2,6-Dibromo-3,5-dimethylpyridine and 2,6-diiodo-3,5-dimethylpyridine.
The title compounds 2,6-dibromo-3,5-dimethylpyridine, C7H7Br2N, (I), and 2,6-diiodo-3,5-dimethylpyridine, C7H7I2N, (II), constitute the first structurally characterized examples of 2,6-dihalo-3,5-dimethylpyridines. Compound (I) crystallizes as a racemic twin with two symmetry-independent molecules in the asymmetric unit, while (II) is non-planar with the pyridine ring slightly deformed into a saddle shape, and exhibits crystallographically imposed twofold symmetry. Both (I) and (II) exhibit aromatic face-to-face pi-stacking in the solid state, although there are no other long-range interactions. In (I), alternate molecules are oriented at 90 degrees, resulting in X-shaped columns, while in (II), molecules pack in a parallel fashion, leading to a zigzag array.
Pugh
David
D
Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, England. dpugh1@soton.ac.uk