Liesegang Banding for Controlled Size and Growth of Zeolitic‐Imidazolate Frameworks

Here, the formation of periodic precipitation (Liesegang bands) from hybrid (organic–inorganic) components is reported, namely ZIF‐8, ZIF‐67, and their mixed metal derivatives. The spacing and width laws that characterize the Liesegang system are determined and the resulting pattern is exploited to crystal engineer various sizes and doping of the ZIF material. Several key parameters that govern the crystallization process of ZIF‐8 are investigated in each band and the growth of the particles in each band is found to follow an Ostwald ripening mechanism. The first fully characterized Liesegang banding of hybrid components is reported here to synthesize ZIF‐8 crystals via the reaction–diffusion framework. The periodic precipitation is further exploited to produce a gradient of crystal sizes within the same tube as well as heterometallic (Zn/Co) ZIF‐8 with controlled composition.