organic compounds
1-Nitro-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, 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).
CCDC reference: 974754
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).
Experimental
Crystal data
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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: 974754
https://doi.org/10.1107/S1600536813032704/ff2123sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813032704/ff2123Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536813032704/ff2123Isup3.cml
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. → 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.
(light petroleum:CH2Cl2 75:25The 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 and refined with anisotropic displacement parameters. The H atoms were located in difference Fourier maps and freely refined.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 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)°.
P21/n with one molecule in the As expected, due to the conjugatedThe 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).
For application of arylamines as electron donors, see: Shirota & Kageyama (2007); Tao et al. (2011); Yook & Lee (2012); Kautny et al. (2013). For synthesis of the catalyst (NHC)Pd(allyl)Cl, see: Marion et al. (2006).
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).C12H8N2O2 | F(000) = 440 |
Mr = 212.2 | Dx = 1.493 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 17802 reflections |
a = 10.4400 (3) Å | θ = 2.4–30.1° |
b = 5.3148 (2) Å | µ = 0.11 mm−1 |
c = 17.2638 (6) Å | T = 100 K |
β = 99.7460 (16)° | Plate, dark yellow |
V = 944.08 (6) Å3 | 0.76 × 0.42 × 0.20 mm |
Z = 4 |
Bruker Kappa APEXII CCD diffractometer | 2794 independent reflections |
Radiation source: X-ray tube | 2397 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.021 |
ω and φ scans | θmax = 30.2°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Bruker, 2013) | h = −14→14 |
Tmin = 0.95, Tmax = 0.98 | k = −7→7 |
30130 measured reflections | l = −24→24 |
Refinement on F | 0 constraints |
R[F > 3σ(F)] = 0.040 | All H-atom parameters refined |
wR(F) = 0.068 | Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0009F2) |
S = 1.89 | (Δ/σ)max = 0.015 |
2794 reflections | Δρmax = 0.32 e Å−3 |
177 parameters | Δρmin = −0.21 e Å−3 |
0 restraints |
C12H8N2O2 | V = 944.08 (6) Å3 |
Mr = 212.2 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.4400 (3) Å | µ = 0.11 mm−1 |
b = 5.3148 (2) Å | T = 100 K |
c = 17.2638 (6) Å | 0.76 × 0.42 × 0.20 mm |
β = 99.7460 (16)° |
Bruker Kappa APEXII CCD diffractometer | 2794 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2013) | 2397 reflections with I > 3σ(I) |
Tmin = 0.95, Tmax = 0.98 | Rint = 0.021 |
30130 measured reflections |
R[F > 3σ(F)] = 0.040 | 0 restraints |
wR(F) = 0.068 | All H-atom parameters refined |
S = 1.89 | Δρmax = 0.32 e Å−3 |
2794 reflections | Δρmin = −0.21 e Å−3 |
177 parameters |
x | y | z | Uiso*/Ueq | ||
O1 | 0.89295 (6) | 0.40415 (13) | 0.03186 (4) | 0.0210 (2) | |
O2 | 0.72187 (8) | 0.32391 (14) | 0.08415 (4) | 0.0262 (2) | |
N1 | 0.94574 (7) | 0.15206 (14) | −0.09492 (4) | 0.0148 (2) | |
N2 | 0.79470 (7) | 0.27907 (15) | 0.03678 (4) | 0.0172 (2) | |
C1 | 0.84182 (8) | 0.02688 (16) | −0.07504 (5) | 0.0136 (2) | |
C2 | 0.76585 (8) | 0.07065 (16) | −0.01702 (5) | 0.0155 (2) | |
C3 | 0.66091 (8) | −0.08542 (18) | −0.01060 (5) | 0.0190 (3) | |
C4 | 0.62951 (9) | −0.28368 (19) | −0.06284 (6) | 0.0210 (3) | |
C5 | 0.70463 (9) | −0.33376 (17) | −0.12071 (6) | 0.0184 (3) | |
C6 | 0.81094 (8) | −0.18269 (16) | −0.12662 (5) | 0.0145 (2) | |
C7 | 0.90505 (8) | −0.17966 (16) | −0.17915 (5) | 0.0148 (2) | |
C8 | 0.92934 (10) | −0.33696 (17) | −0.24006 (5) | 0.0193 (3) | |
C9 | 1.03157 (10) | −0.27687 (19) | −0.27885 (6) | 0.0226 (3) | |
C10 | 1.10889 (9) | −0.06296 (19) | −0.25785 (6) | 0.0222 (3) | |
C11 | 1.08747 (9) | 0.09238 (17) | −0.19688 (6) | 0.0187 (3) | |
C12 | 0.98542 (8) | 0.03034 (16) | −0.15802 (5) | 0.0145 (2) | |
H11 | 1.1422 (11) | 0.232 (3) | −0.1779 (8) | 0.028 (3)* | |
H5 | 0.6817 (11) | −0.477 (2) | −0.1571 (7) | 0.019 (3)* | |
H4 | 0.5546 (13) | −0.390 (2) | −0.0614 (8) | 0.027 (3)* | |
H8 | 0.8730 (12) | −0.480 (2) | −0.2542 (8) | 0.020 (3)* | |
H9 | 1.0526 (14) | −0.384 (3) | −0.3211 (10) | 0.039 (4)* | |
H3 | 0.6077 (12) | −0.069 (2) | 0.0296 (8) | 0.026 (3)* | |
H10 | 1.1776 (11) | −0.026 (2) | −0.2858 (7) | 0.018 (3)* | |
Hn1 | 0.9851 (12) | 0.275 (3) | −0.0690 (9) | 0.029 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0207 (3) | 0.0221 (4) | 0.0196 (3) | −0.0021 (3) | 0.0017 (3) | −0.0039 (3) |
O2 | 0.0301 (4) | 0.0324 (4) | 0.0187 (4) | 0.0068 (3) | 0.0117 (3) | −0.0020 (3) |
N1 | 0.0153 (3) | 0.0140 (4) | 0.0157 (4) | −0.0019 (3) | 0.0041 (3) | −0.0018 (3) |
N2 | 0.0185 (4) | 0.0198 (4) | 0.0132 (4) | 0.0041 (3) | 0.0026 (3) | 0.0014 (3) |
C1 | 0.0124 (4) | 0.0148 (4) | 0.0133 (4) | 0.0004 (3) | 0.0010 (3) | 0.0016 (3) |
C2 | 0.0141 (4) | 0.0184 (4) | 0.0137 (4) | 0.0018 (3) | 0.0017 (3) | 0.0012 (3) |
C3 | 0.0138 (4) | 0.0248 (5) | 0.0187 (4) | 0.0012 (3) | 0.0033 (3) | 0.0059 (3) |
C4 | 0.0158 (4) | 0.0226 (5) | 0.0242 (5) | −0.0035 (3) | 0.0018 (3) | 0.0064 (4) |
C5 | 0.0177 (4) | 0.0170 (4) | 0.0187 (4) | −0.0024 (3) | −0.0017 (3) | 0.0033 (3) |
C6 | 0.0149 (4) | 0.0141 (4) | 0.0135 (4) | 0.0003 (3) | −0.0005 (3) | 0.0014 (3) |
C7 | 0.0163 (4) | 0.0146 (4) | 0.0127 (4) | 0.0016 (3) | 0.0007 (3) | 0.0013 (3) |
C8 | 0.0246 (5) | 0.0171 (4) | 0.0151 (4) | 0.0053 (3) | −0.0001 (3) | −0.0013 (3) |
C9 | 0.0279 (5) | 0.0244 (5) | 0.0160 (4) | 0.0102 (4) | 0.0053 (3) | 0.0004 (3) |
C10 | 0.0237 (4) | 0.0246 (5) | 0.0201 (4) | 0.0095 (4) | 0.0089 (3) | 0.0064 (3) |
C11 | 0.0177 (4) | 0.0182 (4) | 0.0215 (4) | 0.0026 (3) | 0.0067 (3) | 0.0045 (3) |
C12 | 0.0152 (4) | 0.0140 (4) | 0.0144 (4) | 0.0024 (3) | 0.0030 (3) | 0.0018 (3) |
O1—N2 | 1.2372 (11) | C5—C6 | 1.3875 (13) |
O2—N2 | 1.2305 (12) | C5—H5 | 0.991 (11) |
N1—C1 | 1.3651 (12) | C6—C7 | 1.4456 (13) |
N1—C12 | 1.3890 (12) | C7—C8 | 1.3997 (13) |
N1—Hn1 | 0.857 (13) | C7—C12 | 1.4068 (12) |
N2—C2 | 1.4442 (11) | C8—C9 | 1.3898 (15) |
C1—C2 | 1.3984 (13) | C8—H8 | 0.969 (13) |
C1—C6 | 1.4283 (12) | C9—C10 | 1.4058 (14) |
C2—C3 | 1.3935 (13) | C9—H9 | 0.981 (16) |
C3—C4 | 1.3897 (14) | C10—C11 | 1.3854 (14) |
C3—H3 | 0.964 (15) | C10—H10 | 0.951 (13) |
C4—C5 | 1.3962 (15) | C11—C12 | 1.3914 (14) |
C4—H4 | 0.967 (13) | C11—H11 | 0.960 (13) |
C1—N1—C12 | 108.99 (7) | C1—C6—C5 | 120.29 (8) |
C1—N1—Hn1 | 124.9 (10) | C1—C6—C7 | 106.06 (7) |
C12—N1—Hn1 | 125.8 (10) | C5—C6—C7 | 133.60 (8) |
O1—N2—O2 | 123.66 (8) | C6—C7—C8 | 133.90 (8) |
O1—N2—C2 | 116.94 (8) | C6—C7—C12 | 106.56 (7) |
O2—N2—C2 | 119.40 (8) | C8—C7—C12 | 119.52 (8) |
N1—C1—C2 | 132.09 (8) | C7—C8—C9 | 118.44 (8) |
N1—C1—C6 | 109.18 (8) | C7—C8—H8 | 118.6 (8) |
C2—C1—C6 | 118.73 (8) | C9—C8—H8 | 122.9 (8) |
N2—C2—C1 | 120.43 (8) | C8—C9—C10 | 121.06 (9) |
N2—C2—C3 | 119.11 (8) | C8—C9—H9 | 120.8 (9) |
C1—C2—C3 | 120.46 (8) | C10—C9—H9 | 118.1 (9) |
C2—C3—C4 | 120.13 (9) | C9—C10—C11 | 121.22 (10) |
C2—C3—H3 | 124.0 (7) | C9—C10—H10 | 119.1 (7) |
C4—C3—H3 | 115.9 (7) | C11—C10—H10 | 119.7 (7) |
C3—C4—C5 | 120.64 (9) | C10—C11—C12 | 117.41 (8) |
C3—C4—H4 | 121.8 (9) | C10—C11—H11 | 123.9 (8) |
C5—C4—H4 | 117.5 (9) | C12—C11—H11 | 118.6 (8) |
C4—C5—C6 | 119.70 (8) | N1—C12—C7 | 109.20 (8) |
C4—C5—H5 | 119.7 (7) | N1—C12—C11 | 128.47 (8) |
C6—C5—H5 | 120.6 (7) | C7—C12—C11 | 122.32 (8) |
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) |
Symmetry code: (i) −x+2, −y+1, −z. |
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) |
Symmetry code: (i) −x+2, −y+1, −z. |
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
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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).