Strong Effects of Higher-Valent Cations on the Structure of the Zeolitic Zn(2-methylimidazole)₂ Framework (ZIF-8)

Porous zeolite-like metal−organic frameworks (ZMOFs) are novel materials for their potential applications due to their unique structures and ultrahigh surface areas. The most promising representative of the ZMOFs is Zn(2-methylimidazole) 2 (ZIF-8), which is highly resistant to water and organic solvents. However, this paper reports that the high stability of ZIF-8 was challenged by high-valent cations in solution. The X-ray diffraction and surface area measurements showed that, although univalent metal cations exerted no effect on the structure of ZIF-8, bivalent or higher-valent metal cations caused its structural collapse. Those results could be explained by density functional theory calculations.