Crystal structure of 3-hydroxy-6-methoxyflavone, C16H12O4

Abstract

Table 3. Rnal atomic coordinates and displacement parameters (in Â^) Source of material: Indofine Chemical Company. Crystals grown from methanol/toluene (mp 477 К 478 К). An inter (ί/(04 ·Η33) = 1.96 Â) and an intramolecular attraction (?(04 -H33) = 2.25 Â) resulted in a bifurcated hydrogen bond between the 3-hydroxy and the carbonyl. An intramolecular H-bond (d(03· H6') = 2.22 Â) is also formed between the oxygen of the hydroxyl and the H6' of the phenyl ring. The major differences between the crystal structure of the title compound and 3-hydroxy7-methoxyflavone (see ref. 1) are in the С6 ' -СГ-С2-СЗ torsion angle and the С2-СГ bond distance. The torsion angle of 11.3(5)° and the C2-C1'distance of 1.471(4) Â for the title compound are different from the reported values of 1.2(6) and 1.462(5) Â. The widening in angle causes the bond distance to be longer, giving the С2-СГ less double bond character (see ref. 2). The οοπφβηβοη between the two crystal structures clearly indicates the effect of the molecular packing and shows the importance of the X-ray study in this type of behavior.