Synthesis and crystal structure of poly[(2,6-di-methyl-py-ra-zine-κN 4)(μ3-thiocyanato-κ3 N:S:S)copper(I)].

Crystals of the title compound, [Cu(NCS)(C6H8N2)] n (C6H8N2 = 2,6-di-methyl-pyrazine), were prepared by the reaction of CuNCS and 2,6-di-methyl-pyrazine in aceto-nitrile. The asymmetric unit consists of one CuI cation, one thio-cyanate anion and one 2,6-di-methyl-pyrazine ligand with all atoms lying on general positions. The copper cations are tetra-hedrally coordinated by two S- and one N-bonded thio-cyanate anions and one 2,6-di-methyl-pyrazine ligand, which s coordinated to the metal center with the N atom that is not adjacent to the methyl groups. The copper cations are linked by the μ-1,3,3 (N,S,S) bridging thio-cyanate anions into layers that lie parallel to the ac plane. The layers are stacked perpendicular to the b-axis direction and are separated by the 2,6-di-methyl-pyrazine ligands. The title crystal structure is compared with those of related CuNCS compounds with isomeric di-methyl-pyrazine ligands.