Increasing the Stability of Metal-Organic Frameworks

Figure 2

The copper paddlewheel unit of the PCN-6X series, found in many MOFs. Typically, it is coordinated equatorially by 4 ligand carboxylates, while the axial ligands are solvent molecules that may be removed by activation. The zinc paddlewheel is almost identical, but unlike the copper paddlewheel, attempted activation usually causes framework collapse.