N,N-Dimethyl-4-[(E)-2-(3,6,7-tribromo-9-butyl-9H-carbazol-2-yl)ethenyl]aniline

In the title molecule, C26H25Br3N2, a dihedral angle of 6.15 (10)° is present between the carbazole and benzene ring systems with an E conformation about the C=C bond [1.335 (4) Å]. The butyl group is almost perpendicular to the carbazole plane [C—N—C—C torsion angle = −98.7 (3)°]. In the crystal, supramolecular double chains along [-7,18,-16] are formed via C—H⋯Br and π–π interactions [centroid(carbazole five-membered ring)⋯centroid(carbazole six-membered ring) distance = 3.6333 (13) Å].

In (I), the carbazole fused-ring system is planar with the r.m.s. deviation of the 13 fitted non-hydrogen atoms = 0.006 Å; the Br1, Br2 and Br3 atoms lie 0.058 (1), 0.062 (1) and 0.043 (1) Å out of this plane, respectively. The least-squares plane through the carbazole residue forms a dihedral angle of 6.15 (10)° with the benzene ring, indicating a small twist between the terminal ring systems. This twist is manifested in the value of the C15-C14-C17-C18 torsion angle of -11.2 (4)°.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.95 to 0.99 Å, U iso (H) = 1.2 to 1.5U eq (C)] and were included in the refinement in the riding model approximation. The maximum and minimum residual electron density peaks of 1.18 and 0.81 e Å -3 , respectively, were located 0.86 Å and 0.44 Å from the H2 and Br1 atoms, respectively.

Figure 1
The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.

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