Synthesis and Applications of Isoreticular Metal–Organic Frameworks IRMOFs-n (n = 1, 3, 6, 8)

Isoreticular metal–organic frameworks (IRMOFs) are a series of MOFs that own similar network topology. By simple substitution of organic linkers of IRMOF-1 (i.e., MOF-5), other IRMOFs can be obtained and have unique features such as large BET surface areas and high chemical stability. IRMOF has been exalted to be an important branch of MOFs because the unique features endow IRMOF with potential applications including adsorption, catalysis, and sensing. Large BET surface areas of IRMOFs make them candidates for adsorbing small gases such as H2, CO2, and CH4. Additionally, IRMOF-3, IRMOF-6, and IRMOF-8 can separate various mixtures. Due to different catalytic active sites and pore sizes, IRMOFs can catalyze a wide range of reactions. For instance, IRMOF-1 is able to catalyze the Friedel–Crafts alkylation reaction because of its coordination-unsaturated open metal sites. NH2-containing IRMOF-3 acts as a basic catalyst for Knoevenagel condensation. Many keen sensors have been fabricated based on luminescent IRMOF-1 and IRMOF-3. IRMOF-8 with high porosity can be utilized to synthesize electrochemical sensor. This Review mainly introduces the applications of IRMOFs-n (n = 1, 3, 6, 8) and their derivatives in adsorption, catalysis, and sensing. Moreover, different strategies for synthesis and modification of IRMOFs are compared and discussed in this Review. The experiments and proposed mechanisms related to the applications of IRMOFs-n (n = 1, 3, 6, 8) are also summarized to provide an overview of IRMOFs.