Due to their uniquely ordered structures, highly porous Metal Organic Frameworks (MOFs) are preferable to Zeolites or similar oxide based materials. However, the issue with most MOFs is stability, which is largely determined by the structure of the inorganic brick and the nature of the chemical bonding between inorganic bricks and the linker.
40-1105, Zirconium 1,4‐dicarboxybenzene MOF (UiO‐66, Zr6O4(OH)4(CO2)12), which has been developed at University of Oslo in Norway, provided a breakthrough in this respect. UiO‐66 consists of an inner Zr6O4(OH)4 octahedra core that is 12‐fold connected to adjacent octahedra through a 1,4‐benzene‐dicarboxylate (BDC) linker.
The Zr‐O bonds formed between the cluster and carboxylate ligands is believed to be the source of increased stability of Zr‐based MOFs. After dehydroxylation of the cluster at 250-300°C, a lattice breakdown takes place at 540°C, when the bond between the benzene rings and the terminal carboxyl group is severed. However, connection between the linker and the inorganic brick remains active. The Zr‐O bonds formed between the cluster and carboxylate ligands are believed to be the source of increased stability of Zr‐based MOFs.
UiO‐66 has surface area of 1147m2/g (Langmuir); particle size is 0.25‐0.35 mm, and has clearly visible facets.
Reference:
1) K. P. Lillerud et al. A New Zirconium Inorganic Building Brick Forming Metal Organic Frameworks with Exceptional Stability. J. Am. Chem. Soc., 2008, 130, 13850.
Product mentioned in this blog:
40-1105: Zirconium 1,4-dicarboxybenzene MOF (UiO-66), CAS # 1072413-80-9