Metal complexes containing nitrogen-heterocycle based aryloxide or arylamido derivatives as discrete catalysts for ring-opening polymerization of cyclic esters

The development of well-defined homogeneous catalysts for the ring-opening polymerization (ROP) of cyclic esters has made enormous progress over the past decade. This perspective focuses on some recent advances in the field of discrete metal complexes modified by various aryloxide or arylamido ligands bearing the nitrogen-containing heterocycle moiety, and their catalytic applications in ROP of lactones. It mainly highlights aryloxide/arylamido ligands that are directly installed by the N-heterocyclic group. The complex structure-ROP performance relationships and the observed trends with respect to their catalytic efficiency affected by ligand modifications are also discussed.