Assigning New Functions to Zeolitic-Imidazolate Framework ZIF-8 Membranes Via Post Synthetic Modifications

Assigning new functions to Zeolitic-imidazolate Framework ZIF-8 Membranes via Post Synthetic Modifications

Hyuk Taek Kwon¹, and Hae-Kwon Jeong*^1,2

¹Artie McFerrin Department of Chemical Engineering and ²Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843-3122

* Corresponding author: hjeong7@tamu.edu

Material properties of metal organic frameworks (MOFs) can be fine-tuned via a couple of strategies. One is the direct construction of MOFs with pre-designed ligands and metal ions having customized functions.¹ The other is post synthetic treatments, for instance, ligand/metal exchange (PSE) and/or post synthetic modification (PSM) on organic ligands enabled due to the labile nature of MOFs.¹ The former approach has less freedom in terms of property modification due to the fact that the crystallization of MOFs is very specific to synthesis conditions such as temperature, solvent properties, and precursor ratio where ligands and synthesis solvents play a role of structure directing agents.¹ On the other hand, the post synthetic treatments performed in rather mild conditions can impart new functions to parent MOFs in a rather facile manner, which are difficult obtained via a direct synthesis as proven on a series of MOFs.^1-4  Compared with extensive PSE and PSM studies on bulk MOF powders, however, only limited examples of the post synthetic treatments on MOF films^5,6 and membranes⁷ are available.   

Here, we would like to present the modification of chemically inert ZIF-8 membranes via PSM and/or subsequent PSM. The effect of newly introduced functional groups on membrane properties such as gas separation performance and water stability (hydrophobicity) will be systematically discussed.

 

References and Notes

1.         Tanabe KK, Cohen SM. Postsynthetic modification of metal-organic frameworks-a progress report. Chemical Society Reviews. 2011;40(2):498-519.

2.         Fei H, Cahill JF, Prather KA, Cohen SM. Tandem Postsynthetic Metal Ion and Ligand Exchange in Zeolitic Imidazolate Frameworks. Inorganic Chemistry. 2013/04/01 2013;52(7):4011-4016.

3.         Kim M, Cahill JF, Fei H, Prather KA, Cohen SM. Postsynthetic Ligand and Cation Exchange in Robust Metal–Organic Frameworks. Journal of the American Chemical Society. 2012/10/31 2012;134(43):18082-18088.

4.         Liu B, Ma M, Zacher D, et al. Chemistry of SURMOFs: Layer-Selective Installation of Functional Groups and Post-synthetic Covalent Modification Probed by Fluorescence Microscopy. Journal of the American Chemical Society. 2011/02/16 2011;133(6):1734-1737.

5.         Wang Z, Liu J, Arslan HK, et al. Post-Synthetic Modification of Metal–Organic Framework Thin Films Using Click Chemistry: The Importance of Strained C–C Triple Bonds. Langmuir. 2013/12/23 2013;29(51):15958-15964.

6.         Fei H, Pullen S, Wagner A, Ott S, Cohen SM. Functionalization of robust Zr(iv)-based metal-organic framework films via a postsynthetic ligand exchange. Chemical Communications. 2015;51(1):66-69.

7.         Huang A, Caro J. Covalent Post-Functionalization of Zeolitic Imidazolate Framework ZIF-90 Membrane for Enhanced Hydrogen Selectivity. Angewandte Chemie International Edition. 2011;50(21):4979-4982.