2-Iodo-5-nitro­thio­phene

Abstract

The title compound, C₄H₂INO₂S, was synthesized by nitration of iodo­thio­phene with acetyl nitrate. The molecule is essentially planar, withthe nitro group tilted by 1.78 (19)° and the iodine atom displaced by 0.0233 (2) Å with respect to the thiophene ring. In the crystal structure, adjacent mol­ecules are linked through weak I⋯O inter­actions [3.039 (2)Å], forming chains extending along the b axis.

Related literature

For the bioactivity of thio­phene derivatives, see: Wilson et al. (2010 ▶); Rudra et al. (2007 ▶); Altman et al. (2008 ▶); Morley et al. (2006 ▶).

Experimental

Crystal data

• C₄H₂INO₂S

• M _r = 255.03

• Monoclinic,

• a = 9.195 (2) Å

• b = 9.727 (2) Å

• c = 7.6714 (17) Å

• β = 105.043 (4)°

• V = 662.6 (2) ų

• Z = 4

• Mo Kα radiation

• μ = 5.07 mm⁻¹

• T = 110 K

• 0.48 × 0.29 × 0.08 mm

Data collection

• Bruker SMART 1K CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.195, T _max = 0.687

• 3264 measured reflections

• 1419 independent reflections

• 1294 reflections with I > 2σ(I)

• R _int = 0.022

Refinement

• R[F ² > 2σ(F ²)] = 0.025

• wR(F ²) = 0.065

• S = 1.09

• 1419 reflections

• 82 parameters

• H-atom parameters constrained

• Δρ_max = 1.65 e Å⁻³

• Δρ_min = −1.07 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT-Plus (Bruker, 1999 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

supplementary crystallographic information

Comment

Many thiophene derivatives show important bioactivities and are employed as antibacterial (Morley et al., 2006), as inhibitors of Janus kinases (Wilson et al., 2010), in the identification of RBx 8700 (Rudra et al., 2007) and in the treatment of myeloproliferative disorders and cancers (Altman et al., 2008). This is the reason they have attracted our interest.

The molecule of the title compound (Fig. 1) is essentially planar, with the nitro group tilted by 1.78 (19)° and the iodine atom displaced by 0.0233 (2) Å with respect to the thiophene ring. In the crystal structure, adjacent molecules are linked through weak I···O interactions to form chains extending along the b axis. (Fig. 2).

Experimental

Iodothiophene (6.5 g, 31 mmol) dissolved in 10 ml of acetic anhydride was introduced into a round flask, provided with a stirrer and a cooling device. Acetyl nitrate was added dropwise in forty-five minutes and the temperature was kept under 273 K. When the addition was over, the mixture was stirred for half an hour continuously at the same temperature. The nitrating flask was then surrounded with ice and kept in a refrigerator for 24 hours. The product was poured, with stirring, into finely crushed ice. After filtration, the precipitate was collected as a yellow solid. The impure product was dissolved in methanol, pale yellow monoclinic crystals suitable for X-ray analysis (m.p. 348 K, 67% yield) grew over a period of five days on slow evaporation of the solvent at room temperature.

Refinement

All non-H atoms were refined with anisotropic displacement parameters. The H atoms were positioned geometrically (C—H = 0.95 Å) and refined using a riding model, with U_iso = 1.2 U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Fig. 2.

Crystal packing of the the title compound viewed along the c axis. Dashed lines indicate weak intermolecular interactions.

Crystal data

C4H2INO2S	F(000) = 472
Mr = 255.03	Dx = 2.556 Mg m−3
Monoclinic, P21/c	Melting point: 348 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 9.195 (2) Å	Cell parameters from 2600 reflections
b = 9.727 (2) Å	θ = 2.3–27.0°
c = 7.6714 (17) Å	µ = 5.07 mm−1
β = 105.043 (4)°	T = 110 K
V = 662.6 (2) Å3	Plate, pale yellow
Z = 4	0.48 × 0.29 × 0.08 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer	1419 independent reflections
Radiation source: fine-focus sealed tube	1294 reflections with I > 2σ(I)
graphite	Rint = 0.022
φ and ω scans	θmax = 27.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→10
Tmin = 0.195, Tmax = 0.687	k = −12→6
3264 measured reflections	l = −9→9

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.025	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.065	H-atom parameters constrained
S = 1.09	w = 1/[σ2(Fo2) + (0.0417P)2 + 0.2502P] where P = (Fo2 + 2Fc2)/3
1419 reflections	(Δ/σ)max = 0.001
82 parameters	Δρmax = 1.65 e Å−3
0 restraints	Δρmin = −1.07 e Å−3

Special details

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. 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 (Ų)

	x	y	z	Uiso*/Ueq
I1	0.742893 (19)	0.45070 (2)	−0.00911 (2)	0.01661 (11)
S1	0.63408 (8)	0.77403 (7)	−0.09375 (9)	0.01554 (17)
C1	0.7728 (3)	0.6618 (3)	0.0128 (3)	0.0154 (6)
O2	0.5694 (3)	1.06507 (19)	−0.1375 (3)	0.0224 (5)
N1	0.6975 (3)	1.0473 (2)	−0.0419 (3)	0.0173 (5)
C2	0.9003 (3)	0.7266 (3)	0.1129 (4)	0.0176 (6)
H2	0.9873	0.6796	0.1805	0.021*
C3	0.8865 (3)	0.8712 (3)	0.1034 (3)	0.0171 (6)
H3	0.9627	0.9336	0.1630	0.021*
O1	0.7865 (3)	1.1411 (2)	0.0229 (3)	0.0257 (5)
C4	0.7496 (3)	0.9090 (4)	−0.0027 (3)	0.0148 (6)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
I1	0.02192 (16)	0.00881 (16)	0.01937 (15)	0.00103 (5)	0.00585 (10)	0.00003 (5)
S1	0.0171 (4)	0.0104 (3)	0.0176 (3)	0.0009 (2)	0.0018 (3)	−0.0006 (2)
C1	0.0216 (14)	0.0082 (14)	0.0184 (14)	0.0040 (10)	0.0087 (11)	0.0022 (9)
O2	0.0232 (12)	0.0178 (10)	0.0254 (11)	0.0056 (8)	0.0047 (9)	0.0048 (8)
N1	0.0215 (15)	0.0148 (13)	0.0163 (12)	0.0016 (9)	0.0060 (11)	0.0011 (8)
C2	0.0165 (14)	0.0168 (13)	0.0196 (14)	0.0021 (10)	0.0046 (11)	0.0006 (10)
C3	0.0176 (14)	0.0132 (13)	0.0201 (14)	−0.0027 (10)	0.0042 (11)	−0.0028 (10)
O1	0.0331 (12)	0.0094 (11)	0.0324 (12)	−0.0033 (9)	0.0044 (10)	−0.0019 (8)
C4	0.0206 (18)	0.0087 (16)	0.0167 (16)	−0.0007 (9)	0.0079 (13)	−0.0021 (8)

Geometric parameters (Å, °)

I1—C1	2.073 (3)	N1—C4	1.433 (4)
S1—C1	1.716 (3)	C2—C3	1.412 (4)
S1—C4	1.719 (3)	C2—H2	0.9500
C1—C2	1.376 (4)	C3—C4	1.361 (4)
O2—N1	1.227 (4)	C3—H3	0.9500
N1—O1	1.241 (3)
C1—S1—C4	89.32 (14)	C1—C2—H2	124.0
C2—C1—S1	113.2 (2)	C3—C2—H2	124.0
C2—C1—I1	125.1 (2)	C4—C3—C2	110.9 (3)
S1—C1—I1	121.68 (16)	C4—C3—H3	124.5
O2—N1—O1	124.5 (2)	C2—C3—H3	124.5
O2—N1—C4	118.3 (2)	C3—C4—N1	125.9 (3)
O1—N1—C4	117.2 (3)	C3—C4—S1	114.5 (3)
C1—C2—C3	112.0 (3)	N1—C4—S1	119.59 (19)
C4—S1—C1—C2	0.2 (2)	O2—N1—C4—C3	−178.6 (2)
C4—S1—C1—I1	179.18 (13)	O1—N1—C4—C3	1.9 (4)
S1—C1—C2—C3	−0.2 (3)	O2—N1—C4—S1	1.5 (3)
I1—C1—C2—C3	−179.22 (17)	O1—N1—C4—S1	−178.06 (17)
C1—C2—C3—C4	0.2 (3)	C1—S1—C4—C3	0.0 (2)
C2—C3—C4—N1	180.0 (2)	C1—S1—C4—N1	179.92 (18)
C2—C3—C4—S1	−0.1 (3)