Crystal structure of a tetra-kis-substituted pyrazine compound: 2,3,5,6-tetra-kis-(bromo-meth-yl)pyrazine.

Abstract

The title compound, C8H8Br4N2, crystallizes in the enanti-omorphic-defining space group P41212 and has a refined Flack x parameter of 0.04 (4). In the asymmetric unit, there are two half-mol-ecules; the whole mol-ecules (A and B) are generated by twofold rotation symmetry. In mol-ecule A, the twofold axis is normal to the pyrazine ring passing through the centre of the ring, while in mol-ecule B, the twofold rotation axis lies in the plane of the pyrazine ring bis-ecting the C-C aromatic bonds. The two mol-ecules are pseudo-mirror images of one another, and the best fit of the two mol-ecules was obtained for inverted mol-ecule B on mol-ecule A, with an r.m.s. deviation of 0.1048 Å and a maximum deviation of any two equivalent atoms of 0.2246 Å. In the crystal, the A mol-ecules are linked by weak C-H⋯Br hydrogen bonds and Br⋯Br inter-actions [3.524 (3) Å], forming a three-dimensional framework. The B mol-ecules are also linked by weak C-H⋯Br hydrogen bonds and Br⋯Br inter-actions [3.548 (3) Å], forming a three-dimensional network that inter-penetrates the network of A mol-ecules.