9. Transformation of Metal–Organic Framework Secondary Building Units into Hexanuclear Zr-Alkyl Catalysts for Ethylene Polymerization

Pengfei Ji†, Joseph B. Solomon†, Zekai Lin, Alison Johnson, Richard F. Jordan, and Wenbin Lin* 

We report the stepwise and quantitative transformation of the Zr₆(μ₃-O)₄(μ₃-OH)₄(HCO₂)₆ nodes in Zr-BTC (MOF-808) to the [Zr₆(μ₃-O)₄(μ₃-OH)₄Cl₁₂]^6– nodes in ZrCl₂-BTC, and then to the organometallic [Zr₆(μ₃-O)₄(μ₃-OLi)₄R₁₂]^6– nodes in ZrR₂-BTC (R = CH₂SiMe₃ or Me). Activation of ZrCl₂-BTC with MMAO-12 generates ZrMe-BTC, which is an efficient catalyst for ethylene polymerization. ZrMe-BTC displays unusual electronic and steric properties compared to homogeneous Zr catalysts, possesses multimetallic active sites, and produces high-molecular-weight linear polyethylene. Metal–organic framework nodes can thus be directly transformed into novel single-site solid organometallic catalysts without homogeneous analogs for polymerization reactions.