Convenient Multigram-Scale Synthesis of Phase-Pure Zirconium Metal–Organic Cages

Cationic zirconocene-based metal–organic cages (ZrMOCs) recently found significant research interest for applications in porous salts. However, their widespread use remained hindered by the coexistence of two types of cages, tetrahedral and cigar-shaped, in most syntheses and by low synthesis throughput. Here, we describe the multigram-scale synthesis of several types of ZrMOCs, achieving purity higher than 99% for either tetrahedra or cigars by combining a systematic analysis of reaction conditions and the development of an efficient purification procedure based on the difference in solubility. The access to phase-pure reference compounds also allowed us to analyze the effect of cage coexistence on the physical properties and pore accessibility in mixtures.