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access2,7-Dibromo-9,9-dimethyl-9H-fluorene
aTianjin Basechem Technology Co. Ltd, K1-4-404, No. 6 Haitaifazhan 6th Road Huayuan Industry Area, Tianjin New Technology Industry Park, Tianjin 300384, People's Republic of China
*Correspondence e-mail: jialong.yuan@tjbasechem.com
The title molecule, C15H15Br2, has crystallographic m2m As a result, all atoms, except for those of the methyl groups, are exactly coplanar. In the 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![[Holder, E., Langeveld, B. M. W. & Schubert, U. S. (2005). Adv. Mater. 17, 1109-1121.]](../../../../../../logos/arrows/e_arr.gif "Holder, E., Langeveld, B. M. W. & Schubert, U. S. (2005). Adv. Mater. 17, 1109-1121.")
); 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).
![[Scheme 1]](lh5021scheme1.gif)
Experimental
Crystal data
|
Data collection: SMART-NT (Bruker, 1998); cell 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.
Supporting information
contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810012171/lh5021sup1.cif
Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810012171/lh5021Isup2.hkl
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.
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
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 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 of the title compound has been determined in order to elucidate its 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 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).
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).
Data collection: SMART (Bruker, 1998); cell SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); 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 (Sheldrick, 2008).
![[Figure 1]](./lh5021fig1thm.gif) | Fig. 1. Molecular structure of title compound with the atom labeling of the asymmetric unit, showing displacement ellipsoids at the 30% probability level. |
![[Figure 2]](./lh5021fig2thm.gif) | Fig. 2. Part of the crystal structure with π–π interactions shown as red dashed lines. |
| C15H12Br2 | F(000) = 688 |
| Mr = 352.07 | Dx = 1.773 Mg m−3 |
| 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 mm−1 |
| c = 6.9120 (17) Å | T = 296 K |
| V = 1319.0 (6) Å3 | Block, colourless |
| Z = 4 | 0.38 × 0.36 × 0.32 mm |
| Bruker SMART CCD diffractometer | 662 independent reflections |
| Radiation source: fine-focus sealed tube | 499 reflections with I > 2σ(I) |
| Graphite monochromator | 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 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 Å−3 |
| 54 parameters | Δρmin = −0.38 e Å−3 |
| 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) |
| C15H12Br2 | V = 1319.0 (6) Å3 |
| Mr = 352.07 | Z = 4 |
| Orthorhombic, Cmcm | Mo Kα radiation |
| a = 17.097 (4) Å | µ = 6.12 mm−1 |
| b = 11.161 (3) Å | T = 296 K |
| c = 6.9120 (17) Å | 0.38 × 0.36 × 0.32 mm |
| Bruker SMART CCD diffractometer | 662 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 499 reflections with I > 2σ(I) |
| Tmin = 0.083, Tmax = 1.000 | Rint = 0.047 |
| 3295 measured reflections |
| R[F2 > 2σ(F2)] = 0.032 | 0 restraints |
| wR(F2) = 0.085 | H-atom parameters constrained |
| S = 1.05 | Δρmax = 0.42 e Å−3 |
| 662 reflections | Δρmin = −0.38 e Å−3 |
| 54 parameters |
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. |
| 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 |
| 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) |
| 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. |
Experimental details
| Crystal data | |
| Chemical formula | C15H12Br2 |
| Mr | 352.07 |
| Crystal system, space group | Orthorhombic, Cmcm |
| Temperature (K) | 296 |
| a, b, c (Å) | 17.097 (4), 11.161 (3), 6.9120 (17) |
| V (Å3) | 1319.0 (6) |
| Z | 4 |
| Radiation type | Mo Kα |
| µ (mm−1) | 6.12 |
| Crystal size (mm) | 0.38 × 0.36 × 0.32 |
| Data collection | |
| Diffractometer | Bruker SMART CCD |
| Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
| Tmin, Tmax | 0.083, 1.000 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 3295, 662, 499 |
| Rint | 0.047 |
| (sin θ/λ)max (Å−1) | 0.595 |
| Refinement | |
| R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.085, 1.05 |
| No. of reflections | 662 |
| No. of parameters | 54 |
| H-atom treatment | H-atom parameters constrained |
| Δρmax, Δρmin (e Å−3) | 0.42, −0.38 |
Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Berndt, 1999).
Acknowledgements
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.
References
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| CRYSTALLOGRAPHIC COMMUNICATIONS |
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).