Poly[bis(μ2-2-aminopyrazine-κ2N1:N4)(μ2-nitrato-κ2O:O)(nitrato-κ2O,O′)disilver(I)]: an achiral two-dimensional coordination polymer forming chiral crystals

The solution reaction of AgNO3 and 2-aminopyrazine (apyz) in a 1:1 ratio gives rise to the title compound, [Ag-2(NO3)(2)(C4H5N3)(2)](n), (I), which possesses a chiral crystal structure. In (I), both of the crystallographically independent Ag-I cations are coordinated in tetrahedral geometries by two N atoms from two apyz ligands and two O atoms from nitrate anions; however, the Ag-I centers show two different coordination environments in which one is coordinated by two O atoms from two different symmetry-related nitrate anions and the second is coordinated by two O atoms from a single nitrate anion. The crystal structure consists of one-dimensional Ag I apyz chains, which are further extended by mu(2)-kappa O-2:O nitrate anions into a two-dimensional (4,4) sheet. N-H center dot center dot center dot O and C-apyz-H center dot center dot center dot O hydrogen bonds connect neighboring sheets to form a three-dimensional supramolecular framework.