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Reticular Chemistry-Guided Synthesis and Post Synthesis Functionalization of Novel Zirconium-Based Metal-Organic Frameworks
Abstract
Metal-organic frameworks (MOFs), belonging to a class of crystalline porous materials, have gained prominence over the past few decades. Comprising of organic linkers and inorganic secondary building units (clusters or single metal ions), these materials by way of solvothermal synthesis, self-aggregate by coordinate covalent bonding to form highly ordered and extended two or three-dimensional structures. The ability to carefully select the functionality and symmetry of the organic linker has resulted in the discovery of hundreds of MOFs with fascinating properties that have found important applications in heterogeneous catalysis, solar energy conversion, gas storage, and separation, among many others.Guided by the principles of reticular chemistry, we construct Zr-MOFs largely based on planar and tetrahedral tetratopic ligands. The highlights of our work include the symmetry-guided, one-pot synthesis of mixed-ligand MOFs for light-harvesting and energy transfer (EnT), using two topologically distinct and photoactive linkers. The mixed ligand MOF (NPF-500-H2TCPP) act as an efficient EnT system, which is exemplified by time resolved fluorescence spectroscopy and utilized to enhance the photocatalytic efficiency of oxygenation of thioanisole. In addition, we explore the structural diversity of tetrahedral ligands, by synthesizing a series of N,N’-Bicarbazole ligand rotamers. This leads to a very rare zirconium cluster, whose utility is currently under study towards heterogenous catalysis. By using planar tetratopic ligands, we demonstrate the rational design of Zr-MOFs based on the scu topology via symmetry reduction from the ftw topology. The unmodified pristine MOF, NPF-600, offer the capability to incorporate four secondary bifunctional linkers to metalate a second type of metal center inside the framework. This strategy shows the importance of design factors to consider for constructing multicomponent MOFs via post synthetic linker insertion and metalation. Finally, we utilize the concept of Isoreticular expansion and contraction to assemble a series of hierarchally porous Zr-MOFs based on the csq topology. The structural flexibility of the framework allows for the post synthesis incorporation of three functionally distinct secondary ligands.
Subject Area
Chemistry
Recommended Citation
Fiankor, Christian, "Reticular Chemistry-Guided Synthesis and Post Synthesis Functionalization of Novel Zirconium-Based Metal-Organic Frameworks" (2022). ETD collection for University of Nebraska-Lincoln. AAI29208356.
https://digitalcommons.unl.edu/dissertations/AAI29208356