complex formation with (1)O2. Intramolecularly hydrogen-bonded hydroxyanthraquinones found in aloe also show a similar positive and linear correlation, which can be understood in the same way.
authors.affiliation: Department of Chemistry, Faculty of Science and Graduate School of Science and Engineering, Ehime University , Matsuyama 790-8577, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Nagaoka
authors.forename: Hikaru
authors.initials: H
authors.lastname: Endo
authors.forename: Keishi
authors.initials: K
authors.lastname: Ohara
authors.forename: Umpei
authors.initials: U
authors.lastname: Nagashima
mesh_terms: D000880:Anthraquinones / Q000737:chemistry*; D011522:Protons; D026082:Singlet Oxygen / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; D011522:Protons; D026082:Singlet Oxygen