C−H Bond Activation by Dicationic Platinum(II) Complexes

Double protonolysis of diimine platinum dimethyls [(N-N)PtMe2] (N-N = ArNC(Me)C(Me)NAr)
generates dicationic Pt(II) complexes that can activate a variety of C−H bonds, liberating 1 equiv of
acid and forming organoplatinum species that are moderately stable to the resulting acidic conditions.
Ethylbenzenes lead to η3-benzyl complexes; mechanistic experiments suggest that η3-benzyl product
formation proceeds via C−H bond activation at the benzylic methylene position. In some cases π-arene
complexes can be observed, but their role in the C−H activation process is not clear. Cyclohexane and
1-pentene react to give η3-allyl complexes; allylbenzene gives a chelated phenyl-η2-olefin structure, as
determined by X-ray diffraction. No stable C−H activation products are obtained from methylbenzenes,
benzene itself, or alkanes.