Reduced Symmetry Metal-Organic Cage-to-Framework Materials

Metal-organic frameworks (MOFs) are typically assembled from inflexible, 2D aromatic linker units to provide structural predictability, rigidity and prevent architectural collapse. Limiting the pool of structural units from which these materials are derived, however, inevitably restricts the diversity of architectures that can be realised. In this work, we have explored organic cages with 1,2,3-triazole struts as 3D linkers for Ag(I)-based MOFs. These linkers are unusual in two key facets. First, the cage structure is semi-rigid, providing both shape persistence and (limited) conformational freedom. Second, in contrast to the reticular design concepts of traditional MOFs, minor structural modifications at locations remote from the coordinating units were found to induce profound changes to the resultant MOF architectures, which included 2D honeycomb structures, 2D corrugated sheets and an interpenetrated 3D network. This is the first report of the incorporation of reduced symmetry cage linkers into metal-organic cage-to-framework structures, providing a blueprint for the introduction of low-symmetry and chiral intrinsic porosity into framework materials.