Alfa Chemistry Introduces Five Typical Metal Organic Frameworks (MOFs)

Metal-Organic Frameworks, commonly known as MOFs, are hybrid porous materials consisting of metal ions or clusters connected by organic ligands. These materials have transformed the material science industry due to their unique characteristics such as extremely high surface area, tunable pore size, low density, and unparalleled chemical diversity, and have a wide range of applications, such as gas storage, gas separation, catalysis, drug delivery, and sensing, among others. There are several types of MOFs, each with its unique characteristics and advantages. Some typical examples include MOF-5, Zeolitic Imidazolate Frameworks (ZIFs), HKUST-1, UiO-66, and MIL-53.
 
MOF-5
This is one of the first MOFs to be synthesized, by Omar M. Yaghi and his group in 1999. Its structure, a cubic lattice, is composed of zinc and 1,4-benzenedicarboxylic acid. MOF-5 is a pioneer in showing the proof-of-concept for MOFs and their high surface area (approximately 3300 m2/g). Exceptional surface area, superior to many materials, make MOF-5 an excellent candidate for gas storage such as hydrogen and carbon dioxide. Also, the modifiable structure supports incorporation of different functional groups for diverse applications, including the capture of harmful gases, catalysis, and drug delivery.
 
Zeolitic Imidazolate Frameworks (ZIFs)
Following this, stepping into ZIFs is exciting. They are a subclass of MOFs with zeolite-like topology, hence the name. ZIFs are composed typically of zinc or cobalt with imidazolate linkers with permanent microporosity and high surface area. The types of MOFs are prolific and include well-known structures like ZIF-8 and ZIF-67. And they exhibit exceptional gas separation properties and can also hold large quantities of gas, which have been demonstrated to be an excellent choice for the capture and storage of carbon dioxide. Notable for their high thermal and chemical stability, they are potential candidates for harsh application conditions.
 
HKUST-1
HKUST-1, also recognized as MOF-199 or Cu-BTC, is named after the Hong Kong University of Science and Technology where it was synthesized. This blue colored MOF is structurally composed of copper paddle-wheel clusters linked with benzene-1,3,5-tricarboxylate ligands. The open metal sites and high porosity make it significantly efficient for gas adsorption and separation. This includes the adsorption of methane, carbon dioxide, hydrogen, and more. Moreover, its unique potential in catalysis and sensing is also still under exploration.
 
UiO-66
Another noteworthy MOF is UiO-66, named after the University of Oslo where it was first synthesized. It is composed of zirconium ions linked by terephthalate (BDC) ligands. Its distinctive feature is its exceptional stability, owed to the strong bonds between the nodes and linkers. This stability allows UiO-66 to endure even harsh processing conditions, making it a good candidate for numerous applications. Some examples include heterogeneous catalysis, sensor technologies, and toxic gas removal.
 
MIL-53
MIL-53 is constructed from aluminium or chromium ions and terephthalate (BDC) ligands, which has a unique breathing effect – an ability to drastically adjust its pore size with the change in external stimuli, like temperature or pressure. This breathing MOF is interesting for applications like adsorption, separation, and drug carrier, being able to trap and release substances with the shift of external conditions.
 
To sum up, these typical MOFs mentioned manifest the impressive versatility of such materials in terms of structure and application. Their fascinating properties and potentials are not only opening diverse doors for their deployment but also inspiring the continuous exploration and development in the realm of MOFs. The future of MOFs is indeed promising and exciting to anticipate.