Topological Transformation and Dimensional Reduction in Multicomponent Metal–Organic Frameworks for Gas Separations

Abstract

Multicomponent MOFs have offered a wide range of opportunities to harness new properties. However, the synthesis of multicomponent MOFs remains challenging. This work demonstrates the synthesis of a family of multicomponent MOFs by topological transformation from well‐established multicomponent partitioned acs (pacs) structures. Such transformation is based on the new understanding on the self‐assembly process of pacs MOFs. A key to this understanding is that pacs structures, topologically regarded as the introduction of a pore‐partitioning ligand into MOF‐235/MIL‐88 type framework, are likely to be formed in a layer‐pillar‐layer fashion in practical reactions. As the π–π interaction between layers and other chemical interactions during the self‐assembly process are recognized, the structural transformation can be modulated from 3D pacs structures to 2D interrupted pacs structures (denoted i‐pacs). It is especially noteworthy that such dimensional reduction is first observed in metal‐organic frameworks and the i‐pacs MOFs contain four structural modules and up to five components, which have the highest complexity among 2D MOFs. Interestingly, the i‐pacs MOFs have significantly enhanced performance for CO₂/N₂ separation in comparison with pacs MOFs.