Hydrocarbon Bond Activation with Platinum(II) Complexes
- Author(s): Bowring, Miriam Anna
- Advisor(s): Bergman, Robert G;
- Tilley, T Don
- et al.
Chapter 1. The hydroarylation of unactivated olefins effected by Pt(II) precatalysts is found to proceed through the in situ production of protic acid followed by a Friedel-Crafts mechanism. The reaction is investigated using the hindered base 2,6-di-tert-butyl-4-methylpyridine and a variety of substrates.
Chapter 2. The catalytic cleavage of two C-C single bonds is achieved by treatment of the hydrocarbon substrate spiro[bicyclo[2.2.1]hept-2-ene-7,1'-cyclopropane] with Pt(II) catalysts such as (Me2bpy)PtPh(NTf2) (Me2bpy = 4,4'-dimethyl-2,2'-bipyridine, NTf2- = N(SO2CF3)2-). The surprising rearrangement product 1,2,4,7,7-pentahydroindene is generated in good yield. The mechanism of C-C bond activation is investigated using NMR spectroscopy, electrospray ionization mass spectrometry, and deuterium labeling, along with DFT calculations. These studies support an unusual catalytic mechanism in which an initial masked C-H bond activation initiates successive C-C bond cleavage events.
Chapter 3. A dicationic Pt complex [(tBu2bpy)Pt](NTf2)2·½ C6H6 (tBu2bpy = 4,4'-di-tert-butyl-2,2'-bipyridine) is isolated and characterized. The new complex is supported by a simple bidentate bipyridine ligand and weakly coordinating, easily displaced triflimidate counterions. The dication is competent for allylic C-H activation in aprotic, non-polar media.