A twofold inter­penetrating three-dimensional zinc–organic framework built from naphthalene-1,4-di­carboxyl­ate and 4,4′-bi­pyridine ligands

In a novel three-dimensional Zn^II complex prepared by the solvothermal assembly of Zn(NO₃)·6H₂O, naphthalene-1,4-di­carb­oxy­lic acid (1,4-H₂ndc) and 4,4′-bi­pyridine (bpy), the two crystallographically independent Zn atoms adopt the same four-coordinated tetra­hedral ZnO₃N geometry. The supra­molecular secondary building unit (SBU) is a distorted paddle-wheel-like {Zn₂(COO)₂N₂O₂} unit and these units are linked by 1,4-ndc ligands within the layer to form a two-dimensional net parallel to the ab plane, which is further connected by bpy ligands to give rise to a three-dimensional framework.