Preparation of Microporous Solids from Molecular Building Blocks

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This project, funded by the Inorganic, Bioinorganic and Organometallic Chemistry Program, will support the research of Professor Omar Yaghi of Arizona State University on the synthesis of new porous solids from soluble molecular building blocks. The focus of the project is the development and understanding of two fundamental issues that are relevant to the preparation of solids from molecular building blocks: 1) how to control the relative orientation of the molecular components so that the resulting structure has the desired structure, stability and physical properties, and 2) how to obtain the solid product in crystalline form so that its structure is readily determined. The general method to be used will involve the room-temperature condensation polymerization of inorganic clusters or suitably functionalized coordination compounds using polymeric matrices as diffusion and reaction media for addition copolymerization and condensation polymerization reactions. The anticipated zeolitic type structures are expected to have voids that can accommodate guest molecules or ions and thus to be useful in separations, ion-exchange, and catalysis. In principle, these framework structures can be chemically modified and manipulated to predictably vary their properties. The term porous solid applies to a class of network solids that contain channels and voids that are comparable in size to many small molecules and ions. Such species often may diffuse into these solids to be exchanged for an existing ion or to be otherwise retained as a result of intermolecular interactions. Such solids are widely used industrially for the selective adsorption and catalytic transformation of molecular structures, particularly through acid catalyzed pathways. Such materials are usually synthesized by high temperature processes that often do not provide crystalline products. This research project will attempt the synthesis of porous solids by formation of bonds between small pre-formed fragments of the desired structure through various types of room-temperature, condensation polymerization reactions. Polymeric matrices will be used as reaction media to prevent the formation of more dense structures and to slow the condensation process such that crystals are more likely to be formed. The materials that result from this project may be useful in separations technology and in catalysis.