A second polymorph of (2E)-1-(4-fluoro-phen-yl)-3-(3,4,5-trimethoxy-phen-yl)prop-2-en-1-one.

ABSTRACT: The crystal structure of the title compound, C(18)H(17)FO(4), reported here is a polymorph of the structure first reported by Patil et al. [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (2007), 461, 123-130]. It is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between the mean planes of the aromatic rings within the 4-fluoro-phenyl and trimethoxy-phenyl groups is 28.7?(1)° compared to 20.8?(6)° in the published structure. The angles between the mean plane of the prop-2-ene-1-one group and the mean plane of aromatic rings within the 4-fluoro-phenyl and trimethoxy-phenyl groups are 30.3?(4) and 7.4?(7)°, respectively, in contast to 10.7?(3) and 12.36° for the polymorph. While the two 3-meth-oxy groups are in the plane of the trimeth-oxy-substituted ring, the 4-meth-oxy group is in a synclinical [-sc = -78.1?(2)°] or anti-clinical [+ac = 104.0?(4)°] position, compared to a +sc [53.0?(4)°] or -ac [-132.4?(7)°] position. While no classical hydrogen bonds are present, weak inter-molecular C-H??-ring inter-actions are observed which contribute to the stability of the crystal packing. The two polymorphs crystallize in the same space group, P2(1)/c, but have different cell parameters for the a, b and c axes and the ? angle. A comparison of the mol-ecular geometries of both polymorphs to a geometry optimized density functional theory (DFT) calculation at the B3-LYP/6-311+G(d,p) level for each structure provides additional support to these observations.

SUBMITTER: Jasinski JP 

PROVIDER: S-EPMC2977262 | biostudies-other | 2009

REPOSITORIES: biostudies-other