Part I. Coordination chemistry of high-valent osmium polyanionic chelating ligand complexes with imine, imido and nitrido ligands. Part II. Asymmetric hydrogenation using a resolved chiral scandium hydride complex

Citation

Barner, Claudia Jane (1990) Part I. Coordination chemistry of high-valent osmium polyanionic chelating ligand complexes with imine, imido and nitrido ligands. Part II. Asymmetric hydrogenation using a resolved chiral scandium hydride complex. Dissertation (Ph.D.), California Institute of Technology. https://resolver.caltech.edu/CaltechETD:etd-06112007-095040

Abstract

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Part I: The chemistry of high-valent osmium polyanionic chelating ligand complexes with imine, imido and nitrido ligands is explored. The synthesis and x-ray diffraction study of Os([...]-HBA-B)(NC6H5NHC6H4) is reported. A neutral, octahedral Os(VIII) intermediate complex is postulated. The synthesis and x-ray diffraction study of [OsN([...]-HBA-B)]- is reported. The mechanism of formation is discussed. These complexes represent two of the first examples of non-planar amide ligands in transition metal chemistry. The synthesis of a five-coordinate imido complex, Os(N-C10H16), is reported. The formation of the first osmium-osmium quadruply-bonded complex, [Os([...]-HBA-B)]2, is reported. Reactions with the nitrido complex, [OsN([...]-HBA-B)]-,and the methylimido complex, OsNMe([...]-HBA-B), are also reported.

Part II: The asymmetric hydrogenation of the prochiral substrate, methylene indane, is induced by the resolved chiral scandium complex, Me2Si([...]-C5Me4)([...]-(C5H3(1R,2R,5S)-menthyl)ScH, in substoichiometric quantities. Methylene indane is hydrogenated to produce methylindane with an enantiomeric excess of 34% and a maximum turnover of four.

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