3,4-Diiodo-2,5-dimethyl­thio­phene

Cseh, L.; Mehl, G.H.; Clark, S.; Archibald, S.J.

doi:10.1107/S160053680700760X

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 63| Part 3| March 2007| Pages o1393-o1394

https://doi.org/10.1107/S160053680700760X

3,4-Diiodo-2,5-dimethylthiophene

Liliana Cseh,^a Georg H. Mehl,^a Stephen Clark ^a and Stephen J. Archibald ^a ^*

^aDepartment of Chemistry, University of Hull, Hull HU6 7RX, England
^*Correspondence e-mail: s.j.archibald@hull.ac.uk

(Received 9 February 2007; accepted 14 February 2007; online 23 February 2007)

In the crystal structure of the title compound, C₆H₆I₂S, the molecules pack to form one-dimensional chains connected by intermolecular S⋯I interactions.

Comment

The title compound, (I) (Fig. 1), was prepared as part of a study aimed at producing new photochromic materials. Thiophene derivatives are important intermediates in the synthesis of photochromic compounds, organic light emitting diodes (OLED) and organic conductors. For photochromic compounds, potential applications are in the areas of optical recording, full-colour display and photoswitches.

The molecule of compound (I) possesses normal geometric parameters and is essentially planar. Intermolecular S⋯I interactions are observed in the structure with a distance of 3.641 (4) Å (Fig. 2). Such intermolecular interactions are also observed in the structure of tetraiodothiophene cocrystallized with tetrabutylammonium iodide (Bock & Holl, 2002 ), with S⋯I distances of 3.58 and 3.59 Å, and other work involving I₂ interactions with thioethers suggest the distances are typical e.g. 3.70 Å in the formation of extended structural networks (Blake et al., 1997 and 1998 ). Weak intermolecular C—H⋯I interactions are not observed in this structure.

Figure 1
The molecular structure of (I)

, showing 50% probability ellipsoids for non-H atoms.

Figure 2
The unit-cell contents of (I)

, viewed along [010] (50% probability ellipsoids). The dashed lines indicate the closest intermolecular S⋯I contacts.

Figure 3
The unit-cell contents of (I)

, viewed along [100] (50% probability ellipsoids). The dashed lines indicate the closest intermolecular S⋯I contacts.

Experimental

To a vigorously stirred mixture of iodine (11.5 g, 45 mmol), water (25 ml), iodic acid (3.9 g, 22 mmol), sulfuric acid (3 ml) and glacial acetic acid (75 ml) was added 2,5-dimethylthiophene (5 ml, 44 mmol). The solution was stirred at 323 K for 3 h and saturated aqueous sodium thiosulfate (150 ml) was added. The organic phase was extracted with diethyl ether (4 × 50 ml), dried over MgSO₄ and the solvent was removed under reduced pressure. The crude product was dissolved in dichloromethane and the solution was passed through a column of silica gel to remove the coloured material (9.15 g, 57%). The compound was recrystallized from dichloromethane at room temperature, giving crystals of (I) suitable for X-ray analysis (yield 9.15 g, 57%).

Crystal data

C₆H₆I₂S
M_r = 363.97
Monoclinic, P 2₁ /c
a = 10.0141 (13) Å
b = 6.7478 (6) Å
c = 13.4597 (17) Å
β = 98.156 (10)°
V = 900.31 (18) Å³
Z = 4
Mo Kα radiation
μ = 7.14 mm⁻¹
T = 150 (2) K
0.49 × 0.45 × 0.35 mm

Data collection

Stoe IPDSII image-plate diffractometer
Absorption correction: numerical (X-RED32; Stoe & Cie, 2002 ) T_min = 0.073, T_max = 0.145
7570 measured reflections
3171 independent reflections
2876 reflections with I > 2σ(I)
R_int = 0.053

Refinement

R[F² > 2σ(F²)] = 0.037
wR(F²) = 0.094
S = 1.08
3171 reflections
85 parameters
H-atom parameters constrained
Δρ_max = 1.84 e Å⁻³
Δρ_min = −1.56 e Å⁻³

H atoms were placed in idealized positions (C—H = 0.98 Å) and refined as riding atoms, with U_iso(H) = 1.2 U_eq(C). The highest residual electron-density peak is located 1.05 Å from atom I1 and the deepest hole is located 0.67 Å from the same atom.

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and WinGX (Farrugia,1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S160053680700760X/si2002sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053680700760X/si2002Isup2.hkl

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and WinGX (Farrugia,1999).

3,4-diiodo-2,5-dimethylthiophene top

Crystal data top

C₆H₆I₂S	F(000) = 656
M_r = 363.97	D_x = 2.685 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1487 reflections
a = 10.0141 (13) Å	θ = 3.1–34.8°
b = 6.7478 (6) Å	µ = 7.14 mm⁻¹
c = 13.4597 (17) Å	T = 150 K
β = 98.156 (10)°	Block, colourless
V = 900.31 (18) Å³	0.49 × 0.45 × 0.35 mm
Z = 4

Data collection top

Stoe IPDSII image plate diffractometer	3171 independent reflections
Radiation source: fine-focus sealed tube	2876 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.053
ω scans,125 frames at 1^o intervals, exposure time 1 minute	θ_max = 32.5°, θ_min = 3.1°
Absorption correction: numerical (X-RED32; Stoe & Cie, 2002)	h = −15→12
T_min = 0.073, T_max = 0.145	k = −10→8
7570 measured reflections	l = −19→20

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)] = 0.037	H-atom parameters constrained
wR(F²) = 0.094	w = 1/[σ²(F_o²) + (0.0455P)² + 2.0477P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.041
3171 reflections	Δρ_max = 1.84 e Å⁻³
85 parameters	Δρ_min = −1.56 e Å⁻³
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0094 (5)

Special details top

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.

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
I1	0.95491 (2)	0.33976 (4)	0.148780 (18)	0.02573 (9)
I2	0.72610 (3)	0.78586 (4)	0.149067 (19)	0.02665 (9)
S1	0.65840 (10)	0.41677 (16)	−0.13796 (7)	0.02577 (19)
C1	0.7839 (4)	0.3079 (6)	−0.0553 (3)	0.0224 (6)
C2	0.8076 (3)	0.4170 (6)	0.0308 (3)	0.0208 (6)
C4	0.6355 (4)	0.6116 (6)	−0.0584 (3)	0.0241 (6)
C3	0.7227 (4)	0.5899 (6)	0.0289 (3)	0.0223 (6)
C6	0.8507 (5)	0.1212 (7)	−0.0829 (3)	0.0301 (8)
H2	0.9409	0.1521	−0.0989	0.036*
H3	0.7966	0.0609	−0.1415	0.036*
H1	0.8584	0.0284	−0.0264	0.036*
C5	0.5330 (4)	0.7677 (8)	−0.0880 (4)	0.0336 (9)
H5	0.4744	0.7267	−0.1492	0.040*
H4	0.5783	0.8920	−0.1006	0.040*
H6	0.4785	0.7874	−0.0338	0.040*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.02439 (13)	0.02973 (15)	0.02117 (13)	0.00487 (8)	−0.00335 (9)	0.00026 (8)
I2	0.02565 (13)	0.02720 (15)	0.02611 (14)	0.00265 (8)	0.00028 (9)	−0.00559 (8)
S1	0.0258 (4)	0.0318 (5)	0.0183 (4)	0.0018 (3)	−0.0021 (3)	−0.0003 (3)
C1	0.0227 (15)	0.0244 (16)	0.0201 (15)	0.0015 (12)	0.0032 (12)	0.0020 (12)
C2	0.0191 (13)	0.0227 (16)	0.0201 (14)	0.0022 (11)	0.0011 (11)	0.0026 (11)
C4	0.0222 (14)	0.0266 (17)	0.0227 (16)	0.0025 (13)	0.0001 (12)	0.0009 (13)
C3	0.0200 (14)	0.0254 (17)	0.0205 (15)	0.0015 (12)	−0.0003 (12)	−0.0004 (12)
C6	0.0346 (19)	0.031 (2)	0.0253 (18)	0.0046 (16)	0.0065 (15)	−0.0039 (15)
C5	0.0266 (18)	0.039 (2)	0.034 (2)	0.0124 (17)	0.0003 (16)	0.0070 (17)

Geometric parameters (Å, º) top

I1—C2	2.074 (4)	C4—C5	1.486 (6)
I2—C3	2.085 (4)	C6—H2	0.9800
S1—C1	1.721 (4)	C6—H3	0.9800
S1—C4	1.731 (4)	C6—H1	0.9800
C1—C2	1.365 (5)	C5—H5	0.9800
C1—C6	1.498 (6)	C5—H4	0.9800
C2—C3	1.442 (5)	C5—H6	0.9800
C4—C3	1.369 (5)

C1—S1—C4	94.18 (19)	C1—C6—H2	109.5
C2—C1—C6	129.4 (4)	C1—C6—H3	109.5
C2—C1—S1	110.0 (3)	H2—C6—H3	109.5
C6—C1—S1	120.6 (3)	C1—C6—H1	109.5
C1—C2—C3	113.0 (3)	H2—C6—H1	109.5
C1—C2—I1	122.2 (3)	H3—C6—H1	109.5
C3—C2—I1	124.8 (3)	C4—C5—H5	109.5
C3—C4—C5	129.6 (4)	C4—C5—H4	109.5
C3—C4—S1	109.0 (3)	H5—C5—H4	109.5
C5—C4—S1	121.3 (3)	C4—C5—H6	109.5
C4—C3—C2	113.8 (4)	H5—C5—H6	109.5
C4—C3—I2	122.5 (3)	H4—C5—H6	109.5
C2—C3—I2	123.7 (3)

C4—S1—C1—C2	0.1 (3)	C5—C4—C3—C2	179.5 (4)
C4—S1—C1—C6	−179.4 (3)	S1—C4—C3—C2	0.3 (4)
C6—C1—C2—C3	179.5 (4)	C5—C4—C3—I2	1.4 (6)
S1—C1—C2—C3	0.0 (4)	S1—C4—C3—I2	−177.81 (19)
C6—C1—C2—I1	0.9 (6)	C1—C2—C3—C4	−0.2 (5)
S1—C1—C2—I1	−178.60 (18)	I1—C2—C3—C4	178.4 (3)
C1—S1—C4—C3	−0.2 (3)	C1—C2—C3—I2	177.9 (3)
C1—S1—C4—C5	−179.5 (4)	I1—C2—C3—I2	−3.6 (4)

Acknowledgements

We thank the EPSRC for funds which enabled the purchase of the Stoe IPDSII diffractometer. We acknowledge the use of the EPSRC's Chemical Database Service at Daresbury (Fletcher et al., 1996 ).

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