Aluminum Salen Complexes Modified with Unsaturated Alcohol: Synthesis, Characterization, and Their Activity towards Ring-Opening Polymerization of ε-Caprolactone and D , L -Lactide.

A highly efficient one-step approach to the macromonomer synthesis using modified aluminum complexes as catalysts of ring-opening polymerization (ROP) of ε-caprolactone and D , L -lactide was developed. The syntheses, structures, and catalytic activities of a wide range of aluminum salen complexes, 3a-c , functionalized with unsaturated alcohol (HO(CH 2 ) 4 OCH=CH 2 ) are reported. X-Ray diffraction studies revealed a tetragonal pyramidal structure for 3c . Among the complexes 3a - c , the highest activity in bulk ROP of ε-caprolactone and D , L -lactide was displayed by 3b , affording polyesters with controlled molecular weights at low monomer to initiator ratios ( M n up to 15,000 g mol -1 ), relatively high polydispersities (Ð~1.8) and high number-average functionalities ( F n up to 85%).