Titanium pyridonates for the homo- and copolymerization of rac-lactide and ε-caprolactone

A series of titanium pyridonate complexes have been synthesized under very mild reaction conditions from a common precursor, Ti(NMe2)4. These complexes have been explored as initiators for the ring-opening polymerization of rac-lactide and ε-caprolactone and have proven to be competitive with leading titanium initiators. Furthermore, these complexes have been shown to be competent initiators for the synthesis of copolymers (CL–LA block copolymers and random copolymers). Metal complex reactivity trends in both homo- and copolymerization show that poly(lactic acid) is most susceptible to chain scission and transesterification.