A Supported Ziegler-Type Organohafnium Site Metabolizes Polypropyl-ene

Cp2Hf(CH3)2 reacts with silica containing strong aluminum Lewis acid sites to form Cp2Hf–13CH3+ paired to aluminate ani-ons. Solid-state NMR characterization shows that this reaction also forms neutral organohafnium and hafnium sites lacking methyl groups. Cp2Hf–13CH3+ reacts with isotatic polypropylene (iPP, Mn = 13.3 kDa; Đ = 2.4; mmmm = 94 %; ~110 C3H6/Hf) in the presence of H2 to form oils with moderate molecular weights (Mn = 290 - 1200 Da) in good yields. The ali-phatic oils show characteristic 13C{1H} NMR properties consistent with complete loss of diastereoselectivity and formation of regioirregular errors under 1 atm H2. These results show that a typical Ziegler-Natta type active site is compatible in a common reaction used to digest waste plastic into smaller aliphatic fragments.