Structure Reports Online

Volume 67, Part 1 (January 2011)

organic compounds

rz2523 scheme

Acta Cryst. (2011). E67, o33-o34 [ doi:10.1107/S1600536810049299 ]

(1E,4E)-1,5-Bis(2,4,6-trimethoxyphenyl)penta-1,4-dien-3-one

P. Ruanwas, S. Chantrapromma and H.-K. Fun

Abstract: There are two crystallographically independent molecules in the asymmetric unit of the title bischalcone derivative, C₂₃H₂₆O₇. The molecules are unsymmetrical and almost planar: the dihedral angle between two benzene rings is 1.04 (7)° in one molecule and 2.31 (7)° in the other. The central penta-1,4-dien-3-one fragment makes dihedral angles of 7.61 (7) and 6.82 (7)° with the two adjacent benzene rings in one molecule, while the corresponding values are 7.85 (7) and 9.42 (6)° in the other. In both molecules, the three methoxy groups of the two 2,4,6-trimethoxyphenyl units are coplanar with the attached benzene rings [C-O-C-C- torsion angles of -1.5 (2), -7.2 (2) and 4.1 (2)° in one molecule and -0.7 (2), -5.5 (2) and -0.6 (2)° in the other]. The molecular conformations are stabilized by weak intramolecular C-HO interactions generating two S(6) ring motifs. In the crystal, molecules are linked by weak intermolecular C-HO interactions into zigzag chains parallel to the c axis. The crystal structure is further stabilized by C-H [pi] interactions and [pi] - [pi] interactions with centroid-centroid distances of 3.6433 (8) Å.