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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 7| July 2012| Page o2001
https://doi.org/10.1107/S1600536812024713

2-(2,4-Di­fluoro­phen­yl)-5-nitro­pyridine

Feng Sun,a Xuan Shen,a* Rui Zhao,a Xin Wanga and Dun-Ru Zhua*

aState Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China
*Correspondence e-mail: shenxuan@njut.edu.cn, zhudr@njut.edu.cn

(Received 18 May 2012; accepted 30 May 2012; online 2 June 2012)

In the title mol­ecule, C11H6F2N2O2, the benzene and pyridine rings form a dihedral angle of 32.57 (6)°. The nitro group is tilted with respect to the pyridine ring by 12.26 (9)°. An intra­molecular C—H⋯F hydrogen bond is present. In the crystal, mol­ecules inter­act through π–π stacking inter­actions [centroid–centroid distances = 3.7457 (14) Å], forming columnar arrangements along the b axis. The crystal packing is further enforced by inter­molecular C—H⋯O and C—H⋯N hydrogen bonds.

Related literature

For general background to organic light-emitting diodes (OLEDs), see: Baldo et al. (2000[Baldo, M. A., Thompson, M. E. & Forrest, S. R. (2000). Nature (London), 403, 750-753.]); Flamigni et al. (2007[Flamigni, L., Barbieri, A., Sabatini, C., Ventura, B. & Barigelletti, F. (2007). Top. Curr. Chem. 281, 143-203.]); Yang et al. (2007[Yang, C.-H., Cheng, Y.-M., Chi, Y., Hsu, C.-J., Fang, F.-C., Wong, K.-T., Chou, P.-T., Chang, C.-H., Tsai, M.-H. & Wu, C.-C. (2007). Angew. Chem. Int. Ed. 46, 2418-2421.]); Yersin (2008[Yersin, H. (2008). In Highly Efficient OLEDs with Phosphorescent Materials. Weinheim: Wiley-VCH.]). For luminescent IrIII complexes containing 2-phenyl­pyridine or its derivatives, see: Nazeeruddin et al. (2003[Nazeeruddin, Md. K., Humphry-Baker, R., Berner, D., Rivier, S., Zuppiroli, L. & Graetzel, M. (2003). J. Am. Chem. Soc. 125, 8790-8797.]); Dedeian et al. (2007[Dedeian, K., Shi, J., Forsythe, E. & Morton, D. C. (2007). Inorg. Chem. 46, 1603-1611.]); Chin et al. (2007[Chin, C. S., Eum, M.-S., Kim, S. Y., Kim, C. & Kang, S. K. (2007). Eur. J. Inorg. Chem. pp. 372-375.]); Shen et al. (2011[Shen, X., Wang, F.-L., Sun, F., Zhao, R., Wang, X., Jing, S., Xu, Y. & Zhu, D.-R. (2011). Inorg. Chem. Commun. 14, 1511-1515.]).

[Scheme 1]

Experimental

Crystal data

  • C11H6F2N2O2

  • Mr = 236.18

  • Orthorhombic, P n a 21

  • a = 22.185 (4) Å

  • b = 3.7457 (6) Å

  • c = 11.894 (2) Å

  • V = 988.4 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.14 mm−1

  • T = 296 K

  • 0.14 × 0.12 × 0.08 mm
Data collection

  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS.. University of Göttingen, Germany.]) Tmin = 0.981, Tmax = 0.989

  • 6331 measured reflections

  • 1750 independent reflections

  • 1450 reflections with I > 2σ(I)

  • Rint = 0.032
Refinement

  • R[F2 > 2σ(F2)] = 0.034

  • wR(F2) = 0.081

  • S = 1.06

  • 1750 reflections

  • 155 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.14 e Å−3

  • Δρmin = −0.12 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C10—H10A⋯O1i 0.93 2.56 3.306 (3) 138
C8—H8A⋯N1ii 0.93 2.58 3.448 (3) 156
C4—H4A⋯F1 0.93 2.40 2.893 (3) 113
Symmetry codes: (i) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z]; (ii) [-x+1, -y+2, z-{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536812024713/rz2765sup1.cif

Supporting information file. DOI: https://doi.org/10.1107/S1600536812024713/rz2765Isup2.mol

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812024713/rz2765Isup3.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536812024713/rz2765Isup4.cml

checkCIF report


Comment top

In recent years, IrIII cyclometalated complexes have received considerable attention because of their outstanding photochemical and photophysical properties, which make this class of complexes widely suitable to a variety of photonic applications and promising emissive materials in organic light-emitting diodes (OLEDs) (Baldo et al., 2000; Flamigni et al., 2007; Yang et al., 2007; Yersin, 2008). IrIII complexes containing 2-phenylpyridine (ppy) and its derivatives are known to exhibit high triplet quantum yields due to mixing the singlet and the triplet excited states via spin-orbit coupling, leading to high phosphorescence efficiencies (Nazeeruddin et al., 2003; Dedeian et al., 2007; Chin et al., 2007). It has been concluded that ppy-containing IrIII complexes can emit lights covering a full range of visible colors by introducing electron-donating or -withdrawing groups to the pyridyl or phenyl rings, which can adjust the HOMO-LUMO energy gaps of the complexes (Shen et al., 2011). As a contribution to this research field, we report herein the synthesis and crystal structure of the title compound. The electron-withdrawing fluoro and nitro groups have been introduced on the phenyl and pyridine rings, respectively, of the title compound, and investigations on IrIII complexes containing the title compound will be carried out soon.

The X-ray analysis of the title compound (Fig. 1) shows that the molecule is non-planar, the phenyl and pyridine rings forming a dihedral angle of 32.57 (6)°. The nitro group is slightly skewed with respect to the pyridine ring with a dihedral angle of 12.26 (9)%. An intramolecular C—H···F hydrogen bond (Table 1) stabilizes the molecular conformation. In the crystal structure (Fig. 2), π–π stacking interactions involving overlapping benzene and pyridine rings with centroid-to-centroid distances of 3.7457 (14) Å pack the molecules in columnar arrays running parallel the b axis. Furthermore, the columns interact via intermolecular C—H···O and C—H···N hydrogen bonds (Table 1).

Related literature top

For general background to organic light-emitting diodes (OLEDs), see: Baldo et al. (2000); Flamigni et al. (2007); Yang et al. (2007); Yersin (2008). For luminescent IrIII complexes containing 2-phenylpyridine or its derivatives, see: Nazeeruddin et al. (2003); Dedeian et al. (2007); Chin et al. (2007); Shen et al. (2011).

Experimental top

2-Chloro-5-nitropyridine (3.18 g, 20.0 mmol), 2,4-difluorophenylboric acid (4.00 g, 25.0 mmol) and triphenylphosphine (0.524 g, 2.0 mmol) were dissolved in THF (50 ml). After an aqueous solution of sodium carbonate (2 M, 30 ml) and palladium diacetate (0.122 g, 0.5 mmol) were added in, the mixture was refluxed under argon atmosphere for 24 h. After being cooled to room temperature, the reacted mixture was poured into water (50 ml) and was further extracted with dichloromethane (50 ml × 3). The combined extract was washed with saturated brine, dried over magnesium sulfate, and then evaporated to dryness. The crude product was purified by silica gel column chromatography (eluant: petroleum ether/ethyl acetate, 6:1 v/v), and colourless crystals of the title compound were at last obtained by recrystallization from ethanol in a yield of 70.5% (3.32 g).

Refinement top

All H atoms were positioned geometrically and refined using a riding model with C—H = 0.93 Å for phenyl and pyridyl H–atoms. The Uiso(H) were allowed at 1.2Ueq(C).

Structure description top

In recent years, IrIII cyclometalated complexes have received considerable attention because of their outstanding photochemical and photophysical properties, which make this class of complexes widely suitable to a variety of photonic applications and promising emissive materials in organic light-emitting diodes (OLEDs) (Baldo et al., 2000; Flamigni et al., 2007; Yang et al., 2007; Yersin, 2008). IrIII complexes containing 2-phenylpyridine (ppy) and its derivatives are known to exhibit high triplet quantum yields due to mixing the singlet and the triplet excited states via spin-orbit coupling, leading to high phosphorescence efficiencies (Nazeeruddin et al., 2003; Dedeian et al., 2007; Chin et al., 2007). It has been concluded that ppy-containing IrIII complexes can emit lights covering a full range of visible colors by introducing electron-donating or -withdrawing groups to the pyridyl or phenyl rings, which can adjust the HOMO-LUMO energy gaps of the complexes (Shen et al., 2011). As a contribution to this research field, we report herein the synthesis and crystal structure of the title compound. The electron-withdrawing fluoro and nitro groups have been introduced on the phenyl and pyridine rings, respectively, of the title compound, and investigations on IrIII complexes containing the title compound will be carried out soon.

The X-ray analysis of the title compound (Fig. 1) shows that the molecule is non-planar, the phenyl and pyridine rings forming a dihedral angle of 32.57 (6)°. The nitro group is slightly skewed with respect to the pyridine ring with a dihedral angle of 12.26 (9)%. An intramolecular C—H···F hydrogen bond (Table 1) stabilizes the molecular conformation. In the crystal structure (Fig. 2), π–π stacking interactions involving overlapping benzene and pyridine rings with centroid-to-centroid distances of 3.7457 (14) Å pack the molecules in columnar arrays running parallel the b axis. Furthermore, the columns interact via intermolecular C—H···O and C—H···N hydrogen bonds (Table 1).

For general background to organic light-emitting diodes (OLEDs), see: Baldo et al. (2000); Flamigni et al. (2007); Yang et al. (2007); Yersin (2008). For luminescent IrIII complexes containing 2-phenylpyridine or its derivatives, see: Nazeeruddin et al. (2003); Dedeian et al. (2007); Chin et al. (2007); Shen et al. (2011).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: 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).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids.
[Figure 2] Fig. 2. Partial packing diagram of the title compound showing the hydrogen bonding network and π···π interactions as red dashed lines.
2-(2,4-Difluorophenyl)-5-nitropyridine top
Crystal data top
C11H6F2N2O2F(000) = 480
Mr = 236.18Dx = 1.587 Mg m−3
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2nCell parameters from 24 reflections
a = 22.185 (4) Åθ = 1.9–26.7°
b = 3.7457 (6) ŵ = 0.14 mm−1
c = 11.894 (2) ÅT = 296 K
V = 988.4 (3) Å3Block, colourless
Z = 40.14 × 0.12 × 0.08 mm
Data collection top
Bruker APEXII CCD
diffractometer		1750 independent reflections
Radiation source: fine-focus sealed tube1450 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
ω scansθmax = 25.0°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −24→26
Tmin = 0.981, Tmax = 0.989k = −4→4
6331 measured reflectionsl = −14→14
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.034 w = 1/[σ2(Fo2) + (0.0417P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.081(Δ/σ)max < 0.001
S = 1.06Δρmax = 0.14 e Å−3
1750 reflectionsΔρmin = −0.12 e Å−3
155 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraintExtinction coefficient: 0.020 (2)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 823 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 1.3 (9)
Crystal data top
C11H6F2N2O2V = 988.4 (3) Å3
Mr = 236.18Z = 4
Orthorhombic, Pna21Mo Kα radiation
a = 22.185 (4) ŵ = 0.14 mm−1
b = 3.7457 (6) ÅT = 296 K
c = 11.894 (2) Å0.14 × 0.12 × 0.08 mm
Data collection top
Bruker APEXII CCD
diffractometer		1750 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		1450 reflections with I > 2σ(I)
Tmin = 0.981, Tmax = 0.989Rint = 0.032
6331 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.034H-atom parameters constrained
wR(F2) = 0.081Δρmax = 0.14 e Å−3
S = 1.06Δρmin = −0.12 e Å−3
1750 reflectionsAbsolute structure: Flack (1983), 823 Friedel pairs
155 parametersAbsolute structure parameter: 1.3 (9)
1 restraint
Special details top

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) top
xyzUiso*/Ueq
F10.43717 (7)0.8814 (4)0.19399 (11)0.0706 (5)
F20.64096 (6)0.8761 (5)0.29027 (14)0.0783 (5)
N10.39001 (8)0.6832 (5)0.52314 (14)0.0468 (5)
N20.23174 (9)0.3925 (7)0.5480 (2)0.0604 (6)
C10.33559 (10)0.6124 (6)0.56308 (18)0.0487 (6)
H1A0.32780.65460.63880.058*
C20.29008 (9)0.4788 (6)0.4966 (2)0.0461 (5)
C30.29993 (10)0.4202 (6)0.38367 (19)0.0499 (6)
H3A0.26960.33160.33760.060*
C40.35623 (9)0.4973 (6)0.34139 (19)0.0480 (6)
H4A0.36440.46470.26540.058*
C50.40050 (9)0.6236 (5)0.41293 (17)0.0392 (5)
C60.46353 (9)0.6929 (5)0.37757 (17)0.0406 (5)
C70.48022 (10)0.8139 (6)0.27144 (19)0.0457 (6)
C80.53882 (12)0.8781 (6)0.2407 (2)0.0529 (6)
H8A0.54850.96180.16930.064*
C90.58240 (10)0.8137 (6)0.3194 (2)0.0524 (6)
C100.57000 (11)0.6967 (7)0.4255 (2)0.0552 (7)
H10A0.60070.65810.47730.066*
C110.51028 (9)0.6372 (6)0.45341 (19)0.0468 (6)
H11A0.50110.55710.52540.056*
O10.19644 (9)0.2185 (6)0.49287 (19)0.0910 (7)
O20.22205 (9)0.4973 (7)0.6427 (2)0.1016 (8)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F10.0672 (10)0.0979 (13)0.0468 (8)0.0059 (9)−0.0017 (7)0.0135 (8)
F20.0529 (8)0.1004 (11)0.0818 (11)−0.0123 (8)0.0206 (8)−0.0020 (9)
N10.0453 (11)0.0560 (12)0.0390 (11)−0.0035 (9)0.0008 (8)−0.0029 (9)
N20.0466 (13)0.0676 (13)0.0671 (16)−0.0070 (11)0.0044 (12)0.0016 (11)
C10.0491 (13)0.0584 (14)0.0387 (13)−0.0033 (12)0.0016 (10)−0.0016 (10)
C20.0423 (12)0.0445 (12)0.0514 (15)0.0006 (10)0.0018 (11)0.0024 (11)
C30.0468 (13)0.0535 (13)0.0494 (14)−0.0034 (11)−0.0103 (11)−0.0086 (12)
C40.0531 (14)0.0548 (14)0.0360 (12)0.0004 (11)−0.0040 (11)−0.0040 (11)
C50.0446 (12)0.0343 (11)0.0386 (11)0.0014 (10)−0.0010 (9)0.0006 (9)
C60.0492 (14)0.0339 (11)0.0387 (12)0.0036 (9)0.0022 (11)−0.0021 (10)
C70.0543 (15)0.0437 (13)0.0392 (12)0.0042 (11)0.0012 (11)0.0027 (11)
C80.0614 (16)0.0494 (16)0.0480 (13)−0.0010 (12)0.0133 (12)0.0017 (11)
C90.0449 (14)0.0506 (14)0.0617 (16)−0.0035 (11)0.0146 (13)−0.0053 (12)
C100.0486 (15)0.0605 (16)0.0564 (16)0.0036 (11)0.0012 (12)0.0028 (13)
C110.0443 (13)0.0487 (14)0.0474 (13)0.0022 (10)0.0016 (11)0.0038 (11)
O10.0561 (11)0.1191 (18)0.0978 (18)−0.0343 (12)−0.0064 (12)−0.0072 (13)
O20.0777 (15)0.151 (2)0.0764 (15)−0.0335 (14)0.0293 (12)−0.0233 (16)
Geometric parameters (Å, º) top
F1—C71.351 (3)C4—C51.383 (3)
F2—C91.365 (2)C4—H4A0.9300
N1—C11.324 (3)C5—C61.483 (3)
N1—C51.350 (3)C6—C111.390 (3)
N2—O11.212 (3)C6—C71.391 (3)
N2—O21.213 (3)C7—C81.372 (3)
N2—C21.467 (3)C8—C91.367 (4)
C1—C21.377 (3)C8—H8A0.9300
C1—H1A0.9300C9—C101.364 (4)
C2—C31.378 (3)C10—C111.384 (3)
C3—C41.377 (3)C10—H10A0.9300
C3—H3A0.9300C11—H11A0.9300
C1—N1—C5118.19 (19)C11—C6—C7116.04 (19)
O1—N2—O2124.2 (2)C11—C6—C5119.54 (19)
O1—N2—C2117.6 (2)C7—C6—C5124.4 (2)
O2—N2—C2118.2 (2)F1—C7—C8117.1 (2)
N1—C1—C2122.4 (2)F1—C7—C6119.44 (19)
N1—C1—H1A118.8C8—C7—C6123.5 (2)
C2—C1—H1A118.8C9—C8—C7117.1 (2)
C1—C2—C3120.1 (2)C9—C8—H8A121.4
C1—C2—N2119.2 (2)C7—C8—H8A121.4
C3—C2—N2120.7 (2)C10—C9—F2118.8 (2)
C4—C3—C2117.8 (2)C10—C9—C8123.2 (2)
C4—C3—H3A121.1F2—C9—C8118.0 (2)
C2—C3—H3A121.1C9—C10—C11117.8 (2)
C3—C4—C5119.4 (2)C9—C10—H10A121.1
C3—C4—H4A120.3C11—C10—H10A121.1
C5—C4—H4A120.3C10—C11—C6122.3 (2)
N1—C5—C4122.1 (2)C10—C11—H11A118.9
N1—C5—C6114.14 (19)C6—C11—H11A118.9
C4—C5—C6123.72 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10A···O1i0.932.563.306 (3)138
C8—H8A···N1ii0.932.583.448 (3)156
C4—H4A···F10.932.402.893 (3)113
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) −x+1, −y+2, z−1/2.

Experimental details

Crystal data
Chemical formulaC11H6F2N2O2
Mr236.18
Crystal system, space groupOrthorhombic, Pna21
Temperature (K)296
a, b, c (Å)22.185 (4), 3.7457 (6), 11.894 (2)
V (Å3)988.4 (3)
Z4
Radiation typeMo Kα
µ (mm−1)0.14
Crystal size (mm)0.14 × 0.12 × 0.08
Data collection
DiffractometerBruker APEXII CCD
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.981, 0.989
No. of measured, independent and
observed [I > 2σ(I)] reflections		6331, 1750, 1450
Rint0.032
(sin θ/λ)max (Å−1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.081, 1.06
No. of reflections1750
No. of parameters155
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.14, −0.12
Absolute structureFlack (1983), 823 Friedel pairs
Absolute structure parameter1.3 (9)

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10A···O1i0.932.563.3059 (33)138
C8—H8A···N1ii0.932.583.4481 (30)156
C4—H4A···F10.932.402.8927 (26)113
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) −x+1, −y+2, z−1/2.
 

Acknowledgements

We are grateful to the Open Project Program of the State Key Laboratory of Materials-Oriented Chemical Engineering, China (grant No. KL10–14) and the National Natural Science Foundation of China (grant No. 21171093) for financial support.

References

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ISSN: 2056-9890
Volume 68| Part 7| July 2012| Page o2001
https://doi.org/10.1107/S1600536812024713
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