1-(10-Bromoanthracen-9-yl)-1H-imidazole

In the title molecule, C17H11BrN2, the planes of the anthracene ring system [maximum deviation from the mean plane = 0.036 (3) Å] and the imidazole ring form a dihedral angle of 85.14 (14)°. In the crystal, weak C—H⋯N and C—H⋯Br hydrogen bonds link the molecules into double chains propagating along [01-1]. In addition, π–π stacking interactions between pairs of benzene rings are observed, with centroid–centroid distances of 3.7968 (17) and 3.8496 (16) Å.

In the title molecule, C 17 H 11 BrN 2 , the planes of the anthracene ring system [maximum deviation from the mean plane = 0.036 (3) Å ] and the imidazole ring form a dihedral angle of 85.14 (14) . In the crystal, weak C-HÁ Á ÁN and C-HÁ Á ÁBr hydrogen bonds link the molecules into double chains propagating along [011]. In addition,stacking interactions between pairs of benzene rings are observed, with centroidcentroid distances of 3.7968 (17) and 3.8496 (16) Å .

Comment
The title compound is a side-product in the preparation of 9,10-di(1H-imidazol-1-yl)anthracene. The latter compound is a ditopic bis(imidazole) ligand which can form intriguing coordination polymers with transition metal ions (Lee et al., et al. 2011). The title compound however, features only one imidazole moiety. 9-(10′-Bromo-9′-anthryl)carbazole is a structure in the literature which is related to the title compound (Boyer et al. 1993).
The molecular structure of the title compound is shown in Fig. 1. The anthracene ring system [maximum deviation from the mean plane = 0.036 (3)Å for C11] and imidazole ring form a dihedral angle of 85.14 (14) Å. In the crystal, weak hydrogen bonds of the type C-H···N and C-H···Br link the molecules into one-dimensional double chains propagating along [0, 1, -1] (Fig. 2). Double chains are further stablized by π-π stacking interaction between pairs of anthracene rings.

Experimental
The compound was isolated as a side-product in the preparation of 9,10-di(1H-imidazol-1-yl)anthracene (dia) (Lee et al., 2011). Suitable crystals were obtained by slow evaporation of a methanol solution of the compound at room temperature.

Refinement
The hydrogen atom upon C2 was located in a difference Fourier map and freely refined. All the other hydrogen atoms were positioned geometrically and refined as riding atoms, with C-H = 0.95 Å with U iso (H) = 1.2U eq (C).  The molecular structure of the title compound, showing 50% probability displacement ellipsoids for the non-hydrogen atoms. The H atoms are dipicted by circles of an arbitrary radius.

Figure 2
A view of a double chain displaying the hydrogen bonds as dashed lines. The viewing direction is along [1,1,1].

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