Hongfan Hu - Petrochina Petrochemical Research Institute, Petrochina Company Limited, Beijing ۱۰۲۲۰۶, China
Rongqing Ma - Provincial Key Laboratory of Polyolefin New Materials, College of Chemistry & Chemical Engineering, the Northeast Petroleum University, Daqing ۱۶۳۳۱۸, China
Chenxi Cui - Petrochina Petrochemical Research Institute, Petrochina Company Limited, Beijing ۱۰۲۲۰۶, China
Guoliang Mao - Provincial Key Laboratory of Polyolefin New Materials, College of Chemistry & Chemical Engineering, the Northeast Petroleum University, Daqing ۱۶۳۳۱۸, China
Shixuan Xin - Petrochina Petrochemical Research Institute, Petrochina Company Limited, Beijing ۱۰۲۲۰۶, China

Due to the large ionic radius and high electro-positivity nature, rare earth metal complexes are difficult to stabilize and undergo pathways like ligand redistribution and intramolecular C-H activation. To solve such problems and retain reactive versatility, rare earth complexes supported by a variety of tridentate PNP pincer ligands have been explored. Such complexes can serve as perfect precursors for preparing ultra-active rare earth species containing two metal-carbon bands, let alone Ln=N and Ln=P multiple bonds. In addition, the combined stability and activity of the cation rare earth mediates made them the best catalysts for the polymerization of olefins and other non-polar hydrocarbon monomers, especially conjugated dienes. The practical utilization of rare earth metal catalysts for new materials production have also extensively explored by experts from the academic and industries.

PNP ligand, rare earth metals, Lanthanides, Reactivity, catalysis