Vapor-Phase Linker Exchange of the Metal-Organic Framework ZIF-8: A Solvent-Free Approach to Post-Synthetic Modification

Here we present a novel, solvent-free approach to post-synthetic linker exchange in ZIF-8 through exposure to linker vapor. As in the solvent-based approach, this vapor-phase linker exchange (VPLE) method retains the parent SOD topology and proceeds in a single-crystal to single-crystal manner. The scope of linkers that can be incorporated through VPLE was studied and criteria for the selection of further candidates were formulated. In large crystals, the incoming linker was found to form domains instead of distributing homogeneously, similar as for solution-based linker exchange. In contrast to the latter approach, VPLE yields a higher concentration of the incoming linker in the crystal core instead of the shell.