Comparison of structurally analogous Zn2, Co2, and Mg2 catalysts for the polymerization of cyclic esters.

Breyfogle LE, Williams CK, Young VG, Hillmyer MA, Tolman WB

Three dimetallic monoethoxide complexes supported by a binucleating phenoxide ligand, LM2Cl2OEt (M = Zn, Co, or Mg), were prepared and shown by X-ray crystallography to be structurally analogous. Comparative studies of their cyclic ester polymerization reactivity revealed different trends for reactions with epsilon-caprolactone and lactide, however, implicating complicated effects of metal ion variation in these polymerizations.