Syntheses and crystal structures of di-chlorido-(2,6-di-methyl-pyrazine-κN)(methanol-κO)zinc(II), di-bromido-(2,6-di-methyl-pyrazine-κN)(methanol-κO)zinc(II) and aqua-(2,6-di-methyl-pyrazine-κN)di-iodido-zinc(II).

Three new compounds with the compositions [ZnCl2(C6H8N2)(CH3OH)] (1), [ZnBr2(C6H8N2)(CH3OH)] (2) and [ZnI2(C6H8N2)(H2O)] (3) were prepared (C6H8N2 = 2,6-di-methyl-pyrazine). The asymmetric unit of each compound consists of one ZnII cation, two halide anions, one 2,6-di-methyl-pyrazine ligand and one methanol (1 and 2) or water mol-ecule (3), with all atoms located in general positions. Compounds 1 and 2 are not isostructural. In the crystal structures, the metal cations are fourfold coordinated by two halide anions, one 2,6-di-methyl-pyrazine ligand and one methanol or water mol-ecule within a slightly distorted tetra-hedral geometry. In 1 and 2 the discrete complexes are linked into chains via O-H⋯O hydrogen bonds between the O-H H atom of the methanol mol-ecule and the 2,6-di-methyl-pyrazine N atom that is not involved in the metal coordination. These chains are further linked by weak C-H⋯Cl (1) or C-H⋯Br (2) inter-actions. In 3, two complexes are linked by pairwise O-H⋯I hydrogen bonds into centrosymmetric dimeric units that are further connected by strong O-H⋯O hydrogen bonding between the second water H atom and the 2,6-di-methyl-pyrazine N-atom that is adjacent to the two methyl groups.