1,3-Bis(biphenyl-4-yl)-2,2-dibromo-3-oxopropyl acetate

In the title compound, C29H22Br2O3, the dihedral angles between the mean planes of the benzene rings within each biphenyl group are 26.7 (8) and 30.9 (8)°. The mean planes of the terminal and inner benzene rings of the biphenyl groups bonded through a propan-1-one group in the V-shaped molecule are oriented at angles of 66.1 (7) and 60.0 (8)°, respectively. The two Br atoms are opposite the propen-1-one group. Weak intermolecular C—H⋯O and C—H⋯π interactions are observed in the crystal structure.

In the title compound, C 29 H 22 Br 2 O 3 , the dihedral angles between the mean planes of the benzene rings within each biphenyl group are 26.7 (8) and 30.9 (8) . The mean planes of the terminal and inner benzene rings of the biphenyl groups bonded through a propan-1-one group in the V-shaped molecule are oriented at angles of 66.1 (7) and 60.0 (8) , respectively. The two Br atoms are opposite the propen-1-one group. Weak intermolecular C-HÁ Á ÁO and C-HÁ Á Á interactions are observed in the crystal structure.   Table 1 Hydrogen-bond geometry (Å , ).

Comment
Among several organic compounds exhibiting NLO effects, chalcone derivatives are important materials for their excellent blue light transmittance and good crystallizability. It has been observed that substitution of a bromo group on either of the phenyl rings greatly influences non-centrosymmetric crystal packing (Uchida et al., 1998;Tam et al., 1989;Indira et al., 2002). Bromo substituents can obviously improve molecular first-order hyperpolarizabilities and can effectively reduce dipole-dipole interactions between molecules (Zhao et al., 2002). Chalcone derivatives usually have lower melting points, which can be a drawback when their crystals are used in optical instruments. Chalcone dibromides usually have higher melting points and are thermally stable. In order to synthesize the dibromo derivative of this chalcone, (2E)-1,3-di(biphenyl-4-yl)prop-2-en-1-one was brominated using bromine in acetic acid. But instead of the dibromo derivative of this chalcone, a new product 2,2-dibromo-1,3-di(biphenyl-4-yl)-3-oxopropyl acetate (I) has been obtained.
The crystal structures of some dibromo chalcones viz., 2,3-dibromo-3- et al., 2007) have been reported. In continuation of our work on synthesis of various derivatives of chalcone (Samshuddin et al., 2011;Jasinski et al., 2010), the title chalcone dibromide, (I), was prepared and its crystal structure is reported.
In the crystal structure of (I), the dihedral angles between the mean planes of the benzene rings within each biphenyl group are 26.7 (8)° and 30.9 (8)° (Fig. 1). The mean planes of the terminal and inner benzene rings of the biphenyl groups bonded through a propan-1-one group in the V-shaped molecule are oriented at angles of 66.1 (7) and 60.0 (8)°, respectively.
The two bromine atoms are opposite the propen-1-one group extending in an apical configuration. Weak C-H···O and C-H···Cg π-ring intermolecular interactions are observed in the crystal structure (Table 1, Fig. 2).

Experimental
To a solution of (2E)-1,3-di(biphenyl-4-yl)prop-2-en-1-one (3.60 g, 0.01 mol) in acetic acid (25 ml), bromine (1.60 g, 0.01 mol) in acetic acid (10 ml) was added slowly with stirring at 273 K. After completion of the addition of the bromine solution, the reaction mixture was stirred for 5 h. The solid obtained was filtered and recrystallized from acetone. Single crystals were grown from its methanol solution by slow evaporation. The yield of the compound was 86%. (m.p.: 445 K).

Refinement
All of the H atoms were placed in their calculated positions and then refined using the riding model with C-H lengths of 0