Nanoporous Frameworks with High Porosity and Unexpected Rigid Framework Topologies Based on Odd-Numbered Ring-Expanded Linkers

Two tetracarboxylic linkers containing seven-membered rings are synthesized and utilized in metal-organic framework (MOF) syntheses, leading to the two new compounds DUT-184 and DUT-193. The introduced odd angles between carboxylates in a new dihydro-azepine-containing linker lead to exotic Zn-based MOFs: a 3D structure based on two catenated sets of 2D nets in DUT-184 and a cubic structure with so far unknown topology in the DUT-193 framework. The mesoporous DUT-193 shows high porosity upon adsorption of N-2, Ar, CH4, and CO2 at their standard boiling points. Grand canonical Monte Carlo simulations show good agreement between experimental and theoretical results and shine light on the microscopic adsorption mechanism at low pressure.