5-Iodo-2-methyl-3-methyl­sulfinyl-1-benzofuran

The title compound, C₁₀H₉IO₂S, was prepared by the oxidation of 5-iodo-2-methyl-3-methyl­sulfanyl-1-benzofuran using 3-chloro­perbenzoic acid. The O atom and the methyl group of the methyl­sulfinyl substituent lie on opposite sides of the plane of the benzofuran system. The crystal structure is stabilized by short C—H...π inter­actions between the methyl H atoms and the benzene ring of the benzofuran system, and by an I...O halogen bond of 3.139 (2) Å and a nearly linear C—I...O angle of 164.13 (9)°. Additionally, the stacked mol­ecules exhibit an inter­molecular sulfin­yl–sulfinyl inter­action [3.190 (2) Å].

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.028
• wR factor = 0.066
• Data-to-parameter ratio = 21.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT431_ALERT_2_B Short Inter HL..A Contact  I      ..  O2      ..       3.14 Ang.

Author Response: : Explained in "Comment" as halogen bond.

Alert level C
PLAT153_ALERT_1_C The su's on the Cell Axes   are Equal (x 100000)         40 Ang.
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        200 Deg.
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          3
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.20 Ratio

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

As part of our ongoing studies of the synthesis and structure of 5-iodo-1-benzofuran derivatives, we have recently described the crystal structures of 5-iodo-3-methylsulfinyl-2-phenyl-1-benzofuran (Choi et al., 2007a) and 5-iodo-2-methyl-3-phenylsulfinyl-1-benzofuran (Choi et al., 2007b). Herein we report the crystal and molecular structure of the title compound, 5-iodo-2-methyl-3-methylsulfinyl-1-benzofuran (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.007 Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by CH₂—H···π interactions between the hydrogen of 2-methyl group and a benzene ring of benzofuran unit, with a C9—H9B···Cg separation of 2.72 Å (Fig. 2 & Table 1) (Cg is the centroid of C2—C7 benzene ring, symmetry code as in Fig. 2). The molecular packing (Fig. 2) is further stabilized by a I···O halogen bond (Politzer et al., 2007) between the iodine atom and the oxygen of a neighbouring S═O unit, with a I···O2ⁱⁱ distance of 3.139 (2) Å (symmetry code as Fig. 2). In addition, the crystal packing exhibits a sulfinyl-sulfinyl interaction interpreted as similar to a type-II carbonyl-carbonyl interaction (Allen et al., 1998), with S···O2ⁱⁱⁱ and O2···Sⁱⁱⁱ distances of 3.190 (2) Å (symmetry code as Fig. 2).

Related literature

For the crystal structures of similar 5-iodobenzofuran compounds, see: Choi et al. (2007a,b). For a review of halogen bonding, see: Politzer et al. (2007). For a review of carbonyl–carbonyl interactions, see: Allen et al. (1998).

S2. Experimental

3-Chloroperbenzoic acid (77%, 247 mg, 1.1 mmol) was added in small portions to a stirred solution of 5-iodo-2-methyl-3-methylsulfanyl-1-benzofuran (304 mg, 1.0 mmol) in dichloromethane (30 ml) at 273 K. After stirring at room temperature for 2 h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (ethyl acetate) to afford the title compound as a colorless solid [yield 80%, m.p. 420–421 K; R_f = 0.44 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a dilute solution of the title compound in acetone at room temperature.

S3. Refinement

All H atoms were geometrically located in ideal positions and refined using a riding model, with C—H=0.93 Å for aromatic H atoms and 0.96 Å for methyl H atoms, and with U_iso(H) = 1.2Ueq(C) for aromatic H atoms, and 1.5Ueq(C) for methyl H atoms. The highest peak in the difference map is 0.85 Å from I.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The molecular structure of the title compound.showing displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. C—H···π, I···O halogen bond and S···O interaction (dotted lines) in the title compound. Cg denotes ring centroid. [Symmetry code: (i) -x + 1, -y, -z + 1; (ii) -x, -y + 1, -z + 1; (iii) -x, -y, -z.]

5-Iodo-2-methyl-3-methylsulfinyl-1-benzofuran

Crystal data

C10H9IO2S	Z = 2
Mr = 320.13	F(000) = 308
Triclinic, P1	Dx = 1.938 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.1521 (4) Å	Cell parameters from 8333 reflections
b = 8.2671 (4) Å	θ = 2.5–28.3°
c = 8.6870 (4) Å	µ = 3.08 mm^−1
α = 104.585 (2)°	T = 298 K
β = 99.920 (2)°	Block, silver
γ = 97.620 (2)°	0.41 × 0.35 × 0.20 mm
V = 548.52 (5) Å^3

Data collection

Bruker SMART CCD diffractometer	2695 independent reflections
Radiation source: fine-focus sealed tube	2448 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.017
Detector resolution: 10.0 pixels mm^-1	θmax = 28.4°, θmin = 2.5°
ϕ and ω scans	h = −10→9
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	k = −11→10
Tmin = 0.301, Tmax = 0.538	l = −11→11
10576 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.066	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0241P)^2 + 0.6885P] where P = (Fo^2 + 2Fc^2)/3
2695 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 1.31 e Å^−3
0 restraints	Δρmin = −0.73 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
I	0.14093 (3)	0.58796 (3)	0.80417 (3)	0.06018 (9)
S	0.19880 (9)	0.03223 (9)	0.15991 (8)	0.04263 (16)
O1	0.6390 (2)	0.1957 (3)	0.4697 (2)	0.0459 (4)
O2	0.1218 (3)	0.1740 (3)	0.1195 (3)	0.0624 (6)
C1	0.3697 (3)	0.1256 (3)	0.3272 (3)	0.0384 (5)
C2	0.3747 (3)	0.2544 (3)	0.4761 (3)	0.0376 (5)
C3	0.2573 (4)	0.3385 (4)	0.5464 (3)	0.0410 (6)
H3	0.1439	0.3164	0.4936	0.049*
C4	0.3155 (4)	0.4566 (4)	0.6980 (3)	0.0442 (6)
C5	0.4861 (4)	0.4939 (4)	0.7772 (4)	0.0515 (7)
H5	0.5209	0.5748	0.8781	0.062*
C6	0.6037 (4)	0.4119 (4)	0.7075 (4)	0.0501 (7)
H6	0.7177	0.4363	0.7587	0.060*
C7	0.5440 (4)	0.2926 (4)	0.5589 (3)	0.0419 (6)
C8	0.5284 (4)	0.0956 (4)	0.3289 (3)	0.0414 (6)
C9	0.6034 (4)	−0.0215 (4)	0.2141 (4)	0.0519 (7)
H9A	0.5166	−0.0860	0.1213	0.078*
H9B	0.6530	−0.0975	0.2673	0.078*
H9C	0.6892	0.0430	0.1792	0.078*
C10	0.0620 (4)	−0.0694 (5)	0.2611 (4)	0.0599 (8)
H10A	−0.0414	−0.1285	0.1850	0.090*
H10B	0.0369	0.0146	0.3481	0.090*
H10C	0.1168	−0.1490	0.3047	0.090*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I	0.06932 (16)	0.04801 (13)	0.05745 (14)	0.00644 (10)	0.02787 (11)	−0.00282 (9)
S	0.0476 (4)	0.0447 (4)	0.0317 (3)	0.0149 (3)	0.0052 (3)	0.0028 (3)
O1	0.0366 (10)	0.0573 (12)	0.0465 (11)	0.0108 (9)	0.0089 (8)	0.0184 (9)
O2	0.0724 (16)	0.0553 (13)	0.0499 (12)	0.0221 (11)	−0.0116 (11)	0.0088 (10)
C1	0.0401 (13)	0.0418 (13)	0.0339 (12)	0.0108 (11)	0.0071 (10)	0.0105 (10)
C2	0.0393 (13)	0.0415 (13)	0.0327 (12)	0.0074 (10)	0.0059 (10)	0.0128 (10)
C3	0.0410 (14)	0.0423 (14)	0.0371 (13)	0.0074 (11)	0.0071 (11)	0.0079 (11)
C4	0.0534 (16)	0.0392 (13)	0.0380 (13)	0.0051 (12)	0.0140 (12)	0.0066 (11)
C5	0.0615 (19)	0.0483 (16)	0.0355 (14)	−0.0054 (14)	0.0058 (13)	0.0063 (12)
C6	0.0434 (15)	0.0576 (18)	0.0424 (15)	−0.0034 (13)	0.0010 (12)	0.0138 (13)
C7	0.0391 (14)	0.0480 (15)	0.0406 (14)	0.0052 (11)	0.0088 (11)	0.0171 (12)
C8	0.0447 (15)	0.0448 (14)	0.0406 (14)	0.0122 (11)	0.0124 (11)	0.0182 (12)
C9	0.0546 (18)	0.0551 (17)	0.0577 (18)	0.0214 (14)	0.0259 (14)	0.0216 (15)
C10	0.0468 (17)	0.073 (2)	0.0527 (18)	0.0012 (16)	0.0032 (14)	0.0161 (17)

Geometric parameters (Å, º)

I—O2^i	3.139 (2)	C3—H3	0.9300
I—C4	2.100 (3)	C4—C5	1.397 (4)
S—O2	1.489 (2)	C5—C6	1.382 (5)
S—O2^ii	3.190 (2)	C5—H5	0.9300
S—C1	1.761 (3)	C6—C7	1.375 (4)
S—C10	1.784 (4)	C6—H6	0.9300
O1—C7	1.379 (4)	C8—C9	1.478 (4)
O1—C8	1.380 (4)	C9—H9A	0.9600
O2—S^ii	3.190 (2)	C9—H9B	0.9600
C1—C2	1.444 (4)	C9—H9C	0.9600
C1—C8	1.347 (4)	C10—H10A	0.9600
C2—C3	1.392 (4)	C10—H10B	0.9600
C2—C7	1.396 (4)	C10—H10C	0.9600
C3—C4	1.388 (4)
O2—S—C1	106.65 (13)	C7—C6—H6	121.6
O2—S—C10	107.45 (17)	C5—C6—H6	121.6
C1—S—C10	98.26 (14)	C6—C7—O1	126.2 (3)
C4—I—O2^i	164.13 (9)	C6—C7—C2	123.6 (3)
C7—O1—C8	106.4 (2)	O1—C7—C2	110.3 (2)
C8—C1—C2	107.5 (2)	C1—C8—O1	111.0 (2)
C8—C1—S	123.4 (2)	C1—C8—C9	133.2 (3)
C2—C1—S	128.9 (2)	O1—C8—C9	115.8 (3)
C3—C2—C7	119.3 (3)	C8—C9—H9A	109.5
C3—C2—C1	135.8 (3)	C8—C9—H9B	109.5
C7—C2—C1	104.9 (2)	H9A—C9—H9B	109.5
C4—C3—C2	117.6 (3)	C8—C9—H9C	109.5
C4—C3—H3	121.2	H9A—C9—H9C	109.5
C2—C3—H3	121.2	H9B—C9—H9C	109.5
C3—C4—C5	121.9 (3)	S—C10—H10A	109.5
C3—C4—I	118.2 (2)	S—C10—H10B	109.5
C5—C4—I	119.9 (2)	H10A—C10—H10B	109.5
C6—C5—C4	120.8 (3)	S—C10—H10C	109.5
C6—C5—H5	119.6	H10A—C10—H10C	109.5
C4—C5—H5	119.6	H10B—C10—H10C	109.5
C7—C6—C5	116.8 (3)
O2—S—C1—C8	−126.7 (3)	C5—C6—C7—O1	−179.3 (3)
C10—S—C1—C8	122.2 (3)	C5—C6—C7—C2	1.4 (4)
O2—S—C1—C2	47.1 (3)	C8—O1—C7—C6	−179.3 (3)
C10—S—C1—C2	−64.0 (3)	C8—O1—C7—C2	0.1 (3)
C8—C1—C2—C3	−179.8 (3)	C3—C2—C7—C6	−0.9 (4)
S—C1—C2—C3	5.6 (5)	C1—C2—C7—C6	179.4 (3)
C8—C1—C2—C7	−0.1 (3)	C3—C2—C7—O1	179.7 (2)
S—C1—C2—C7	−174.7 (2)	C1—C2—C7—O1	0.0 (3)
C7—C2—C3—C4	−0.6 (4)	C2—C1—C8—O1	0.2 (3)
C1—C2—C3—C4	179.1 (3)	S—C1—C8—O1	175.18 (19)
C2—C3—C4—C5	1.4 (4)	C2—C1—C8—C9	179.2 (3)
C2—C3—C4—I	178.9 (2)	S—C1—C8—C9	−5.8 (5)
C3—C4—C5—C6	−0.9 (5)	C7—O1—C8—C1	−0.2 (3)
I—C4—C5—C6	−178.4 (2)	C7—O1—C8—C9	−179.4 (2)
C4—C5—C6—C7	−0.5 (5)

Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9B···Cg^iii	0.96	2.72	3.527 (3)	142

Symmetry code: (iii) −x+1, −y, −z+1.