| Summary: | 碩士 === 國立中山大學 === 化學系研究所 === 102 === We successfully used N,O and N,S-schiff base ligands to synthesize the aluminum complexes which can catalyze the ring opening polymerization of -caprolactone and L-lactide. These complexes are LOtBuAlMe2, LOPh2AlMe2, LStBuAlMe2, LSPh2AlMe2, LSPh2AlEt2, LSPh2AlClMe. Meanwhile, from kinetic analysis, we have found that the bulkier substituent on the imino group is associated with higher overall reactivity.
In addition, we also concluded that N, S-schiff base aluminum complexes are more reactive than N,O-schiff base aluminum complexes. For example, LSPh2AlMe2 reaches a conversion rate of 92% with a PDI of 1.05 within 80 minutes under 25 ℃.
The data of X-ray crystallography and theoretical calculations revealed that the different electronic density in the
aluminum metal may be responsible for the differences in their catalytic activities.
Otherwise, experimental results showed that LSPh2AlMe2 efficiently catalyzes the ROP of -caprolactone in a controlled fashion yielding polymers with very narrow PDIs in a wide range of monomer-to-initiator ratios.
Keywords: Schiff- base, Aluminum Complexes, Ring-opening Polymerization, -Caprolactone, L- Lactide
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