非对称N_(2)O_(2)配体的镧、钇配合物催化聚乳酸合成的立构选择性研究  

Stereostructural Selectivity of Polylactic Acid Synthesis Catalyzed by Lanthanum and Yttrium Complexes of Asymmetric N_(2)O_(2) Ligands

作　　者：李汝珍[1] 麻文胜[1] Li Ruzhen;Ma Wensheng(Guangxi Vocational Technical College,Nanning 530226,China)

机构地区：[1]广西职业技术学院,广西南宁530226

出　　处：《中国稀土学报》2021年第4期555-561,共7页Journal of the Chinese Society of Rare Earths

基　　金：广西高等学校科学研究资助项目(KY2015YB383)资助。

摘　　要：从廉价的非手性原料出发,合成一种含潜手性N原子的不对称N_(2)O_(2)配体,分别与镧、钇配位得到两种稀土配合物,配体及配合物的结构采用元素分析,MS,1H NMR和13C NMR进行表征,结果显示镧、钇配合物均为单核手性配合物。并考察镧、钇配合物在一定条件下引发外消旋丙交酯开环聚合的催化活性和立构选择性,均获得全同立构的聚乳酸,全同立构键连接概率(Pm)最高达0.81,聚乳酸分子量分布很窄,分布系数(PDI)接近于1,说明这两种稀土配合物催化外消旋丙交酯开环聚合具有良好的可控性,但钇配合物催化活性及立体选择性均不如镧配合物。An asymmetric N_(2)O_(2) ligand containing latent chiral nitrogen atoms from cheap non-chiral materials was synthesized, and two rare earth lanthanum and yttrium complexes were obtained by coordination with N_(2)O_(2) ligand. The structures of the ligand and complexes were characterized by elemental analysis, MS, 1H NMR and 13C NMR. The results showed that lanthanum and yttrium complexes were mononuclear chiral complexes, and which were examined under certain conditions to cause racemic lactide ring-opening polymerization of catalytic activity and structural selectivity, the results obtained are rich in full with the vertical structure of polylactic acid, full with vertical structure key connection probability(Pm) up to 0.81, the polylactic acid is a very narrow molecular weight distribution, and distribution coefficient(PDI) is close to 1, which shows that these two kinds of rare earth complexes catalysis racemic lactide ring-opening polymerization has the very good controllability, but yttrium complex catalytic activity and stereoselectivity are not as good as lanthanum complexes.

关 键 词：立构选择性 聚乳酸 镧配合物 钇配合物 

分 类 号：O621[理学—有机化学]