Phototautomerism in the lowest excited singlet state of 1-hydroxy-2-carboxyanthraquinone.
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.
Salinas
F
F
Department of Analytical Chemistry, Faculty of Sciences, University of Extremadura, 06071 Badajoz, Spain.
de La Peña
A M
AM
Murillo
J A
JA