9-(4-Bromobutyl)-9H-carbazole

In the title compound, C16H16BrN, the tricyclic carbazole system is essentially planar (r.m.s. deviation of all non-H atoms = 0.010 Å). The dihedral angle between the two outer carbazole rings is 1.1 (3)°. There are no directional intermolecular contacts in the crystal packing.


Ellena Comment
The carbazole ring has a highly conjugated π system with desirable optical and charge-transport properties. These characteristics make it an excellent candidate for applications in different areas of science. Indeed, carbazole and its derivatives, heterocyclic compounds with a N atom in their structure, have interesting chemical (Knolker & Reddy, 2002), physical (Koyuncu et al., 2011) andmedicinal (Zhang et al., 2010) properties. Polymers based on carbazole units become promising materials because of their optical, electronic and electrochemical behaviors (Taranekar et al., 2007;Morisaki et al., 2009). One of these derivatives, 9-(4-bromobutyl)-9H-carbazole, the title compound C 16 H 16 BrN, was synthesized and its structure is reported here.
In the title compound (

Experimental
The synthesis of 9-(4-bromobutyl)-9H-carbazole was accomplished by a modified method as reported by Bo et al., 1998. A mixture of 10.32 g (61.72 mmol) of carbazole in toluene (100 ml) containing 1,4-dibromobutane (118.2 g, 547.4 mmol) and tetrabutylammonium bromide (TBAB, 2.0 g) was stirred at 45 °C for 3 h. and then left overnight. After the aqueous layer was removed and washed three times with water and brine, the organic layer was dried over Na 2 SO 4 . The organic solvent was evaporated, and unreacted 1,4-dibromobutane was removed by vacuum distillation. The residue was recrystallized from ethanol to give 16.7 g (89.5% yield) of the title compound, m.p. 379 (1)

Figure 1
Molecular conformation and atom numbering scheme for the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radius.

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.