Synthesis, Characterization, and Impact of Water on the Stability of Postmodified Schiff Base Containing Metal-Organic Frameworks

In this study, the synthesis of a Schiff base containing metal-organic frameworks (MOFs) of the UiO-67 family has been investigated. MOFs featuring free amine groups were successfully synthesized under mild solvothermal conditions using 2-amino-[1,1 '-biphenyl]-4,4 '-dicarboxylic acid and 2,2 '-diamino-[1,1 '-biphenyl]-4,4 '-dicarboxylic acid as bridging ligands, resulting in MOFs with amine groups covalently linked to the bridging ligands. Both types of functionalized MOFs were post-synthetically modified with 4-formylbenzonitrile that resulted in imine formation. All the obtained compounds were characterized by PXRD, TGA, DTA, BET, NMR, and FTIR spectroscopy, while stability in water was monitored with SEM, EDS, and UV-VIS spectroscopy.