title: Phototautomerism in the lowest excited singlet state of 1-hydroxy-2-carboxyanthraquinone.
abstract: The dependence of the absorption and fluorescence spectra of 1-hydroxy-2-carboxy-anthraquinone on pH and Hammett acidity have been studied. This compound exhibits phototautomerism in its uncharged and its singly-charged anionic species in aqueous media. Its ground state (pK(a)) and lowest excited singlet-state (pK(a)( *)) dissociation constants have been determined by absorptiometric and fluorimetric titrations and the assignment of the pK(a) and pK( *)(a) values to the equilibria concerned has been carefully considered.
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Extremadura, 06071 Badajoz, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Salinas
authors.forename: A M
authors.initials: AM
authors.lastname: de La Peña
authors.forename: J A
authors.initials: JA
authors.lastname: Murillo