CRYSTAL-STRUCTURES OF 2 MODIFICATIONS OF TRANS-1,3-BIS(3,4-DIMETHOXYPHENYL)-2,3-EPOXY-1-PROPANONE

trans-1,3-Bis(3,4-dimethoxyphenyl)-2,3-epoxy-1-propanone exhibits dimorphism and crystallizes in a monoclinic form from ethanol and in a trigonal form from chloroform/hexane. The crystal structures of the two modifications were determined by single-crystal X-ray diffraction methods. The monoclinic form crystallizes in space group P2(1)/c with a = 8.709(2), b = 7.986(1), c = 25.223(4) Angstrom, beta = 94.83(2)degrees, V = 1747.9(6) Angstrom(3) and Z = 4. R = 0.052 for 1236 reflections [I > 3 sigma(I)]. The trigonal form crystallizes in space group R $($) over bar$$ 3 with a = 36.048(6), c = 8.313(5) Angstrom, V = 9355(6) Angstrom(3) and Z = 18 (hexagonal axes). R = 0.101 for 1216 reflections [I > 3 sigma(I)]. In the trigonal crystals there are channels in the c-direction with a diameter of approximately 10 Angstrom. Possible explanations for the comparatively high R-value are discussed.