Synthesis and crystal structure of poly[(2,6-dimethylpyrazine-κ <i>N</i> ⁴ )(μ ₃ -thiocyanato-κ ³ <i>N</i> : <i>S</i> : <i>S</i> )copper(I)]

Crystals of the title compound, [Cu(NCS)(C₆H₈N₂)] _<i>n</i> (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 Cu^I 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 (<i>N</i>,<i>S</i>,<i>S</i>) bridging thio-cyanate anions into layers that lie parallel to the <i>ac</i> plane. The layers are stacked perpendicular to the <i>b</i>-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.