Organometallic Magnetic Couplers

The subject of this research proposal is a systematic study of the magnetic interactions between purely organic radicals using organometallic systems as spin-coupling bridges. As organic radicals nitronyl nitroxides will be used and metallocenes or metal-phorphyrins will serve as couplers. The synthesis, detailed spectroscopic characterization, reactivity and magnetochemical properties of this class of compounds will be investigated in detail. The knowledge of the molecular packing studied by single-crystal X-ray analysis is crucial in order to understand and correlate the bulk properties of a given material with its microscopic characteristics. The metallocenes can act as spin couplers and additionally as redox-active electrophores, enhancing thereby magnetic interactions between attached nitronyl nitroxide radicals. The phenomenon of magnetic coupling can also be transmitted by conjugated bridges connecting the organometallic-system and the nitronyl nitroxide radicals. Based on the results obtained already on metallocenes (Fe, Ru, Os) with nitronyl nitroxide radicals the proposed goal of synthesizing and investigating new organometallic magnetic compounds will be achieved. Specifically the epr and magnetic susceptibility of one two or more nitronyl nitroxide radicals attached to ferrocene or other open shell metallocenes like cobaltocene or metal-phorphyrins will reveal trends for the improvement in the design of new magnetic materials.