(189f) Selectively Etched Hierarchical IRMOF-3 and Its Improved CO2 Adsorption Properties

Metal-organic frameworks (MOFs) have attracted numerous research interest due to their potential applications for hydrogen storage, selective gas adsorption, catalysis, and enantioselective separation.1 With a judicious choice of organic linker groups, it is possible to fine-tune size, shape, and chemical functionality of the cavities and the internal surfaces. Among numerous MOFs, iso-reticular MOFs (IRMOFs) have been most extensively studied due to the simplicity of their synthesis and their potential applications for gas storage. IRMOFs consist of zinc-based clusters and benzenedicarboxylate (BDC) organic linkers, showing similar crystal structures.2 Especially IRMOF-3 is of particular interest due to the presence of amine groups in the linkers. These amine groups can be functionalized by post-synthetic modifications (PSM) so that both the pore size and the surface property of the MOF can be engineered.3 The amines are also important for the catalytic and CO2 sorption properties of the MOF. The catalytic and gas sorption properties of the MOFs are typically hindered by transport of molecules. Therefore, it would be desirable to create hierarchical pore structures to minimize the mass-transport limitation. In this talk, we will present the synthesis and characterization of the post-synthetically modified IRMOF-3 using cyanuric chloride (CC) (hereafterIRMOF-3-CC), for the first time. The IRMOF-3-CC shows hierarchical pore structures, which we attributeto self-limited surface modification. Various techniques were used to characterize the materials, including XPS, SEM, XRD, and nitrogen isotherm. The hierarchical IRMOF-3-CC show improved CO2 adsorption properties as compared to unmodified ones. 1 Long, J.R. & Yaghi, O.M., The pervasive chemistry of metal?organic frameworks. Chem. Soc. Rev. 38, 1213-1214 (2009). 2 Eddaoudi, M. et al., Systematic design of pore size and functionality in isoreticular MOFs and their application in methane storage. Science 295 (5554), 469-472 (2002). 3 Wang, Z.Q. & Cohen, S.M., Postsynthetic covalent modification of a neutral metal-organic framework. J. Am. Chem. Soc. 129 (41), 12368-+ (2007).