Quantum-chemical and correlation study of the tautomerism and ionization of 1,2,3-Trihydroxy-9,10-anthraquinone

1,2,3-Trihydroxy-9,10-anthraquinone (anthragallol) exists as an equilibrium mixture of the 9,10-, 2,9-, 1,2-, and 2,3-quinoid tautomers. Its anion was detected in the 9,10-, 1,10-, 2,9-, and 2,3-quinoid forms, and its metal complexes, the 9,10-and 2,9-quinoid forms. Ionization and complexation of anthragallol can shift the tautomeric equilibrium. © 2008 MAIK Nauka.