1-(3,5-Difluorophenyl)-4,4,4-trifluorobutane-1,3-dione

In the title compound, C10H5F5O2, the C=O bonds are syn to one another. In the crystal, molecules are linked into C(9) chains parallel to [101] through weak C—H⋯O interactions, with the O atom adjacent to the –CF3 group acting as the acceptor.

In the title compound, C 10 H 5 F 5 O 2 , the C O bonds are syn to one another. In the crystal, molecules are linked into C(9) chains parallel to [101] through weak C-HÁ Á ÁO interactions, with the O atom adjacent to the -CF 3 group acting as the acceptor.

Comment
As part of our ongoing studies of the biological activities of compounds with a trifluoromethyl substituent (Manoj Kumar et al., 2013), we now describe the structure of the title compound, (I).

Experimental
3,5-Difluoroacetophenone (1 mmol) and sodium hydride (1.5 mmol) were taken in dry THF (20 ml), and the solution was stirred for 30 min at 0°C. To this solution trifluoroethylacetate (1.2 mmol) was added and the reaction mixture was stirred for 10 h at room temperature under nitrogen atmosphere. The reaction was monitored by TLC. The crude mass was purified by column chromatography using petroleum ether and ethyl acetate as an eluent (7:3), to obtain a yellow solid.

Refinement
The H atoms were positioned with idealized geometry using a riding model with C-H = 0.93-0.97 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).

Figure 2
Molecular packing foming C(9) chains parallel to [101] with hydrogen bonding shown as dashed lines. 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 C1 0.0373 (