(E)-3-(4-Bromo-5-methylthiophen-2-yl)acrylonitrile

In the title structure, C8H6BrNS, the molecules are planar with the exception of the methyl H atoms. In the crystal, molecules are linked by intermolecular C—H⋯N interactions to form ribbons parallel to the b axis. Groups of ribbons are arranged in a herringbone pattern to form a layered structure parallel to the ab plane.

In the title structure, C 8 H 6 BrNS, the molecules are planar with the exception of the methyl H atoms. In the crystal, molecules are linked by intermolecular C-HÁ Á ÁN interactions to form ribbons parallel to the b axis. Groups of ribbons are arranged in a herringbone pattern to form a layered structure parallel to the ab plane.

Comment
During the research focused on new synthetic routes towards novel substituted thiophene derivatives, we have synthesized the title compound (I), which was isolated in high yield. Thiophene derivatives are interesting compounds (Zhao et al., 2009). They can be used in a wide range of applications such as enzyme inhibitors (Perner et al., 2003), photochromic materials (Kose, 2004;Pu et al., 2010), bioprobes (Chandra et al., 2006) and dyes (Dinçalp et al., 2011).
The ribbons run parallel to the b axis and, within a ribbon, the orientation of consecutive molecules alternates to the left and right (Fig. 2). Groups of ribbons are arranged in a herringbone pattern to form a layered structure with layers parallel to the ab plane (Fig. 3).

Refinement
H atoms were positioned geometrically and refined using a riding model. For sp 2 H atoms, U iso (H) is constrained to 1.2 times the U eq for the atoms they are bonded to and the C-H distance is 0.93 Å. For the methyl group, U iso (H) is 1.5 times the U eq for C atom they are bonded to and the C-H distance is 0.96 Å, with free rotation about the C-C bond.

Figure 1
A molecule of I showing atom labels and 50% probability displacement ellipsoids for non-H atoms.   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.74 e Å −3 Δρ min = −1.12 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.030 (3) Absolute structure: Flack (1983), 699 Friedel pairs Absolute structure parameter: 0.03 (2) 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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.