Tuning the Ionicity of Stable Metal–Organic Frameworks through Ionic Linker Installation

The predictable topologies and designable
structures of metal–organic
frameworks (MOFs) are the most important advantages for this emerging
crystalline material compared to traditional porous materials. However,
pore-environment engineering in MOF materials is still a huge challenge
when it comes to the growing requirements of expanded applications.
A useful method for the regulation of pore-environments, linker installation,
has been developed and applied to a series of microporous MOFs. Herein,
employing PCN-700 and PCN-608 as platforms, ionic linker installation
was successfully implemented in both microporous and mesoporous Zr-based
MOFs to afford a series of ionic frameworks. Selective ionic dye capture
results support the ionic nature of these MOFs. The mesopores in PCN-608
are able to survive after installation of the ionic linkers, which
is useful for ion exchange and further catalysis. To illustrate this,
Ru­(bpy)32+, a commonly used photoactive cation,
was encapsulated into the anionic mesoporous PCN-608-SBDC via ion
exchange. Photocatalytic activity of Ru­(bpy)3@PCN-608-SBDC
was examined by aza-Henry reactions, which show good catalytic performance
over three catalytic cycles.