Acta Cryst. (2013). E69, o1231 [ doi:10.1107/S1600536813018503 ]
Abstract: The 1,3-diketone group of the title compound, C21H20O6, exists in a keto-enol form stabilized by a strong intramolecular O-HO hydrogen bond. As a result, a planar (mean deviation = 0.0099 Å) six-membered hydrogen-bonded ring is formed. The C-O and C-C bond lengths suggest significant electron delocalization in the ring. The dihedral angle between the six-membered hydrogen-bonded ring and its adjacent benzene ring is 8.78 (5)° and that between the benzene rings is 19.70 (5)°. In the crystal, molecules are packed in a layered structure parallel to the b axis through C-HO and - interactions [centroid-centroid distance between stacked benzene rings = 3.868 (2) Å].
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