2,4-Di­chloro-1-iodo-6-nitro­benzene

In the crystal structure of the title compound, C₆H₂Cl₂INO₂, there are weak C—H⋯Cl inter­actions and I⋯O [3.387 (4) Å] close contacts. These inter­actions form sheets in the ac plane, with the closest contact between adjacent planes occurring between inversion-related nitro O atoms [3.025 (8) Å]. The molecule possesses mirror symmetry, with the halogen, N and C atoms all lying in the mirror plane. Hence, the dihedral angle between the benzene ring and the nitro group is 90°.

Related literature

For crystal structures of similar substituted nitro­benzenes, see: Li et al. (2012); Tahir et al. (2009). For information about polychlorinated bi­phenyls (PCBs) and their synthesis, see: Joshi et al. (2011); Lehmler et al. (2010); Lehmler & Robertson (2001). For the synthesis of the title compound, see: Sohn et al. (2003).

Experimental

Crystal data

• C₆H₂Cl₂INO₂

• M_r = 317.89

• Orthorhombic, P n m a

• a = 8.7760 (5) Å

• b = 6.8989 (4) Å

• c = 14.3518 (8) Å

• V = 868.93 (9) ų

• Z = 4

• Cu Kα radiation

• μ = 34.30 mm⁻¹

• T = 90 K

• 0.13 × 0.10 × 0.04 mm

Data collection

• Bruker X8 Proteum diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2008b) T_min = 0.052, T_max = 0.216

• 9625 measured reflections

• 862 independent reflections

• 827 reflections with I > 2σ(I)

• R_int = 0.082

Refinement

• R[F² > 2σ(F²)] = 0.037

• wR(F²) = 0.098

• S = 1.12

• 862 reflections

• 71 parameters

• H-atom parameters constrained

• Δρ_max = 0.67 e Å⁻³

• Δρ_min = −0.68 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯Cl2^i	0.95	2.77	3.718 (7)	179
Symmetry code: (i) .

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008a); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008a); molecular graphics: XP in SHELXTL (Sheldrick, 2008a); software used to prepare material for publication: SHELXTL and CIFFIX (Parkin, 2013).

Supporting information

S1. Comment

The title compound was synthesized as a precursor for the preparation of chiral polychlorinated biphenyl (PCB) derivatives (Lehmler et al., 2010) using the Suzuki-coupling reaction (Joshi et al., 2011; Lehmler & Robertson, 2001). There are C3—H3···Cl2 (x - 0.5, y, 0.5 - z) interactions [C3···Cl2 = 3.718 (7) Å] that link the molecules into flat ribbons along the a axis. Between adjacent ribbons there are close contacts between iodine atoms and the nitro group O atoms, with I···O distances of 3.387 (4) Å. Each iodine atom is the same distance from both oxygen atoms because they are equivalent by virtue of the mirror plane. The linking of adjacent ribbons in the crystal structure give sheets in the ac plane (since the mirror plane is perpendicular to b). The closest contact between adjacent planes occurs between inversion (1 - x, 1 - y, 1 - z) related nitro O atoms [3.025 (8) Å]. The distance between layers is simply half the b axis length. Viewed along the b axis, molecules appear to stack in an alternating fashion about a 2₁ screw (-x, 0.5 + y,-z), which places Cl1 of one molecule directly over the benzene ring of its screw-related counterpart.

As a result of the symmetrical interaction between the iodines and both nitro group O atoms, the molecular structure of the title compound displayed a 90° dihedral angle between the plane of the nitro group and the plane of the benzene ring (which lies on the mirror plane). Only a few solid state structures of structurally related molecules with a 1-iodo-2-nitrobenzene moiety have been reported previously. The molecular structures of 4-chloro-1-iodo-2-nitrobenzene, a structurally related halogenated nitrobenzene with one iodo substituent ortho to the nitro group, display smaller dihedral angles between benzene ring and nitro group [51.0 (3)° and 29.0 (2)°] in the solid state (Tahir et al., 2009). In contrast, 2,4-diiodo-3-nitroanisole, a nitrobenzene with two iodo substituents ortho to the nitro group, displayed dihedral angle of 88.0 (3)° (Li et al., 2012), probably due to the steric demand of the two ortho iodo substituents. These differences demonstrate that packing effects can make significant contributions to the molecular structure (i.e. the dihedral angle between benzene ring and nitro group) in the solid state.

Related literature

For similar crystal structures of substituted nitrobenzenes, see: Li et al. (2012); Tahir et al. (2009). For information about polychlorinated biphenyls (PCBs) and their synthesis, see: Joshi et al. (2011); Lehmler et al. (2010); Lehmler & Robertson (2001). For the synthesis of the title compound, see: Sohn et al. (2003).

S2. Experimental

The title compound was synthesized from 2,4-dichloro-6-nitroaniline by sequential diazotization and iodonization with NaNO₂–HCl–KI system (Sohn et al., 2003). Crystals of the title compound suitable for crystal structure analysis were obtained by slow evaporation of a solution of the title compound in hexane-ethyl acetate (10:1).

S3. Refinement

H atoms were found in difference Fourier maps, but subsequently included in the refinement using riding models, with constrained distances set to 0.95Å (C_sp2H). U_iso(H) values were set to 1.2U_eq of the attached atom.

Computing details

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008a); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008a); molecular graphics: XP in SHELXTL (Sheldrick, 2008a); software used to prepare material for publication: SHELXTL (Sheldrick, 2008a) and CIFFIX (Parkin, 2013).

Figures

Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level. Symmetry code: (A) x, -y+1/2, z.

2,4-Dichloro-1-iodo-6-nitrobenzene

Crystal data

C6H2Cl2INO2	Dx = 2.430 Mg m^−3
Mr = 317.89	Cu Kα radiation, λ = 1.54178 Å
Orthorhombic, Pnma	Cell parameters from 6956 reflections
a = 8.7760 (5) Å	θ = 5.9–67.7°
b = 6.8989 (4) Å	µ = 34.30 mm^−1
c = 14.3518 (8) Å	T = 90 K
V = 868.93 (9) Å^3	Rounded block, pale yellow
Z = 4	0.13 × 0.10 × 0.04 mm
F(000) = 592

Data collection

Bruker X8 Proteum diffractometer	862 independent reflections
Radiation source: fine-focus rotating anode	827 reflections with I > 2σ(I)
Detector resolution: 5.6 pixels mm^-1	Rint = 0.082
ϕ and ω scans	θmax = 68.0°, θmin = 5.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008b)	h = −10→7
Tmin = 0.052, Tmax = 0.216	k = −8→8
9625 measured reflections	l = −13→17

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	H-atom parameters constrained
wR(F^2) = 0.098	w = 1/[σ^2(Fo^2) + (0.0668P)^2 + 0.2013P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max = 0.001
862 reflections	Δρmax = 0.67 e Å^−3
71 parameters	Δρmin = −0.68 e Å^−3
0 restraints	Extinction correction: SHELXL2013 (Sheldrick, 2008a), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0021 (4)

Special details

Experimental. Diffraction data were collected with the crystal at 90 K, which is standard practice in this laboratory for the majority of flash-cooled crystals.

A correction for radiation damage was included in the SADABS (Sheldrick, 2008b) run. This seems to have resulted in all the atomic displacement parameter ellipsoids looking more spherical than usual.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
I1	0.10397 (4)	0.2500	0.70325 (2)	0.0776 (3)
Cl1	−0.18714 (15)	0.2500	0.54761 (10)	0.0783 (4)
Cl2	0.16156 (18)	0.2500	0.24439 (10)	0.0807 (4)
N1	0.4037 (5)	0.2500	0.5700 (4)	0.0797 (14)
O1	0.4576 (4)	0.4066 (6)	0.5918 (2)	0.0946 (9)
C1	0.1230 (7)	0.2500	0.5590 (5)	0.0739 (13)
C2	−0.0053 (7)	0.2500	0.5003 (5)	0.0753 (13)
C3	0.0065 (7)	0.2500	0.4060 (4)	0.0754 (13)
H3	−0.0828	0.2500	0.3686	0.090*
C4	0.1510 (8)	0.2500	0.3637 (5)	0.0740 (13)
C5	0.2811 (7)	0.2500	0.4179 (5)	0.0765 (13)
H5	0.3796	0.2500	0.3904	0.092*
C6	0.2624 (7)	0.2500	0.5133 (4)	0.0757 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0812 (4)	0.0798 (4)	0.0718 (4)	0.000	0.00182 (13)	0.000
Cl1	0.0753 (8)	0.0786 (8)	0.0810 (8)	0.000	0.0026 (6)	0.000
Cl2	0.0828 (9)	0.0878 (9)	0.0715 (8)	0.000	0.0000 (6)	0.000
N1	0.079 (3)	0.091 (4)	0.070 (3)	0.000	0.003 (2)	0.000
O1	0.0929 (19)	0.097 (2)	0.0936 (18)	−0.0143 (17)	−0.0113 (16)	−0.0056 (17)
C1	0.081 (3)	0.071 (3)	0.069 (3)	0.000	−0.001 (2)	0.000
C2	0.074 (3)	0.067 (3)	0.084 (3)	0.000	0.002 (3)	0.000
C3	0.084 (3)	0.065 (3)	0.077 (3)	0.000	−0.004 (3)	0.000
C4	0.079 (3)	0.069 (3)	0.074 (3)	0.000	−0.004 (3)	0.000
C5	0.076 (3)	0.073 (3)	0.081 (3)	0.000	0.005 (3)	0.000
C6	0.076 (3)	0.073 (3)	0.078 (3)	0.000	−0.003 (3)	0.000

Geometric parameters (Å, º)

I1—C1	2.077 (7)	C1—C2	1.406 (9)
Cl1—C2	1.734 (7)	C2—C3	1.358 (9)
Cl2—C4	1.715 (7)	C3—C4	1.406 (10)
N1—O1	1.220 (4)	C3—H3	0.9500
N1—O1^i	1.220 (4)	C4—C5	1.381 (9)
N1—C6	1.484 (8)	C5—C6	1.379 (9)
C1—C6	1.388 (9)	C5—H5	0.9500
O1—N1—O1^i	124.6 (6)	C4—C3—H3	120.0
O1—N1—C6	117.7 (3)	C5—C4—C3	120.2 (6)
O1^i—N1—C6	117.7 (3)	C5—C4—Cl2	121.1 (5)
C6—C1—C2	114.9 (6)	C3—C4—Cl2	118.7 (5)
C6—C1—I1	122.9 (5)	C6—C5—C4	117.4 (6)
C2—C1—I1	122.2 (5)	C6—C5—H5	121.3
C3—C2—C1	122.4 (6)	C4—C5—H5	121.3
C3—C2—Cl1	117.4 (5)	C5—C6—C1	125.1 (6)
C1—C2—Cl1	120.2 (5)	C5—C6—N1	116.5 (5)
C2—C3—C4	119.9 (6)	C1—C6—N1	118.4 (5)
C2—C3—H3	120.0
C6—C1—C2—C3	0.000 (2)	C4—C5—C6—C1	0.000 (2)
I1—C1—C2—C3	180.000 (1)	C4—C5—C6—N1	180.000 (1)
C6—C1—C2—Cl1	180.000 (1)	C2—C1—C6—C5	0.000 (2)
I1—C1—C2—Cl1	0.000 (1)	I1—C1—C6—C5	180.000 (1)
C1—C2—C3—C4	0.000 (2)	C2—C1—C6—N1	180.000 (1)
Cl1—C2—C3—C4	180.000 (1)	I1—C1—C6—N1	0.000 (2)
C2—C3—C4—C5	0.000 (2)	O1—N1—C6—C5	90.0 (5)
C2—C3—C4—Cl2	180.000 (1)	O1^i—N1—C6—C5	−90.0 (5)
C3—C4—C5—C6	0.000 (1)	O1—N1—C6—C1	−90.0 (5)
Cl2—C4—C5—C6	180.000 (1)	O1^i—N1—C6—C1	90.0 (5)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···Cl2^ii	0.95	2.77	3.718 (7)	179

Symmetry code: (ii) x−1/2, y, −z+1/2.