Solid-State Reactions of Molecular Crystals

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TECHNICAL EXPLANATION This project will explore natural processes that take place within, or on the surface of, aggregates or molecular crystals. In order to understand these processes, and more importantly, to learn how to control them, the most fruitful approach is to study reactions in crystalline solids. Such reactions also hold considerable promise for the synthetic chemist, since many of them are highly selective, giving products of very high purity that are often not available from solution processes. The proposed research will identify and exploit efficient new, unprecedented reactions that occur in the absence of solvent. Beyond the new materials obtained in the research, reactions in this environmentally-friendly area of "Green Chemistry" promise to require less energy, and produce less waste, than their solution counterparts. Primary instruction in solid-state and materials chemistry (symmetry, crystallography and reactions) is being distributed through sets of interactive PowerPoint courses, one of which is already available on the PI's website. With a view to establishing a firm educational base and stimulation for budding scientists, the approach will be implemented in a secondary school version, covering symmetry and early concepts in solid-state chemistry, in collaboration with local high school teachers. For US scientists to sustain a leadership role in chemistry and materials science in the 21st century, it is critical that the current and coming generations receive the best possible technical instruction. Participants will receive key training in the physical and synthetic aspects of materials and environmentally-benign chemistry, and will have the opportunity to work abroad during their training period through NSF International and Max Planck Research School programs.NON-TECHNICAL EXPLANATIONStudies of solid-state reactions offer exceptional opportunities for the discovery of new classes of materials that undergo stereospecific intermolecular transformations. In these unusual processes, where crystalline metal salts and organic materials are treated with heat, UV or gamma-rays, only one out of several possible chemically distinct isomers is produced. In addition to providing state-of-the-art training for students, studies using X-ray crystallography, full product characterization, isotopic labeling, laser photochemistry and X-ray topography will yield a detailed understanding of the geometrical, physical and chemical mechanisms of intermolecular reactions in solids. Overall, the proposed work, as a contribution to "Green" chemistry, promises to yield new, efficient solventless processes, as well as providing a mechanistic basis for understanding how those processes occur. In addition, an interactive PowerPoint-based course in Space Group Symmetry, a primary area of instruction in solid-state chemistry, is available from the PI's website. The novel learning approaches will be implemented in a secondary school version, covering symmetry and beginning concepts in solid-state chemistry, in collaboration with local high school teachers. For U.S. scientists to sustain a leadership role in chemistry and materials science in the 21st century, it is critical that the current and coming generations receive the best possible technical instruction.