2-(2,2-Dibromo-ethen-yl)thio-phene.

The title compound, C(6)H(4)Br(2)S, represents a versatile building block for the preparation of π-conjugated redox-active thienyl oligomers and metal-mediated cross-coupling reactions. This is due to the presence of an electrochemically active thienyl heterocycle and a reactive dibromo-vinyl substituent, which easily undergoes dehydro-bromination in the presence of n-butyl-lithium to afford 2-ethynyl-thio-phene. In the molecule, the alkenyl unit and the thio-phene ring are almost coplanar with an angle of 3.5 (2)° between the normals of the best planes of the thio-phene ring and the vinyl moiety.

Related literature

The title compound was first prepared in 1980, see: Bestmann et al. (1980 ▶). For an alternative synthesis using a Corey–Fuchs reaction, see: Beny et al. (1982 ▶). For a structural comparison with 2,2-dibromo­vin­yl[2,2]paracyclo­phane [PCP—C(H)=CBr2], (2,2-dibromo­vin­yl)ferrocene [Fc—C(H)=CBr2], and 2-thienyl­methyl­enemalononitrile [C4H3S—C(H)=C(CN)2], see: Clément et al. (2007a ▶,b ▶) and Mukherjee et al. (1984 ▶), respectively. For recent applications, see: Herz et al. (1999 ▶); Rao et al. (2010 ▶); Zhang et al. (2010 ▶).

Experimental

Crystal data

C6H4Br2S

M = 267.97

Monoclinic,

a = 9.6843 (19) Å

b = 7.2379 (14) Å

c = 11.484 (2) Å

β = 109.16 (3)°

V = 760.4 (3) Å3

Z = 4

Mo Kα radiation

μ = 10.84 mm−1

T = 173 K

0.4 × 0.4 × 0.2 mm

Data collection

Stoe IPDS diffractometer

Absorption correction: numerical (FACEIT in IPDS; Stoe & Cie, 1999 ▶) T min = 0.188, T max = 0.658

6492 measured reflections

1667 independent reflections

1444 reflections with I > 2σ(I)

R int = 0.064

Refinement

R[F 2 > 2σ(F 2)] = 0.058

wR(F 2) = 0.139

S = 1.04

1667 reflections

82 parameters

H-atom parameters not refined

Δρmax = 1.36 e Å−3

Δρmin = −1.73 e Å−3

Data collection: EXPOSE in IPDS (Stoe & Cie, 1999 ▶); cell refinement: CELL in IPDS; data reduction: INTEGRATE in IPDS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811002522/im2256sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811002522/im2256Isup2.hkl

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

C6H4Br2S	F(000) = 504
Mr = 267.97	Dx = 2.341 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 980 reflections
a = 9.6843 (19) Å	θ = 2.2–27.0°
b = 7.2379 (14) Å	µ = 10.84 mm−1
c = 11.484 (2) Å	T = 173 K
β = 109.16 (3)°	Plates, colourless
V = 760.4 (3) Å3	0.4 × 0.4 × 0.2 mm
Z = 4

Stoe IPDS diffractometer	1444 reflections with I > 2σ(I)
graphite	Rint = 0.064
φ scans	θmax = 27.0°, θmin = 2.2°
Absorption correction: numerical (FACEIT in IPDS; Stoe & Cie, 1999)	h = −11→12
Tmin = 0.188, Tmax = 0.658	k = −9→9
6492 measured reflections	l = −14→14
1667 independent reflections

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.139	H-atom parameters not refined
S = 1.04	w = 1/[σ2(Fo2) + (0.1099P)2] where P = (Fo2 + 2Fc2)/3
1667 reflections	(Δ/σ)max < 0.001
82 parameters	Δρmax = 1.36 e Å−3
0 restraints	Δρmin = −1.73 e Å−3

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.

	x	y	z	Uiso*/Ueq
Br1	0.90429 (5)	0.69525 (7)	0.15399 (5)	0.0306 (2)
Br2	0.75506 (5)	0.94572 (7)	0.30330 (4)	0.0290 (2)
C1	0.7287 (5)	0.7946 (6)	0.1647 (4)	0.0214 (9)
C2	0.5999 (5)	0.7559 (7)	0.0803 (4)	0.0225 (9)
H2	0.6061	0.6818	0.0139	0.027*
C3	0.4530 (5)	0.8068 (6)	0.0720 (4)	0.0188 (8)
C4	0.3277 (5)	0.7471 (7)	−0.0213 (4)	0.0225 (9)
H4	0.3305	0.6695	−0.0873	0.027*
C5	0.1970 (6)	0.8134 (7)	−0.0080 (5)	0.0307 (11)
H5	0.1026	0.7857	−0.0637	0.037*
C6	0.2213 (5)	0.9216 (7)	0.0939 (5)	0.0289 (10)
H6	0.1455	0.9771	0.1174	0.035*
S	0.40366 (13)	0.94655 (17)	0.17497 (12)	0.0265 (3)

	U11	U22	U33	U12	U13	U23
Br1	0.0220 (3)	0.0379 (4)	0.0324 (3)	0.00528 (18)	0.0097 (2)	−0.0004 (2)
Br2	0.0268 (3)	0.0342 (3)	0.0250 (3)	−0.00466 (18)	0.0072 (2)	−0.00800 (17)
C1	0.024 (2)	0.021 (2)	0.0202 (19)	0.0009 (16)	0.0089 (17)	0.0037 (16)
C2	0.024 (2)	0.020 (2)	0.024 (2)	0.0027 (18)	0.0104 (18)	0.0016 (17)
C3	0.024 (2)	0.0157 (19)	0.0183 (19)	0.0008 (15)	0.0095 (17)	0.0015 (15)
C4	0.024 (2)	0.020 (2)	0.024 (2)	0.0029 (17)	0.0083 (18)	0.0041 (17)
C5	0.020 (2)	0.034 (3)	0.036 (3)	−0.0005 (18)	0.005 (2)	0.006 (2)
C6	0.022 (2)	0.028 (2)	0.037 (3)	−0.0003 (18)	0.011 (2)	0.003 (2)
S	0.0256 (6)	0.0287 (6)	0.0277 (6)	0.0006 (4)	0.0121 (5)	−0.0054 (4)

Br1—C1	1.887 (5)	C4—C5	1.408 (7)
Br2—C1	1.878 (5)	C4—H4	0.95
C1—C2	1.335 (7)	C5—C6	1.362 (8)
C2—C3	1.442 (6)	C5—H5	0.95
C2—H2	0.95	C6—S	1.714 (5)
C3—C4	1.397 (7)	C6—H6	0.95
C3—S	1.738 (4)
C2—C1—Br2	124.9 (4)	C3—C4—H4	123.3
C2—C1—Br1	121.3 (4)	C5—C4—H4	123.3
Br2—C1—Br1	113.7 (3)	C6—C5—C4	112.4 (5)
C1—C2—C3	131.4 (4)	C6—C5—H5	123.8
C1—C2—H2	114.3	C4—C5—H5	123.8
C3—C2—H2	114.3	C5—C6—S	112.6 (4)
C4—C3—C2	124.1 (4)	C5—C6—H6	123.7
C4—C3—S	109.8 (3)	S—C6—H6	123.7
C2—C3—S	126.1 (3)	C6—S—C3	91.9 (2)
C3—C4—C5	113.3 (4)