Cationic Group-IV pincer-type complexes for polymerization and hydroamination catalysis

Neutral Zr-IV and Hf-IV dimethyl complexes stabilized by unsymmetrical dianionic {N, C, N'} pincer ligands have been prepared from their corresponding bis-amido complexes upon treatment with AlMe3. Their structure consists of a central s-bonded aryl donor group (C) capable of forming robust M-C bonds with the metal center, enforced by the synergic effect of both the coordination of peripheral donor groups (N) and the chelating rigid structure of the {N, C, N} ligand framework. Such a combination translates into systems having a unique balance between stability and reactivity. These Zr-IV and Hf-IV dimethyl complexes were converted in situ into cationic species [M-IV{N-, C-, N} Me][B(C6F5)(4)] which are active catalysts for the room temperature (r.t.) intramolecular hydroamination/cyclization of primary and secondary aminoalkenes as well as for the high temperature ethylene-1-octene copolymerizations.