Syntheses and crystal structures of di-chlorido-bis(2,3-di-methyl-pyrazine-κN)zinc(II) and catena-poly[[di-chlorido-zinc(II)]-μ-2,3-di-methyl-pyrazine-κ(2) N (1):N (4)].

The reactions of zinc(II)chloride with 2,3-di-methyl-pyrazine (C(6)H(8)N(2)) in different ratios in aceto-nitrile lead to the formation of [ZnCl(2)(C(6)H(8)N(2))(2)] (1) and [ZnCl(2)(C(6)H(8)N(2))] (n) (2). The asymmetric unit of 1 consists of one Zn cation located on a twofold rotation axis, one chloride anion and one 2,3-di-methyl-pyrazine ligand that occupy general positions. In compound 2 the asymmetric unit is built up of one zinc cation, two chloride anions and one 2,3-di-methyl-pyrazine ligand that are located in general positions in the uncommon trigonal space group P3(2). In compound 1, the Zn cations are tetra-hedrally coordinated by two chloride anions and two 2,3-di-methyl-pyrazine ligands forming discrete complexes. These complexes are arranged in columns that proceed along the c-axis direction. The Zn cations in 2 are also tetra-hedrally coordinated by two chloride anions and two 2,3-di-methyl-pyrazine ligands but linked via the bridging 2,3-di-methyl-pyrazine ligands into helical infinite chains that propagate along the c-axis direction. Powder X-ray diffraction measurements indicate that both compounds were obtained as pure crystalline phases.