Bis[(amidomethyl)pyridine] Zirconium(IV) Complexes: Synthesis, Characterization, and Activity as Olefin Polymerization Catalysts†

This contribution describes the synthesis, characterization, and olefin polymerization reactivity of bis(chelate)zirconium complexes bearing (amidomethyl)pyridine ligands [(6-X-C5H3N)CH2NC6F5, X = CH3 (Lig1H), Br (Lig2H), H (Lig3H)]. Metathesis reaction, alkane elimination, and amine elimination provided routes to compounds (Lig1)2ZrCl2 (1), (Lig1)2ZrBz2 (4; Bz = CH2C6H5), and (Lig2)2Zr(NMe2)2 (5). Attempts to prepare (Lig1)2Zr(NMe2)2 in a reaction between Zr(NMe2)4 and Lig1H led instead to compound (Lig1)(Lig1*)ZrF(NMe2) (2), in which one dimethylamino group had been exchanged with one ortho fluoride on the perfluorophenyl ring of the ligand via an aromatic nucleophilic substitution reaction. Halide displacement reaction performed on compound 2 afforded the dichloride compound (Lig1)(Lig1*)ZrCl2 (3). Reaction between Zr(NMe2)4 and Lig3H provided a mixture of (Lig3)2Zr(NMe2)2 and (Lig3)(Lig3*)ZrF(NMe2), the latter being analogous to 2. X-ray crystallographic analysis showed for compound 1 a distorted octa...