organic compounds
9-(4-Bromophenyl)-9H-carbazole
aInstitute for Applied Synthetic Chemistry, Division Organic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-OC, A-1060 Vienna, Austria, and bInstitute for Chemical Technologies and Analytics, Division Structural Chemistry, Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria
*Correspondence e-mail: bstoeger@mail.tuwien.ac.at
In the title molecule, C18H12BrN, the 4-bromophenyl ring is inclined to the mean plane of the carbazole moiety (r.m.s. devation = 0.027 Å) by 49.87 (5)°. In the crystal, molecules stack along [001] and are linked by C—H⋯π interactions forming a corrugated two-dimensional network lying parallel to (100).
CCDC reference: 987662
Related literature
For isostructural crystal structures, see: Saha & Samanta (1999); Chen et al. (2005). For related carbazole-based crystal structures, see: Kim et al. (2011); Liu et al. (2010); Wu et al. (2007); Chen et al. (2012). For a chemically related non-isostructural compound, see: Xie et al. (2012). For applications of arylamines as functional materials, see: Shirota & Kageyama (2007); Tao et al. (2011); Yook & Lee (2012); Kautny et al. (2014). For isostructurality, see: Kálmán et al. (1999). For merotypism and its application to organic compounds, see: Ferraris et al. (2004); Stöger et al. (2012). For the synthesis of the title compound, see: Xu et al. (2007).
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2013); cell SAINT-Plus (Bruker, 2013); data reduction: SAINT-Plus; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: ATOMS (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
CCDC reference: 987662
10.1107/S1600536814003705/kj2237sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536814003705/kj2237Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536814003705/kj2237Isup3.cml
The synthesis of (I) was performed according to the procedure described by Xu et al. (2007). A fused silica ampoule was charged with 9H-carbazole (5.35 g, 32.0 mmol, 1.00 eq.), 1,4-dibromobenzene (9.06 g, 38.4 mmol, 1.20 eq.), CuSO4·5H2O (400 mg, 1.6 mmol, 0.05 eq.) and K2CO3 (4.42 g, 32.0 mmol, 1.00 eq.) The sealed ampoule was heated to 250 °C for 68 h. After cooling, the tube was carefully opened with a diamond blade, releasing a small amount of gas. The solid residue was partitioned between toluene and water and the aqueous phase was extracted with toluene. The combined organic layers were washed with water, dried over anhydrous Na2SO4 and concentrated under reduced pressure. Purification was performed by
(light petroleum:DCM 75:25) yielding 9-(4-bromophenyl)-9H-carbazole (4.22 g, 13.1 mmol, 41%) as white solid. Large single crystals of (I) were grown by slow evaporation of a CDCl3 solution.The structure was refined against F values using the Jana2006 software package (Petříček et al., 2006). The non-H atoms were located in the
obtained by charge-flipping implemented in SUPERFLIP (Palatinus & Chapuis, 2007) and refined with anisotropic displacement parameters. The H atoms were placed at calculated positions and refined as riding on the parent C atoms.Data collection: APEX2 (Bruker, 2013); cell
SAINT-Plus (Bruker, 2013); data reduction: SAINT-Plus (Bruker, 2013); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: ATOMS (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).Fig. 1. The molecular structure of (I). C, N and Br are represented by grey, blue and green ellipsoids drawn at the 75% probability levels, H atoms by white spheres of arbitrary radius. | |
Fig. 2. Crystal structure of (I) viewed down (a) [100] and (b) [001]. C, N and Br atoms are represented by spheres of arbitrary radius. H atoms were omitted for clarity. Colour codes as in Fig. 1. The position of the crystallo-chemical layers is indicated to the left, the position of the A and B slabs to the right | |
Fig. 3. The (a) A and (b) B slabs of (I) composed of 9H-carbazol-9-yl and 4-bromophenyl fragments, respectively projected on (001). (c) The A slabs in 9-(4-(2-(4-(2,1,3-benzothiadiazol-4-ylethynyl)phenyl)vinyl)phenyl)-9H-carbazole (coordinates from Chen, et al., (2012)). Colour codes as in Fig. 1. | |
Fig. 4. 4-(9H-carbazol-9-yl)-phenyl derivatives crystallizing with A slabs isotypic to (I). | |
Fig. 5. The crystal structure of 9-(4-(2-(4-(2,1,3-benzothiadiazol-4-ylethynyl)phenyl)vinyl)phenyl)-9H-carbazole. S atoms are yellow, other colour codes as in Fig. 1. |
C18H12BrN | F(000) = 648 |
Mr = 322.2 | Dx = 1.544 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ycb | Cell parameters from 25237 reflections |
a = 8.4137 (3) Å | θ = 2.5–32.5° |
b = 20.1179 (7) Å | µ = 2.95 mm−1 |
c = 8.6346 (3) Å | T = 100 K |
β = 108.5322 (14)° | Block, clear colourless |
V = 1385.76 (8) Å3 | 0.75 × 0.55 × 0.42 mm |
Z = 4 |
Bruker Kappa APEXII CCD diffractometer | 5056 independent reflections |
Radiation source: X-ray tube | 4340 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.035 |
ω and φ scans | θmax = 32.8°, θmin = 2.6° |
Absorption correction: multi-scan (SADABS; Bruker, 2013) | h = −12→12 |
Tmin = 0.16, Tmax = 0.29 | k = −30→30 |
53140 measured reflections | l = −13→13 |
Refinement on F | Primary atom site location: iterative |
R[F2 > 2σ(F2)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.047 | H-atom parameters constrained |
S = 1.69 | Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0004F2) |
5056 reflections | (Δ/σ)max = 0.026 |
181 parameters | Δρmax = 0.47 e Å−3 |
0 restraints | Δρmin = −0.51 e Å−3 |
48 constraints |
C18H12BrN | V = 1385.76 (8) Å3 |
Mr = 322.2 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.4137 (3) Å | µ = 2.95 mm−1 |
b = 20.1179 (7) Å | T = 100 K |
c = 8.6346 (3) Å | 0.75 × 0.55 × 0.42 mm |
β = 108.5322 (14)° |
Bruker Kappa APEXII CCD diffractometer | 5056 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2013) | 4340 reflections with I > 3σ(I) |
Tmin = 0.16, Tmax = 0.29 | Rint = 0.035 |
53140 measured reflections |
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.047 | H-atom parameters constrained |
S = 1.69 | Δρmax = 0.47 e Å−3 |
5056 reflections | Δρmin = −0.51 e Å−3 |
181 parameters |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.84651 (2) | −0.036314 (8) | −0.405902 (18) | 0.02427 (6) | |
N1 | 0.51185 (14) | 0.12342 (5) | 0.00001 (13) | 0.0116 (3) | |
C1 | 0.58687 (16) | 0.08548 (6) | −0.09658 (15) | 0.0111 (3) | |
C2 | 0.69269 (18) | 0.03277 (6) | −0.02622 (17) | 0.0133 (4) | |
C3 | 0.77018 (17) | −0.00373 (6) | −0.11813 (17) | 0.0139 (4) | |
C4 | 0.73532 (17) | 0.01171 (7) | −0.28261 (16) | 0.0139 (4) | |
C5 | 0.62817 (17) | 0.06309 (7) | −0.35594 (16) | 0.0148 (4) | |
C6 | 0.55565 (17) | 0.10094 (7) | −0.26077 (15) | 0.0135 (3) | |
C7 | 0.34167 (16) | 0.13791 (6) | −0.03947 (16) | 0.0118 (3) | |
C8 | 0.21016 (17) | 0.12051 (7) | −0.17824 (16) | 0.0147 (4) | |
C9 | 0.04953 (18) | 0.13772 (7) | −0.18154 (18) | 0.0174 (4) | |
C10 | 0.01993 (18) | 0.17175 (7) | −0.05191 (19) | 0.0190 (4) | |
C11 | 0.15091 (18) | 0.18942 (7) | 0.08536 (18) | 0.0172 (4) | |
C12 | 0.31464 (17) | 0.17212 (6) | 0.09265 (16) | 0.0127 (4) | |
C13 | 0.47576 (17) | 0.17913 (6) | 0.21673 (16) | 0.0122 (3) | |
C14 | 0.52962 (19) | 0.20908 (6) | 0.37103 (17) | 0.0164 (4) | |
C15 | 0.6979 (2) | 0.20772 (7) | 0.46009 (17) | 0.0186 (4) | |
C16 | 0.81376 (18) | 0.17722 (7) | 0.39656 (17) | 0.0168 (4) | |
C17 | 0.76424 (17) | 0.14676 (6) | 0.24474 (16) | 0.0143 (4) | |
C18 | 0.59415 (16) | 0.14789 (6) | 0.15611 (15) | 0.0116 (3) | |
H1c2 | 0.712034 | 0.021682 | 0.086423 | 0.016* | |
H1c3 | 0.846464 | −0.038992 | −0.069149 | 0.0167* | |
H1c5 | 0.604265 | 0.072462 | −0.470097 | 0.0178* | |
H1c6 | 0.484129 | 0.13771 | −0.308549 | 0.0162* | |
H1c8 | 0.229898 | 0.097553 | −0.267885 | 0.0176* | |
H1c9 | −0.043798 | 0.125999 | −0.275106 | 0.0208* | |
H1c10 | −0.092883 | 0.182992 | −0.058358 | 0.0228* | |
H1c11 | 0.130161 | 0.212998 | 0.17367 | 0.0206* | |
H1c14 | 0.450589 | 0.230279 | 0.414296 | 0.0197* | |
H1c15 | 0.735971 | 0.227799 | 0.566404 | 0.0223* | |
H1c16 | 0.930439 | 0.177463 | 0.459918 | 0.0202* | |
H1c17 | 0.844122 | 0.125706 | 0.202336 | 0.0172* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02113 (9) | 0.03450 (10) | 0.02083 (9) | 0.00656 (6) | 0.01183 (6) | −0.00729 (6) |
N1 | 0.0095 (5) | 0.0143 (5) | 0.0113 (4) | 0.0012 (4) | 0.0040 (4) | −0.0020 (4) |
C1 | 0.0106 (5) | 0.0134 (5) | 0.0109 (5) | −0.0005 (4) | 0.0055 (4) | −0.0013 (4) |
C2 | 0.0139 (6) | 0.0133 (5) | 0.0145 (6) | −0.0009 (4) | 0.0069 (5) | 0.0000 (4) |
C3 | 0.0127 (6) | 0.0132 (5) | 0.0174 (6) | 0.0004 (4) | 0.0071 (5) | −0.0009 (4) |
C4 | 0.0121 (5) | 0.0173 (6) | 0.0148 (5) | −0.0017 (5) | 0.0079 (5) | −0.0046 (5) |
C5 | 0.0147 (6) | 0.0199 (6) | 0.0116 (5) | −0.0005 (5) | 0.0066 (5) | −0.0015 (5) |
C6 | 0.0125 (5) | 0.0166 (6) | 0.0120 (5) | 0.0007 (4) | 0.0047 (4) | 0.0003 (4) |
C7 | 0.0105 (5) | 0.0114 (5) | 0.0147 (5) | 0.0016 (4) | 0.0059 (4) | 0.0011 (4) |
C8 | 0.0128 (6) | 0.0167 (6) | 0.0145 (5) | 0.0000 (4) | 0.0042 (4) | 0.0010 (4) |
C9 | 0.0126 (6) | 0.0192 (6) | 0.0192 (6) | 0.0008 (5) | 0.0034 (5) | 0.0048 (5) |
C10 | 0.0130 (6) | 0.0174 (6) | 0.0286 (7) | 0.0043 (5) | 0.0094 (5) | 0.0044 (5) |
C11 | 0.0167 (6) | 0.0140 (6) | 0.0249 (7) | 0.0037 (5) | 0.0123 (5) | 0.0008 (5) |
C12 | 0.0134 (5) | 0.0105 (5) | 0.0161 (6) | 0.0016 (4) | 0.0073 (5) | 0.0008 (4) |
C13 | 0.0157 (6) | 0.0091 (5) | 0.0135 (5) | 0.0001 (4) | 0.0071 (4) | −0.0005 (4) |
C14 | 0.0222 (7) | 0.0117 (5) | 0.0172 (6) | 0.0004 (5) | 0.0090 (5) | −0.0034 (4) |
C15 | 0.0260 (7) | 0.0148 (6) | 0.0140 (6) | −0.0028 (5) | 0.0051 (5) | −0.0039 (5) |
C16 | 0.0181 (6) | 0.0151 (6) | 0.0158 (6) | −0.0031 (5) | 0.0033 (5) | −0.0003 (5) |
C17 | 0.0139 (6) | 0.0147 (5) | 0.0144 (5) | 0.0000 (4) | 0.0046 (5) | −0.0003 (4) |
C18 | 0.0133 (5) | 0.0109 (5) | 0.0113 (5) | −0.0007 (4) | 0.0051 (4) | −0.0011 (4) |
Br1—C4 | 1.8909 (15) | C9—C10 | 1.400 (2) |
N1—C1 | 1.4182 (19) | C9—H1c9 | 0.96 |
N1—C7 | 1.3932 (17) | C10—C11 | 1.3840 (18) |
N1—C18 | 1.3947 (15) | C10—H1c10 | 0.96 |
C1—C2 | 1.3937 (17) | C11—C12 | 1.403 (2) |
C1—C6 | 1.3925 (18) | C11—H1c11 | 0.96 |
C2—C3 | 1.387 (2) | C12—C13 | 1.4430 (17) |
C2—H1c2 | 0.96 | C13—C14 | 1.3999 (18) |
C3—C4 | 1.3910 (19) | C13—C18 | 1.412 (2) |
C3—H1c3 | 0.96 | C14—C15 | 1.380 (2) |
C4—C5 | 1.3853 (18) | C14—H1c14 | 0.96 |
C5—C6 | 1.395 (2) | C15—C16 | 1.403 (2) |
C5—H1c5 | 0.96 | C15—H1c15 | 0.96 |
C6—H1c6 | 0.96 | C16—C17 | 1.3858 (19) |
C7—C8 | 1.3928 (16) | C16—H1c16 | 0.96 |
C7—C12 | 1.411 (2) | C17—C18 | 1.3922 (18) |
C8—C9 | 1.387 (2) | C17—H1c17 | 0.96 |
C8—H1c8 | 0.96 | ||
C1—N1—C7 | 125.70 (10) | C10—C9—H1c9 | 119.15 |
C1—N1—C18 | 125.54 (11) | C9—C10—C11 | 120.97 (14) |
C7—N1—C18 | 108.58 (12) | C9—C10—H1c10 | 119.51 |
N1—C1—C2 | 119.68 (12) | C11—C10—H1c10 | 119.51 |
N1—C1—C6 | 120.22 (11) | C10—C11—C12 | 118.56 (14) |
C2—C1—C6 | 120.10 (13) | C10—C11—H1c11 | 120.72 |
C1—C2—C3 | 120.32 (13) | C12—C11—H1c11 | 120.72 |
C1—C2—H1c2 | 119.84 | C7—C12—C11 | 119.54 (11) |
C3—C2—H1c2 | 119.84 | C7—C12—C13 | 107.05 (12) |
C2—C3—C4 | 118.76 (12) | C11—C12—C13 | 133.35 (13) |
C2—C3—H1c3 | 120.62 | C12—C13—C14 | 133.82 (14) |
C4—C3—H1c3 | 120.62 | C12—C13—C18 | 106.75 (11) |
Br1—C4—C3 | 118.63 (10) | C14—C13—C18 | 119.43 (12) |
Br1—C4—C5 | 119.37 (11) | C13—C14—C15 | 119.10 (15) |
C3—C4—C5 | 121.92 (14) | C13—C14—H1c14 | 120.45 |
C4—C5—C6 | 118.75 (12) | C15—C14—H1c14 | 120.45 |
C4—C5—H1c5 | 120.62 | C14—C15—C16 | 120.54 (13) |
C6—C5—H1c5 | 120.63 | C14—C15—H1c15 | 119.73 |
C1—C6—C5 | 120.10 (12) | C16—C15—H1c15 | 119.73 |
C1—C6—H1c6 | 119.95 | C15—C16—C17 | 121.73 (12) |
C5—C6—H1c6 | 119.95 | C15—C16—H1c16 | 119.13 |
N1—C7—C8 | 129.17 (13) | C17—C16—H1c16 | 119.13 |
N1—C7—C12 | 108.74 (10) | C16—C17—C18 | 117.40 (14) |
C8—C7—C12 | 122.00 (13) | C16—C17—H1c17 | 121.3 |
C7—C8—C9 | 117.23 (13) | C18—C17—H1c17 | 121.3 |
C7—C8—H1c8 | 121.39 | N1—C18—C13 | 108.87 (11) |
C9—C8—H1c8 | 121.39 | N1—C18—C17 | 129.30 (14) |
C8—C9—C10 | 121.70 (12) | C13—C18—C17 | 121.78 (12) |
C8—C9—H1c9 | 119.15 |
Cg1, Cg3 and Cg4 are the centroids of the N1/C7/C12/C13/C18, C7–C12 and C13–C18 rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H1C3···Cg3i | 0.96 | 2.57 | 3.3237 (14) | 135 |
C5—H1C5···Cg4ii | 0.96 | 2.96 | 3.7527 (15) | 141 |
C14—H1C14···Cg1iii | 0.96 | 2.79 | 3.5367 (14) | 135 |
Symmetry codes: (i) −x+1, −y, −z; (ii) x, y, z−1; (iii) x, −y+1/2, z+1/2. |
Cg1, Cg3 and Cg4 are the centroids of the N1/C7/C12/C13/C18, C7–C12 and C13–C18 rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H1C3···Cg3i | 0.96 | 2.57 | 3.3237 (14) | 135 |
C5—H1C5···Cg4ii | 0.96 | 2.96 | 3.7527 (15) | 141 |
C14—H1C14···Cg1iii | 0.96 | 2.79 | 3.5367 (14) | 135 |
Symmetry codes: (i) −x+1, −y, −z; (ii) x, y, z−1; (iii) x, −y+1/2, z+1/2. |
Acknowledgements
The X-ray centre (XRC) of the Vienna University of Technology is acknowledged for providing access to the single-crystal diffractometer and for financial support.
References
Bruker (2013). SAINT-Plus, APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chen, S., Chen, N., Yan, Y.-L., Liu, T., Yu, Y., Li, Y., Liu, H., Zhao, Y.-S. & Li, Y. (2012). Chem. Commun. 48, 9011–9013. Web of Science CSD CrossRef CAS Google Scholar
Chen, L.-Q., Yang, C.-L., Meng, X.-G. & Qin, J.-G. (2005). Acta Cryst. E61, o3073–o3075. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Dowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee, USA. Google Scholar
Ferraris, G., Makovicky, E. & Merlino, S. (2004). Crystallography of Modular Materials, Vol. 15, IUCr Monographs on Crystallography. Oxford University Press. Google Scholar
Kálmán, A., Párkányi, L. & Argay, G. (1999). Chem. Commun. pp. 605–606. Google Scholar
Kautny, P., Lumpi, D., Wang, Y., Tissot, A., Bintinger, J., Horkel, E., Stöger, B., Hametner, C., Hagemann, H., Ma, D. & Fröhlich, J. (2014). J. Mater. Chem. C. Accepted. doi:10.1039/C3TC32338B. Google Scholar
Kim, B.-S., Kim, S.-H., Shinya, M. & Son, Y. A. (2011). Z. Kristallogr. New Cryst. Struct. 226, 177. Google Scholar
Liu, R., Zhu, H., Chang, J., Xiao, Q., Li, Y. & Chen, H. (2010). J. Lumin. 130, 1183–1188. Web of Science CSD CrossRef CAS Google Scholar
Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786–790. Web of Science CrossRef CAS IUCr Journals Google Scholar
Petříček, V., Dušek, M. & Palatinus, L. (2006). JANA2006. Institute of Physics, Praha, Czech Republic. Google Scholar
Saha, S. & Samanta, A. (1999). Acta Cryst. C55, 1299–1300. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Shirota, Y. & Kageyama, H. (2007). Chem. Rev. 107, 953–1010. Web of Science CrossRef PubMed CAS Google Scholar
Stöger, B., Kautny, P., Lumpi, D., Zobetz, E. & Fröhlich, J. (2012). Acta Cryst. B68, 667–676. Web of Science CSD CrossRef IUCr Journals Google Scholar
Tao, Y., Yang, C. & Qin, J. (2011). Chem. Soc. Rev. 40, 2943–2970. Web of Science CrossRef CAS PubMed Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wu, J.-Y., Pan, Y.-L., Zhang, X.-J., Sun, T., Tian, Y.-P., Yang, J.-X. & Chen, Z.-N. (2007). Inorg. Chim. Acta, 360, 2083–2091. Web of Science CSD CrossRef CAS Google Scholar
Xie, Y.-Z., Jin, J.-Y. & Qu, X.-C. (2012). Acta Cryst. E68, o1199. CSD CrossRef IUCr Journals Google Scholar
Xu, H., Yin, K. & Huang, W. (2007). Chem. Eur. J. 13, 10281–10293. Web of Science CrossRef PubMed CAS Google Scholar
Yook, K. S. & Lee, J. Y. (2012). Adv. Mater. 24, 3169–3190. Web of Science CrossRef CAS PubMed Google Scholar
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Arylamines are widely used as electron donors in functional organic materials (Shirota & Kageyama, 2007; Tao et al., 2011; Yook & Lee, 2012). In our recent work we investigated the effect of increasingly planarized triarylamine donors (from N,N-diphenylbenzenamine to 9-phenyl-9H-carbazole and indolo[3,2,1-jk]carbazole) on material properties of bipolar compounds (Kautny et al., 2014). Thus, the title compound 9-(4-bromophenyl)-9H-carbazole (I) was synthesized as a key intermediate towards materials incorporating 9-phenyl-9H-carbazole donor subunits.
(I) crystallizes in the space group P21/c with one molecule (Fig. 1) in the asymmetric unit. The molecules are arranged in distinct crystallo-chemical layers parallel to (010). The layers contact via the carbazoles (Fig. 2 (a,b)). The contacting carbazoles are strongly inclined to each other [angle between least squares (l.s.) plane 59.08°], thus π-π interactions can be ruled out. The phenyl rings inside the layers are related by inversion and therefore coplanar. Nevertheless, the rings do not overlap, excluding π-π interactions (Fig. 2(b)).
Two structures that can be considered as isostructural (Kálmán et al., 1999) with (I) have been described, viz. the analogues with Br substituted by the pseudo-halogenide CN (Saha and Samanta, 1999) or by a NO2 group (Chen et al., 2005). A second polymorph of the CN analogue is structurally unrelated (Xie et al., 2012). In all three isostructural crystals the benzene ring is strongly inclined with respect to the carbazole moiety [angles between l.s. planes of both aromatic systems: (I): 49.87 (5)°; CN: 47.89 (6)°; NO2: 53.08 (6)°]. The inclination of the carbazole and phenyl moieties is of particular interest, since it determines the overall degree of conjugation and therefore greatly influences the electro-chemical and photo-physical properties of bipolar materials (Tao et al., 2011).
Several structures with distinctly more bulky substituents on the para-position of the phenyl ring have been described which nevertheless feature a virtually identical arrangement of the carbazole rings as observed in (I). Thus, it is useful to ,,slice'' the crystal structure of (I) into two kinds of slabs parallel to (010) which do not correspond to layers in the crystallo-chemical sense as depicted in Fig. 1. The slabs designated as A are made up of the carbazole rings of two adjacent crystallo-chemical layers (Fig. 3(a)), whereas the B slabs are composed of the 4-bromophenyl moieties (Fig. 3(b)). The A and B slabs feature p1(c)1 (the parentheses mark the direction missing translational symmetry) and p1 layer symmetry, respectively. Examples of structures which feature isostructural A slabs and structurally unrelated B slabs are 2-(4-(9H-carbazol-9-yl)benzylidene)indan-1-one (Fig. 4(a)) (Kim et al., 2011), 9-(4-((4-methylphenyl)ethynyl)phenyl)-9H-carbazole (Fig. 4(b)) and the isostructural 4-bromophenyl analogue (Fig. 4(c)) (Liu et al., 2010), the mono-toluene solvate of 3-(4-(9H-carbazol-9-yl)phenyl)acrylic acid (Fig. 4(d)) (Wu et al., 2007) and 9-(4-(2-(4-(2,1,3-benzothiadiazol-4-ylethynyl)phenyl)vinyl)phenyl)-9H-carbazole (Fig. 4(e)) (Chen, et al., 2012). The crystal structure of the latter is depicted in Fig. 5 and a comparison of the A slabs to those in (I) is given in Fig. 3(c). Despite being structurally unrelated, the B slabs in all these structures feature, like the corresponding slab in (I), p1 symmetry. Therefore, these structures possess likewise overall P21/c space group symmetry. In the crystal chemistry of inorganic compounds, the A and B slabs are called modules and the structures given above can be considered as members of a merotypic series (Ferraris et al., 2004). Whereas describing crystal structures of organic molecules in terms of modular materials is uncommon, we have recently applied these concepts to the solvatomorphs of a carbazole based organic molecule related to (I) (Stöger et al., 2012).