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Acta Crystallogr Sect E Struct Rep Online. 2009 September 1; 65(Pt 9): o2108.
Published online 2009 August 8. doi:  10.1107/S1600536809030438
PMCID: PMC2970149

2,4-Diiodo­aniline

Abstract

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 [triangle]). For the synthesis, see: Dains et al. (1935 [triangle]); Hodgson & Marsden (1937 [triangle]); O’Neil (2001 [triangle]). For graph-set analysis of hydrogen bonding, see: Etter et al. (1990 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o2108-scheme1.jpg

Experimental

Crystal data

  • C6H5I2N
  • M r = 344.91
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2108-efi3.jpg
  • 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 [triangle]) 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[F 2 > 2σ(F 2)] = 0.018
  • wR(F 2) = 0.038
  • S = 1.05
  • 1873 reflections
  • 90 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.38 e Å−3
  • Δρmin = −0.47 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 737 Friedel pairs
  • Flack parameter: −0.03 (4)

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

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

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

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

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

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

supplementary crystallographic information

Comment

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).

Experimental

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).

Refinement

The hydrogen atoms of the amino group were located in a difference Fourier map and their positional and isotropic displacement parameters were refined freely. Other H-atoms were included in the refinement in calculated positions [C—H = 0.93 Å) and treated using a riding model approximation, with Uiso(H) = 1.2Ueq(C).

Figures

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]. ...

Crystal data

C6H5I2NDx = 2.806 Mg m3
Mr = 344.91Melting point = 368–369 K
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 5620 reflections
a = 4.3870 (1) Åθ = 3.0–32.2°
b = 10.9626 (3) ŵ = 7.62 mm1
c = 16.9778 (4) ÅT = 200 K
V = 816.51 (3) Å3Needle, colourless
Z = 40.30 × 0.18 × 0.18 mm
F(000) = 616

Data collection

Oxford Diffraction Gemini-S Ultra CCD-detector diffractometer1873 independent reflections
Radiation source: Enhance (Mo) X-ray tube1790 reflections with I > 2σ(I)
graphiteRint = 0.024
ω scansθmax = 27.5°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −5→5
Tmin = 0.146, Tmax = 0.250k = −13→14
6739 measured reflectionsl = −22→18

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.018H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.038w = 1/[σ2(Fo2) + (0.0207P)2] where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max = 0.003
1873 reflectionsΔρmax = 0.38 e Å3
90 parametersΔρmin = −0.47 e Å3
0 restraintsAbsolute structure: Flack (1983), 737 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: −0.03 (4)

Special details

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)

xyzUiso*/Ueq
I20.57888 (5)0.42657 (2)1.08868 (1)0.0293 (1)
I40.48489 (5)0.28546 (2)0.75021 (1)0.0330 (1)
N10.1721 (9)0.6552 (3)1.0212 (2)0.0291 (11)
C10.2299 (7)0.5690 (3)0.9630 (2)0.0218 (9)
C20.4096 (8)0.4658 (3)0.97570 (19)0.0221 (9)
C30.4807 (8)0.3859 (3)0.9156 (2)0.0247 (9)
C40.3689 (8)0.4074 (3)0.8407 (2)0.0235 (10)
C50.1876 (8)0.5075 (3)0.8256 (2)0.0260 (11)
C60.1216 (9)0.5877 (3)0.8865 (2)0.0278 (11)
H30.602800.318200.925300.0300*
H50.110700.521000.775300.0310*
H60.001900.655800.876100.0330*
H110.190 (8)0.626 (3)1.062 (2)0.038 (9)*
H120.043 (8)0.704 (4)1.010 (2)0.040 (9)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
I20.0335 (1)0.0341 (1)0.0202 (1)0.0009 (1)−0.0038 (1)0.0021 (1)
I40.0383 (1)0.0389 (1)0.0219 (1)0.0022 (1)0.0017 (1)−0.0069 (1)
N10.037 (2)0.0222 (16)0.028 (2)0.0055 (15)−0.0021 (16)0.0013 (15)
C10.0214 (15)0.0191 (16)0.0248 (18)−0.0039 (15)0.0014 (14)0.0021 (14)
C20.0251 (16)0.0226 (16)0.0186 (17)−0.0034 (15)−0.0009 (14)0.0032 (11)
C30.0289 (18)0.0218 (14)0.0234 (17)−0.0007 (11)−0.0010 (16)0.0015 (12)
C40.0252 (17)0.0226 (18)0.0228 (18)−0.0031 (13)0.0028 (14)−0.0029 (13)
C50.027 (2)0.0313 (19)0.0197 (19)−0.0028 (14)−0.0018 (15)0.0044 (14)
C60.0323 (19)0.0236 (18)0.0276 (19)0.0028 (15)0.0007 (15)0.0051 (13)

Geometric parameters (Å, °)

I2—C22.101 (3)C2—C31.381 (5)
I4—C42.099 (3)C3—C41.383 (5)
N1—C11.391 (5)C4—C51.379 (5)
N1—H120.80 (4)C5—C61.388 (5)
N1—H110.77 (3)C3—H30.9300
C1—C61.398 (5)C5—H50.9300
C1—C21.396 (5)C6—H60.9300
H11—N1—H12124 (4)I4—C4—C3118.6 (2)
C1—N1—H11110 (3)C3—C4—C5120.7 (3)
C1—N1—H12114 (3)C4—C5—C6119.1 (3)
N1—C1—C6119.9 (3)C1—C6—C5121.9 (3)
N1—C1—C2123.0 (3)C2—C3—H3120.00
C2—C1—C6117.0 (3)C4—C3—H3120.00
I2—C2—C1120.4 (2)C4—C5—H5120.00
I2—C2—C3117.7 (2)C6—C5—H5121.00
C1—C2—C3121.9 (3)C1—C6—H6119.00
C2—C3—C4119.4 (3)C5—C6—H6119.00
I4—C4—C5120.7 (2)
N1—C1—C2—I25.0 (5)C1—C2—C3—C4−0.7 (5)
N1—C1—C2—C3−175.5 (3)C2—C3—C4—I4179.3 (3)
C6—C1—C2—I2−178.9 (2)C2—C3—C4—C50.0 (5)
C6—C1—C2—C30.6 (5)I4—C4—C5—C6−178.5 (3)
N1—C1—C6—C5176.5 (3)C3—C4—C5—C60.9 (5)
C2—C1—C6—C50.3 (5)C4—C5—C6—C1−1.0 (5)
I2—C2—C3—C4178.8 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H11···I20.77 (3)2.81 (3)3.283 (4)122 (3)
N1—H12···N1i0.80 (4)2.30 (4)3.106 (5)180 (5)

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IS2440).

References

  • Dains, F. B., Brewster, R. Q. & Davis, J. A. (1935). J. Am. Chem. Soc.57, 2326–2327.
  • Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262. [PubMed]
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  • Garden, S. J., Fontes, S. P., Wardell, J. L., Skakle, J. M. S., Low, J. N. & Glidewell, C. (2002). Acta Cryst. B58, 701–709. [PubMed]
  • Hodgson, H. H. & Marsden, E. (1937). J. Chem. Soc. pp. 1365–1366.
  • O’Neil, M. J. (2001). Editor. The Merck Index 13th ed., p. 560. Whitehouse Station, NJ, USA: Merck & Co.
  • Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED Oxford Diffraction Ltd, Abingdon, England.
  • Sheldrick, G. M. (1996). SADABS, University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]

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