A Zirconium Macrocyclic Metal-Organic Framework with Predesigned Shape-Persistent Apertures.

A microporous metal-organic framework (MOF) was synthesized from [Zr6 O4 (OH)4 (C6 H5 COO)12 ] clusters and a triacid ligand based on a shape-persistent arylene ethynylene macrocycle. This framework, dubbed Zr-MCMOF, is held together by metal-ligand coordination and multiple weak interactions: hydrogen bonding, [π⋅⋅⋅π] stacking, and [C-H⋅⋅⋅π] interactions. The rigid ligand has a 9 Å-wide central void, which serves as a predesigned aperture for the 1D channels; all of the porosity of Zr-MCMOF comes from the ligand. The resulting framework possesses high hydrolytic and thermal stability and a flexible structure unique among Zr-based MOFs.