Tautomerism in Athraquinones: II. α-Hydroxy-substituted Anthraquinones

The fine structure of experimental π_l,π*-absorption bands of the α hydroxyanthraquinones originates from the prototropic anthraquinoid tautomerism. The tautomeric transformations occur both in the ground and excited states of the molecules; therewith the excited states are more sensitive to the tautomerization than the ground ones. The wavelength and intensity of the π_l,π*-bands, the values of all quantum-chemical characteristics studied for the tautomers of α hydroxyanthraquinones are linearly related to the number of hydroxy groups. The effect of the isomerism of di- and trihydroxyanthraquinones on this relationship was considered.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 722–729.Original Russian Text Copyright © 2005 by Fain, Zaitsev, Ryabov.