Crystal Structure of 7,3'-Dihydroxy-4'-methoxyisoflavone

The title compound 7,3-dihydroxy-4-methoxyisoflavone isolated from the stems of Eremosparton songoricum was characterized by IR, 1H-NMR, 13C-NMR, H1-H1COSY, HMQC, HMBC and EIMS, and its crystal structure was determined by single-crystal X-ray diffraction with the following data: C16H12O5, monoclinic, P21/c, Z = 4, a = 9.926(8), b = 17.091(5), c = 8.001(4) , = 99.07(3) , V = 1340(1) 3, Mr = 284.26, Dc = 1.409 g/cm3, F(000) = 592, = 0.106 mm-1, R = 0.065 and wR = 0.1337 for 2084 observed reflections (I > 2.0s(I)). The molecular backbone of the compound includes a benzopyrone and a phenyl ring, and the dihedral angle between them is 50.21. The molecules form extensive networks through the intra- and intermolecular hydrogen bonds.