(E)-1-(4-Fluorophenyl)-3-(4-methylphenyl)prop-2-en-1-one

The title compound, C16H13FO, adopts an E configuration with respect to the C=C bond of the propenone unit. The dihedral angle between the two benzene rings is 47.0 (5)°. Intramolecular C—H⋯O hydrogen bonds generate an S(5) ring motif. In the crystal structure, molecules are packed into columns along the c axis and the structure is stabilized by weak intramolecular C—H⋯O hydrogen bonds and intermolecular C—H⋯π interactions involving both aromatic rings.

The title compound, C 16 H 13 FO, adopts an E configuration with respect to the C C bond of the propenone unit. The dihedral angle between the two benzene rings is 47.0 (5) . Intramolecular C-HÁ Á ÁO hydrogen bonds generate an S(5) ring motif. In the crystal structure, molecules are packed into columns along the c axis and the structure is stabilized by weak intramolecular C-HÁ Á ÁO hydrogen bonds and intermolecular C-HÁ Á Á interactions involving both aromatic rings.

Comment
Significant studies on applications of chalcones in nonlinear optics have motivated us to further to identify materials, especially chalcone derivatives, with appropriate absorption in the UV region along with a transmission window in the NIR range contributing to multi-photon absorption (Agrinskaya et al., 1999;Gu et al., 2008;Patil et al., 2007a-c). Here we report the crystal structure of the title chalcone derivative, (I), Fig. 1.
In (I), the molecule exhibits an E configuration with respect to the C8═C9 double bond with the C7-C8-C9-C10 torsion angle 174.6 (2)°. The bond lengths and angles in (I) are comparable to those observed in related structures (Patil et al., 2007a-c). The dihedral angle between the two benzene rings is 47.0 (2)°.
Intramolecular C-H···O hydrogen bonds generate an S(5) ring motif. In the crystal structure molecules are packed into columns along the c axis and the structure is stabilised by weak intramolecular C-H···O hydrogen bonds and intermolecular C-H···π interactions involving both aromatic rings, Table 1.

Experimental
The compound (I) was synthesized by the condensation of p-tolualdehyde (0.01 mol) with 4-fluoroacetophenone (0.01 mol) in methanol (60 ml) in the presence of a catalytic amount of sodium hydroxide solution (5 ml, 30%). After stirring (4 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 acetone.

Refinement
All the H atoms were positioned geometrically and refined using a riding model with C-H = 0.93Å for aromatic and 0.96Å for CH 3 . The U iso values were constrained to be 1.5U eq of the carrier atom for the methyl H atoms and 1.2U equ for the remaining hydrogen atoms. Fig. 1. The asymmetric unit of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme. The intramolecular H-bond is drawn as a dashed line.   (6) 0.0029 (6) 0.0013 (6)  C16 0.0277 (9) 0.0317 (10) 0.0273 (9) 0.0009 (7) −0.0041 (7) −0.0021 (7) Geometric parameters (Å, °)