An example of a rationally synthesized MOF@MOF (cubic HKUST-1@MOF-5). Image: KAIST.
An example of a rationally synthesized MOF@MOF (cubic HKUST-1@MOF-5). Image: KAIST.

The integration of metal-organic frameworks (MOFs) with other metal nanoparticles has increasingly led to the creation of new multifunctional materials. Many researchers have integrated MOFs with other classes of materials to produce new structures with synergetic properties.

But despite there being over 70,000 collections of synthesized MOFs that can be used as building blocks, researchers have struggled to integrate different MOFs, as the precise nature of the interaction and bonding at their interface remains unknown. The question is how to pick out the right matching pairs from these 70,000 MOFs.

An algorithmic study reported in Nature Communications by a team from the Korea Advanced Institute of Science and Technology (KAIST) now offers a way to find the perfect pairs. The team, led by Ji-Han Kim from the Department of Chemical and Biomolecular Engineering, developed a joint computational and experimental approach to rationally design composite MOFs known as MOF@MOFs, which are produced by growing one MOF on a different MOF.

In collaboration with researchers at the Ulsan National Institute of Science and Technology (UNIST) in Korea, Kim’s team noted that the metal node of one MOF can co-ordinately bond with the linker of a different MOF. They also noted that precisely matching interface configurations at atomic and molecular levels can enhance the likelihood of synthesizing MOF@MOFs.

Using this knowledge, they screened thousands of MOFs and identified optimal MOF pairs that can seamlessly connect to one another, due to the metal node of one MOF forming coordination bonds with the linkers of the second MOF. Six pairs predicted by the computational algorithm successfully grew into single crystals.

This computational workflow can readily extend into other classes of materials and can lead to the rapid exploration of the composite MOF arena for accelerated materials development. Furthermore, the workflow can enhance the likelihood of synthesizing MOF@MOFs in the form of large single crystals, demonstrating the utility of rationally designing MOF@MOFs.

This study showcases the first algorithm for predicting the synthesis of composite MOFs. “The number of predicted pairs can increase even more with the more general 2D lattice matching, and it is worth investigating in the future,” said Kim.

This story is adapted from material from KAIST, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.