Highly porous architectures through designed rational self-assembly

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Coordination polymers and metal-organic frameworks (MOFs) range from micro to mesoporous materials and have garnered a staggering amount of research interest in the past 15 years. These coordination motifs result from a large variety of metal pivots and organic linker combinations and the potential exists to synthesize rationally designed MOFs with an enormous range of applications (ex. intra-MOF catalysis of gas phase reactions related to green chemistry and fuel cell technology, facile gas storage and recovery for hydrogen- and methane-based fuel cells, CO2 sequestration in the oil-and-gas industry and unique optical based switches.) In this proposed research program, the structure-function properties of macrocycles and metal-organic frameworks with paramagnetic metals will be studied. New organic linkers will be synthesized in order to make framework that exhibit porosity at both ends of the scale: large pore size will be targeted in order to study the selective uptake of guest molecules as a function of metal oxidation state, with applications in the area of small molecule separation and storage, while small pore size will be targeted for functional materials that exhibit high metal density, with applications as materials for bit pattern media in the area of magnetic memory storage. Success in these two areas would have broad ranging implications, including vessels for the transport of cleaner burning fuels, and increased computing capabilities over current technology. The objectives required to meet these goals can be broken into three broad categories: (a) the design, synthesis and characterization of new metal-organic frameworks and coordination polymers, (b) gas adsorption studies of metal complexes as a step towards device functionalization in the area of small molecule storage, separation or memory devices, and (c) surface studies of metal complexes as a step towards device functionalization in the area of bit pattern media. In regards to the third objective, paramagnetic properties of the frameworks could allow for external stimulus to control gating properties, while introducing electron rich substituents as external anchors to the organic ligands could provide sites for possible surface attachment of the polymetallic assemblies. Magnetic MOF device application has not yet been achieved, in part due to the difficulties in the preparation of thin films of these materials, and the use of physical-stimulus to induce switching. The objectives of this research program will contribute significant new fundamental and applied knowledge in this area.