Intermolecular interactions of flavanthrone and indanthrone pigments

Using computational chemistry techniques, the structures of flavanthrone (1) and indanthrone (2) have been re-examined. The similarity in the packing motifs of indanthrone and flavanthrone has been studied and the important intermolecular interactions have been determined. The role of weak hydrogen bonds of the type C-HO in the formation of the three dimensional structures have been clarified.