A neutral trianionic pincer [NCN]CrIV–Me complex as a highly active ethylene polymerization precatalyst

Trianionic pincer ligands are a new class of ligands that constrain three anionic metal–ligand bonds to the meridional plane and are capable of supporting highly reactive metal species exploitable for alkene polymerization. The previously reported NCN3- trianionic pincer CrIV–Me complex [2,6-iPrNCN]CrIV(Me)THF (1), upon activation by triisobutylaluminum (TIBA), catalyzes the polymerization of ethylene. Complex 1 (1 μmol) in the presence of 35 equiv. of TIBA polymerizes ethylene with an activity of 7.02 × 106 g PE(molCr)−1 h−1 (75 °C).