Synthesis, Characterization and Physical Properties of Alkalides and Electrides

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Abstract 9402016 Dye This research involves the synthesis and characterization of crystalline salts and vapor-deposited thin films that contain alkali metal anions (alkalides) or trapped electrons (electrides) and cations that are complexed by cyclic or bicyclic poly-oxa molecules. Particular emphasis will be given to the study of the optical, magnetic and electrical properties of single crystals using a variety of techniques. Because different electrides have widely different properties, and since their behavior often is dependent on the thermal history of the sample, new complexants will be synthesized to provide a wider assortment of crystalline electrides. Recent theoretical treatments have pointed out the importance of anionic cavities and empty channels in electrides and the extended nature of the unpaired electron wavefunction in molecular electrides. To relate experiment to theory, simple complexants for Li+, such as 9-crown-3, 12-crown-3 and cryptand 1.1.1 will be synthesized and used to prepare electrides for study. The use of alkalides and electrides to prepare nanoscale transition metal and intermetallic particles, both free and in zeolite cages will be studied. %%% This research is concerned with the synthesis and characterization of crystalline salts and vapor-deposited thin films that contain alkali metal anions (alkalides) or trapped electrons (electrides) and cations. Alkalides and electrides are two new, interesting classes of materials. Electrides, in particular, provide the unique opportunity to examine the behavior of electrons that do not "belong" to a particular atom or molecule, but rather, occupy the holes and channels between close-packed large complexed cations. They provide the opportunity to study such phenomena as non-metal to metal transitions in systems that approach a lattice of nearly free electrons, and magnetic interactions and electronic conductivity in 1, 2, and 3 dimensions. Emphasis will be given to the study of the optical, magnetic and ele ctrical properties of single crystals using many characterization methods.