Isotactic-Specific Polymerization of Propene by aCs-Symmetric Zirconium(IV) Complex Bearing a Dianionic Tridentate [−NNN−] Amidomethylpyrrolidepyridine Ligand

The synthesis and characterization of a new tridentate amidomethylpyrrolidepyridine ligand ( LigH 2 ) and of the corresponding LigZr(NMe 2 ) 2 complex ( 1 ) are described. Characterization of 1 by single-crystal X-ray diffraction analysis showed a slightly distorted square-pyramidal geometry. Variable-temperature NMR analysis suggested that 1 adopts a C s -symmetric structure in solution. Complex 1 in combination with Al i Bu 2 H and methylalumoxane afforded a highly active single-site catalyst for the polymerization of ethylene and propene, producing ultrahigh molecular weight linear polyethylene and isotactic polypropylene via an “ enantiomorphic sites” mechanism of steric control.