(E)-1-(3-Bromophenyl)-3-(4-ethoxyphenyl)prop-2-en-1-one

The title compound, C17H15BrO2, adopts an E configuration. The dihedral angle between the two benzene rings is 10.09 (11)°. The enone plane makes dihedral angles of 12.05 (11) and 9.87 (11)°, respectively, with the bromophenyl and ethoxyphenyl rings. The ethoxy group is nearly coplanar with the attached benzene ring. In the crystal structure, the molecules are linked by C—H⋯O hydrogen bonds, forming a zigzag ribbon-like structure along the b-axis direction.

The title compound, C 17 H 15 BrO 2 , adopts an E configuration. The dihedral angle between the two benzene rings is 10.09 (11) . The enone plane makes dihedral angles of 12.05 (11) and 9.87 (11) , respectively, with the bromophenyl and ethoxyphenyl rings. The ethoxy group is nearly coplanar with the attached benzene ring. In the crystal structure, the molecules are linked by C-HÁ Á ÁO hydrogen bonds, forming a zigzag ribbon-like structure along the b-axis direction.

Comment
Extensive research in recent years suggests organic materials to be the ideal candidates for tailoring the material properties.
As an interesting type of organic materials, chalcone and its derivatives have received much attention from physicists, chemists and material scientists who have been extensively investigating their optical, physical and chemical properties for fundamental understanding and technological applications (Chopra et al., 2007;Lokaj et al., 2001;Low et al., 2002;Sathiya Moorthi et al., 2005a,b;Schmalle et al., 1990;Wang et al., 2004). Earlier studies have indicated that chalcone and its derivatives are potential candidates for optical limiting applications (Gu et al., 2008a,b). Owing to their electronic structures, chalcones also find unique applications in fluorescent probes for the sensing of metal ions (DiCesare et al., 2000;Jiang et al., 1994), and in biological use (Nel et al., 1998). The chalcone derivatives with typical D-π-A mode have been reported to crystallize in a noncentrosymmetric crystal structure and possess second harmonic generation properties (Patil et al., 2006;Patil et al., 2007b). In our previous investigation, the crystal structure of 1-(4-chlorophenyl)-3-(4-ethoxyphenyl)prop-2-en-1-one has been reported (Patil et al., 2007a). To further understand the structure-property relationship, the title chalcone derivative was synthesized with ethoxy as an electron-donor group.
The title compound crystallized in the non-centrosymmetric monoclinic P2 1 space group and therefore it should exhibit second-order nonlinear optical properties.
The title molecule ( Fig.1) is nearly planar and exists in an E configuration with respect to the C8═C9 double bond A weak C9-H9A···O1 interaction generates an S(5) ring motif. The bond distances and angles have normal values (Allen et al., 1987) and are comparable with those observed in related structures (Patil et al., 2007a,b).
In the crystal structure, the molecules are linked by C-H···O hydrogen bonds (Table 1) to form a zigzag ribbon-like structure along the b direction ( Fig.2 and Fig.3).

Experimental
The title compound was synthesized by the condensation of 4-ethoxybenzaldehyde (0.01mol, 1.39 ml) with 3-bromoacetophenone (0.01 mol, 1.99 g)) in methanol (60 ml) in the presence of a catalytic amount of sodium hydroxide solution (5 ml, 20%). After stirring for 3 h, the contents of the flask were poured into ice-cold water (500 ml) and left to stand for 4 h. The resulting crude solid was filtered and dried. Single crystals were obtained by recrystallization from acetone. supplementary materials sup-2 Refinement All H atoms were placed in calculated positions, with C-H = 0.93 Å, U iso = 1.2U eq (C) for aromatic and CH, C-H = 0.97 Å, U iso = 1.2U eq (C) for CH 2 and C-H = 0.96 Å, U iso = 1.5U eq (C) for CH 3 atoms. A rotating group model was used for the methyl groups. The highest residual electron density peak is located at 0.81 Å from Br1 and the deepest hole is located at 0.76 Å from Br1. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme. The dashed line represent a C-H···O interaction.

Special details
Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment. 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.

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