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

Neutral ZrIV and HfIV 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 centralσ-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 ZrIV and HfIV dimethyl complexes were convertedin situ into cationic species [MIV{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.