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.