Tautomerism of the metal complexes with 1-amino-4-hydroxyanthaquinone

Diversity of electronic absorption spectra of the metal complexes with 1-amino-4-hydroxyan-thraquinone is a consequence of the fact that they exist as equilibrium mixtures of tautomers with the isomeric quinoid structure of the ligand. These complexes are characterized by keto-oxide and amino-imine tautomerism, and samples of the complexes differ by composition of the tautomers. © Pleiades Publishing, Ltd., 2010.