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Acta Crystallogr Sect E Struct Rep Online. 2009 November 1; 65(Pt 11): o2618.
Published online 2009 October 3. doi:  10.1107/S1600536809038999
PMCID: PMC2971233

1,5-Bis(2,5-dimethyl-1H-pyrrol-1-yl)naphthalene

Abstract

In the title compound, C22H22N2, the asymmetric unit contains one half-mol­ecule. A crystallographic inversion centre is located at the mid-point of the bond common to both rings, in the central naphthalene unit. Quantum-mechanical ab initio calculations on the isolated mol­ecule showed that the minimum energy configuration occurs when the naphthalene ring system and the pyrrolyl groups deviate only slightly from perpendicularity. In the crystal, due to the effects of crystal packing, the mol­ecule deviates by approximately 4° from the a priori expected ideal value of 90° [C—C—N—C torsion angle = 86.11 (15)°].

Related literature

For related compounds, see: Andrade et al. (2008 [triangle]); Ramos Silva et al. (2002 [triangle]); Sobral (2006 [triangle]); Sobral & Rocha Gonsalves (2001a [triangle],b [triangle]). For the ab initio calculation method, see: Schmidt et al. (1993 [triangle]).

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Object name is e-65-o2618-scheme1.jpg

Experimental

Crystal data

  • C22H22N2
  • M r = 314.42
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2618-efi1.jpg
  • a = 8.7562 (3) Å
  • b = 7.2806 (2) Å
  • c = 14.1380 (5) Å
  • β = 101.4721 (16)°
  • V = 883.30 (5) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.07 mm−1
  • T = 293 K
  • 0.30 × 0.30 × 0.02 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2000 [triangle]) T min = 0.892, T max = 0.999
  • 23689 measured reflections
  • 2415 independent reflections
  • 1798 reflections with I > 2σ(I)
  • R int = 0.028

Refinement

  • R[F 2 > 2σ(F 2)] = 0.044
  • wR(F 2) = 0.160
  • S = 1.11
  • 2415 reflections
  • 111 parameters
  • H-atom parameters constrained
  • Δρmax = 0.19 e Å−3
  • Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2003 [triangle]); cell refinement: SAINT (Bruker, 2003 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2009 [triangle]); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809038999/pk2188sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809038999/pk2188Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

We gratefully acknowledge LCA-UC for a grant of computer time in the Milipeia cluster.

supplementary crystallographic information

Comment

Complex pyrroles are important synthons in macromolecular chemistry, environmental chemistry, medical chemistry and nano-technologies based on polymeric organic materials. Following our endeavor in synthesizing new pyrrolic compounds for material chemistry (Andrade et al., 2008; Ramos Silva et al., 2002; Sobral & Rocha Gonsalves 2001a, 2001b; Sobral, 2006), we prepared the title compound, by the Paal-Knorr methodology, using iodine as catalyst. Each molecule contains a crystallographic inversion centre at the mid-point of the bond common to both rings of the naphthalene moiety. All bond lengths and valency angles of the molecule lie within the expected range of values for naphtalene derivatives.

Approximate free rotation of the pyrrolyl group around the formal σ C—N bond is expected. Thus, the conformation observed for such groups in the solid state should be determined by steric rather than electronic effects. We observe in this structure a value of 86.11 (15)° for the C9–C8–N1–C1 dihedral angle, which is close to the a priori expected ideal value of 90° where the steric effects should be at a minimum.

In order to gain some insight into how the crystal packing might affect the molecular geometry we have performed a quantum chemical calculation on the equilibrium geometry of the free molecule. These calculations were performed with the computer program GAMESS (Schmidt et al., 1993). A molecular orbital Roothan Hartree-Fock method was used with an extended 6–31 G(d,p) basis set. Tight conditions for convergence of both the self-consistent field cycles and maximum density and energy gradient variations were imposed (10-6atomic units). The program was run on the Milipeia cluster of UC-LCA (using 16 Opteron cores, 2.2 GHz runing Linux).

The ab-initio calculations reproduce well the observed experimental bond length and angles of the molecule. All angles match the experimental values within 1°. Calculated and experimental bond distances agree within 0.023 Å. The calculated C9–C8–N1–C1 dihedral angle is 91.82°, a value closer to the ideal value of 90° than the experimental value in the solid state.

A check for weak intermolecular interactions in the crystal on the basis of short contacts revealed that a possible C—H···π interaction may exist between atoms C2 and the pyrrole ring [C2—H2···Cg: 3.7791 (16) Å, 159°]

Experimental

0.680 g (4.3 mmol) of 1,4-phenylenedimethanamine and 1 ml (8.5 mmol) of hexane-2,5-dione were dissolved in 20 ml of tetrahydrofuran, under nitrogen atmosphere. 0.172 g (0.678 mmol) of iodine was added to the stirred solution at 40°C. The procedure was monitored by TLC. After completion of the reaction (6 h), 20 ml of dichlorometane were added to the mixture. The resulting mixture was washed successively with 5% Na2S2O3 solution (2 ml), NaHCO3 solution (2 ml) and brine (2 ml). The organic layer was then dried with anhydrous sodium sulfate and concentrated. The product was purified by flash chromatography in silica gel 60H FLUKA/dichloromethane and recrystallized in cold dichloromethane, by slow solvent evaporation, to give needle shape crystals 0.473 grams corresponding to 1.5 mmoles (%) = 35; GC/MS (100 µmol/ml in CH2Cl2) m/z = 314; 1H-NMR (0.1 M in CDCl3, 499.428 MHz) σ 1.96 (s, 12H, Methyl), σ 5.34 (s, 4H, pyrrole), σ 7.25 (dd, 2H, Aromatic, J = 0.99, J = 7.49 Hz), 7.48 (dd, 2H, Aromatic, J = 0.99 Hz, J = 6.99 Hz), 7.55 (t, 2H, Aromatic, J = 7.0 Hz); 13C - NMR (0.1 M in CDCl3, 125.692 MHz) σ 12.5 (Methyl), σ 105.6 (Pyrrole), σ 129.8 (Pyrrole), σ 126.7 (Aromatic), σ 132.7 (Aromatic). Melting point: Decomposes at 288 °C.

Refinement

The methyl H atoms were constrained to an ideal geometry (C—H = 0.96 Å) with Uiso(H)= 1.5Ueq(C), but were allowed to rotate freely about the C—C bonds. All remaining H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with Uiso(H) = 1.2Ueq(parent atom).

Figures

Fig. 1.
Ellipsoid plot of the title compound. Displacement ellipsoids are drawn at the 50% level. Unlabelled atoms are generated by inversion through the origin.

Crystal data

C22H22N2F(000) = 336
Mr = 314.42Dx = 1.182 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 8233 reflections
a = 8.7562 (3) Åθ = 2.4–28.6°
b = 7.2806 (2) ŵ = 0.07 mm1
c = 14.1380 (5) ÅT = 293 K
β = 101.4721 (16)°Plate, brown
V = 883.30 (5) Å30.30 × 0.30 × 0.02 mm
Z = 2

Data collection

Bruker APEXII CCD area-detector diffractometer2415 independent reflections
Radiation source: fine-focus sealed tube1798 reflections with I > 2σ(I)
graphiteRint = 0.028
[var phi] and ω scansθmax = 29.5°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)h = −12→11
Tmin = 0.892, Tmax = 0.999k = −10→9
23689 measured reflectionsl = −18→19

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.160H-atom parameters constrained
S = 1.11w = 1/[σ2(Fo2) + (0.0861P)2 + 0.0939P] where P = (Fo2 + 2Fc2)/3
2415 reflections(Δ/σ)max < 0.001
111 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = −0.20 e Å3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
N1−0.25783 (11)0.16842 (14)−0.15743 (7)0.0413 (3)
C1−0.37264 (14)0.28237 (17)−0.13576 (10)0.0457 (3)
C2−0.40388 (17)0.41020 (19)−0.20743 (11)0.0581 (4)
H2−0.47650.5046−0.21170.070*
C4−0.21687 (17)0.2256 (2)−0.24234 (10)0.0543 (4)
C3−0.3073 (2)0.3747 (2)−0.27363 (11)0.0644 (5)
H3−0.30540.4416−0.32940.077*
C5−0.4403 (2)0.2558 (2)−0.04885 (14)0.0677 (5)
H5A−0.52350.3419−0.04960.102*
H5B−0.36120.27520.00790.102*
H5C−0.48000.1329−0.04840.102*
C6−0.0984 (3)0.1270 (3)−0.28455 (14)0.0867 (6)
H6A−0.08870.1846−0.34410.130*
H6B−0.12980.0015−0.29660.130*
H6C0.00010.1310−0.24030.130*
C7−0.03746 (12)0.07020 (14)−0.03141 (8)0.0338 (3)
C8−0.18058 (13)0.02723 (15)−0.09515 (8)0.0374 (3)
C9−0.24388 (15)−0.14418 (17)−0.09648 (10)0.0472 (3)
H9−0.3369−0.1703−0.13890.057*
C10−0.16905 (15)−0.28164 (17)−0.03401 (10)0.0478 (3)
H10−0.2135−0.3978−0.03520.057*
C11−0.03195 (14)−0.24638 (15)0.02834 (9)0.0403 (3)
H110.0162−0.33870.06910.048*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0373 (5)0.0397 (5)0.0418 (6)0.0034 (4)−0.0041 (4)0.0032 (4)
C10.0380 (6)0.0377 (6)0.0544 (7)0.0016 (5)−0.0074 (5)−0.0072 (5)
C20.0550 (9)0.0415 (7)0.0643 (9)0.0071 (6)−0.0209 (7)−0.0012 (6)
C40.0542 (8)0.0616 (9)0.0425 (7)0.0017 (6)−0.0016 (6)0.0083 (6)
C30.0725 (10)0.0591 (9)0.0505 (8)−0.0008 (7)−0.0144 (7)0.0161 (7)
C50.0623 (10)0.0612 (9)0.0825 (11)0.0101 (7)0.0214 (8)−0.0053 (8)
C60.0921 (14)0.1113 (16)0.0625 (10)0.0227 (12)0.0292 (10)0.0146 (10)
C70.0322 (6)0.0315 (5)0.0362 (6)0.0009 (4)0.0033 (4)0.0000 (4)
C80.0344 (6)0.0360 (6)0.0390 (6)0.0030 (4)0.0003 (5)0.0012 (4)
C90.0376 (7)0.0421 (6)0.0551 (7)−0.0048 (5)−0.0071 (5)−0.0012 (5)
C100.0444 (7)0.0332 (6)0.0611 (8)−0.0075 (5)−0.0012 (6)0.0011 (5)
C110.0401 (6)0.0316 (5)0.0468 (7)0.0005 (4)0.0026 (5)0.0042 (4)

Geometric parameters (Å, °)

N1—C41.3835 (17)C6—H6A0.9600
N1—C11.3840 (16)C6—H6B0.9600
N1—C81.4326 (14)C6—H6C0.9600
C1—C21.3628 (19)C7—C11i1.4164 (15)
C1—C51.479 (2)C7—C81.4253 (15)
C2—C31.404 (3)C7—C7i1.426 (2)
C2—H20.9300C8—C91.3642 (17)
C4—C31.365 (2)C9—C101.4075 (18)
C4—C61.481 (2)C9—H90.9300
C3—H30.9300C10—C111.3649 (17)
C5—H5A0.9600C10—H100.9300
C5—H5B0.9600C11—C7i1.4164 (15)
C5—H5C0.9600C11—H110.9300
C4—N1—C1109.68 (11)C4—C6—H6A109.5
C4—N1—C8125.23 (11)C4—C6—H6B109.5
C1—N1—C8124.69 (11)H6A—C6—H6B109.5
C2—C1—N1106.98 (13)C4—C6—H6C109.5
C2—C1—C5130.75 (14)H6A—C6—H6C109.5
N1—C1—C5122.26 (12)H6B—C6—H6C109.5
C1—C2—C3108.15 (13)C11i—C7—C8122.42 (10)
C1—C2—H2125.9C11i—C7—C7i119.26 (12)
C3—C2—H2125.9C8—C7—C7i118.32 (12)
C3—C4—N1106.65 (14)C9—C8—C7120.88 (10)
C3—C4—C6131.51 (15)C9—C8—N1120.47 (10)
N1—C4—C6121.82 (13)C7—C8—N1118.64 (10)
C4—C3—C2108.53 (13)C8—C9—C10120.31 (11)
C4—C3—H3125.7C8—C9—H9119.8
C2—C3—H3125.7C10—C9—H9119.8
C1—C5—H5A109.5C11—C10—C9120.76 (11)
C1—C5—H5B109.5C11—C10—H10119.6
H5A—C5—H5B109.5C9—C10—H10119.6
C1—C5—H5C109.5C10—C11—C7i120.47 (11)
H5A—C5—H5C109.5C10—C11—H11119.8
H5B—C5—H5C109.5C7i—C11—H11119.8
C4—N1—C1—C20.28 (14)C11i—C7—C8—C9179.75 (12)
C8—N1—C1—C2173.32 (11)C7i—C7—C8—C9−0.4 (2)
C4—N1—C1—C5−179.96 (13)C11i—C7—C8—N1−0.83 (18)
C8—N1—C1—C5−6.91 (19)C7i—C7—C8—N1179.03 (12)
N1—C1—C2—C3−0.09 (15)C4—N1—C8—C9−101.92 (16)
C5—C1—C2—C3−179.82 (15)C1—N1—C8—C986.11 (15)
C1—N1—C4—C3−0.36 (16)C4—N1—C8—C778.66 (16)
C8—N1—C4—C3−173.36 (11)C1—N1—C8—C7−93.32 (14)
C1—N1—C4—C6−178.79 (15)C7—C8—C9—C100.5 (2)
C8—N1—C4—C68.2 (2)N1—C8—C9—C10−178.89 (12)
N1—C4—C3—C20.30 (17)C8—C9—C10—C11−0.4 (2)
C6—C4—C3—C2178.52 (17)C9—C10—C11—C7i0.1 (2)
C1—C2—C3—C4−0.14 (17)

Symmetry codes: (i) −x, −y, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PK2188).

References

  • Andrade, S. M., Teixeira, R., Costa, S. M. B. & Sobral, A. J. F. N. (2008). Biophys. Chem.133, 1–10. [PubMed]
  • Bruker (2003). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Ramos Silva, M., Matos Beja, A., Paixão, J. A., Sobral, A. J. F. N., Lopes, S. H. & Rocha Gonsalves, A. M. d’A. (2002). Acta Cryst. C58, o572–o574. [PubMed]
  • Schmidt, M. W., Baldrige, K. K., Boatz, J. A., Elbert, S. T., Gordon, M. S., Jensen, J. J., Koseki, S., Matsunaga, N., Nguyen, K. A., Sue, S., Windus, T. L., Dupuis, M. & Montgomery, J. A. (1993). J. Comput. Chem.14, 1347–1363.
  • Sheldrick, G. M. (2000). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Sobral, A. J. F. N. (2006). J. Chem. Educ.83, 1665–1666.
  • Sobral, A. J. F. N. & Rocha Gonsalves, A. M. D. (2001a). J. Porph. Phthal.5, 428–430.
  • Sobral, A. J. F. N. & Rocha Gonsalves, A. M. D. (2001b). J. Porph. Phthal.5, 861–866.
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]

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