Synthesis and reactivity of ruthenium alkyl and aryl complexes and their application towards aromatic C-H bond activation and olefin hydroarylation

by 1972- Lail, Marty A.

LAIL, MARTY A. Synthesis and Reactivity of Ruthenium Alkyl and Aryl Complexes and Their Application towards Aromatic C-H Bond Activation and Olefin Hydroarylation. (Under the direction of T. Brent Gunnoe .) Herein we report on a Ru(II) system, TpRu(CO)(NCMe)(Ph) {Tp = hydridotris(pyrazolyl)borate} that activates the C-H bonds of aromatic substrates towards addition across unsaturated C-C bonds. Details of the mechanism of catalysis were elucidated both experimentally and computationally. In addition, the potential for an assymmetric RuIII complex seemed a promising route towards a more reactive hydroarylation catalyst and encouraged us to explore single-electron oxidation sequences of the Ru(II) complexes TpRu(L)(L?)(R) (L = CO, L? = NCMe, and R = Me or CH2CH2Ph; L = L? = PMe3 and R = Me). The putative Ru(III) systems [TpRu(L)(L?)(R)][OTf] (OTf = trifluoromethanesulfonate) undergo reductive elimination through bond homolysis and returns to formal Ru(II) oxidation states. We also sought to synthesize a second generation of Ru(II) scorpionate complexes, TpRu(L)(L?)R {L = phosphine, L’ = phosphine or NCMe, R = Me or Ph} using phosphine ligands in place of CO which could activate C-H bonds and potentially serve as hydroarylation catalysts. Synthesis and Reactivity of Ruthenium Alkyl and Aryl Complexes and Their Application towards Aromatic C-H Bond Activation and Olefin Hydroarylation by Marty A. Lail A dissertation submitted to the Graduate Faculty of North Carolina State University In partial fulfillment of the Requirements for the degree of Doctor of Philosophy