Synthesis of a Hydrophobic/Hydrophilic Nano-Patterned Metal-Organic Framework Material

Metal-Organic Framework (MOF) materials are supramolecular structures that are formed from the assembly of organic molecules that[AL1] have multiple binding sites with compatible metal cations. The resulting structure is a uniform and porous 3D grid-like with metal vertices that are connected by organic linkers. MOFs have several potential uses such as catalysis, detection, and gas storage, and new strategies to synthesize functional MOFs continue to be developed. One strategy is post synthetic modification (PSM), a process where different chemical groups are grafted onto the organic linkers via chemical reaction. The main objective of this research is to demonstrate that a MOF material with two different channels can be functionalized with two incompatible chemical groups resulting in the groups self-sorting into different channels. Onto a bifunctional MOF material we first graft a hydrophobic carbon chain, then we graft a hydrophilic carboxylic acid chain. The synthesis scheme involves three chemical reactions: The synthesis of our MOF KSU-1, a PSM targeting the -NH2 group in KSU-1 with hexanoic anhydride, and a second PSM targeting the -OH group in KSU-1 with succinic anhydride. KSU-1 uses zinc nitrate as the metal, 2-aminoterephthalic acid (BDC-NH2), and meso-α,β-di(pyridyl) Glycol (DPG). The material uses N,N-dimethylformamide as the solvent but switches to chloroform for both PSMs. Proton nuclear magnetic resonance (1H-NMR) spectroscopy and powder X-ray diffraction (PXRD) will be used to confirm product formation. Thermogravimetric analysis (TGA) experiments will be used to determine whether the different functionalities have self-sorted into different channels