posted on 2021-11-05, 17:03authored byBrandon He, Lauren K. Macreadie, James Gardiner, Shane G. Telfer, Matthew R. Hill
Access to the potential applications
of metal–organic frameworks
(MOFs) depends on rapid fabrication. While there have been advances
in the large-scale production of single-component MOFs, rapid synthesis
of multicomponent MOFs presents greater challenges. Multicomponent
systems subjected to rapid synthesis conditions have the opportunity
to form separate kinetic phases that are each built up using just
one linker. We sought to investigate whether continuous flow chemistry
could be adapted to the rapid formation of multicomponent MOFs, exploring
the UMCM-1 and MUF-77 series. Surprisingly, phase pure, highly crystalline
multicomponent materials emerge under these conditions. To explore
this, in situ WAXS was undertaken to gain an understanding
of the formation mechanisms at play during flow synthesis. Key differences
were found between the ternary UMCM-1 and the quaternary MUF-7, and
key details about how the MOFs form were then uncovered. Counterintuitively,
despite consisting of just two ligands UMCM-1 proceeds via MOF-5,
whereas MUF-7 consists of three ligands but is generated directly
from the reaction mixture. By taking advantage of the scalable high-quality
materials produced, C6 separations were achieved in breakthrough settings.