Synthesis and crystal structure of 3,6-dimethyl-9(4-nitrophenyl)-1,8-oxo-2,7,10-trioxanthene

The crystal structure of the title compound (C19H13NO7) has been determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P2(1)/c with a = 10.669(1), b = 11.544(1), c = 14.045(2) Angstrom, beta = 105.98(1)degrees, V = 1663.0(3) Angstrom(3), M-r = 367.30, Z = 4, D-c = 1.467 g/cm(3), lambda = 0.71073 Angstrom, mu(MoKalpha) = 0.114 mm(-1) and F(000) = 760. The structure was refined to R = 0.0380 and wR = 0.0944 for 2093 observed reflections with I > 2sigma(I). X-ray analysis reveals that the dihedral angles between planes 1 and 2, 1 and 3, 1 and 4, 2 and 3, 2 and 4, and 3 and 4 are 94.24, 90.66, 96.84, 3.88, 3.30 and 7.11degrees, respectively. There exists a conjugated system in the molecular structure.