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

The title compound, C13H9ClOS, adopts an E configuration with respect to the C=C double bond of the propenone unit. The thienyl and benzene rings are slightly twisted from each other, making a dihedral angle of 6.38 (3)°. An intramolecular C—H⋯O hydrogen bond generates an S(5) ring motif. A weak intermolecular C—H⋯O interaction, a short intramolecular S⋯O contact [2.932 (2) Å] and two π–π interactions between the thienyl and benzene rings are observed. The centroid–centroid distances of the π–π interactions are 3.7899 (16) and 3.7891 (16) Å.


Comment
Since some chalcone derivatives have shown to be potential nonlinear optical materials (Agrinskaya et al., 1999), a series of new chalcone derivatives have been prepared in our laboratory Gu, Ji, Patil, Dharmaprakash & Wang, 2008;Fun et al., 2008;Patil et al., 2006).
As part of the ongoing investigation, the title compound has recently been prepared and its crystal structure is reported here.
In the crystal structure of the title compound, (I), the molecule exhibits an E configuration with respect to the C6═C7 double bond with the C5-C6-C7-C8 torsion angle being 180.0 (3)°. The bond lengths and bond angles in (I) are found to have normal values (Allen et al., 1987). The thienyl (S1/C1-C4) and benzene (C8-C13) rings are essentially planar with the maximum deviation from planarity being -0.001 (2) Å for atom S1 and 0.011 (3) Å for atom C8. The thienyl ring and the benzene ring are slightly twisted from each other with a dihedral angle of 6.38 (8)°.
After stirring (10 h), the contents of the flask were poured into ice-cold water (500 ml) and left to stand for 5 h. The resulting crude solid was filtered and dried. The precipitated compound was recrystallized from N, N-dimethylformamide (DMF).

Refinement
H atoms were positioned geometrically (C-H = 0.93 Å) and refined using a riding model, with U iso (H) = 1.2U eq (C). The highest peak in the difference Fourier map is located 0.82 Å from atom S1. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme.

Figures
supplementary materials sup-2  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 Rfactors(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.