2,6-Di­chloro-4-nitro­toluene

Medjroubi, M.L.; Boudjada, A.; Hamdouni, N.; Jeannin, O.; Meinnel, J.

doi:10.1107/S2414314617006721

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 5| May 2017| x170672

https://doi.org/10.1107/S2414314617006721

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2,6-Dichloro-4-nitrotoluene

Mohamed Larbi Medjroubi,^a ^* Ali Boudjada,^a Noudjoud Hamdouni,^a Olivier Jeannin ^b and Jean Meinnel ^b

^aLaboratoire de Cristallographie, Département de Physique, Université Mentouri-Constantine, 25000 Constantine, Algeria, and ^bUMR 6226 CNRS–Université Rennes 1 `Sciences Chimiques de Rennes', Equipe `Matière Condensée et Systèmes Electroactifs', Bâtiment 10C, Campus de Beaulieu, 263 Avenue du Général Leclerc, F-35042 Rennes, France
^*Correspondence e-mail: mlmedj@gmail.com

Edited by A. J. Lough, University of Toronto, Canada (Received 4 April 2017; accepted 4 May 2017; online 9 May 2017)

The title compound, C₇H₅Cl₂NO₂ [systematic name: 1,3-dichloro-2-methyl-5-nitrobenzene], crystallizes in the chiral space group P2₁2₁2₁ with a Flack parameter of −0.03 (5). The methyl C atom, the Cl atoms and the N atom of the nitro substituent all lie extremely close to the plane of the benzene ring; the deviations are 0.028 (3) Å for the methyl C atom, −0.016 (1) and 0.007 (1) Å for the two Cl atoms, and −0.017 (3) Å for the nitro N atom. Hence, no significant steric hindrance of the methyl group by the ortho halogen atoms is observed. The nitro group is inclined to the benzene ring by 9.8 (3)°. In the crystal, molecules are linked by weak C—H⋯O and C—H⋯Cl hydrogen bonds, forming layers parallel to the ab plane.

Keywords: crystal structure; dichloronitrotoluene; hydrogen bonding.

CCDC reference: 1547823

Structure description

Our group is interested in understanding the methyl radical behaviour of benzene molecules substituted by halogen and methyl substituents. Studies first focused on various mesityl halogens (Boudjada et al., 2001 ; Tazi et al., 1995 ; Hernandez et al., 2003 ) to be extended thereafter to other products. In order to better identify the behaviour of the methyl group, a study of dihalogen-nitrotoluene molecules has been undertaken. The crystal structure of the dibromo analogue (DBNT) of the title compound (DCNT) was reported on recently by our group (Medjroubi et al., 2016 ).

The molecular structure of the title compound is shown in Fig. 1. In the crystal structure of DBNT, there are two independent molecules per asymmetric unit and the methyl group H atoms are positionally disordered. For the title compound, DCNT, there is only one molecule per asymmetric unit and no disorder is observed for the methyl group H atoms. The dibromo analogue crystallizes in the centrosymmetric triclinic space group P $[\overline{1}]$ , while the title dichloro analogue crystallizes in the chiral orthorhombic space group P2₁2₁2₁ [Flack parameter of −0.03 (5)].

Figure 1
The molecular structure of the title compound, with the atom labelling and displacement ellipsoids drawn at the 50% probability level.

In the DCNT molecule, the methyl C atom, the Cl atoms and the N atom of the nitro substituent all lie extremely close to the plane of the benzene ring: deviations are 0.028 (3) Å for C7, −0.016 (1) Å for Cl21, 0.007 (1) Å for Cl61 and −0.017 (3) Å for N4. Hence, no significant steric hindrance of the methyl group by the ortho halogen atoms is observed. The nitro group N4/O41/O42 is inclined to the benzene ring by 9.8 (3)°, compared with 2.5 (5) and 5.9 (4) ° in DBNT.

In the crystal, molecules are linked by weak C—H⋯O and C—H⋯Cl hydrogen bonds forming layers parallel to the ab plane (Table 1 and Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O42ⁱ	0.95	2.47	3.389 (3)	163
C5—H5⋯Cl61ⁱⁱ	0.95	2.94	3.862 (3)	163
Symmetry codes: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ ; (ii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ .

Figure 2
A view along the c axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1

) and the two H atoms involved in hydrogen bonding are shown as grey balls.

Synthesis and crystallization

The commercially available title compound (DCNT; Sigma–Aldrich) was recrystallized from an ethanol solution. Colourless needle-shaped single crystals several mm in length and having a section of a few hundredths of a mm² were obtained. Examination of the crystals using polarized light and X-ray diffraction revealed that they are generally twinned and consequently it was necessary to examine a large number of crystals to find a suitable single-crystal for the present X-ray diffraction study.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₇H₅Cl₂NO₂
M_r	206.02
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	150
a, b, c (Å)	3.8145 (3), 12.4829 (10), 17.4438 (15)
V (Å³)	830.60 (12)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.73
Crystal size (mm)	0.26 × 0.15 × 0.05

Data collection
Diffractometer	Bruker APEXII
Absorption correction	Multi-scan
T_min, T_max	0.876, 0.964
No. of measured, independent and observed [I > 2σ(I)] reflections	4472, 1879, 1756
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.651

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.066, 1.07
No. of reflections	1879
No. of parameters	110
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.20
Absolute structure	Flack x determined using 640 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	−0.03 (5)
Computer programs: APEX2 and SAINT (Bruker, 2006 ), SIR2003 (Burla et al., 2005 ), SHELXL2013 (Sheldrick, 2015 ), CAMERON (Watkin et al., 1996 ). Mercury (Macrae et al., 2008 ), WinGX (Farrugia, 2012 ) and PLATON (Spek, 2009 ).

Structural data

CCDC reference: 1547823

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314617006721/lh4019sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617006721/lh4019Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314617006721/lh4019Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SIR2003 (Burla et al., 2005); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015); molecular graphics: CAMERON (Watkin et al., 1996) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

1,3-Dichloro-2-methyl-5-nitrobenzene top

Crystal data top

C₇H₅Cl₂NO₂	D_x = 1.647 Mg m⁻³
M_r = 206.02	Mo Kα radiation, λ = 0.7107 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 2377 reflections
a = 3.8145 (3) Å	θ = 2.9–27.3°
b = 12.4829 (10) Å	µ = 0.73 mm⁻¹
c = 17.4438 (15) Å	T = 150 K
V = 830.60 (12) Å³	Needle, colourless
Z = 4	0.26 × 0.15 × 0.05 mm
F(000) = 416

Data collection top

Bruker APEXII diffractometer	1756 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.028
CCD rotation images, thin slices scans	θ_max = 27.6°, θ_min = 2.9°
Absorption correction: multi-scan	h = −3→4
T_min = 0.876, T_max = 0.964	k = −16→15
4472 measured reflections	l = −19→22
1879 independent reflections

Refinement top

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)] = 0.030	H-atom parameters constrained
wR(F²) = 0.066	w = 1/[σ²(F_o²) + (0.0243P)² + 0.1882P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max = 0.001
1879 reflections	Δρ_max = 0.23 e Å⁻³
110 parameters	Δρ_min = −0.20 e Å⁻³
0 restraints	Absolute structure: Flack x determined using 640 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (5)

Special details top

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. Reflections were merged by SHELXL according to the crystal class for the calculation of statistics and refinement.

_reflns_Friedel_fraction is defined as the number of unique Friedel pairs measured divided by the number that would be possible theoretically, ignoring centric projections and systematic absences.

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

	x	y	z	U_iso*/U_eq
Cl21	0.9157 (2)	0.39246 (5)	0.72626 (4)	0.0367 (2)
Cl61	0.36788 (19)	0.75690 (4)	0.60731 (4)	0.03019 (17)
O41	0.3055 (7)	0.4621 (2)	0.40010 (12)	0.0573 (7)
O42	0.6101 (8)	0.32613 (16)	0.43872 (12)	0.0550 (7)
N4	0.4803 (7)	0.41449 (19)	0.44804 (14)	0.0377 (6)
C1	0.6402 (7)	0.57082 (18)	0.66257 (13)	0.0192 (5)
C2	0.7342 (7)	0.46378 (18)	0.65064 (14)	0.0225 (5)
C3	0.6879 (7)	0.41103 (18)	0.58177 (15)	0.0256 (6)
H3	0.7561	0.3384	0.5755	0.031*
C4	0.5384 (7)	0.4682 (2)	0.52239 (14)	0.0248 (6)
C5	0.4406 (7)	0.57402 (19)	0.52939 (14)	0.0226 (5)
H5	0.3402	0.6119	0.4875	0.027*
C6	0.4937 (6)	0.62324 (17)	0.59953 (14)	0.0195 (5)
C7	0.6911 (7)	0.6243 (2)	0.73951 (14)	0.0285 (6)
H7A	0.6030	0.6980	0.7371	0.043*
H7B	0.9411	0.6252	0.7524	0.043*
H7C	0.5621	0.5845	0.7789	0.043*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl21	0.0325 (4)	0.0369 (3)	0.0408 (4)	0.0052 (3)	−0.0004 (3)	0.0215 (3)
Cl61	0.0322 (4)	0.0211 (3)	0.0372 (3)	0.0057 (3)	0.0049 (3)	0.0043 (2)
O41	0.0589 (17)	0.0823 (17)	0.0307 (11)	−0.0038 (15)	−0.0097 (12)	−0.0140 (11)
O42	0.0769 (18)	0.0380 (11)	0.0502 (13)	−0.0141 (14)	0.0164 (15)	−0.0218 (10)
N4	0.0402 (16)	0.0421 (14)	0.0308 (13)	−0.0149 (12)	0.0094 (12)	−0.0116 (11)
C1	0.0140 (12)	0.0228 (10)	0.0208 (10)	−0.0033 (10)	0.0023 (11)	0.0020 (8)
C2	0.0174 (13)	0.0235 (11)	0.0264 (12)	−0.0010 (10)	0.0024 (11)	0.0093 (10)
C3	0.0220 (14)	0.0182 (11)	0.0366 (13)	−0.0021 (11)	0.0089 (12)	0.0016 (10)
C4	0.0237 (14)	0.0278 (12)	0.0229 (12)	−0.0085 (11)	0.0066 (11)	−0.0043 (10)
C5	0.0173 (13)	0.0305 (12)	0.0200 (11)	−0.0027 (11)	0.0010 (11)	0.0061 (9)
C6	0.0154 (12)	0.0170 (10)	0.0261 (12)	−0.0013 (9)	0.0065 (10)	0.0030 (9)
C7	0.0252 (14)	0.0370 (14)	0.0232 (12)	−0.0024 (12)	0.0000 (11)	0.0001 (10)

Geometric parameters (Å, º) top

Cl21—C2	1.735 (2)	C3—C4	1.381 (4)
Cl61—C6	1.741 (2)	C3—H3	0.9500
O41—N4	1.224 (3)	C4—C5	1.378 (3)
O42—N4	1.220 (3)	C5—C6	1.384 (3)
N4—C4	1.477 (3)	C5—H5	0.9500
C1—C6	1.396 (3)	C7—H7A	0.9800
C1—C2	1.399 (3)	C7—H7B	0.9800
C1—C7	1.512 (3)	C7—H7C	0.9800
C2—C3	1.381 (3)

O42—N4—O41	124.7 (2)	C3—C4—N4	119.0 (2)
O42—N4—C4	117.8 (3)	C4—C5—C6	117.7 (2)
O41—N4—C4	117.5 (2)	C4—C5—H5	121.2
C6—C1—C2	115.7 (2)	C6—C5—H5	121.2
C6—C1—C7	122.9 (2)	C5—C6—C1	123.1 (2)
C2—C1—C7	121.4 (2)	C5—C6—Cl61	116.99 (18)
C3—C2—C1	123.5 (2)	C1—C6—Cl61	119.87 (18)
C3—C2—Cl21	117.87 (18)	C1—C7—H7A	109.5
C1—C2—Cl21	118.63 (19)	C1—C7—H7B	109.5
C2—C3—C4	117.3 (2)	H7A—C7—H7B	109.5
C2—C3—H3	121.4	C1—C7—H7C	109.5
C4—C3—H3	121.4	H7A—C7—H7C	109.5
C5—C4—C3	122.7 (2)	H7B—C7—H7C	109.5
C5—C4—N4	118.2 (2)

C6—C1—C2—C3	−0.1 (4)	O42—N4—C4—C3	−9.8 (4)
C7—C1—C2—C3	179.0 (3)	O41—N4—C4—C3	170.3 (3)
C6—C1—C2—Cl21	−179.59 (19)	C3—C4—C5—C6	−0.6 (4)
C7—C1—C2—Cl21	−0.5 (3)	N4—C4—C5—C6	179.5 (2)
C1—C2—C3—C4	−0.4 (4)	C4—C5—C6—C1	0.0 (4)
Cl21—C2—C3—C4	179.05 (19)	C4—C5—C6—Cl61	−179.92 (19)
C2—C3—C4—C5	0.8 (4)	C2—C1—C6—C5	0.3 (4)
C2—C3—C4—N4	−179.3 (2)	C7—C1—C6—C5	−178.8 (2)
O42—N4—C4—C5	170.1 (3)	C2—C1—C6—Cl61	−179.73 (18)
O41—N4—C4—C5	−9.8 (4)	C7—C1—C6—Cl61	1.2 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O42ⁱ	0.95	2.47	3.389 (3)	163
C5—H5···Cl61ⁱⁱ	0.95	2.94	3.862 (3)	163

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

Acknowledgements

We would like to thank the Centre de diffractométrie de l'Université de Rennes 1 for the opportunity to collect the X-ray diffraction data.

References

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