organic compounds
9-Ethyl-9H-carbazole-3-carbaldehyde
aCollege of Science, Northwest A&F University, Yangling 712100, Shannxi Province, People's Republic of China, and bHospital of Northwest A&F University, Yangling 712100, Shannxi Province, People's Republic of China
*Correspondence e-mail: yuanms@nwsuaf.edu.cn
The title molecule, C15H13NO, approximates a planar conformation except for the alkyl chain (ethyl group) bonded to the N atom with a maximum deviation from the least-squares plane through the 15 planar atoms of 0.120 (2) Å for the O atom. The distance of the formyl O atom from the plane of the carbazole ring is 0.227 (2) Å. The N—C bond lengths in the central ring are significantly different, reflecting the electron-withdrawing properties of the aldehyde group. As a consequence, charge transfer may occur from the carbazole N atom to the substituted benzene ring.
Related literature
For the properties of carbazole derivatives, see: van Dijken et al. (2004); Li et al. (2005). For the X-ray structure of 9-ethyl-3,6-diformyl-9H-carbazole, see: Wang et al. (2008) and of 9-ethyl-9H-carbazole, see: Kimura et al. (1985).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2005); cell SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
https://doi.org/10.1107/S1600536810025183/bh2297sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810025183/bh2297Isup2.hkl
9-Ethyl-9H-carbazole (0.30 g, 1.54 mmol) was dissolved in N,N-dimethylformamide (DMF, 10 ml). After cooling the mixture to 273 K, a DMF solution of POCl3 (0.24 g, 1.60 mmol) was slowly added. After stirring for 10 h., the mixture was poured into ice water and further stirred for 0.5 h. The solution was extracted with chloroform and dried over Na2SO4. After removing the solvent, the crude product was purified by recrystallization from ethanol, affording the title compound, (I) (0.29 g, 85%). Then, compound (I) was dissolved in a mixture of solvents, chloroform and hexane, and colorless block crystals were formed on slow evaporation at room temperature over one week.
All H atoms were placed in geometrically calculated positions and refined using a riding model with C—H = 0.93 Å (for aromatic CH), C—H = 0.97 %A (for CH2 groups), and 0.96 %A (for CH3 groups). Their isotropic displacement parameters were set to 1.2 times (1.5 times for CH3 groups) the equivalent displacement parameter of their parent atoms.
Carbazole is a conjugated unit which has interesting optical and electronic properties. A number of carbazole derivatives have been designed and synthesized to be used as luminescent materials and hole-transporting materials (van Dijken et al., 2004; Li et al., 2005). In the course of exploring new luminescent compounds, we obtained an intermediate compound, 9-ethyl-3-formyl-9H-carbazole (I). Here we report the structure and synthesis of (I).
The molecule (Fig. 1) lies approximately in a plane besides the alkyl chain (ethyl group). There is a minor displacement between the oxygen atom O1 and the plane of the carbazole ring. And the distance from the oxygen atom O1 to the carbazole plane (the least-squares plane defined by all the 13 atoms of the carbazole framework) is 0.227 (2) Å. The remarkable difference of N—C bond lengths is observed in this structure: N1—C1 = 1.372 (3), N1—C12 = 1.391 (3) Å, which is obviously different from that of 9-ethyl-3,6-diformyl-9H-carbazole (Wang et al., 2008) and that of 9-ethyl-9H-carbazole (Kimura et al., 1985). The different N—C bond lengths maybe root from the structural asymmetry. The pull-electron property of aldehyde group induces a charge-transfer from nitrogen atom N1 to the benzene ring which connects with the aldehyde group.
The molecules are packed in P21/n
which is the same as for 9-ethyl-3,6-diformyl-9H-carbazole, but different from that of 9-ethyl-9H-carbazole (Pbca). There are no classic hydrogen bonds in this structure. However, the weak intermolecular interaction C11—H11···O1 (symmetry code for O1: x-1, y, z), is helpful to the stabilization of the (Fig. 2). This intermolecular hydrogen bond is characterized by the H11···O1 separation of 2.54 Å.For the properties of carbazole derivatives, see: van Dijken et al. (2004); Li et al. (2005). For the X-ray structure of 9-ethyl-3,6-diformyl-9H-carbazole, see: Wang et al. (2008) and for the X-ray structure of 9-ethyl-9H-carbazole, see: Kimura et al. (1985).
Data collection: APEX2 (Bruker, 2005); cell
SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level. | |
Fig. 2. A view of the molecular packing of (I) along axis b. |
C15H13NO | F(000) = 472 |
Mr = 223.26 | Dx = 1.265 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 1960 reflections |
a = 10.6523 (10) Å | θ = 2.8–25.2° |
b = 8.2312 (6) Å | µ = 0.08 mm−1 |
c = 13.8005 (12) Å | T = 298 K |
β = 104.387 (1)° | Block, colorless |
V = 1172.10 (17) Å3 | 0.50 × 0.44 × 0.43 mm |
Z = 4 |
Bruker APEXII CCD area-detector diffractometer | 2065 independent reflections |
Radiation source: fine-focus sealed tube | 1313 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
φ and ω scans | θmax = 25.0°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −12→12 |
Tmin = 0.961, Tmax = 0.967 | k = −9→5 |
5763 measured reflections | l = −16→16 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.116 | H-atom parameters constrained |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0369P)2 + 0.3721P] where P = (Fo2 + 2Fc2)/3 |
2065 reflections | (Δ/σ)max < 0.001 |
155 parameters | Δρmax = 0.13 e Å−3 |
0 restraints | Δρmin = −0.11 e Å−3 |
0 constraints |
C15H13NO | V = 1172.10 (17) Å3 |
Mr = 223.26 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.6523 (10) Å | µ = 0.08 mm−1 |
b = 8.2312 (6) Å | T = 298 K |
c = 13.8005 (12) Å | 0.50 × 0.44 × 0.43 mm |
β = 104.387 (1)° |
Bruker APEXII CCD area-detector diffractometer | 2065 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 1313 reflections with I > 2σ(I) |
Tmin = 0.961, Tmax = 0.967 | Rint = 0.029 |
5763 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.116 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.13 e Å−3 |
2065 reflections | Δρmin = −0.11 e Å−3 |
155 parameters |
x | y | z | Uiso*/Ueq | ||
N1 | 0.23808 (16) | 0.0604 (2) | 0.36043 (12) | 0.0579 (5) | |
O1 | 0.83067 (17) | 0.1354 (3) | 0.36513 (14) | 0.0966 (6) | |
C1 | 0.3591 (2) | 0.0376 (3) | 0.34470 (15) | 0.0518 (5) | |
C2 | 0.3972 (2) | −0.0683 (3) | 0.27949 (16) | 0.0631 (6) | |
H2 | 0.3382 | −0.1383 | 0.2390 | 0.076* | |
C3 | 0.5250 (2) | −0.0665 (3) | 0.27648 (16) | 0.0626 (6) | |
H3 | 0.5528 | −0.1382 | 0.2340 | 0.075* | |
C4 | 0.6142 (2) | 0.0397 (3) | 0.33530 (15) | 0.0545 (6) | |
C5 | 0.5753 (2) | 0.1450 (3) | 0.40056 (14) | 0.0529 (5) | |
H5 | 0.6347 | 0.2157 | 0.4401 | 0.063* | |
C6 | 0.44792 (19) | 0.1444 (2) | 0.40663 (13) | 0.0466 (5) | |
C7 | 0.37450 (19) | 0.2342 (2) | 0.46404 (14) | 0.0489 (5) | |
C8 | 0.4063 (2) | 0.3526 (3) | 0.53694 (16) | 0.0639 (6) | |
H8 | 0.4914 | 0.3886 | 0.5592 | 0.077* | |
C9 | 0.3104 (3) | 0.4162 (3) | 0.57591 (18) | 0.0766 (7) | |
H9 | 0.3304 | 0.4973 | 0.6242 | 0.092* | |
C10 | 0.1842 (3) | 0.3611 (3) | 0.54428 (19) | 0.0773 (7) | |
H10 | 0.1211 | 0.4063 | 0.5720 | 0.093* | |
C11 | 0.1490 (2) | 0.2417 (3) | 0.47318 (17) | 0.0666 (7) | |
H11 | 0.0640 | 0.2049 | 0.4524 | 0.080* | |
C12 | 0.2467 (2) | 0.1786 (3) | 0.43386 (15) | 0.0531 (5) | |
C13 | 0.7479 (2) | 0.0386 (3) | 0.32700 (18) | 0.0709 (7) | |
H13 | 0.7716 | −0.0439 | 0.2890 | 0.085* | |
C14 | 0.1223 (2) | −0.0304 (3) | 0.31232 (18) | 0.0747 (7) | |
H14A | 0.1251 | −0.0561 | 0.2443 | 0.090* | |
H14B | 0.0467 | 0.0368 | 0.3092 | 0.090* | |
C15 | 0.1098 (3) | −0.1842 (4) | 0.3666 (2) | 0.1012 (10) | |
H15A | 0.1832 | −0.2527 | 0.3679 | 0.152* | |
H15B | 0.0318 | −0.2395 | 0.3329 | 0.152* | |
H15C | 0.1065 | −0.1593 | 0.4339 | 0.152* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0484 (11) | 0.0677 (12) | 0.0556 (11) | −0.0109 (9) | 0.0089 (8) | −0.0058 (10) |
O1 | 0.0640 (12) | 0.1300 (18) | 0.1015 (14) | −0.0201 (12) | 0.0310 (10) | 0.0030 (13) |
C1 | 0.0529 (13) | 0.0550 (13) | 0.0474 (12) | −0.0049 (10) | 0.0122 (10) | 0.0044 (10) |
C2 | 0.0631 (15) | 0.0672 (16) | 0.0590 (14) | −0.0122 (12) | 0.0152 (11) | −0.0083 (12) |
C3 | 0.0731 (17) | 0.0609 (15) | 0.0577 (14) | 0.0011 (12) | 0.0239 (12) | −0.0005 (12) |
C4 | 0.0584 (14) | 0.0573 (14) | 0.0494 (12) | −0.0012 (11) | 0.0169 (10) | 0.0115 (11) |
C5 | 0.0529 (13) | 0.0560 (13) | 0.0480 (12) | −0.0121 (10) | 0.0093 (10) | 0.0098 (11) |
C6 | 0.0495 (12) | 0.0483 (12) | 0.0411 (11) | −0.0056 (10) | 0.0093 (9) | 0.0083 (10) |
C7 | 0.0567 (13) | 0.0473 (12) | 0.0427 (11) | −0.0095 (10) | 0.0123 (9) | 0.0086 (10) |
C8 | 0.0803 (17) | 0.0608 (15) | 0.0553 (13) | −0.0202 (13) | 0.0257 (12) | −0.0002 (12) |
C9 | 0.109 (2) | 0.0605 (16) | 0.0702 (16) | −0.0180 (15) | 0.0410 (15) | −0.0074 (13) |
C10 | 0.095 (2) | 0.0729 (17) | 0.0764 (17) | 0.0029 (16) | 0.0449 (15) | 0.0022 (15) |
C11 | 0.0623 (15) | 0.0761 (17) | 0.0652 (14) | −0.0018 (13) | 0.0228 (12) | 0.0092 (14) |
C12 | 0.0581 (14) | 0.0559 (13) | 0.0454 (11) | −0.0020 (11) | 0.0129 (10) | 0.0079 (11) |
C13 | 0.0654 (17) | 0.0861 (19) | 0.0677 (16) | 0.0026 (14) | 0.0289 (13) | 0.0157 (14) |
C14 | 0.0548 (15) | 0.097 (2) | 0.0704 (15) | −0.0197 (13) | 0.0114 (12) | −0.0166 (15) |
C15 | 0.108 (2) | 0.108 (2) | 0.092 (2) | −0.0571 (19) | 0.0328 (17) | −0.0225 (19) |
N1—C1 | 1.372 (3) | C7—C12 | 1.398 (3) |
N1—C12 | 1.391 (3) | C8—C9 | 1.371 (3) |
N1—C14 | 1.453 (3) | C8—H8 | 0.9300 |
O1—C13 | 1.208 (3) | C9—C10 | 1.382 (3) |
C1—C2 | 1.384 (3) | C9—H9 | 0.9300 |
C1—C6 | 1.413 (3) | C10—C11 | 1.374 (3) |
C2—C3 | 1.372 (3) | C10—H10 | 0.9300 |
C2—H2 | 0.9300 | C11—C12 | 1.388 (3) |
C3—C4 | 1.394 (3) | C11—H11 | 0.9300 |
C3—H3 | 0.9300 | C13—H13 | 0.9300 |
C4—C5 | 1.385 (3) | C14—C15 | 1.494 (4) |
C4—C13 | 1.457 (3) | C14—H14A | 0.9700 |
C5—C6 | 1.380 (3) | C14—H14B | 0.9700 |
C5—H5 | 0.9300 | C15—H15A | 0.9600 |
C6—C7 | 1.447 (3) | C15—H15B | 0.9600 |
C7—C8 | 1.381 (3) | C15—H15C | 0.9600 |
C1—N1—C12 | 108.45 (16) | C8—C9—C10 | 120.8 (2) |
C1—N1—C14 | 125.50 (19) | C8—C9—H9 | 119.6 |
C12—N1—C14 | 125.96 (19) | C10—C9—H9 | 119.6 |
N1—C1—C2 | 128.9 (2) | C11—C10—C9 | 122.1 (2) |
N1—C1—C6 | 109.47 (18) | C11—C10—H10 | 118.9 |
C2—C1—C6 | 121.60 (19) | C9—C10—H10 | 118.9 |
C3—C2—C1 | 117.8 (2) | C10—C11—C12 | 116.7 (2) |
C3—C2—H2 | 121.1 | C10—C11—H11 | 121.7 |
C1—C2—H2 | 121.1 | C12—C11—H11 | 121.7 |
C2—C3—C4 | 121.8 (2) | C11—C12—N1 | 128.8 (2) |
C2—C3—H3 | 119.1 | C11—C12—C7 | 122.0 (2) |
C4—C3—H3 | 119.1 | N1—C12—C7 | 109.22 (18) |
C5—C4—C3 | 120.0 (2) | O1—C13—C4 | 125.7 (3) |
C5—C4—C13 | 120.7 (2) | O1—C13—H13 | 117.1 |
C3—C4—C13 | 119.2 (2) | C4—C13—H13 | 117.1 |
C6—C5—C4 | 119.61 (19) | N1—C14—C15 | 112.2 (2) |
C6—C5—H5 | 120.2 | N1—C14—H14A | 109.2 |
C4—C5—H5 | 120.2 | C15—C14—H14A | 109.2 |
C5—C6—C1 | 119.12 (19) | N1—C14—H14B | 109.2 |
C5—C6—C7 | 134.79 (19) | C15—C14—H14B | 109.2 |
C1—C6—C7 | 106.09 (17) | H14A—C14—H14B | 107.9 |
C8—C7—C12 | 119.5 (2) | C14—C15—H15A | 109.5 |
C8—C7—C6 | 133.74 (19) | C14—C15—H15B | 109.5 |
C12—C7—C6 | 106.76 (18) | H15A—C15—H15B | 109.5 |
C9—C8—C7 | 118.9 (2) | C14—C15—H15C | 109.5 |
C9—C8—H8 | 120.6 | H15A—C15—H15C | 109.5 |
C7—C8—H8 | 120.6 | H15B—C15—H15C | 109.5 |
C12—N1—C1—C2 | 179.4 (2) | C1—C6—C7—C12 | −0.3 (2) |
C14—N1—C1—C2 | 2.6 (3) | C12—C7—C8—C9 | −1.9 (3) |
C12—N1—C1—C6 | −1.4 (2) | C6—C7—C8—C9 | 178.8 (2) |
C14—N1—C1—C6 | −178.23 (19) | C7—C8—C9—C10 | 1.1 (3) |
N1—C1—C2—C3 | 179.0 (2) | C8—C9—C10—C11 | 0.0 (4) |
C6—C1—C2—C3 | −0.1 (3) | C9—C10—C11—C12 | −0.2 (3) |
C1—C2—C3—C4 | −1.2 (3) | C10—C11—C12—N1 | −178.6 (2) |
C2—C3—C4—C5 | 1.4 (3) | C10—C11—C12—C7 | −0.6 (3) |
C2—C3—C4—C13 | −178.5 (2) | C1—N1—C12—C11 | 179.4 (2) |
C3—C4—C5—C6 | −0.2 (3) | C14—N1—C12—C11 | −3.8 (3) |
C13—C4—C5—C6 | 179.62 (18) | C1—N1—C12—C7 | 1.2 (2) |
C4—C5—C6—C1 | −1.0 (3) | C14—N1—C12—C7 | 178.0 (2) |
C4—C5—C6—C7 | −179.8 (2) | C8—C7—C12—C11 | 1.7 (3) |
N1—C1—C6—C5 | −178.10 (17) | C6—C7—C12—C11 | −178.88 (19) |
C2—C1—C6—C5 | 1.2 (3) | C8—C7—C12—N1 | −179.94 (17) |
N1—C1—C6—C7 | 1.1 (2) | C6—C7—C12—N1 | −0.5 (2) |
C2—C1—C6—C7 | −179.68 (19) | C5—C4—C13—O1 | −8.4 (3) |
C5—C6—C7—C8 | −2.0 (4) | C3—C4—C13—O1 | 171.5 (2) |
C1—C6—C7—C8 | 179.0 (2) | C1—N1—C14—C15 | 86.1 (3) |
C5—C6—C7—C12 | 178.6 (2) | C12—N1—C14—C15 | −90.2 (3) |
Experimental details
Crystal data | |
Chemical formula | C15H13NO |
Mr | 223.26 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 298 |
a, b, c (Å) | 10.6523 (10), 8.2312 (6), 13.8005 (12) |
β (°) | 104.387 (1) |
V (Å3) | 1172.10 (17) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.50 × 0.44 × 0.43 |
Data collection | |
Diffractometer | Bruker APEXII CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.961, 0.967 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5763, 2065, 1313 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.116, 1.05 |
No. of reflections | 2065 |
No. of parameters | 155 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.13, −0.11 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
N1—C1 | 1.372 (3) | N1—C14 | 1.453 (3) |
N1—C12 | 1.391 (3) | O1—C13 | 1.208 (3) |
C1—N1—C12 | 108.45 (16) | C12—N1—C14 | 125.96 (19) |
C1—N1—C14 | 125.50 (19) |
Acknowledgements
This work was supported by the PhD Programs Foundation of the Ministry of Education of China (No. 20090204120033).
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Carbazole is a conjugated unit which has interesting optical and electronic properties. A number of carbazole derivatives have been designed and synthesized to be used as luminescent materials and hole-transporting materials (van Dijken et al., 2004; Li et al., 2005). In the course of exploring new luminescent compounds, we obtained an intermediate compound, 9-ethyl-3-formyl-9H-carbazole (I). Here we report the structure and synthesis of (I).
The molecule (Fig. 1) lies approximately in a plane besides the alkyl chain (ethyl group). There is a minor displacement between the oxygen atom O1 and the plane of the carbazole ring. And the distance from the oxygen atom O1 to the carbazole plane (the least-squares plane defined by all the 13 atoms of the carbazole framework) is 0.227 (2) Å. The remarkable difference of N—C bond lengths is observed in this structure: N1—C1 = 1.372 (3), N1—C12 = 1.391 (3) Å, which is obviously different from that of 9-ethyl-3,6-diformyl-9H-carbazole (Wang et al., 2008) and that of 9-ethyl-9H-carbazole (Kimura et al., 1985). The different N—C bond lengths maybe root from the structural asymmetry. The pull-electron property of aldehyde group induces a charge-transfer from nitrogen atom N1 to the benzene ring which connects with the aldehyde group.
The molecules are packed in P21/n space group, which is the same as for 9-ethyl-3,6-diformyl-9H-carbazole, but different from that of 9-ethyl-9H-carbazole (Pbca). There are no classic hydrogen bonds in this structure. However, the weak intermolecular interaction C11—H11···O1 (symmetry code for O1: x-1, y, z), is helpful to the stabilization of the crystal structure (Fig. 2). This intermolecular hydrogen bond is characterized by the H11···O1 separation of 2.54 Å.