A rare porous zinc phosphonocarboxylate framework with high thermal stability and interesting structural transformation

A rare porous zinc-organic framework with ultrahigh thermal stability over 500 °C was obtained, which exhibits a CaF₂-type topology formed by 8-connected tetranuclear Zn₄ clusters and 4-connected phosphonocarboxylate ligands. Interestingly, the similar reactions to the zinc-organic framework but in the absence of H₂O or by the replacement of Zn²⁺ with Co²⁺ can yield three different 3D cluster-based frameworks but with the same CaF₂-type topology.