Electrophilic Metal Complexes in Bond Activations and Catalysis
Studies of electrophilic of late metal (e.g., platinum) complexes focus on C-H and N-H bond activations, particularly in the context of catalytic hydroarylation and hydroamination. For example, platinum complexes containing anionic analogs of bipyridine (e.g., 3,5-diphenyl-2-(2-pyridyl)pyrrolide, PyPyr) were used to explore C-N bond formation via couplings of amido and olefinic groups at platinum. Observed reactions proceed via external nucleophilic attack of amides onto a coordinated ethylene.1 In a collaboration with Professor Alex Bell in Chemical Engineering, mechanistic studies on hydroaminations of olefins with sulfonamides targeted a series of platinum bis(triflate) catalysts of the type L2Pt(OTf)2. Kinetic and mechanistic experiments suggest that catalytic hydroamination occurs by formation of a highly acidic species of the type [L2Pt(NH2R)(OTf)]+OTf+, which then undergoes proton transfer to a coordinated olefin. This work has broad implications for interpretation of results from catalytic reactions involving bond activations mediated by electrophilic, late metal complexes.2
