A novel threefold-interpenetrating primitive cubic network based on a dinuclear Zn2 node.

In the mixed-ligand metal–organic polymeric compound poly[[μ2-1,4-bis­(imidazol-1-yl)benzene](μ2-terephthalato)dizinc(II)], [Zn2(C8H4O4)2(C12H10N4)]n or [Zn2(bdc)2(bib)]n [H2bdc is terephthalic acid and bib is 1,4-bis­(imidazol-1-yl)benzene], the asymmetric unit contains one ZnII ion, with two half bdc anions and one half bib mol­ecule lying around inversion centers. The ZnII ion is in a slightly distorted tetra­hedral environment, coordinated by three carboxyl­ate O atoms from three different bdc anions and by one bib N atom. The crystal structure is constructed from the secondary building unit (SBU) [Zn2(CO2)2N2O2], in which the two metal centers are held together by two bdc linkers with bis­(syn,syn-bridging bidentate) bonding modes. The SBU is connected by bdc bridges to form a two-dimensional grid-like (4,4)-layer, which is further pillared by the bib ligand. Topologically, the dinuclear SBU can be considered to be a six-connected node, and the extended structure exhibits an elongated primitive approximately cubic framework. The three-dimensional framework possesses a large cavity with dimensions of approximately 10 × 13 × 17 A in cross-section. The potential porosity is filled with mutual inter­penetration of two identical equivalent frameworks, generating a novel threefold inter­penetrating network with an α-polonium topology [Abrahams, Hoskins, Robson & Slizys (2002). CrystEngComm, 4, 478–482].