Polymerization of propylene by Cp*TiMe2(mu-Me)B(C6F5)(3) in the presence of increasing partial pressures of H-2 results in ever decreasing polymer molecular weights, which is consistent with the hydrogenolytic chain transfer processes involving metal-polymer bonds in many heterogeneous and homogeneous systems. However, catalytic activities are not significantly increased as the extent of hydrogenolysis increases, unlike metallocene catalyst systems in which the H-2 reacts primarily with dormant catalytic sites containing propylene 2,1-insertion products. It was shown previously that monocyclopentadienyl systems do not become seriously deactivated following 2,1 insertions, and thus hydrogenolysis does not result in enhanced activities.