(E)-3-(3,4-Difluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one

In the title compound, C17H14F2O3, the dihedral angle between the benzene rings is 20.56 (8)° and the H atoms at the central propenone group are trans configured. One of the F atoms is disordered over two positions (occupancy ratio 0.57:0.43) and was refined using a split model. In the crystal, the molecules are linked into centrosymmetrical dimers and are further connected into a three-dimensional network via weak C—H⋯O interactions.

In the title compound, C 17 H 14 F 2 O 3 , the dihedral angle between the benzene rings is 20.56 (8) and the H atoms at the central propenone group are trans configured. One of the F atoms is disordered over two positions (occupancy ratio 0.57:0.43) and was refined using a split model. In the crystal, the molecules are linked into centrosymmetrical dimers and are further connected into a three-dimensional network via weak C-HÁ Á ÁO interactions.

Experimental
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. The title compound is a biologically active derivative of chalcone. Chalcones constitute an important group of natural products and some of them possess a wide range of biological activities including anti-inflammatory and anti-tumor (Boumendjel et al., 2008;Kumar et al., 2011;Zhang et al., 2011). As part of our ongoing studies on chalcones (Wu et al., 2012a,b;, the title compound was synthesized and its crystal structure is reported here. In the crystal structure, the dihedral angle between the mean planes of the difluorophenyl and the dimethoxyphenyl rings amount to 20.56 (8)°. The H atoms of the central propenone group are trans configurated. The two methoxy groups attached to C13 and C14 are almost coplanar with the benzene ring.
Experimental 1-(3,4-difluorophenyl) ethanone (0.01 mol) and 2,3-dimethoxybenzaldehyde (0.01 mol) were dissolved in methanol (50 ml). Sodium hydroxide (5 ml, 20%) was added drop wised to the solution, which was stirred at ambient temperature. The content of the flask were poured into ice-cold water, and the resulting crude solid was collected by filtration. The compound was purified by flash column and single crystals were obtained by slow evaporation from an ethanol/ dichloromethane solution (1:2, v/v) at 293 K.

Refinement
The hydrogen atoms were positioned with idalized geometry and refined isotropic with U iso (H) = 1.2 U eq (C) (1.5 for methyl H atoms) using a riding model. One of the fluorine atoms was disordered over two positions and was refined using a split model with sof = 0.55 and 0.45.
Disordering is shown as full and open bonds.

(E)-3-(3,4-Difluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one
Crystal data Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (