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 epsilon-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(CH2)(4)OCH=CH2) 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 epsilon-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 ((sic)similar to 1.8) and high number-average functionalities (F-n up to 85%).

Automated summary

A highly efficient one-step approach to macromonomer synthesis using modified aluminum complexes as catalysts was developed. Aluminum salen complexes functionalized with unsaturated alcohol were synthesized and their structures and catalytic activities were studied. Among the complexes, 3b exhibited the highest activity in ROP, producing polyesters with controlled molecular weights and high number-average functionalities.