3,6-Dichloro-9-(prop-2-yn-1-yl)-9H-carbazole

The tricyclic aromatic ring system of the title compound, C15H9Cl2N, is essentially planar (r.m.s. deviation = 0.002 Å). The two Cl atoms lie slightly out of the plane of the carbazole ring system, with the C—Cl bonds forming angles of 1.23 (8) and 1.14 (8)° with the plane. The acetylene group has a syn orientation with respect to the ring system. In the crystal, no weak hydrogen bonds nor any π–π stacking interactions are observed.

The tricyclic aromatic ring system of the title compound, C 15 H 9 Cl 2 N, is essentially planar (r.m.s. deviation = 0.002 Å ). The two Cl atoms lie slightly out of the plane of the carbazole ring system, with the C-Cl bonds forming angles of 1.23 (8) and 1.14 (8) with the plane. The acetylene group has a syn orientation with respect to the ring system. In the crystal, no weak hydrogen bonds nor anystacking interactions are observed. Experimental Crystal data C 15 H 9 Cl 2 N M r = 274.13 Orthorhombic, P2 1 2 1 2 1 a = 3.9825 (1) Å b = 11.1705 (4) Å c = 27.4417 (9) Å V = 1220.79 (7)

Comment
In recent years, carbazoles have been used as photoconductors, semiconductors and for their light-emitting properties, making them interesting organic tools for physics experiments (Zhang et al., 1998). Moreover, several alkaloids based on a carbazole structure are known to possess interesting biological activities such as antitumor, antibacterial, antiinflammatory, psychotropic and anti-histamine properties (Liu & Larock, 2007). Many synthetic carbazole derivatives are of significant pharmacological relevance because of their antifungal, antibiotic, and antitumor activities (Hussain et al., 2011;Zhang et al., 2010;Conchon et al., 2006). The introduction of functional groups onto the carbazole scaffold is essential to generate compounds suitable for biological and physical investigations. Based on such facts we herein report the crystal structure of the title compound.
In the title compound ( Fig. 1), the carbazole ring system is essentially planar (r.m.s. deviation = 0.002 Å). The Cl1 and Cl2 atoms lie slightly out of the plane of the carbazole ring system which makes angles of 1.23 (8)

Experimental
Propargyl bromide (1.1 g, 9 mmol) was added to a suspension solution of 3,6-dichloro-9H-carbazole (0.7 g, 3 mmol) and K 2 CO 3 (0.82 g, 6 mmol) in DMF (15 ml) and stirred at room temperature for 6 h. The excess solvent was evaporated to dryness in vacuo. The residue was diluted with water and then extracted with CH 2 Cl 2 (3 x 30 ml). The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered and evaporated under reduced pressure to give the corresponding product as colourless crystals (0.61 g, 75%) yield, mp 469-471 K.

Refinement
All H atoms were placed geometrically and refined using a riding model with C-H = 0.95 -0.99 Å, and with U iso (H) = 1.2U iso (C).  Perspective view of the title compound with 50% probability ellipsoids.

Figure 2
Packing of the title compound viewed along the a axis.  (14), 150 (2), 122 (2), 98 (2), 75 (4). Anal. for C 15 H 9 Cl 2 N: calcd. C,65.72;H,3.31;Cl,25.86;N,5.11. Found: C,65.38;H,3.11;N,4.95%. Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.  (3)