Trifluoromethoxy- and Fluorobenzhydryl-Tuned Nickel Catalysts for Polyethylene Elastomers.

A series of -trifluoromethoxy-substituted and fluorobenzhydryl-functionalized 1,2-bis(imine)acenaphthene ligands: 1-[2,6-{(4-F-CH)CH}-4-FCOCHN]-2-(ArN)CCH (Ar = 2,6-MeCH, 2,6-EtCH, 2,6-iPrCH, 2,4,6-MeCH, 2,6-Et-4-MeCH), were synthesized and used to generate their corresponding nickel(II) bromide complexes (-). Elemental analysis, F NMR, and FT-IR spectroscopy were employed to characterize these five nickel complexes. Single-crystal X-ray diffraction of and confirmed distorted tetrahedral geometries. Upon activation with either EtAlCl (ethylaluminum dichloride) or EASC (ethyl aluminum sesquichloride), these complexes showed exceptional high activities (up to 22.0 × 10 g PE mol (Ni) h) and remarkable thermal stability (4.82 × 10 g PE mol(Ni) h at 80 °C) towards ethylene polymerization. The resulting polyethylenes are highly branched, with the type and extent of branches tunable by temperature, solvent, and co-catalyst choice. Moreover, these polymers demonstrated excellent tensile strength ( up to 20.7 MPa) and elastic recovery (up to 58%), characteristic of thermoplastic elastomers (TPEs). These results highlight the dual role of trifluoromethoxy and fluorobenzhydryl groups in enhancing catalytic performance and polymer properties.