6,8-Di­iodo-4-oxo-4H-chromene-3-carbalde­hyde

Ishikawa, Y.

doi:10.1107/S1600536814006904

organic compounds

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ISSN: 2056-9890

Volume 70| Part 5| May 2014| Page o536

doi:10.1107/S1600536814006904

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6,8-Diiodo-4-oxo-4H-chromene-3-carbaldehyde

Yoshinobu Ishikawa ^a ^*

^aSchool of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
^*Correspondence e-mail: ishi206@u-shizuoka-ken.ac.jp

(Received 16 March 2014; accepted 27 March 2014; online 12 April 2014)

The title compound, C₁₀H₄I₂O₃, is an iodinated 3-formylchromone derivative, and the atoms are essentially coplanar [r.m.s. deviation = 0.049 Å, largest deviation from the least-squares plane = 0.111 (9) Å for the CH(=O) C atom]. In the crystal, molecules are linked into a three-dimensional network through halogen bonds [I⋯O = 3.352 (5) and 3.405 (7) Å, C—I⋯O = 144.2 (3) and 154.5 (3)°, and C=O⋯I = 134.9 (6) and 146.0 (6)°], and π–π stacking interactions [centroid–centroid distance = 3.527 (6) Å].

CCDC reference: 994113

Related literature

For the preparation of the precursor of the title compound, see: Khansole et al. (2008 ). For related structures, see: Ishikawa & Motohashi (2013 ); Ishikawa (2014 ). For halogen bonding, see: Auffinger et al. (2004 ); Metrangolo et al. (2005 ); Wilcken et al. (2013); Sirimulla et al. (2013 ).

Experimental

Crystal data

C₁₀H₄I₂O₃
M_r = 425.95
Triclinic, $[P \overline 1]$
a = 7.290 (3) Å
b = 8.779 (5) Å
c = 9.767 (4) Å
α = 63.82 (3)°
β = 75.44 (3)°
γ = 68.05 (4)°
V = 517.5 (5) Å³
Z = 2
Mo Kα radiation
μ = 6.06 mm⁻¹
T = 100 K
0.48 × 0.30 × 0.25 mm

Data collection

Rigaku AFC-7R diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.152, T_max = 0.220
2933 measured reflections
2383 independent reflections
2361 reflections with F² > 2σ(F²)
R_int = 0.026
3 standard reflections every 150 reflections intensity decay: −1.1%

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.147
S = 1.23
2383 reflections
137 parameters
H-atom parameters constrained
Δρ_max = 3.56 e Å⁻³
Δρ_min = −3.01 e Å⁻³

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999 $[Rigaku (1999). WinAFC Diffractometer Control Software. Rigaku Corporation, Tokyo, Japan.]$ ); cell refinement: WinAFC Diffractometer Control Software; data reduction: WinAFC Diffractometer Control Software; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: CrystalStructure (Rigaku, 2010 ); software used to prepare material for publication: CrystalStructure.

Supporting information

CCDC reference: 994113

Crystal structure: contains datablocks General, I. DOI: 10.1107/S1600536814006904/zl2583sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814006904/zl2583Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814006904/zl2583Isup3.cml

checkCIF report

Comment top

Halogen bonds have been found to occur in organic, inorganic, and biological systems, and have recently attracted much attention in medicinal chemistry, chemical biology and supramolecular chemistry (Auffinger et al., 2004, Metrangolo et al., 2005, Wilcken et al., 2013, Sirimulla et al., 2013). We have recently reported the crystal structures of halogenated 3-formylchromone derivatives, 6,8-dichloro-4-oxochromene-3-carbaldehyde and 6,8-dibromo-4-oxochromene-3-carbaldehyde (Ishikawa & Motohashi, 2013; Ishikawa, 2014). It was found that these molecules are linked through halogen bonds in a similar fashion in the crystals. As part of our interest in chemical bonding, we herein report the crystal structure of 6,8-diiodo-4-oxochromene-3-carbaldehyde, which was prepared by the Vilsmeier–Haack reaction of 2-hydroxy-3,5-diiodoacetophenone with N,N-dimethylformamide (DMF) in the presence of POCl₃ in good yield.

The mean deviation of the least-square planes for the non-hydrogen atoms is 0.0487 Å, and the largest deviations is 0.111 (9) Å for C10. These mean that the atoms are essentially coplanar.

In the crystal, the molecule is assembled through characteristic intermolecular interactions between the I1 atom at the 6-position and the O2 atom of the α,β-unsaturated carbonyl group of its inversion-symmetry equivalent [I1···O2; 3.405 (7) Å, C5–I1···O2ⁱ = 154.5 (3)°, I1···O2ⁱ–C3ⁱ = 134.9 (6)° (i): -x + 1, -y + 2, -z + 1, Fig. 1], and between the I2 atom at the 6-position and the O2 atom of the α,β-unsaturated carbonyl group of its translation-symmetry equivalent [I2···O2; 3.352 (5) Å, C7–I2···O2ⁱⁱ = 144.2 (3)°, I2···O2ⁱⁱ–C3ⁱⁱ = 146.0 (6)° (i): x, y - 1, z+1, Fig. 2]. The short contact and the geometry of the I···O interactions come within the range of halogen bonding (Auffinger et al., 2004). It is noted that the geometry of the I···O interactions for the title compound is different from that for 6,8-dichloro-4-oxochromene-3-carbaldehyde and 6,8-dibromo-4-oxochromene-3-carbaldehyde. The three-dimensional network via the halogen bonds in the crystal of the title compound is more extensive. This is probably due to the larger size of the positive σ-holes of the I1 and I2 atoms (Auffinger et al., 2004, Sirimulla et al., 2013). The intermolecular π-π stacking interaction of the benzene ring of the molecule with that of the inversion-symmetry equivalentⁱⁱⁱ is also observed [centroid–centroid distance = 3.527 (6) Å (iii): -x + 1, -y + 1, -z + 1], as shown in Fig. 2.

Related literature top

For the preparation of the precursor of the title compound, see: Khansole et al. (2008). For related structures, see: Ishikawa & Motohashi (2013); Ishikawa (2014). For halogen bonding, see: Auffinger et al. (2004); Metrangolo et al. (2005); Wilcken et al. (2013); Sirimulla et al. (2013).

Experimental top

2-Hydroxy-3,5-diiodoacetophenone was prepared according to the literature method (Khansole et al., 2008). To a solution of 2-hydroxy-3,5-diiodoacetophenone (134 mmol) in DMF (5 ml) was added dropwise POCl₃ (335 mmol) for 5 min at 0 °C. After the mixture was stirred for 15 h at room temperature, water (20 ml) was added. The precipitates were collected, washed with water and dried in vacuo (yield: 81.1%). ¹H NMR (400 MHz, DMSO-d₆): δ = 8.31 (d, 1H, J = 2.0 Hz), 8.63 (d, 1H, J = 2.0 Hz), 9.04 (s, 1H), 10.07 (s, 1H). DART-MS calcd for [C₁₀H₄I₂O₃ + H⁺]: 426.825, found 426.869. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of an ethyl acetate solution of the title compound at room temperature.

Computing details top

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999); cell refinement: WinAFC Diffractometer Control Software (Rigaku, 1999); data reduction: WinAFC Diffractometer Control Software (Rigaku, 1999); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku, 2010); software used to prepare material for publication: CrystalStructure (Rigaku, 2010).

Figures top

	Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level. Hydrogen atoms are shown as small spheres of arbitrary radius. The intermolecular interaction of the title compound is represented as dashed lines for I···O.
	Fig. 2. A view of the intermolecular interactions of the title compound, represented as dashed lines for I···O interactions.

6,8-Diiodo-4-oxo-4H-chromene-3-carbaldehyde top

Crystal data top

C₁₀H₄I₂O₃	Z = 2
M_r = 425.95	F(000) = 388.00
Triclinic, P1	D_x = 2.733 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 7.290 (3) Å	Cell parameters from 25 reflections
b = 8.779 (5) Å	θ = 15.2–17.1°
c = 9.767 (4) Å	µ = 6.06 mm⁻¹
α = 63.82 (3)°	T = 100 K
β = 75.44 (3)°	Block, yellow
γ = 68.05 (4)°	0.48 × 0.30 × 0.25 mm
V = 517.5 (5) Å³

Data collection top

Rigaku AFC-7R diffractometer	R_int = 0.026
ω–2θ scans	θ_max = 27.5°
Absorption correction: ψ scan (North et al., 1968)	h = −5→9
T_min = 0.152, T_max = 0.220	k = −10→11
2933 measured reflections	l = −12→12
2383 independent reflections	3 standard reflections every 150 reflections
2361 reflections with F² > 2σ(F²)	intensity decay: −1.1%

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.051	H-atom parameters constrained
wR(F²) = 0.147	w = 1/[σ²(F_o²) + (0.0884P)² + 4.3985P] where P = (F_o² + 2F_c²)/3
S = 1.23	(Δ/σ)_max = 0.001
2383 reflections	Δρ_max = 3.56 e Å⁻³
137 parameters	Δρ_min = −3.01 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008)
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.018 (3)
Secondary atom site location: difference Fourier map

Crystal data top

C₁₀H₄I₂O₃	γ = 68.05 (4)°
M_r = 425.95	V = 517.5 (5) Å³
Triclinic, P1	Z = 2
a = 7.290 (3) Å	Mo Kα radiation
b = 8.779 (5) Å	µ = 6.06 mm⁻¹
c = 9.767 (4) Å	T = 100 K
α = 63.82 (3)°	0.48 × 0.30 × 0.25 mm
β = 75.44 (3)°

Data collection top

Rigaku AFC-7R diffractometer	2361 reflections with F² > 2σ(F²)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.026
T_min = 0.152, T_max = 0.220	3 standard reflections every 150 reflections
2933 measured reflections	intensity decay: −1.1%
2383 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	0 restraints
wR(F²) = 0.147	H-atom parameters constrained
S = 1.23	Δρ_max = 3.56 e Å⁻³
2383 reflections	Δρ_min = −3.01 e Å⁻³
137 parameters

Special details top

Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 σ(F²) is used only for calculating R-factor (gt).

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

	x	y	z	U_iso*/U_eq
I1	0.32790 (6)	0.83369 (5)	0.74688 (5)	0.0152 (3)
I2	0.74091 (6)	0.06022 (5)	0.85492 (5)	0.0179 (3)
O1	0.9121 (7)	0.2469 (6)	0.5147 (6)	0.0131 (9)
O2	0.8156 (8)	0.7689 (7)	0.2159 (6)	0.0180 (10)
O3	1.2172 (8)	0.3795 (8)	0.0749 (6)	0.0197 (10)
C1	1.0076 (10)	0.2949 (10)	0.3730 (8)	0.0163 (13)
C2	0.9844 (9)	0.4629 (10)	0.2687 (8)	0.0129 (12)
C3	0.8432 (9)	0.6141 (9)	0.3051 (7)	0.0109 (12)
C4	0.6053 (10)	0.6899 (9)	0.5166 (8)	0.0125 (12)
C5	0.5157 (10)	0.6387 (9)	0.6645 (8)	0.0135 (12)
C6	0.5540 (10)	0.4571 (10)	0.7630 (8)	0.0146 (12)
C7	0.6876 (10)	0.3271 (9)	0.7098 (7)	0.0128 (12)
C8	0.7425 (9)	0.5587 (9)	0.4625 (7)	0.0118 (12)
C9	0.7809 (9)	0.3800 (8)	0.5608 (7)	0.0104 (11)
C10	1.1073 (10)	0.4944 (9)	0.1196 (8)	0.0128 (12)
H1	1.1002	0.2020	0.3435	0.0196*
H2	0.5756	0.8124	0.4509	0.0150*
H3	0.4896	0.4234	0.8646	0.0176*
H4	1.0995	0.6144	0.0536	0.0153*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.0159 (3)	0.0127 (3)	0.0163 (3)	−0.00142 (18)	0.00485 (17)	−0.0107 (2)
I2	0.0180 (3)	0.0106 (3)	0.0169 (3)	−0.00243 (19)	0.00704 (18)	−0.0045 (2)
O1	0.014 (2)	0.010 (2)	0.013 (2)	−0.0006 (17)	0.0030 (17)	−0.0082 (17)
O2	0.019 (3)	0.016 (3)	0.012 (3)	−0.0030 (19)	0.0043 (18)	−0.0046 (19)
O3	0.017 (3)	0.026 (3)	0.015 (3)	−0.003 (2)	0.0040 (18)	−0.012 (2)
C1	0.014 (3)	0.021 (4)	0.016 (3)	−0.004 (3)	0.001 (3)	−0.012 (3)
C2	0.007 (3)	0.023 (4)	0.015 (3)	−0.006 (3)	0.004 (3)	−0.015 (3)
C3	0.008 (3)	0.016 (3)	0.010 (3)	−0.003 (3)	0.003 (2)	−0.010 (3)
C4	0.015 (3)	0.009 (3)	0.013 (3)	−0.002 (3)	−0.005 (3)	−0.004 (3)
C5	0.011 (3)	0.016 (3)	0.018 (3)	−0.005 (3)	0.002 (3)	−0.011 (3)
C6	0.014 (3)	0.026 (4)	0.010 (3)	−0.010 (3)	0.006 (2)	−0.012 (3)
C7	0.014 (3)	0.016 (3)	0.011 (3)	−0.006 (3)	0.002 (3)	−0.007 (3)
C8	0.013 (3)	0.015 (3)	0.009 (3)	−0.007 (3)	0.003 (3)	−0.006 (3)
C9	0.013 (3)	0.010 (3)	0.011 (3)	−0.003 (3)	0.002 (3)	−0.008 (3)
C10	0.012 (3)	0.015 (3)	0.010 (3)	−0.001 (3)	0.001 (3)	−0.008 (3)

Geometric parameters (Å, º) top

I1—C5	2.088 (8)	C4—C5	1.373 (9)
I2—C7	2.077 (7)	C4—C8	1.420 (10)
O1—C1	1.340 (8)	C5—C6	1.412 (9)
O1—C9	1.377 (9)	C6—C7	1.399 (11)
O2—C3	1.219 (8)	C7—C9	1.392 (9)
O3—C10	1.208 (10)	C8—C9	1.392 (8)
C1—C2	1.348 (9)	C1—H1	0.950
C2—C3	1.470 (10)	C4—H2	0.950
C2—C10	1.474 (9)	C6—H3	0.950
C3—C8	1.476 (9)	C10—H4	0.950

I2···O1	3.150 (5)	C9···C5^v	3.539 (13)
O1···C3	2.884 (8)	C10···O3^vii	2.980 (10)
O2···C1	3.566 (9)	C10···C5ⁱⁱ	3.421 (11)
O2···C4	2.862 (8)	C10···C6ⁱⁱ	3.199 (13)
O2···C10	2.895 (9)	C10···C7ⁱⁱ	3.574 (14)
O3···C1	2.840 (8)	C10···C10^vii	3.072 (13)
C1···C7	3.579 (10)	I1···H2	3.0418
C1···C8	2.730 (11)	I1···H3	3.0886
C2···C9	2.778 (9)	I2···H3	3.0562
C4···C7	2.811 (9)	O2···H2	2.5939
C5···C9	2.772 (10)	O2···H4	2.6052
C6···C8	2.806 (9)	O3···H1	2.5096
I1···O2ⁱ	3.405 (7)	C1···H4	3.2682
I1···O3ⁱⁱ	3.594 (6)	C3···H1	3.2906
I2···O2ⁱⁱⁱ	3.352 (5)	C3···H2	2.6671
I2···O3^iv	3.514 (7)	C3···H4	2.6866
O1···C3ⁱⁱ	3.587 (12)	C4···H3	3.2790
O1···C5^v	3.557 (10)	C6···H2	3.2839
O2···I1ⁱ	3.405 (7)	C9···H1	3.1762
O2···I2^vi	3.352 (5)	C9···H2	3.2812
O2···C7ⁱⁱ	3.585 (10)	C9···H3	3.2682
O2···C9ⁱⁱ	3.599 (10)	C10···H1	2.5423
O3···I1ⁱⁱ	3.594 (6)	H1···H4	3.4744
O3···I2^iv	3.514 (7)	I1···H2ⁱ	3.0877
O3···O3^vii	3.353 (8)	I1···H4^ix	3.2019
O3···C2^vii	3.493 (10)	I2···H1^iv	3.3483
O3···C5ⁱⁱ	3.492 (12)	O1···H1^iv	3.5832
O3···C6^viii	3.381 (8)	O3···H3^viii	2.4768
O3···C6ⁱⁱ	3.531 (13)	O3···H3ⁱⁱ	3.4952
O3···C10^vii	2.980 (10)	O3···H4^vii	2.8657
C1···C4ⁱⁱ	3.329 (13)	C1···H2ⁱⁱ	3.4833
C1···C8ⁱⁱ	3.548 (14)	C3···H3^v	3.4417
C2···O3^vii	3.493 (10)	C4···H1ⁱⁱ	3.3938
C2···C4ⁱⁱ	3.580 (11)	C5···H1ⁱⁱ	3.5387
C2···C5ⁱⁱ	3.571 (11)	C6···H4ⁱⁱ	3.1756
C2···C8ⁱⁱ	3.577 (12)	C7···H2^v	3.5512
C2···C9ⁱⁱ	3.581 (14)	C7···H4ⁱⁱ	3.3859
C3···O1ⁱⁱ	3.587 (12)	C10···H3^viii	3.3078
C3···C6^v	3.451 (13)	C10···H3ⁱⁱ	3.3304
C3···C9ⁱⁱ	3.346 (12)	C10···H4^vii	3.1352
C4···C1ⁱⁱ	3.329 (13)	H1···I2^iv	3.3483
C4···C2ⁱⁱ	3.580 (11)	H1···O1^iv	3.5832
C4···C7^v	3.518 (13)	H1···C4ⁱⁱ	3.3938
C4···C9^v	3.413 (12)	H1···C5ⁱⁱ	3.5387
C5···O1^v	3.557 (10)	H1···H2ⁱⁱ	3.4018
C5···O3ⁱⁱ	3.492 (12)	H2···I1ⁱ	3.0877
C5···C2ⁱⁱ	3.571 (11)	H2···C1ⁱⁱ	3.4833
C5···C9^v	3.539 (13)	H2···C7^v	3.5512
C5···C10ⁱⁱ	3.421 (11)	H2···H1ⁱⁱ	3.4018
C6···O3^ix	3.381 (8)	H2···H2ⁱ	3.5393
C6···O3ⁱⁱ	3.531 (13)	H3···O3^ix	2.4768
C6···C3^v	3.451 (13)	H3···O3ⁱⁱ	3.4952
C6···C8^v	3.526 (13)	H3···C3^v	3.4417
C6···C10ⁱⁱ	3.199 (13)	H3···C10^ix	3.3078
C7···O2ⁱⁱ	3.585 (10)	H3···C10ⁱⁱ	3.3304
C7···C4^v	3.518 (13)	H3···H3^x	3.5106
C7···C8^v	3.533 (11)	H3···H4^ix	3.2916
C7···C10ⁱⁱ	3.574 (14)	H3···H4ⁱⁱ	3.1545
C8···C1ⁱⁱ	3.548 (14)	H4···I1^viii	3.2019
C8···C2ⁱⁱ	3.577 (12)	H4···O3^vii	2.8657
C8···C6^v	3.526 (13)	H4···C6ⁱⁱ	3.1756
C8···C7^v	3.533 (11)	H4···C7ⁱⁱ	3.3859
C9···O2ⁱⁱ	3.599 (10)	H4···C10^vii	3.1352
C9···C2ⁱⁱ	3.581 (14)	H4···H3^viii	3.2916
C9···C3ⁱⁱ	3.346 (12)	H4···H3ⁱⁱ	3.1545
C9···C4^v	3.413 (12)	H4···H4^vii	3.4680

C1—O1—C9	117.8 (5)	C3—C8—C4	119.6 (6)
O1—C1—C2	126.0 (7)	C3—C8—C9	121.5 (6)
C1—C2—C3	120.3 (6)	C4—C8—C9	118.9 (6)
C1—C2—C10	119.5 (7)	O1—C9—C7	116.8 (6)
C3—C2—C10	120.2 (6)	O1—C9—C8	121.5 (6)
O2—C3—C2	123.5 (6)	C7—C9—C8	121.7 (6)
O2—C3—C8	123.7 (7)	O3—C10—C2	125.0 (7)
C2—C3—C8	112.8 (5)	O1—C1—H1	116.984
C5—C4—C8	119.7 (6)	C2—C1—H1	116.981
I1—C5—C4	119.2 (5)	C5—C4—H2	120.173
I1—C5—C6	119.6 (5)	C8—C4—H2	120.164
C4—C5—C6	121.1 (7)	C5—C6—H3	120.281
C5—C6—C7	119.4 (6)	C7—C6—H3	120.280
I2—C7—C6	119.1 (5)	O3—C10—H4	117.476
I2—C7—C9	121.7 (5)	C2—C10—H4	117.479
C6—C7—C9	119.2 (6)

C1—O1—C9—C7	−178.3 (7)	C8—C4—C5—I1	176.2 (7)
C1—O1—C9—C8	2.2 (11)	C8—C4—C5—C6	−1.5 (13)
C9—O1—C1—C2	−1.6 (13)	H2—C4—C5—I1	−3.8
C9—O1—C1—H1	178.5	H2—C4—C5—C6	178.5
O1—C1—C2—C3	−0.3 (14)	H2—C4—C8—C3	1.8
O1—C1—C2—C10	177.4 (8)	H2—C4—C8—C9	−179.1
H1—C1—C2—C3	179.7	I1—C5—C6—C7	−176.9 (5)
H1—C1—C2—C10	−2.6	I1—C5—C6—H3	3.1
C1—C2—C3—O2	179.9 (8)	C4—C5—C6—C7	0.9 (13)
C1—C2—C3—C8	1.4 (12)	C4—C5—C6—H3	−179.1
C1—C2—C10—O3	7.6 (14)	C5—C6—C7—I2	−179.4 (7)
C1—C2—C10—H4	−172.4	C5—C6—C7—C9	0.4 (13)
C3—C2—C10—O3	−174.7 (8)	H3—C6—C7—I2	0.6
C3—C2—C10—H4	5.3	H3—C6—C7—C9	−179.6
C10—C2—C3—O2	2.3 (13)	I2—C7—C9—O1	−0.7 (11)
C10—C2—C3—C8	−176.3 (7)	I2—C7—C9—C8	178.8 (5)
O2—C3—C8—C4	−0.2 (13)	C6—C7—C9—O1	179.5 (7)
O2—C3—C8—C9	−179.3 (8)	C6—C7—C9—C8	−1.0 (13)
C2—C3—C8—C4	178.4 (7)	C3—C8—C9—O1	−1.1 (12)
C2—C3—C8—C9	−0.7 (11)	C3—C8—C9—C7	179.5 (7)
C5—C4—C8—C3	−178.2 (7)	C4—C8—C9—O1	179.8 (7)
C5—C4—C8—C9	0.9 (12)	C4—C8—C9—C7	0.3 (12)

Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+2, −y+1, −z+1; (iii) x, y−1, z+1; (iv) −x+2, −y, −z+1; (v) −x+1, −y+1, −z+1; (vi) x, y+1, z−1; (vii) −x+2, −y+1, −z; (viii) x+1, y, z−1; (ix) x−1, y, z+1; (x) −x+1, −y+1, −z+2.

Experimental details

Crystal data
Chemical formula	C₁₀H₄I₂O₃
M_r	425.95
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	7.290 (3), 8.779 (5), 9.767 (4)
α, β, γ (°)	63.82 (3), 75.44 (3), 68.05 (4)
V (Å³)	517.5 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	6.06
Crystal size (mm)	0.48 × 0.30 × 0.25

Data collection
Diffractometer	Rigaku AFC-7R diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.152, 0.220
No. of measured, independent and observed [F² > 2σ(F²)] reflections	2933, 2383, 2361
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.147, 1.23
No. of reflections	2383
No. of parameters	137
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	3.56, −3.01

Computer programs: WinAFC Diffractometer Control Software (Rigaku, 1999), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), CrystalStructure (Rigaku, 2010).

Acknowledgements

We acknowledge the University of Shizuoka for instrumental support.

References

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