Crystal structure of a tetrakis-substituted pyrazine compound: 2,3,5,6-tetrakis(bromomethyl) pyrazine

The title compound, C8H8Br4N2, crystallizes in the enantiomorphic-defining space group P4(1)2(1)2 and has a refined Flack x parameter of 0.04 (4). In the asymmetric unit, there are two half-molecules; the whole molecules (A and B) are generated by twofold rotation symmetry. In molecule A, the twofold axis is normal to the pyrazine ring passing through the centre of the ring, while in molecule B, the twofold rotation axis lies in the plane of the pyrazine ring bisecting the C-C aromatic bonds. The two molecules are pseudo-mirror images of one another, and the best fit of the two molecules was obtained for inverted molecule B on molecule A, with an r.m.s. deviation of 0.1048 angstrom and a maximum deviation of any two equivalent atoms of 0.2246 angstrom. In the crystal, the A molecules are linked by weak C-H center dot center dot center dot Br hydrogen bonds and Br center dot center dot center dot Br interactions [3.524 (3) angstrom], forming a three-dimensional framework. The B molecules are also linked by weak C-H center dot center dot center dot Br hydrogen bonds and Br center dot center dot center dot Br interactions [3.548 (3) angstrom], forming a three-dimensional network that interpenetrates the network of A molecules.