Silver(I) nitrate two-dimensional coordination polymers of two new pyrazine-thio-phane ligands: 5,7-di-hydro-1H,3H-dithieno[3,4-b:3',4'-e]pyrazine and 3,4,8,10,11,13-hexa-hydro-1H,6H-bis-([1,4]di-thio-cino)[6,7-b:6',7'-e]pyrazine.

The two new pyrazine-ophanes, 5,7-di-hydro-1H,3H-dithieno[3,4-b:3',4'-e]pyrazine, C(8)H(8)N(2)S(2), L1, and 3,4,8,10,11,13-hexa-hydro-1H,6H-bis-([1,4]di-thio-cino)[6,7-b:6',7'-e]pyrazine, C(12)H(16)N(2)S(4), L2, both crystallize with half a mol-ecule in the asymmetric unit; the whole mol-ecules are generated by inversion symmetry. The mol-ecule of L1, which is planar (r.m.s. deviation = 0.008†à ), consists of two sulfur atoms linked by a rigid tetra-2,3,5,6-methyl-ene-pyrazine unit, forming planar five-membered rings. The mol-ecule of L2 is step-shaped and consists of two S-CH(2)-CH(2)-S chains linked by the central rigid tetra-2,3,5,6-methyl-ene-pyrazine unit, forming eight-membered rings that have twist-boat-chair con-fig-urations. In the crystals of both compounds, there are no significant inter-molecular inter-actions present. The reaction of L1 with silver nitrate leads to the formation of a two-dimensional coordination polymer, poly[(μ-5,7-di-hydro-1H,3H-dithieno[3,4-b;3',4'-e]pyrazine-κ(2) S:S')(μ-nitrato-κ(2) O:O')silver(I)], [Ag(NO(3))(C(8)H(8)N(2)S(2))] (n) , (I), with the nitrato anion bridging two equivalent silver atoms. The central pyrazine ring is situated about an inversion center and the silver atom lies on a twofold rotation axis that bis-ects the nitrato anion. The silver atom has a fourfold AgO(2)S(2) coordination sphere with a distorted shape. The reaction of L2 with silver nitrate also leads to the formation of a two-dimensional coordination polymer, poly[[μ(3)3,4,8,10,11,13-hexa-hydro-1H,6H-bis-([1,4]di-thio-cino)[6,7-b;6',7'-e]pyrazine-κ(3) S:S':S''](nitrato-κO)silver(I)], [Ag(NO(3))(C(12)H(16)N(2)S(4))] (n) , (II), with the nitrate anion coordinating in a monodentate manner to the silver atom. The silver atom has a fourfold AgOS(3) coordination sphere with a distorted shape. In the crystals of both complexes, the networks are linked by C-H⋯O hydrogen bonds, forming supra-molecular frameworks. There are additional C-H⋯S contacts present in the supra-molecular framework of II.