2,4-Diiodo­aniline

Smith, G.; Wermuth, U.D.

doi:10.1107/S1600536809030438

organic compounds

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ISSN: 2056-9890

Volume 65| Part 9| September 2009| Page o2108

doi:10.1107/S1600536809030438

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2,4-Diiodoaniline

Graham Smith ^a ^* and Urs D. Wermuth ^a

^aSchool of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Qld 4001, Australia
^*Correspondence e-mail: g.smith@qut.edu.au

(Received 14 July 2009; accepted 31 July 2009; online 8 August 2009)

The structure of the title compound, C₆H₅I₂N, shows a weak intermolecular amine–amine N—H⋯N hydrogen-bonding interaction, giving a helical chain which extends along the a axis. An intramolecular N—H⋯I hydrogen bond is also observed.

Related literature

For related structures, see: Garden et al. (2002 ). For the synthesis, see: Dains et al. (1935 ); Hodgson & Marsden (1937 ); O'Neil (2001 ). For graph-set analysis of hydrogen bonding, see: Etter et al. (1990 ).

Experimental

Crystal data

C₆H₅I₂N
M_r = 344.91
Orthorhombic, P 2₁ 2₁ 2₁
a = 4.3870 (1) Å
b = 10.9626 (3) Å
c = 16.9778 (4) Å
V = 816.51 (3) Å³
Z = 4
Mo Kα radiation
μ = 7.62 mm⁻¹
T = 200 K
0.30 × 0.18 × 0.18 mm

Data collection

Oxford Diffraction Gemini-S Ultra CCD-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.146, T_max = 0.250
6739 measured reflections
1873 independent reflections
1790 reflections with I > 2σ(I)
R_int = 0.024

Refinement

R[F² > 2σ(F²)] = 0.018
wR(F²) = 0.038
S = 1.05
1873 reflections
90 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.47 e Å⁻³
Absolute structure: Flack (1983 ), 737 Friedel pairs
Flack parameter: −0.03 (4)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H11⋯I2	0.77 (3)	2.81 (3)	3.283 (4)	122 (3)
N1—H12⋯N1ⁱ	0.80 (4)	2.30 (4)	3.106 (5)	180 (5)
Symmetry code: (i) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+2]$ .

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 $[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 $[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ) within WinGX (Farrugia, 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999); molecular graphics: PLATON (Spek, 2009 ); software used to prepare material for publication: PLATON.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809030438/is2440sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809030438/is2440Isup2.hkl

checkCIF report

Comment top

Although the crystal structures of a number of nitro-substituted iodoanilines including 3-nitro-2,4-diodoaniline have been reported (Garden et al., 2002), that of the title compound 2,4-diiodoaniline C₆H₆I₂N (I) has not been determined and the structure is reported here. The compound was isolated as the major crystalline product in the attempted synthesis of an adduct of 4,5-dichlorophthalic acid with 4-iodoaniline in aqueous ethanol. This conversion of 4-iodoaniline to 2,4-diiodoaniline has been reported previously (Dains et al., 1935), where solid 4-iodoaniline was observed to undergo a ca 25% conversion to the diiodo analogue in a sealed container over a period of three years. Hodgson & Marsden (1937) also reported the ready formation of the diiodo derivative along with 4-iodoaniline from the reaction of aniline with iodine.

In the structure of (I) (Fig. 1), single weak intermolecular hydrogen bonds are found [N1—H1···N1ⁱ, 3.106 (5) Å; symmetry code: (i) x - 1/2, -y + 3/2, -z + 2] [graph set S(4) (Etter et al., 1990)], linking the amine groups of 2₁ screw-related molecules. These form one-dimensional chains which extend down the a cell direction in the unit cell (Fig. 2).

In this structure there are, not unexpectedly, short intramoleculer N—H···I interactions [N1···I2, 3.283 (4) Å], which are also present in the structure of 2,4-diiodo-3-nitroaniline [3.254 (7) Å (Garden et al., 2002)]. However, unlike the nitro-derivative, no π–π stacking interactions are present in the structure of (I).

Related literature top

For related structures, see: Garden et al. (2002). For the synthesis, see: Dains et al. (1935); Hodgson & Marsden (1937); O'Neil (2001). For graph-set analysis of hydrogen bonding, see: Etter et al. (1990).

Experimental top

The title compound was formed in the attempted synthesis of a proton-transfer salt of 4,5-dichlorophthalic acid with 4-iodoaniline by heating together under reflux for 10 minutes 1 mmol quantities of the two reagents in 50 ml of 50% ethanol-water. After concentration to ca 30 ml, partial room temperature evaporation of the hot-filtered solution gave colourless needle prisms of 2,4-diiodoaniline [m.p. 368–389 K (O'Neil, 2001)] as the major product. This conversion of 4-iodoaniline to 2,4-diiodoaniline in the solid state has been reported previously (Dains et al., 1935).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) within WinGX (Farrugia, 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).

Figures top

	Fig. 1. Molecular configuration and atom naming scheme for (I). Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. The one-dimensional hydrogen-bonded chain structure of (I) extending down the a axial direction of the unit cell, showing hydrogen-bonding associations as dashed lines. Non-interactive H atoms are omitted. [Symmetry code (i): x - 1/2, -y + 3/2, -z + 2].

2,4-Diiodoaniline top

Crystal data top

C₆H₅I₂N	D_x = 2.806 Mg m⁻³
M_r = 344.91	Melting point = 368–369 K
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 5620 reflections
a = 4.3870 (1) Å	θ = 3.0–32.2°
b = 10.9626 (3) Å	µ = 7.62 mm⁻¹
c = 16.9778 (4) Å	T = 200 K
V = 816.51 (3) Å³	Needle, colourless
Z = 4	0.30 × 0.18 × 0.18 mm
F(000) = 616

Data collection top

Oxford Diffraction Gemini-S Ultra CCD-detector diffractometer	1873 independent reflections
Radiation source: Enhance (Mo) X-ray tube	1790 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.024
ω scans	θ_max = 27.5°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→5
T_min = 0.146, T_max = 0.250	k = −13→14
6739 measured reflections	l = −22→18

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)] = 0.018	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.038	w = 1/[σ²(F_o²) + (0.0207P)²] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max = 0.003
1873 reflections	Δρ_max = 0.38 e Å⁻³
90 parameters	Δρ_min = −0.47 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 737 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (4)

Crystal data top

C₆H₅I₂N	V = 816.51 (3) Å³
M_r = 344.91	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 4.3870 (1) Å	µ = 7.62 mm⁻¹
b = 10.9626 (3) Å	T = 200 K
c = 16.9778 (4) Å	0.30 × 0.18 × 0.18 mm

Data collection top

Oxford Diffraction Gemini-S Ultra CCD-detector diffractometer	1873 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1790 reflections with I > 2σ(I)
T_min = 0.146, T_max = 0.250	R_int = 0.024
6739 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.018	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.038	Δρ_max = 0.38 e Å⁻³
S = 1.05	Δρ_min = −0.47 e Å⁻³
1873 reflections	Absolute structure: Flack (1983), 737 Friedel pairs
90 parameters	Absolute structure parameter: −0.03 (4)
0 restraints

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
I2	0.57888 (5)	0.42657 (2)	1.08868 (1)	0.0293 (1)
I4	0.48489 (5)	0.28546 (2)	0.75021 (1)	0.0330 (1)
N1	0.1721 (9)	0.6552 (3)	1.0212 (2)	0.0291 (11)
C1	0.2299 (7)	0.5690 (3)	0.9630 (2)	0.0218 (9)
C2	0.4096 (8)	0.4658 (3)	0.97570 (19)	0.0221 (9)
C3	0.4807 (8)	0.3859 (3)	0.9156 (2)	0.0247 (9)
C4	0.3689 (8)	0.4074 (3)	0.8407 (2)	0.0235 (10)
C5	0.1876 (8)	0.5075 (3)	0.8256 (2)	0.0260 (11)
C6	0.1216 (9)	0.5877 (3)	0.8865 (2)	0.0278 (11)
H3	0.60280	0.31820	0.92530	0.0300*
H5	0.11070	0.52100	0.77530	0.0310*
H6	0.00190	0.65580	0.87610	0.0330*
H11	0.190 (8)	0.626 (3)	1.062 (2)	0.038 (9)*
H12	0.043 (8)	0.704 (4)	1.010 (2)	0.040 (9)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I2	0.0335 (1)	0.0341 (1)	0.0202 (1)	0.0009 (1)	−0.0038 (1)	0.0021 (1)
I4	0.0383 (1)	0.0389 (1)	0.0219 (1)	0.0022 (1)	0.0017 (1)	−0.0069 (1)
N1	0.037 (2)	0.0222 (16)	0.028 (2)	0.0055 (15)	−0.0021 (16)	0.0013 (15)
C1	0.0214 (15)	0.0191 (16)	0.0248 (18)	−0.0039 (15)	0.0014 (14)	0.0021 (14)
C2	0.0251 (16)	0.0226 (16)	0.0186 (17)	−0.0034 (15)	−0.0009 (14)	0.0032 (11)
C3	0.0289 (18)	0.0218 (14)	0.0234 (17)	−0.0007 (11)	−0.0010 (16)	0.0015 (12)
C4	0.0252 (17)	0.0226 (18)	0.0228 (18)	−0.0031 (13)	0.0028 (14)	−0.0029 (13)
C5	0.027 (2)	0.0313 (19)	0.0197 (19)	−0.0028 (14)	−0.0018 (15)	0.0044 (14)
C6	0.0323 (19)	0.0236 (18)	0.0276 (19)	0.0028 (15)	0.0007 (15)	0.0051 (13)

Geometric parameters (Å, º) top

I2—C2	2.101 (3)	C2—C3	1.381 (5)
I4—C4	2.099 (3)	C3—C4	1.383 (5)
N1—C1	1.391 (5)	C4—C5	1.379 (5)
N1—H12	0.80 (4)	C5—C6	1.388 (5)
N1—H11	0.77 (3)	C3—H3	0.9300
C1—C6	1.398 (5)	C5—H5	0.9300
C1—C2	1.396 (5)	C6—H6	0.9300

H11—N1—H12	124 (4)	I4—C4—C3	118.6 (2)
C1—N1—H11	110 (3)	C3—C4—C5	120.7 (3)
C1—N1—H12	114 (3)	C4—C5—C6	119.1 (3)
N1—C1—C6	119.9 (3)	C1—C6—C5	121.9 (3)
N1—C1—C2	123.0 (3)	C2—C3—H3	120.00
C2—C1—C6	117.0 (3)	C4—C3—H3	120.00
I2—C2—C1	120.4 (2)	C4—C5—H5	120.00
I2—C2—C3	117.7 (2)	C6—C5—H5	121.00
C1—C2—C3	121.9 (3)	C1—C6—H6	119.00
C2—C3—C4	119.4 (3)	C5—C6—H6	119.00
I4—C4—C5	120.7 (2)

N1—C1—C2—I2	5.0 (5)	C1—C2—C3—C4	−0.7 (5)
N1—C1—C2—C3	−175.5 (3)	C2—C3—C4—I4	179.3 (3)
C6—C1—C2—I2	−178.9 (2)	C2—C3—C4—C5	0.0 (5)
C6—C1—C2—C3	0.6 (5)	I4—C4—C5—C6	−178.5 (3)
N1—C1—C6—C5	176.5 (3)	C3—C4—C5—C6	0.9 (5)
C2—C1—C6—C5	0.3 (5)	C4—C5—C6—C1	−1.0 (5)
I2—C2—C3—C4	178.8 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11···I2	0.77 (3)	2.81 (3)	3.283 (4)	122 (3)
N1—H12···N1ⁱ	0.80 (4)	2.30 (4)	3.106 (5)	180 (5)

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

Experimental details

Crystal data
Chemical formula	C₆H₅I₂N
M_r	344.91
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	200
a, b, c (Å)	4.3870 (1), 10.9626 (3), 16.9778 (4)
V (Å³)	816.51 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	7.62
Crystal size (mm)	0.30 × 0.18 × 0.18

Data collection
Diffractometer	Oxford Diffraction Gemini-S Ultra CCD-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.146, 0.250
No. of measured, independent and observed [I > 2σ(I)] reflections	6739, 1873, 1790
R_int	0.024
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.018, 0.038, 1.05
No. of reflections	1873
No. of parameters	90
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.38, −0.47
Absolute structure	Flack (1983), 737 Friedel pairs
Absolute structure parameter	−0.03 (4)

Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SHELXS97 (Sheldrick, 2008) within WinGX (Farrugia, 1999), SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11···I2	0.77 (3)	2.81 (3)	3.283 (4)	122 (3)
N1—H12···N1ⁱ	0.80 (4)	2.30 (4)	3.106 (5)	180 (5)

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

Acknowledgements

The authors acknowledge financial support from the Australian Research Council and the School of Physical and Chemical Sciences, Queensland University of Technology.

References

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