Synthesis and Reactivity of Metallaradicals

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9421802 Theopold University of Delaware Dr. Klaus H. Theopold, Chemistry Department, University of Delaware, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division to study the reaction chemistry of paramagnetic organometallic compounds. The project concentrates on chromium and is directed, in part, toward understanding and developing Cr based catalysts. A series of Cr(III) alkyls, higher oxidation state oxochromium alkyls, and chromium alkylidenes in which the Cr oxidation state is greater than (III) will be prepared. The goals of this phase of the investigation will be to obtain cationic, catalytically active species, ones which indicate the existence of agostic ligand-chromium interactions, and species which will serve as oxidants in organic reactions. In order to explore the interactions between paramagnetic Cr ions, a series of chromium-hydride clusters which may behave as molecular magnets will be sought. Uniting the oxo-complex and cluster themes, a series of complexes with an oxo-cubane or related core will be prepared. These will model several important commercial olefin polymerization catalysts. Electrons behave like little magnets. In many metal compounds there are an even numbers of electrons which align so that the magnetism of one is canceled by another. However, there are a few compounds which have an odd number of electrons and, consequently, these compounds behave as small magnets. In addition, an odd number of electrons often leads to increased chemical reactivity. The object of this project is to prepare a number of different types of these "paramagnetic" complexes. These species will then be evaluated as new reagents, as catalysts for important industrial processes, and as magnetic materials.