由於環保意識日益提升，具可降解性與可回收特性之聚酯材料成為高分子研究的重要方向之一。其中 poly(ε-caprolactone)（PCL）係由 ε-caprolactone（CL）經開環聚合而成，因其價格相對低廉，且降解產物可被人體逐漸代謝等優點而廣泛受到關注。另一方面，鋁金屬之地殼含量豐富、價格低廉及毒性相對低，常被應用於開環聚合反應之金屬催化劑。本研究合成一系列以 bipyrazole ligand 作為配位基之鋁金屬錯合物，並藉由單晶 X-ray 繞射分析確認其結構，接著透過調整金屬中心上之取代基，探討其對催化行為之影響。所合成之鋁錯合物進一步應用於 ε-caprolactone（CL）及 δ-valerolactone（VL）之開環聚合反應，探討起始劑劑量、催化劑種類及單體種類對聚合結果之影響。結果顯示，較高之起始劑劑量可提升觀測速率常數（kobs）；催化劑活性與其電子效應及金屬核數具有明顯關聯，單體本身之環張力亦會影響聚合效率。此外也進一步探討 CL 與 VL 之共聚行為，¹³C NMR 結果顯示，共聚物 poly(CL-co-VL) 之鏈段排列會隨實驗操作方式不同而有所差異。本研究初步探討了新合成鋁錯合物之結構與催化行為，可作為後續鋁金屬催化劑設計及反應條件優化之基礎。;Due to the increasing awareness of environmental sustainability， biodegradable and recyclable materials have become an important topic in polymer research. Among them， poly(ε-caprolactone) (PCL)， obtained from the ring-opening polymerization of ε-caprolactone (CL)， has received much attention due to its relatively low cost and the ability to be gradually metabolized in the human body. On the other hand， aluminum is abundant， inexpensive， and relatively low in toxicity; therefore， aluminum complexes have been widely applied as metal catalysts in ring-opening polymerization.In this study， a series of aluminum complexes bearing bipyrazole ligands were synthesized. Structures were confirmed by single-crystal X-ray diffraction analysis. By modifying the substituents on the metal center， the influence of structural variation on catalytic behavior was investigated. The synthesized aluminum complexes were further applied to the ring-opening polymerization of ε-caprolactone (CL) and δ-valerolactone (VL)， and the effects of initiator loading， catalyst structure， and monomer type on the polymerization results were examined. The results showed that a higher initiator loading led to an increase in the observed rate constant (kobs). The catalytic activity was found to be closely related to the electronic effect and nuclearity of the aluminum complexes， while the ring strain of the monomer also determines the polymerization efficiency. In addition， the copolymerization behavior of CL and VL was further investigated. The ¹³C NMR results indicated that the chain sequence distribution of poly(CL-co-VL) varied depending on the experimental procedure. Overall， this study provides a preliminary investigation of the structures and catalytic behaviors of newly synthesized aluminum complexes， offering a foundation for the future design of aluminum-based catalysts and optimization of reaction conditions.
