Knowledge Bank

The infrared spectra of several hydroxyl-substituted anthraquinones have been obtained under moderately high resolution between 1000 and $1500cm-1$ in the vapor state, in $CCl4$ solution, and on the sublimed solid. In addition to the very broad bands around $3100cm-1$ attributed to the strongly intramolecularly bonded hydroxyl, sharp bands are observed at about $3540cm-1$ in solution which are attributed to unbonded hydroxyl, indicating appreciable dissociation of the intramolecular bonds even at room temperature. Intermolecular bonds in the solid give rise to sharp bands near $3400cm-1$. Attention has been given to the band contours, positions, and approximate intensities. High resolution nuclear magnetic resonance spectra were obtained at several temperatures and in several solvents. Preliminary x-ray data been obtained for one compound.