(E)-3-(4-Chlorophenyl)-1-(4-fluorophenyl)prop-2-en-1-one

In the title compound, C15H10ClFO, the fluoro-substituted benzene ring forms a dihedral angle of 44.41 (6)° with the chloro-substituted benzene ring. The only significant directional bonds in the crystal are weak C—H⋯π interactions.

In the title compound, C 15 H 10 ClFO, the fluoro-substituted benzene ring forms a dihedral angle of 44.41 (6) with the chloro-substituted benzene ring. The only significant directional bonds in the crystal are weak C-HÁ Á Á interactions.

Related literature
For related structures and background to chalcone derivatives, see : Fun, Loh et al. (2011) ;Fun, Arshad et al. (2011a,b). For the stability of the temperature controller used for data collection, see: Cosier & Glazer (1986 Table 1 Hydrogen-bond geometry (Å , ).
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009  In continuation of our work on the synthesis and structures of chalcone derivatives (Fun, Arshad et al., 2011a,b;Fun, Loh et al., 2011), the title compound was prepared and its crystal structure is reported.
The molecular structure of the title compound is shown in Fig. 1. The least-squares plane of the fluoro-substituted benzene ring (C1-C6) makes a dihedral angle of 44.41 (6)° with the least-squares plane of the chloro-substituted benzene ring (C10-C15). Bond lengths are comparable to those in related structures (Fun, Arshad et al., 2011a,b;Fun, Loh et al., 2011).
In the crystal structure, no significant intermolecular hydrogen bonds are observed. The crystal structure features were C-H···π interactions (Table 1), involving the centroid of C10-C15 benzene ring.

Experimental
To a mixture of 4-fluoroacetophenone (1.38 g, 0.01 mol) and 4-chlorobenzaldehyde (1.41 g, 0.01 mol) in ethanol (100 ml), 15 ml of 10% sodium hydroxide solution was added and stirred at 0-5 °C for 3 h. The precipitate formed was collected by filtration and purified by recrystallization from ethanol. Colourless blocks were grown from toluene as solvent by the slow evaporation method (m.p.: 405-407 K).

Refinement
All H atoms were positioned geometrically [C-H = 0.93 Å] and refined using a riding model with U iso (H) = 1.2 U eq (C).

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009  The molecular structure of the title compound with 50% probability displacement ellipsoids. Special details Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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.