Metal Organic Framework

Metal Organic Framework List

Metal organic framework is a kind of zeolite-like material with repetitive network structure formed by self-assembly of organic ligands, inorganic ligands and metal ions. As a new type of material, metal organic framework belongs to coordination chemistry field and it is developed rapidly recently. Compared with traditional inorganic porous materials, metal organic framework has larger porosity and specific surface area. In addition, the pore size of metal organic frameworks is adjustable and they can be modified by variable functional groups. Therefore, as a new nanomaterial, metal organic framework has attracted more and more attentions.

Applications:

• Hydrogen storage field: With the improvement of the living standard and the continuous growth of population, energy has become a major issue that all countries need to face, and is also the primary issue related to the survival and development of human beings. Therefore, the demands for new green energy is extremely urgent. Due to non-environmental pollution, good thermal conductivity and various available states, hydrogen energy has become an ideal new generation energy. However, hydrogen is an unstable gas in normal temperature and pressure conditions. Thus, developing solid materials with high payload capacity and high safety during transportation is important for the application of hydrogen energy. With the advantages of large specific surface area and high stable structure, metal organic framework is an ideal hydrogen storage material.
• Gas adsorption and separation field: Adsorption separation is a green and energy-saving method for gas separation. Some metal organic frameworks have selective adsorption performance to small molecule gases, and they have attracted more attention in the application of adsorption and separation of greenhouse gases and toxic gases.
• The others: Metal organic framework can be widely used in catalytic field, including esterification reaction, dehydrogenation reaction, oxidation reaction, coupling reaction, and the others. In addition, metal organic framework has become a widely used drug carrier with high drug load, biological compatibility and functional diversity. Furthermore, some metal organic frameworks have optical, electrical and magnetic properties, so they can be applied to design fluorescent sensors, displays, conductors, and the others.

Figure 1. An example of metal organic framework applied in catalytic field.

Classification:

According to the types of organic ligands, metal ions or metal ion clusters, metal organic frameworks can be divided into the following categories.

• IR-MOF series metal organic frameworks: The IR-MOF series metal organic frameworks are developed by the Yaghi team, and they are made of [Zn₄O]⁶⁺ and aromatic carboxylic acids.

Figure 2. The structure of IRMOF-1.

• ZIF series metal organic frameworks: The ZIF series metal organic frameworks are developed by the Yaghi team, and they are composed of Zn²⁺ or Co²⁺ and imidazole.
• CPL series metal organic frameworks: The CPL series metal organic frameworks are developed by the Kondo M. team, and the key components are six coordination metal elements and carboxylic acid or neutral nitrogen-based heterocyclic molecules.
• MIL series metal organic frameworks: The MIL series are developed by the Ferey team, and they are composed of transition metals and dicarboxylic acids.
• UiO series metal organic frameworks: The UiO series metal organic frameworks are developed by the Lillerud team, and they are made of [Zr₆O₄(OH)₄]₂⁴⁺ and diformic acid.

References

1. Park J, Li J R, Chen Y P, et al. A versatile metal–organic framework for carbon dioxide capture and cooperative catalysis[J]. Chemical Communications, 2012, 48(80):9995-9997.
2. Liu J, Thallapally P K, Mcgrail B P, et al. Progress in adsorption-based CO2 capture by metal–organic frameworks[J]. Chemical Society Reviews, 2012, 41(6):2308.