organic compounds
2,5-Dimethyl-N-[1-(1H-pyrrol-2-yl)ethylidene]aniline
aCollege of Chemistry and Chemical Engineering, Xi'an ShiYou University, Xi'an, Shaanxi 710065, People's Republic of China, and bCollege of Petroleum Engineering, Xi'an ShiYou University, Xi'an, Shaanxi 710065, People's Republic of China
*Correspondence e-mail: subiyun@xsyu.edu.cn
In the title compound, C14H16N2, the pyrrole and benzene rings form a dihedral angle of 72.37 (8)°. In the crystal, centrosymmetrically related molecules are assembled into dimers by by pairs of N—H⋯N hydrogen bonds, generating rings of R22(10) graph-set motif. C—H⋯π interactions also occur.
Related literature
For general background to the iminopyrrole unit, see: Britovsek et al. (2003); Dawson et al. (2000); Wu et al. (2003). For the pyrrole diimine unit, see: Matsuo et al. (2001) and for the pyrrole monoimine unit, see: He et al. (2009); Su et al. (2009a,b).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker,2008); cell SAINT (Bruker,2008); 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: publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536812040858/rz5010sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812040858/rz5010Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812040858/rz5010Isup3.cml
The reagents 2-acetyl pyrrole (0.1528 g, 1.40 mmol) and 2,5-dimethylaniline (0.3393 g, 2.80 mmol) were placed in a 50-ml flask. A few drops of acetic acid was then added in, and the mixture was subjected to radiation in a 800 W microwave oven for 3 min and 2 min on a medium–heat setting. The reaction was monitored by TLC, and the crude product was purified by silica gel νC=N 1659 cm-1. 1H NMR (400 MHz, CDCl3): δ 7.12 (d, 1H, benzene ring aromatic H), δ 7.09 (d, 1H, benzene ring aromatic H), 6.88 (m, 1H, benzene ring aromatic H), 6.56 (d, 1H, pyrrole ring aromatic H), 6.37 (s, 1H, pyrrole ring aromatic H), 6.18 (d, 1H, pyrrole ring aromatic H), 2.18 (s, 6H, phenyl-CH3), 2.05 (s, 3H, –N=C(CH3)-). MS (EI): m/z 212 (M). Anal. Calcd. for C14H16N2: C, 79.21; H, 7.60; N, 13.20. Found: C, 79.72; H, 7.13; N, 12.84.
(eluant: petroleum ether/ethyl acetate, 5:1 v/v). Plate-like colourless single crystals used in X-ray diffraction studies were grown from an ethanolic solution by slow evaporation of the solvent at room temperature; yield 72.79%, 0.2982 g. M.p. 396.8–398.4 K. The purity and the composition of the compound were checked and characterized by IR, 1H NMR, as well as elemental analysis. IR (KBr):All H atoms were placed at calculated positions and refined as riding, with C—H = 0.93–0.96 Å, N—H = 0.86 Å, and with Uiso(H) = 1.2 Ueq(C, N) or 1.5 Ueq(C) for methyl H atoms.
Data collection: APEX2 (Bruker,2008); cell
SAINT (Bruker,2008); data reduction: SAINT (Bruker,2008); 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: publCIF (Westrip, 2010).C14H16N2 | F(000) = 456 |
Mr = 212.29 | Dx = 1.122 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2093 reflections |
a = 12.5894 (17) Å | θ = 2.7–26.0° |
b = 7.3109 (10) Å | µ = 0.07 mm−1 |
c = 14.8425 (19) Å | T = 296 K |
β = 113.118 (2)° | Block, colourless |
V = 1256.4 (3) Å3 | 0.37 × 0.28 × 0.15 mm |
Z = 4 |
Bruker APEXII CCD diffractometer | 2441 independent reflections |
Radiation source: fine-focus sealed tube | 1885 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
ϕ and ω scans | θmax = 26.0°, θmin = 2.7° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −15→13 |
Tmin = 0.976, Tmax = 0.990 | k = −8→8 |
6463 measured reflections | l = −18→15 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.045 | H-atom parameters constrained |
wR(F2) = 0.156 | w = 1/[σ2(Fo2) + (0.1P)2 + 0.1684P] where P = (Fo2 + 2Fc2)/3 |
S = 0.96 | (Δ/σ)max = 0.001 |
2441 reflections | Δρmax = 0.22 e Å−3 |
149 parameters | Δρmin = −0.16 e Å−3 |
0 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.030 (5) |
C14H16N2 | V = 1256.4 (3) Å3 |
Mr = 212.29 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 12.5894 (17) Å | µ = 0.07 mm−1 |
b = 7.3109 (10) Å | T = 296 K |
c = 14.8425 (19) Å | 0.37 × 0.28 × 0.15 mm |
β = 113.118 (2)° |
Bruker APEXII CCD diffractometer | 2441 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 1885 reflections with I > 2σ(I) |
Tmin = 0.976, Tmax = 0.990 | Rint = 0.021 |
6463 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.156 | H-atom parameters constrained |
S = 0.96 | Δρmax = 0.22 e Å−3 |
2441 reflections | Δρmin = −0.16 e Å−3 |
149 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.02765 (11) | 0.93936 (18) | 0.15136 (9) | 0.0509 (4) | |
H1 | −0.0111 | 0.9621 | 0.0903 | 0.061* | |
N2 | 0.16704 (11) | 0.92217 (17) | 0.04350 (9) | 0.0493 (4) | |
C1 | −0.01726 (14) | 0.9302 (2) | 0.22049 (12) | 0.0556 (5) | |
H1A | −0.0944 | 0.9481 | 0.2098 | 0.067* | |
C2 | 0.06832 (16) | 0.8908 (2) | 0.30727 (13) | 0.0606 (5) | |
H2 | 0.0608 | 0.8759 | 0.3667 | 0.073* | |
C3 | 0.17118 (15) | 0.8764 (2) | 0.29152 (12) | 0.0572 (5) | |
H3 | 0.2441 | 0.8510 | 0.3388 | 0.069* | |
C4 | 0.14446 (13) | 0.90679 (19) | 0.19355 (11) | 0.0447 (4) | |
C5 | 0.21617 (12) | 0.90262 (18) | 0.13711 (11) | 0.0429 (4) | |
C6 | 0.34366 (13) | 0.8754 (3) | 0.19343 (12) | 0.0584 (5) | |
H6A | 0.3790 | 0.8420 | 0.1491 | 0.088* | |
H6B | 0.3559 | 0.7799 | 0.2409 | 0.088* | |
H6C | 0.3774 | 0.9870 | 0.2263 | 0.088* | |
C7 | 0.23363 (12) | 0.9170 (2) | −0.01501 (11) | 0.0463 (4) | |
C8 | 0.29383 (12) | 1.0713 (2) | −0.02269 (11) | 0.0495 (4) | |
H8 | 0.2956 | 1.1732 | 0.0154 | 0.059* | |
C9 | 0.35159 (13) | 1.0782 (2) | −0.08547 (12) | 0.0519 (4) | |
C10 | 0.34733 (15) | 0.9243 (2) | −0.14132 (12) | 0.0593 (5) | |
H10 | 0.3852 | 0.9247 | −0.1840 | 0.071* | |
C11 | 0.28748 (15) | 0.7705 (2) | −0.13432 (12) | 0.0596 (5) | |
H11 | 0.2865 | 0.6689 | −0.1723 | 0.072* | |
C12 | 0.22837 (14) | 0.7620 (2) | −0.07228 (11) | 0.0519 (4) | |
C13 | 0.41634 (15) | 1.2478 (3) | −0.09201 (14) | 0.0697 (6) | |
H13A | 0.4961 | 1.2359 | −0.0489 | 0.105* | |
H13B | 0.3837 | 1.3525 | −0.0733 | 0.105* | |
H13C | 0.4104 | 1.2630 | −0.1581 | 0.105* | |
C14 | 0.16000 (19) | 0.5964 (3) | −0.06737 (16) | 0.0763 (6) | |
H14A | 0.1561 | 0.5120 | −0.1181 | 0.115* | |
H14B | 0.0833 | 0.6330 | −0.0762 | 0.115* | |
H14C | 0.1969 | 0.5386 | −0.0047 | 0.115* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0432 (7) | 0.0719 (9) | 0.0400 (7) | 0.0059 (6) | 0.0191 (6) | 0.0070 (6) |
N2 | 0.0423 (7) | 0.0664 (9) | 0.0424 (7) | 0.0002 (6) | 0.0202 (6) | −0.0022 (6) |
C1 | 0.0489 (9) | 0.0738 (11) | 0.0523 (10) | 0.0075 (8) | 0.0288 (8) | 0.0091 (8) |
C2 | 0.0652 (10) | 0.0790 (12) | 0.0473 (9) | 0.0149 (9) | 0.0326 (8) | 0.0163 (8) |
C3 | 0.0541 (9) | 0.0734 (11) | 0.0453 (9) | 0.0149 (8) | 0.0209 (7) | 0.0138 (8) |
C4 | 0.0438 (8) | 0.0480 (8) | 0.0448 (8) | 0.0050 (6) | 0.0201 (7) | 0.0048 (6) |
C5 | 0.0433 (8) | 0.0435 (8) | 0.0443 (8) | 0.0028 (6) | 0.0199 (7) | 0.0018 (6) |
C6 | 0.0464 (9) | 0.0780 (11) | 0.0532 (10) | 0.0155 (8) | 0.0224 (8) | 0.0126 (8) |
C7 | 0.0386 (7) | 0.0633 (10) | 0.0379 (8) | 0.0077 (6) | 0.0160 (6) | 0.0014 (6) |
C8 | 0.0434 (8) | 0.0631 (10) | 0.0434 (9) | 0.0018 (7) | 0.0186 (7) | −0.0037 (7) |
C9 | 0.0407 (8) | 0.0717 (11) | 0.0447 (9) | 0.0111 (7) | 0.0182 (7) | 0.0096 (7) |
C10 | 0.0574 (10) | 0.0814 (13) | 0.0470 (9) | 0.0206 (9) | 0.0290 (8) | 0.0107 (8) |
C11 | 0.0686 (11) | 0.0677 (11) | 0.0442 (9) | 0.0206 (9) | 0.0240 (8) | −0.0019 (7) |
C12 | 0.0515 (9) | 0.0592 (10) | 0.0417 (8) | 0.0093 (7) | 0.0146 (7) | 0.0018 (7) |
C13 | 0.0578 (10) | 0.0887 (14) | 0.0699 (12) | −0.0006 (9) | 0.0330 (9) | 0.0152 (10) |
C14 | 0.0877 (14) | 0.0680 (13) | 0.0735 (14) | −0.0043 (10) | 0.0318 (12) | −0.0063 (9) |
N1—C1 | 1.3536 (19) | C7—C12 | 1.403 (2) |
N1—C4 | 1.3742 (19) | C8—C9 | 1.390 (2) |
N1—H1 | 0.8600 | C8—H8 | 0.9300 |
N2—C5 | 1.288 (2) | C9—C10 | 1.386 (2) |
N2—C7 | 1.4248 (18) | C9—C13 | 1.508 (2) |
C1—C2 | 1.346 (2) | C10—C11 | 1.380 (2) |
C1—H1A | 0.9300 | C10—H10 | 0.9300 |
C2—C3 | 1.407 (2) | C11—C12 | 1.394 (2) |
C2—H2 | 0.9300 | C11—H11 | 0.9300 |
C3—C4 | 1.376 (2) | C12—C14 | 1.504 (2) |
C3—H3 | 0.9300 | C13—H13A | 0.9600 |
C4—C5 | 1.453 (2) | C13—H13B | 0.9600 |
C5—C6 | 1.504 (2) | C13—H13C | 0.9600 |
C6—H6A | 0.9600 | C14—H14A | 0.9600 |
C6—H6B | 0.9600 | C14—H14B | 0.9600 |
C6—H6C | 0.9600 | C14—H14C | 0.9600 |
C7—C8 | 1.388 (2) | ||
C1—N1—C4 | 109.68 (13) | C7—C8—C9 | 122.06 (14) |
C1—N1—H1 | 125.2 | C7—C8—H8 | 119.0 |
C4—N1—H1 | 125.2 | C9—C8—H8 | 119.0 |
C5—N2—C7 | 120.42 (13) | C10—C9—C8 | 117.65 (15) |
C2—C1—N1 | 108.68 (14) | C10—C9—C13 | 121.59 (15) |
C2—C1—H1A | 125.7 | C8—C9—C13 | 120.75 (15) |
N1—C1—H1A | 125.7 | C11—C10—C9 | 120.68 (15) |
C1—C2—C3 | 107.46 (15) | C11—C10—H10 | 119.7 |
C1—C2—H2 | 126.3 | C9—C10—H10 | 119.7 |
C3—C2—H2 | 126.3 | C10—C11—C12 | 122.33 (15) |
C4—C3—C2 | 107.72 (15) | C10—C11—H11 | 118.8 |
C4—C3—H3 | 126.1 | C12—C11—H11 | 118.8 |
C2—C3—H3 | 126.1 | C11—C12—C7 | 117.00 (15) |
N1—C4—C3 | 106.46 (13) | C11—C12—C14 | 122.13 (15) |
N1—C4—C5 | 122.47 (13) | C7—C12—C14 | 120.86 (14) |
C3—C4—C5 | 131.04 (14) | C9—C13—H13A | 109.5 |
N2—C5—C4 | 118.40 (13) | C9—C13—H13B | 109.5 |
N2—C5—C6 | 124.76 (13) | H13A—C13—H13B | 109.5 |
C4—C5—C6 | 116.83 (13) | C9—C13—H13C | 109.5 |
C5—C6—H6A | 109.5 | H13A—C13—H13C | 109.5 |
C5—C6—H6B | 109.5 | H13B—C13—H13C | 109.5 |
H6A—C6—H6B | 109.5 | C12—C14—H14A | 109.5 |
C5—C6—H6C | 109.5 | C12—C14—H14B | 109.5 |
H6A—C6—H6C | 109.5 | H14A—C14—H14B | 109.5 |
H6B—C6—H6C | 109.5 | C12—C14—H14C | 109.5 |
C8—C7—C12 | 120.27 (14) | H14A—C14—H14C | 109.5 |
C8—C7—N2 | 119.97 (13) | H14B—C14—H14C | 109.5 |
C12—C7—N2 | 119.44 (13) | ||
C4—N1—C1—C2 | −0.40 (19) | C5—N2—C7—C12 | 105.74 (16) |
N1—C1—C2—C3 | 0.5 (2) | C12—C7—C8—C9 | −0.7 (2) |
C1—C2—C3—C4 | −0.4 (2) | N2—C7—C8—C9 | −174.23 (13) |
C1—N1—C4—C3 | 0.13 (17) | C7—C8—C9—C10 | 0.1 (2) |
C1—N1—C4—C5 | 178.29 (13) | C7—C8—C9—C13 | −179.93 (15) |
C2—C3—C4—N1 | 0.17 (18) | C8—C9—C10—C11 | 0.1 (2) |
C2—C3—C4—C5 | −177.76 (15) | C13—C9—C10—C11 | −179.93 (15) |
C7—N2—C5—C4 | −179.32 (12) | C9—C10—C11—C12 | 0.5 (3) |
C7—N2—C5—C6 | 0.7 (2) | C10—C11—C12—C7 | −1.1 (2) |
N1—C4—C5—N2 | −3.2 (2) | C10—C11—C12—C14 | 177.92 (16) |
C3—C4—C5—N2 | 174.48 (16) | C8—C7—C12—C11 | 1.2 (2) |
N1—C4—C5—C6 | 176.84 (14) | N2—C7—C12—C11 | 174.73 (13) |
C3—C4—C5—C6 | −5.5 (2) | C8—C7—C12—C14 | −177.81 (15) |
C5—N2—C7—C8 | −80.71 (18) | N2—C7—C12—C14 | −4.3 (2) |
Cg1 is the centroid of the C7–C12 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N2i | 0.86 | 2.34 | 3.1354 (18) | 155 |
C1—H1A···Cg1i | 0.93 | 2.65 | 3.4298 (16) | 142 |
Symmetry code: (i) −x, −y+2, −z. |
Experimental details
Crystal data | |
Chemical formula | C14H16N2 |
Mr | 212.29 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 296 |
a, b, c (Å) | 12.5894 (17), 7.3109 (10), 14.8425 (19) |
β (°) | 113.118 (2) |
V (Å3) | 1256.4 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.37 × 0.28 × 0.15 |
Data collection | |
Diffractometer | Bruker APEXII CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.976, 0.990 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6463, 2441, 1885 |
Rint | 0.021 |
(sin θ/λ)max (Å−1) | 0.616 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.156, 0.96 |
No. of reflections | 2441 |
No. of parameters | 149 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.16 |
Computer programs: APEX2 (Bruker,2008), SAINT (Bruker,2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), publCIF (Westrip, 2010).
Cg1 is the centroid of the C7–C12 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N2i | 0.86 | 2.34 | 3.1354 (18) | 154.9 |
C1—H1A···Cg1i | 0.93 | 2.65 | 3.4298 (16) | 142 |
Symmetry code: (i) −x, −y+2, −z. |
Acknowledgements
This work was supported by the Natural Science Basic Research Plan of Shaanxi Province (No. 2009JQ2006) and the Scientific Research Plan Project of Shaanxi Education Department (Nos. 12 J K0620 and 2010 J K784).
References
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Bis(imino)pyrrole is usually prepared from Schiff bases condensation of 2,5-diacetylpyrrole and the aromatic amine (Matsuo et al., 2001). Schiff bases containing pyrrole units have been extensively investigated because of their excellent and flexible coordination abilities (Wu et al., 2003). As the five-memberd ring substitute of pyridine six-memberd ring (Matsuo et al., 2001; He et al., 2009), pyrrole has been frequently introduced into the skeleton of the bis(imino)pyridine ligand to design new ligands and corresponding metal complexes as catalysts of olefin polymerizations (Britovsek et al., 2003; Dawson et al., 2000). As a part of our studies on mono(imino)pyrrole ligands (Su et al., 2009a,b), the crystal structure of the title compound is reported here.
The X-ray analysis of the title compound (Fig. 1) shows that the molecule is non-planar, with a dihedral angle of 72.37 (8)° formed by the pyrrole and benzene rings. The imino N—C bond length (1.288 (2) Å) indicates a C═N double bond character. In the crystal (Fig. 2), a pair of classical N–H···N hydrogen bonds (Table 1) link centrosymmetrically related molecules into a dimer, generating a ring of R22(10) graph-set motif. The dimer is further enforced by C—H···π hydrogen interactions.