1-Nitro-9H-carbazole

Paul Kautny; Berthold Stöger

doi:10.1107/S1600536813032704

. 2013 Dec 7;70(Pt 1):o28. doi: 10.1107/S1600536813032704

1-Nitro-9H-carbazole

Paul Kautny ^a, Berthold Stöger ^b,^*

PMCID: PMC3914074 PMID: 24526975

Abstract

In the title molecule, C₁₂H₈N₂O₂, the nitro group is tilted slightly with respect to the carbazole moiety [angle between the least-squares planes = 4.43 (9)°]. In the crystal, the molecules are connected via pairs of N—H⋯O hydrogen bonds into dimers with -1 symmetry. The dimers in turn are arranged into layers parallel to (10-1).

Related literature

For the applications of arylamines as electron donors, see: Shirota & Kageyama (2007 ▶); Tao et al. (2011 ▶); Yook & Lee (2012 ▶); Kautny et al. (2014 ▶). For the synthesis of the catalyst (NHC)Pd(allyl)Cl, see: Marion et al. (2006 ▶). graphic file with name e-70-00o28-scheme1.jpg

Experimental

Crystal data

C₁₂H₈N₂O₂
M _r = 212.2
Monoclinic,
a = 10.4400 (3) Å
b = 5.3148 (2) Å
c = 17.2638 (6) Å
β = 99.7460 (16)°
V = 944.08 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 100 K
0.76 × 0.42 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2013 ▶) T _min = 0.95, T _max = 0.98
30130 measured reflections
2794 independent reflections
2397 reflections with I > 3σ(I)
R _int = 0.021

Refinement

R[F ² > 3σ(F ²)] = 0.040
wR(F ²) = 0.068
S = 1.89
2794 reflections
177 parameters
All H-atom parameters refined
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2013 ▶); cell refinement: 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 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813032704/ff2123sup1.cif

e-70-00o28-sup1.cif^{(83.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813032704/ff2123Isup2.hkl

e-70-00o28-Isup2.hkl^{(115.5KB, hkl)}

Click here for additional data file.^{(4KB, cml)}

Supporting information file. DOI: 10.1107/S1600536813032704/ff2123Isup3.cml

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—Hn1⋯O1ⁱ	0.857 (13)	2.159 (13)	2.9940 (10)	164.6 (14)

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Symmetry code: (i) Inline graphic .

Acknowledgments

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.

supplementary crystallographic information

1. Comment

In the last years, arylamines have been widely employed as electron donors in materials for organo-electronic applications as for example organic light emitting diodes (OLEDs) (Shirota and Kageyama, 2007; Tao et al., 2011; Yook and Lee, 2012). In the course of systematic investigations of the impact of planarized arylamine moieties on the photo-physical and electro-chemical properties of bipolar host materials for phosphorescent OLEDs (Kautny, et al., 2013), we synthesized the title compound 1-nitro-9H-carbazole (I) starting from 2-bromo-N-(2-nitrophenyl)benzenamine. Single crystals of (I) grown from CDCl₃ were subjected to X-ray diffraction for structure elucidation. To our knowledge, (I) is the first structurally characterized nitrocarbazole.

(I) crystallizes in the space group P2₁/n with one molecule in the asymmetric unit. As expected, due to the conjugated π-electron system, the molecule is virtually flat. The largest distance from the least-squares (LS) plane defined by the atoms of the carbazole ring (N1, C1–C12) is only 0.1420 (10) Å, as observed for the O1 atom of the nitro group. The N2 atom of the nitro group is located at 0.0512 (10) Å from the plane, all other atoms are closer than 0.04 Å. The plane defined by the three atoms of the nitro group (N2, O1, O2) is inclined to the LS plane of the carbazole ring by 4.43 (9)°.

The molecules are connected via medium-strength N—H···O hydrogen bonds (N···O: 2.9940 (10) Å) to dimers with 1 symmetry (Fig. 1). The packing of the dimers, on the other hand, is solely controlled by van-der-Waals interactions. The dimers are arranged into distinct crystallo-chemical layers parallel to (101), whereby adjacent dimers are related by the n-glide (Fig. 2).

2. Experimental

2-Bromo-N-(2-nitrophenyl)benzenamine (147 mg, 0.50 mmol, 1 eq.), K₂CO₃ (138 mg, 1 mmol, 2 eq.) and (NHC)Pd(allyl)Cl (Marion et al., 2006) (6 mg, 10 µmol, 2 mol%) in DMAc (2.5 ml) were heated at 140 °C for 150 h in a capped vial using a heating block. After cooling the reaction mixture was poured on water and extracted with Et₂O. The combined organic layers were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. Column chromatography (light petroleum:CH₂Cl₂ 75:25 → 60:40) yielded 1-nitro-9H-carbazole (18 mg, 0.08 mmol, 17%) as a yellow solid. ¹H NMR (200 MHz, CDCl₃): δ = 10.01 (bs, 1H), 8.37–8.31 (m, 2H), 8.10 (d, J=7.8 Hz, 1H), 7.60–7.50 (m, 2H), 7.39–7.26 (m, 2H) p.p.m.. ¹³C NMR (50 MHz, CDCl₃): δ = 139.7 (s), 133.7 (s), 132.1 (s), 127.7 (d), 127.5 (d), 127.4 (s), 122.2 (s), 121.9 (d), 121.2 (d), 120.6 (d), 118.7 (d), 111.6 (d) p.p.m.. Crystals suitable for single-crystal diffraction were grown by slow evaporation of a CDCl₃ solution.