2-Bromo-p-terphenyl

In the title compound, C18H13Br, the dihedral angles between the mean planes of the central benzene ring and the mean planes of the outer phenyl and bromophenyl rings are 33.47 (8) and 66.35 (8)°, respectively. In the crystal, weak C—H⋯π and intermolecular Br⋯Br [3.5503 (15) Å] interactions contribute to the stabilization of the packing.

In the title compound, C 18 H 13 Br, the dihedral angles between the mean planes of the central benzene ring and the mean planes of the outer phenyl and bromophenyl rings are 33.47 (8) and 66.35 (8) , respectively. In the crystal, weak C-HÁ Á Á and intermolecular BrÁ Á ÁBr [3.5503 (15) Å ] interactions contribute to the stabilization of the packing.

Related literature
For the synthesis, see: France et al. (1938); Tadashi et al. (1962). For the Suzuki coupling reaction, see: Miyaura & Suzuki (1995).   The introduction of substituents at the ortho-position of biary and terphenyl groups is often used in the preparation of an efficient host with a wide band gap, because the substitients suppress effective π-conjugation throughout the whole molecule.
Therefore, the structures of biaryl and terphenyl derivatives bearing a halogen atom at the ortho -position are attractive as good precursors to materials oriented chemists and physicists. The title compound, C 18 H 13 Br,(I), was synthesized by the Pd-catalyzed cross coupling of 4-biphenylboronic acid with 1-bromo-2-iodobenzene in the presence of base (Na 2 CO 3 ).

Experimental
A mixture of 4-biphenyboronicacid (0.1 mol), 1-bromo-2iodobenzene (0.1 mol), Na 2 CO 3 (0.6 mol, 2M in H 2 O), and Pd(PPh 3 ) 4 (5% mol) was refluxed for 12 h. After being cooled to room temperature, the reaction mixture was quenched by water. The aqueous layer was extracted with CH 2 Cl 2 , and the combined organic layers were sequentially washed with saturated aqueous NaCl (20 mL), dried with MgSO 4 , filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using CH 2 Cl 2 and hexane to give the titled compound as a colorless solid.

Refinement
All H-atoms were positioned geometrically and refined using a riding model with C-H = 0.93 Å, and with U iso (H) = 1.2U eq (C). Fig. 1. Molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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