多齿配位稀土金属催化剂的构筑及生物降解聚酯的可控聚合

Due to the eco-friendly and biodegradable characteristics, polyesters have attracted considerable attention and been widely applied in daily life. Our target here is to develop novel rare earth metal complex catalysts and control/living polymerization of lactides. N-Heterocyclic Carbene (NHC), phenol and alcohol are the promising candidates for the ligand owing to their electronic and steric effects, while rare earth metals will be chosen due to their relative high efficient and hypotoxicity. The synthesized rare earth metal complexes would catalyze ROP of cyclic esters with control/living manner. The conditions of polymerization, electronic and steric effects of ligand and different central metals (Y, La and Lu) effects on catalytic performances will be fully studied. Under optimized conditions, biodegradable polyesters with high molecular weights but narrow distribution and highly regio- or stereo-selectivity are expected. Based on our studies, the relationship between the structures of catalyst and the properties of polyester will be revealed, which is highly meaningful and providing useful guidelines for further researches on design of novel catalysts and synthesis of biodegradable polyesters.

以环境友好的生物降解聚酯材料的合成为研究对象，针对活性聚合和立构选择性聚合对催化剂中给电子配体和大位阻配体的要求，申请项目在新型催化剂的设计上，中心金属选取活性高的稀土金属，辅助配体引入NHC氮杂环卡宾-酚醇配体，通过氮杂环卡宾配体强的给电子性来稳定催化活性中心，以此实现活性聚合；并通过酚醇配体的位阻效应对催化活性中心进行立体调控，使立构选择性聚合得以实现，从而构筑多齿配位稀土金属催化剂。通过聚合反应，对所构筑的新型催化剂及其反应条件进行系统的研究和优化，合成高分子量、窄分子量分布以及特定立体构型的生物降解聚酯，考察配体的电子效应、位阻效应以及中心金属（钇、镧、镥等）对催化性能的影响，揭示催化剂结构与生物降解聚酯性能的构效关系，为今后新型生物降解聚酯催化剂的设计及其生物降解聚酯的合成提供理论依据和实验基础。

可降解脂肪族聚酯是新一代的、有发展前景的环境友好高分子材料，并符合生态和可持续发展的要求。化学方法制备可降解脂肪族聚酯，特别是基于金属催化剂的配位聚合，能够从分子角度来设计聚合物的微观结构，从而精密地调节聚合物的结构和性能，使其具有更广泛的应用。因此，开发新型金属催化剂是配位聚合制备新型、性能优异的可降解脂肪族聚酯高分子材料领域的核心科学问题。本项目设计了一系列氮杂环卡宾-酚醇配体、双官能团水杨醛亚胺配体、不对称萨伦配体和胺基氢化喹啉配体等，成功构筑了相应的金属化合物，进而实现了生物降解聚酯高分子材料的制备，并研究了催化剂结构与生物降解聚酯性能的构效关系，为今后新型金属催化剂的设计及其生物降解聚酯的合成提供理论依据和实验基础。本项目的主要研究成果，在Organometallics, New J. Chem., Polymers, Chinese J. Polym. Sci.杂志发表论文6篇；申请发明专利7件，其中2件获得授权；培养硕士研究生毕业2名，硕士研究生在读4名。