Alkoxides of group 4 metals containing the bis(imino)phenoxide ligand: synthesis, structural characterization and polymerization studies

A variety of group 4 metal compounds containing the bis(imino)phenoxide backbone were synthesized from the reaction of suitable ligands and group 4 metal alkoxides. They were completely characterized with different spectroscopic techniques and single-crystal X-ray diffraction studies on a few of them. These compounds were found extremely active towards the bulk polymerization of epsilon-caprolactone (CL), delta-valerolactone (VL), rac-butyrolactone (rac-BL), L-lactide (L-LA) and raclactide (rac-LA) yielding polymers with high number average molecular weight (M-n) and controlled molecular weight distribution (MWD). The kinetics and mechanistic studies associated with these polymerizations have been performed. In addition, the catalytic activity of these compounds towards the polymerization of ethylene was investigated.