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Acta Crystallographica Section E: Structure Reports Online logoLink to Acta Crystallographica Section E: Structure Reports Online
. 2010 Apr 10;66(Pt 5):o1034. doi: 10.1107/S1600536810012171

2,7-Dibromo-9,9-dimethyl-9H-fluorene

Xiao Chen a, Xinliang Fu a, Yongkuan Qiu a, Jialong Yuan a,*
PMCID: PMC2979143  PMID: 21579097

Abstract

The title mol­ecule, C15H15Br2, has crystallographic m2m site symmetry. As a result, all atoms, except for those of the methyl groups, are exactly coplanar. In the crystal structure, there are weak π–π inter­actions with a centroid–centroid distance of 3.8409 (15) Å between symmetry-related mol­ecules, which stack along the c axis.

Related literature

For applications of fluorene derivatives, see: Holder et al. (2005); Kulkarni et al. (2004); Padmaperuma et al. (2006); Seneclauze et al. (2007); Tsuboyama et al. (2003). For the properties of fluorene-based mol­ecules, see: Scherf & List (2002). For the synthesis of the title compound, see: Belfield et al. (2000).graphic file with name e-66-o1034-scheme1.jpg

Experimental

Crystal data

  • C15H12Br2

  • M r = 352.07

  • Orthorhombic, Inline graphic

  • a = 17.097 (4) Å

  • b = 11.161 (3) Å

  • c = 6.9120 (17) Å

  • V = 1319.0 (6) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 6.12 mm−1

  • T = 296 K

  • 0.38 × 0.36 × 0.32 mm

Data collection

  • Bruker SMART CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T min = 0.083, T max = 1.000

  • 3295 measured reflections

  • 662 independent reflections

  • 499 reflections with I > 2σ(I)

  • R int = 0.047

Refinement

  • R[F 2 > 2σ(F 2)] = 0.032

  • wR(F 2) = 0.085

  • S = 1.05

  • 662 reflections

  • 54 parameters

  • H-atom parameters constrained

  • Δρmax = 0.42 e Å−3

  • Δρmin = −0.38 e Å−3

Data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT-NT (Bruker, 1998); data reduction: SAINT-NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810012171/lh5021sup1.cif

e-66-o1034-sup1.cif (14.1KB, cif)

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810012171/lh5021Isup2.hkl

e-66-o1034-Isup2.hkl (33.3KB, hkl)

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

Acknowledgments

The authors acknowledge the Tianjin Binhai Hi-tech Industry Park Management Committee, Huayuan Industrial Park and Haitai Green Industrial Base for support of this work.

supplementary crystallographic information

Comment

Because of their good thermal and chemical stability along with high emission efficiency, fluorene derivatives have shown many applications as electronic materials, especially for organic light emitting diodes (OLEDs) (Holder et al., 2005; Kulkarni et al., 2004; Seneclauze et al., 2007; Padmaperuma et al., 2006; Tsuboyama et al., 2003). In this regard, small molecules, oligomers, or polymers with the 9,9-dialkylfluorene subunit possess interesting emissive properties. The quality and efficiency of such OLEDs have been shown to depend crucially on the stacking mode of the fluorene motif. On the other hand, the selected alkyl groups with different lengths or branched alkyl chains have a deep influence on the property and the packing mode of fluorene-based molecules (Scherf & List, 2002). During our study on such OLEDs crystalline materials, the crystal structure of the title compound has been determined in order to elucidate its molecular conformation and packing mode, which may be useful for further understanding its properties.

The molecular structure of the title compound is shown in Fig. 1. The complete molecule is generated two mirror planes which intersect each other [ crystallographic m2m site symmetry]. As a result, all the carbon atoms [except for those of the methyl groups] and the bromide atoms are exactly co-planar. In the crystal structure, weak π–π interactions between symmetry related benzene rings [C1-C6] with a centroid to centroid distance of 3.8409 (15) Å and perpendicular distance of 3.456 (1) Å form a one-dimensional chain along the c axis (see Fig. 2).

Experimental

The title compound was prepared according to the literature method (Belfield et al., 2000). Single crystals suitable for X-ray diffraction were obtained by recrystallization of a solution of the title compound in a mixture of ethyl acetate and petroleum ether.

Refinement

H atoms were positioned geometrically and refined as riding atoms, with C—H = 0.96Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms, and C—H = 0.93Å and Uiso(H) = 1.2Ueq(C) for all aromatic H atoms

Figures

Fig. 1.

Fig. 1.

Molecular structure of title compound with the atom labeling of the asymmetric unit, showing displacement ellipsoids at the 30% probability level.

Fig. 2.

Fig. 2.

Part of the crystal structure with π–π interactions shown as red dashed lines.

Crystal data

C15H12Br2 F(000) = 688
Mr = 352.07 Dx = 1.773 Mg m3
Orthorhombic, Cmcm Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2 Cell parameters from 958 reflections
a = 17.097 (4) Å θ = 2.4–24.1°
b = 11.161 (3) Å µ = 6.12 mm1
c = 6.9120 (17) Å T = 296 K
V = 1319.0 (6) Å3 Block, colourless
Z = 4 0.38 × 0.36 × 0.32 mm

Data collection

Bruker SMART CCD diffractometer 662 independent reflections
Radiation source: fine-focus sealed tube 499 reflections with I > 2σ(I)
graphite Rint = 0.047
φ and ω scans θmax = 25.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) h = −18→20
Tmin = 0.083, Tmax = 1.000 k = −13→11
3295 measured reflections l = −7→8

Refinement

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)] = 0.032 H-atom parameters constrained
wR(F2) = 0.085 w = 1/[σ2(Fo2) + (0.0321P)2 + 2.5078P] where P = (Fo2 + 2Fc2)/3
S = 1.05 (Δ/σ)max < 0.001
662 reflections Δρmax = 0.42 e Å3
54 parameters Δρmin = −0.38 e Å3
0 restraints Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods Extinction coefficient: 0.0097 (9)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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)

x y z Uiso*/Ueq Occ. (<1)
Br1 0.19165 (3) 0.13056 (5) 0.2500 0.0696 (4)
C1 0.3008 (3) 0.0990 (4) 0.2500 0.0416 (11)
C2 0.3248 (3) −0.0185 (4) 0.2500 0.0407 (12)
H2 0.2883 −0.0804 0.2500 0.049*
C3 0.4037 (3) −0.0430 (4) 0.2500 0.0373 (11)
H3 0.4210 −0.1220 0.2500 0.045*
C4 0.4574 (3) 0.0500 (3) 0.2500 0.0318 (10)
C5 0.4314 (3) 0.1684 (4) 0.2500 0.0332 (10)
C6 0.3527 (3) 0.1946 (4) 0.2500 0.0392 (11)
H6 0.3350 0.2734 0.2500 0.047*
C7 0.5000 0.2560 (5) 0.2500 0.0373 (15)
C8 0.5000 0.3344 (4) 0.0682 (8) 0.0533 (14)
H8A 0.5000 0.2845 −0.0442 0.080*
H8B 0.5481 0.3785 0.0613 0.080* 0.50
H8C 0.4569 0.3894 0.0736 0.080* 0.50

Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23
Br1 0.0319 (4) 0.0648 (5) 0.1121 (6) 0.0034 (3) 0.000 0.000
C1 0.026 (2) 0.048 (3) 0.051 (3) 0.001 (2) 0.000 0.000
C2 0.038 (3) 0.039 (3) 0.046 (3) −0.006 (2) 0.000 0.000
C3 0.043 (3) 0.026 (2) 0.043 (3) −0.0029 (19) 0.000 0.000
C4 0.034 (2) 0.029 (2) 0.033 (2) 0.0008 (18) 0.000 0.000
C5 0.036 (3) 0.028 (2) 0.036 (2) −0.0029 (19) 0.000 0.000
C6 0.036 (3) 0.031 (2) 0.050 (3) 0.006 (2) 0.000 0.000
C7 0.032 (3) 0.027 (3) 0.053 (4) 0.000 0.000 0.000
C8 0.047 (3) 0.042 (2) 0.071 (4) 0.000 0.000 0.017 (3)

Geometric parameters (Å, °)

Br1—C1 1.899 (4) C5—C6 1.377 (6)
C1—C2 1.374 (7) C5—C7 1.528 (6)
C1—C6 1.388 (7) C6—H6 0.9300
C2—C3 1.377 (6) C7—C5i 1.528 (6)
C2—H2 0.9300 C7—C8ii 1.531 (6)
C3—C4 1.386 (6) C7—C8 1.531 (6)
C3—H3 0.9300 C8—H8A 0.9561
C4—C5 1.394 (6) C8—H8B 0.9600
C4—C4i 1.457 (9) C8—H8C 0.9600
C2—C1—C6 122.9 (4) C5—C6—C1 117.5 (4)
C2—C1—Br1 118.1 (4) C5—C6—H6 121.2
C6—C1—Br1 119.1 (4) C1—C6—H6 121.2
C1—C2—C3 118.8 (4) C5—C7—C5i 100.3 (5)
C1—C2—H2 120.6 C5—C7—C8ii 111.47 (14)
C3—C2—H2 120.6 C5i—C7—C8ii 111.47 (14)
C2—C3—C4 120.0 (4) C5—C7—C8 111.47 (14)
C2—C3—H3 120.0 C5i—C7—C8 111.47 (14)
C4—C3—H3 120.0 C8ii—C7—C8 110.3 (5)
C3—C4—C5 119.9 (4) C7—C8—H8A 109.5
C3—C4—C4i 131.5 (2) C7—C8—H8B 109.5
C5—C4—C4i 108.6 (3) H8A—C8—H8B 104.9
C6—C5—C4 120.9 (4) C7—C8—H8C 109.5
C6—C5—C7 127.9 (4) H8A—C8—H8C 113.8
C4—C5—C7 111.2 (4) H8B—C8—H8C 109.5
C6—C1—C2—C3 0.0 C7—C5—C6—C1 180.0
Br1—C1—C2—C3 180.0 C2—C1—C6—C5 0.0
C1—C2—C3—C4 0.0 Br1—C1—C6—C5 180.0
C2—C3—C4—C5 0.0 C6—C5—C7—C5i 180.0
C2—C3—C4—C4i 180.0 C4—C5—C7—C5i 0.0
C3—C4—C5—C6 0.0 C6—C5—C7—C8ii 61.9 (3)
C4i—C4—C5—C6 180.0 C4—C5—C7—C8ii −118.1 (3)
C3—C4—C5—C7 180.0 C6—C5—C7—C8 −61.9 (3)
C4i—C4—C5—C7 0.0 C4—C5—C7—C8 118.1 (3)
C4—C5—C6—C1 0.0

Symmetry codes: (i) −x+1, y, −z+1/2; (ii) x, y, −z+1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5021).

References

  1. Belfield, K. D., Schafer, K. J., Mourad, W. & Reinhardt, B. A. (2000). J. Org. Chem.65, 4475–4481. [DOI] [PubMed]
  2. Brandenburg, K. & Berndt, M. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.
  3. Bruker (1998). SMART-NT and SAINT-NT Bruker AXS Inc., Madison, Wisconsin, USA.
  4. Holder, E., Langeveld, B. M. W. & Schubert, U. S. (2005). Adv. Mater.17, 1109–1121.
  5. Kulkarni, A. P., Tonzola, C. J., Babel, A. & Jenekhe, S. A. (2004). Chem. Mater.16, 4556–4573.
  6. Padmaperuma, A. B., Sapochak, L. S. & Burrows, P. E. (2006). Chem. Mater.18, 2389–2396.
  7. Scherf, U. & List, E. J. W. (2002). Adv. Mater.14, 447–487.
  8. Seneclauze, J. B., Retailleau, P. & Ziessel, R. (2007). New J. Chem.31, 1412–1416.
  9. Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  10. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [DOI] [PubMed]
  11. Tsuboyama, A., Iwawaki, H., Furugori, M., Mukaide, T., Kamatani, J., Igawa, S., Moriyama, T., Miura, S., Takiguchi, T., Okada, S., Hoshino, M. & Ueno, K. (2003). J. Am. Chem. Soc.125, 12971–12979. [DOI] [PubMed]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810012171/lh5021sup1.cif

e-66-o1034-sup1.cif (14.1KB, cif)

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810012171/lh5021Isup2.hkl

e-66-o1034-Isup2.hkl (33.3KB, hkl)

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


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