1,4-Bis(fluoro­meth­yl)benzene

Fun, H.-K.; Kia, R.; Patil, P.S.; Dharmaprakash, S.M.

doi:10.1107/S1600536809003730

organic compounds

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ISSN: 2056-9890

Volume 65| Part 3| March 2009| Page o459

doi:10.1107/S1600536809003730

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1,4-Bis(fluoromethyl)benzene

Hoong-Kun Fun,^a ^* Reza Kia,^a P. S. Patil ^b ‡ and S. M. Dharmaprakash ^c

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bDepartment of Physics, K. L. E. Society's K. L. E. Institute of Technology, Gokul, Hubli 580 030, India, and ^cDepartment of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574 199, India
^*Correspondence e-mail: hkfun@usm.my

(Received 16 January 2009; accepted 30 January 2009; online 4 February 2009)

The title compound, C₈H₈F₂, lies across a crystallographic inversion centre. The structure features short C⋯F [2.8515 (18) Å] and F⋯F [2.490 (4) Å] contacts, which are significantly shorter than the sum of the van der Waals radii of these atoms. The F atom and methylene H atoms are disordered over two positions with a site-occupancy ratio of 0.633 (3):0.367 (3). In the crystal structure, intermolecular C—H⋯F interactions link neighboring molecules into infinite chains along the b axis. In addition, C—H⋯π interactions link these molecules along [10 $[\overline{1}]$ ], forming a two-dimensional network parallel to (101).

Related literature

For the structures of compounds with non-linear properties, see, for example: Chantrapromma et al. (2006 ); Fun et al. (2008 ); Patil et al. (2007 ).

Experimental

Crystal data

C₈H₈F₂
M_r = 143.15
Monoclinic, P 2₁ /n
a = 6.1886 (2) Å
b = 5.0152 (2) Å
c = 10.4750 (4) Å
β = 95.107 (2)°
V = 323.82 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 100.0 (1) K
0.55 × 0.24 × 0.14 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.935, T_max = 0.982
11592 measured reflections
1591 independent reflections
1343 reflections with I > 2σ(I)
R_int = 0.029

Refinement

R[F² > 2σ(F²)] = 0.074
wR(F²) = 0.251
S = 1.18
1591 reflections
64 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.67 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4D⋯F1Aⁱ	0.96	2.04	2.8515 (18)	141
C4—H4B⋯Cg1ⁱⁱ	0.97	2.84	3.5148 (12)	128
C4—H4C⋯Cg1ⁱⁱ	0.96	2.64	3.5148 (12)	144
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) x, y+1, z. Cg1 is the centroid of the C1–C3/C1A–C3A benzene ring.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809003730/bq2122sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809003730/bq2122Isup2.hkl

checkCIF report

Comment top

As part of an ongoing investigation into compounds with non-linear optical properties (Chantrapromma et al., 2006; Fun et al., 2008; Patil et al., 2007), the crystal structure of the title compound is presented here.

The title compound, (I), lies across a crystallographic inversion centre (Fig. 1). The interesting features of the crystal structure are the short C4A···F1Aⁱ [2.8515 (18)Å; (i) 3/2-x, 1/2+y, 3/2-z] and F1B···F1Bⁱⁱ [2.490 (4)Å; (ii) 1-x, 1-y, 1-z] contacts which are significantly shorter than the sum of the van der Waals radii of these atoms. The fluorine atom and methylene hydrogens are disordered over two positions with a site-occupancy ratio of 0.633 (3):0.367 (3). In the crystal structure, intermolecular C—H···F interactions link neighboring molecules into one-dimensional infinite chains along the b axis (Table 1 and Fig. 2). In addition, C—H···π interactions [C4—H4B···Cg1ⁱⁱⁱ; (iii) x, 1+y, z and C4—H4C···Cg1ⁱⁱⁱ; Cg1 is the centroid of the C1–C3/C1A–C3A benzene ring] link these molecules along the [101] direction, thus forming a two-dimensional network which is parallel to the (101) plane.

Related literature top

For the structures of compounds with non-linear properties, see, for example: Chantrapromma et al. (2006); Fun et al. (2008); Patil et al. (2007). Cg1 is the centroid of the C1–C3/C1A–C3A benzene ring.

Experimental top

Commercially available 1,4-bis(difluoromethyl) benzene was further purified by repeated recrystallization from acetone. Single crystals suitable for X-ray analysis were grown by slow evaporation of an acetone solution at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering. Open bonds indicate the minor disordered component.
	Fig. 2. The crystal packing of the major component of (I), viewed down the a-axis, showing a one-dimensional infinite chain of molecules along the b-axis. Intramolecular and intermolecular interactions are drawn as dashed lines.

1,4-Bis(fluoromethyl)benzene top

Crystal data top

C₈H₈F₂	F(000) = 148
M_r = 143.15	D_x = 1.458 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3653 reflections
a = 6.1886 (2) Å	θ = 2.5–34.7°
b = 5.0152 (2) Å	µ = 0.12 mm⁻¹
c = 10.4750 (4) Å	T = 100 K
β = 95.107 (2)°	Needle, colourless
V = 323.82 (2) Å³	0.55 × 0.24 × 0.14 mm
Z = 2

Data collection top

Bruker APEXII CCD area-detector diffractometer	1591 independent reflections
Radiation source: fine-focus sealed tube	1343 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.029
ϕ and ω scans	θ_max = 36.6°, θ_min = 3.7°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −10→10
T_min = 0.935, T_max = 0.982	k = −7→8
11592 measured reflections	l = −17→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.074	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.251	H atoms treated by a mixture of independent and constrained refinement
S = 1.18	w = 1/[σ²(F_o²) + (0.1441P)² + 0.1329P] where P = (F_o² + 2F_c²)/3
1591 reflections	(Δ/σ)_max < 0.001
64 parameters	Δρ_max = 0.67 e Å⁻³
0 restraints	Δρ_min = −0.59 e Å⁻³

Crystal data top

C₈H₈F₂	V = 323.82 (2) Å³
M_r = 143.15	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 6.1886 (2) Å	µ = 0.12 mm⁻¹
b = 5.0152 (2) Å	T = 100 K
c = 10.4750 (4) Å	0.55 × 0.24 × 0.14 mm
β = 95.107 (2)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	1591 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	1343 reflections with I > 2σ(I)
T_min = 0.935, T_max = 0.982	R_int = 0.029
11592 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.074	0 restraints
wR(F²) = 0.251	H atoms treated by a mixture of independent and constrained refinement
S = 1.18	Δρ_max = 0.67 e Å⁻³
1591 reflections	Δρ_min = −0.59 e Å⁻³
64 parameters

Special details top

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
F1A	0.9163 (2)	0.5267 (3)	0.72717 (12)	0.0219 (3)	0.633 (3)
F1B	0.6221 (4)	0.4849 (5)	0.6008 (3)	0.0260 (6)	0.367 (3)
C4	0.8122 (2)	0.4155 (2)	0.63866 (12)	0.0204 (3)
H4C	0.7640	0.5505	0.5776	0.025*	0.633 (3)
H4D	0.6847	0.3437	0.6718	0.025*	0.633 (3)
H4A	0.8129	0.3600	0.7274	0.025*	0.367 (3)
H4B	0.9052	0.5709	0.6369	0.025*	0.367 (3)
C1	0.7876 (2)	0.0844 (3)	0.46363 (13)	0.0222 (3)
C2	0.9095 (2)	0.1998 (2)	0.56704 (11)	0.0194 (3)
C3	1.1209 (2)	0.1184 (3)	0.60446 (12)	0.0217 (3)
H1	0.620 (4)	0.159 (6)	0.431 (2)	0.037 (6)*
H3	1.207 (4)	0.205 (5)	0.682 (2)	0.026 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1A	0.0227 (6)	0.0216 (6)	0.0215 (6)	0.0012 (4)	0.0030 (4)	−0.0057 (4)
F1B	0.0216 (10)	0.0244 (11)	0.0324 (12)	0.0115 (8)	0.0045 (8)	−0.0018 (8)
C4	0.0224 (5)	0.0170 (5)	0.0227 (5)	0.0024 (4)	0.0064 (4)	0.0013 (4)
C1	0.0204 (5)	0.0220 (5)	0.0243 (5)	0.0030 (4)	0.0023 (4)	0.0001 (4)
C2	0.0208 (5)	0.0176 (5)	0.0204 (5)	0.0020 (3)	0.0048 (4)	0.0013 (4)
C3	0.0207 (5)	0.0217 (6)	0.0226 (5)	0.0016 (4)	0.0007 (4)	−0.0006 (4)

Geometric parameters (Å, º) top

F1A—C4	1.2162 (18)	C4—H4A	0.9699
F1A—H4A	1.0529	C4—H4B	0.9700
F1A—H4B	0.9681	C1—C2	1.3900 (18)
F1B—C4	1.257 (3)	C1—C3ⁱ	1.3916 (19)
F1B—H4C	0.9881	C1—H1	1.13 (3)
F1B—H4D	1.0739	C2—C3	1.3927 (18)
C4—C2	1.4754 (17)	C3—C1ⁱ	1.3916 (19)
C4—H4C	0.9600	C3—H3	1.02 (2)
C4—H4D	0.9600

C4—F1A—H4A	50.0	C2—C4—H4A	108.0
C4—F1A—H4B	51.2	H4C—C4—H4A	144.6
H4A—F1A—H4B	101.2	H4D—C4—H4A	58.7
C4—F1B—H4C	48.9	F1A—C4—H4B	51.1
C4—F1B—H4D	47.9	F1B—C4—H4B	108.2
H4C—F1B—H4D	96.7	C2—C4—H4B	108.0
F1A—C4—F1B	122.09 (16)	H4C—C4—H4B	64.6
F1A—C4—C2	120.74 (12)	H4D—C4—H4B	144.8
F1B—C4—C2	117.11 (16)	H4A—C4—H4B	107.3
F1A—C4—H4C	107.2	C2—C1—C3ⁱ	119.09 (12)
F1B—C4—H4C	50.8	C2—C1—H1	121.3 (14)
C2—C4—H4C	107.2	C3ⁱ—C1—H1	119.6 (14)
F1A—C4—H4D	107.0	C1—C2—C3	121.91 (12)
F1B—C4—H4D	56.0	C1—C2—C4	118.92 (11)
C2—C4—H4D	107.1	C3—C2—C4	119.17 (12)
H4C—C4—H4D	106.8	C1ⁱ—C3—C2	119.00 (12)
F1A—C4—H4A	56.2	C1ⁱ—C3—H3	120.6 (14)
F1B—C4—H4A	107.9	C2—C3—H3	120.4 (14)

C3ⁱ—C1—C2—C3	0.1 (2)	F1A—C4—C2—C3	1.96 (19)
C3ⁱ—C1—C2—C4	179.75 (11)	F1B—C4—C2—C3	179.18 (17)
F1A—C4—C2—C1	−177.73 (13)	C1—C2—C3—C1ⁱ	−0.1 (2)
F1B—C4—C2—C1	−0.5 (2)	C4—C2—C3—C1ⁱ	−179.75 (11)

Symmetry code: (i) −x+2, −y, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4D···F1Aⁱⁱ	0.96	2.04	2.8515 (18)	141
C4—H4B···Cg1ⁱⁱⁱ	0.97	2.84	3.5148 (12)	128
C4—H4C···Cg1ⁱⁱⁱ	0.96	2.64	3.5148 (12)	144

Symmetry codes: (ii) −x+3/2, y−1/2, −z+3/2; (iii) x, y+1, z.

Experimental details

Crystal data
Chemical formula	C₈H₈F₂
M_r	143.15
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	6.1886 (2), 5.0152 (2), 10.4750 (4)
β (°)	95.107 (2)
V (Å³)	323.82 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.55 × 0.24 × 0.14

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.935, 0.982
No. of measured, independent and observed [I > 2σ(I)] reflections	11592, 1591, 1343
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.839

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.074, 0.251, 1.18
No. of reflections	1591
No. of parameters	64
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.67, −0.59

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4D···F1Aⁱ	0.9600	2.04	2.8515 (18)	141
C4—H4B···Cg1ⁱⁱ	0.9700	2.84	3.5148 (12)	128
C4—H4C···Cg1ⁱⁱ	0.9600	2.64	3.5148 (12)	144

Symmetry codes: (i) −x+3/2, y−1/2, −z+3/2; (ii) x, y+1, z.

Footnotes

‡Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574 199, India.

Acknowledgements

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. RK thanks Universiti Sains Malaysia for a post-doctoral research fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

References

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