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

The reaction of ligand 5,7-di­hydro-1H,3H-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-di­hydro-1H,3H-dithieno[3,4-b:3′,4′-e]pyrazine-κ(4) N:N′:S:S′)tetra-μ(3)-iodido-tetra­copper], [Cu(4)I(4)(C(8)H(8)N(2)S(2))]( n ) (I). The asymmetric unit is composed of half a ligand mol­ecule, 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. [Image: see text]