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|Title:||High Oxidation State Organometallic Chemistry: The Synthesis and Reactivity of nitridoruthenium(VI) Alkyl Complexes|
|Author(s):||Schwab, Joseph John|
|Doctoral Committee Chair(s):||Shapley, Patricia A.|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The reaction chemistry of anionic nitridoruthenium(VI) alkyl complexes has been studied. Reactions at the nitrido nitrogen as well as the ruthenium center have been used to synthesize several new ruthenium(VI) complexes. As with nitridoosmium(VI) alkyl complexes, the nitrido ligand was found to undergo alkylation reactions with a variety of electrophiles to give unstable imidoruthenium(VI) complexes. Treatment of the tetraalkyl complexes with Bronsted acids results in protonation of the alkyl ligands.
Nitridoruthenium(VI) complexes were also used to model the reactivity of isopenicillin N synthetase, an enzyme responsible for the biosynthesis of cephalosporin and penicillin antibiotics. Protonation of the nitridoruthenium(VI) tetraalkyl complexes with either 3-mercaptopropionic acid or N-acetyl-L-cysteine provides nitridoruthenium(VI) dialkyl complexes containing the covalently bound 3-mercaptopropionato and N-acetyl-L-cysteinato ligands. Reaction of nitridoruthenium(VI) trimethylsiloxide complex with 3-mercaptopropionamide gives the nitridoruthenium(VI) complex containing two 3-mercaptopropionamidato ligands. The ruthenium complexes are compared to a similar series of nitridoosmium complexes containing the same ligands. The synthesis these complexes provides a model for the binding of $\delta$-(L-$\alpha$-aminoadipyl)-L-cysteinyl-D-valine to iron in the active site of isopenicillin N synthetase.
Several neutral and cationic complexes containing labile solvent ligands, as well as some coordinatively unsaturated complexes were also synthesized. Neutral nitridoruthenium(VI) trialkyl complexes can be trapped with aromatic amines or phosphine ligands. Cationic nitridoruthenium(VI) dialkyl complexes containing two pyridine or acetonitrile ligands are prepared by the protonation of the trapped trialkyl complexes with pyridinium tetrafluoroborate or tetrafluoroboric acid in acetonitrile respectively. These very reactive complexes show a wide variety of reactivities including ethylene polymerization.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1993.
|Date Available in IDEALS:||2014-12-17|