6-Iodo-2-methyl-1,3-benzothiazole

The title compound, C8H6INS, is essentially planar, the largest deviation from the mean plane being for the I atom [0.075 (3) Å]. The crystal structure is mainly stabilized by intermolecular C—I⋯N halogen bonds, forming zigzag supramolecular chains in [10]. Relatively short off-set π–π contacts [centroid–centroid distance = 3.758 (2) Å] between the thiazole rings of inversion-related molecules link neighbouring chains and provide the secondary interactions for building the crystal structure.

The title compound, C 8 H 6 INS, is essentially planar, the largest deviation from the mean plane being for the I atom [0.075 (3) Å ]. The crystal structure is mainly stabilized by intermolecular C-IÁ Á ÁN halogen bonds, forming zigzag supramolecular chains in [101]. Relatively short off-setcontacts [centroid-centroid distance = 3.758 (2) Å ] between the thiazole rings of inversion-related molecules link neighbouring chains and provide the secondary interactions for building the crystal structure.

Comment
This work was a part of our preparative, structural, mechanistic and computational investigation of a series of substituted benzothiazoles (bta), which attract considerable interest due to their biological activities.
The molecule is almost ideally planar (r.m.s. deviation = 0.009 Å), with the largest deviation from the plane being that of atom I1 [0.075 (3) Å] (Fig.1). The geometry of the benzothiazole rings is consistent with other 1,3-benzothiazoles listed in the CSD base (Allen et al., 2002). The two S-C bonds of the thiazole ring [S1-C1 and S1-C2] differ with respect to each other, but both are within two bortherline cases, single S-C [1.82 Å] and double S=C [1.56 Å], while the endocyclic C-N bond is dominantly double in character. The differences in C-C bonds within benzene ring are common for such fused rings.
In the crystal structure halogen bonds are the principal specific interactions responsible for the crystal packing. There is only one short and directional C-I···N contact [C-I = 2.103 (3) Å] (see Table 1) that link the molecules into antiparallel zigzag C(7) chains (Etter, 1990;Bernstein et al., 1995) in [1 0 -1] direction (Figs. 2 and 3).
Relatively short off-set π-π contacts [Cg···Cg = 3.758 (2) Å] between the thiazole rings, belonging to the molecules that are related by an inversion centre, link the neighboring supramolecular chains and provide the secondary interactions for building the crystal structure.
The structure of the title compound is one more example showing that halogen bonding is also as effective and reliable tool for assembling molecules into supramolecular architectures.

Experimental
Colourless single crystals of the title compound were obtained by slow evaporation of a dichloromethane solution.

Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent C atom at distances of 0.93 or 0.96 Å for aromatic or methyl H atoms, respectively, and with U iso (H) = 1.2U eq (C) (for aromatic H) or U iso (H) = 1.5U eq (C) (for methyl group). Fig. 1. Molecular structure of the title compound with the atom labeling scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted Rfactors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.