Catecholate complexes of zirconium: Synthesis, spectroscopic characterization and polymerization studies

Varieties of new catecholate complexes containing zirconium were synthesized in high yields and purity. These derivatives are potent initiators for the ring-opening polymerization (ROP) of rac-lactide, l-lactide, ε{lunate}-caprolactone, δ-valerolactone, rac-β-butyrolactone, ethylene and propylene. The number-average molecular weights of the resulting polymers are slightly higher than the theoretical molecular weight and they have controlled molecular weight distributions. The isopropoxide moiety in these complexes is responsible for initiating the ROP. For ethylene and propylene polymerization, we were able to achieve good activity using methylaluminoxane as a co-catalyst. © 2013 Society of Chemical Industry.