Design and Synthesis of Novel Octacarboxy Porphyrinic Metal-Organic Frameworks

Metal-Organic Frameworks (MOFs) are a class of nanoporous crystalline materials constructed via the interconnection between metal-ions/inorganic clusters and organic ligands. Since the surface area, pore size and distribution, and chemical functionalities of MOFs are highly tunable via the judicious combinations of inorganic clusters and organic ligands, MOFs have attracted intensive interests for a variety of applications including gas adsorption and separation, catalysis, chemical sensing, and drug delivery among others. Porphyrin based ligands are of particular interest for building functional MOFs due to their unique photo-, electro-, and catalytic properties. In addition, the four-fold symmetry of porphyrin ligands offers an effective approach for designing robust MOF structures. Conventional porphyrin ligands for MOF synthesis contain two or four terminal carboxy groups for metal binding, which requires an additional “pillar” molecule in order to form three-dimensional (3D) porous structures and inherently increases the complexity of the crystallization process. Thus, our ligand design strategy is to maintain the high symmetry and rigidity and yet increase the number of carboxy binding sites in the organic linker, which in effect eliminates the need for an additional pillar molecule. Based on our custom designed octatopic porphyrin ligand, our strategy has shown a great deal of success in forming novel 3D MOF frameworks. This dissertation focuses of the design of novel porphyrin MOFs based on our custom designed octatopic porphyrin ligand. Further, we examine performance of our porphyrin MOF systems as heterogeneous photo-catalysts and chemical catalysts