Poly[(μ 4 -5,7-di-hydro-1 H ,3 H -dithieno[3,4- b :3',4'- e ]pyrazine-κ 4 N : N ': S : S ')tetra-μ 3 -iodido-tetra-copper]: a three-dimensional copper(I) coordination polymer.

The reaction of ligand 5,7-di-hydro-1 H ,3 H -dithieno[3,4- b :3',4'- e ]pyrazine ( L ) with CuI lead to the formation of a three-dimensional coordination polymer, incorporating the well known [Cu x I x ] n staircase motif ( x = 4). These polymer [Cu 4 I 4 ] n chains are linked via the N and S atoms of the ligand to form the three-dimensional coordination polymer poly[(μ 4 -5,7-di-hydro-1 H ,3 H -dithieno[3,4- b :3',4'- e ]pyrazine-κ 4 N : N ': S : S ')tetra-μ 3 -iodido-tetra-copper], [Cu 4 I 4 (C 8 H 8 N 2 S 2 )] n ( I ). The asymmetric unit is composed of half a ligand mol-ecule, with the pyrazine ring located about a center of symmetry, and two independent copper(I) atoms and two independent I - ions forming the staircase motif via centers of inversion symmetry. The framework is consolidated by C-H⋯I hydrogen bonds.