A series of Schiff-base compounds containing bimetallic ligands and two aluminum centers have been synthesized and characterized by 1H, 13C NMR and elemental analysis. These compounds could be successfully used as catalysts for the polymerization of rac-lactide and ε-caprolactone. The polylactides (PLAs) prepared with these compounds were highly isotactic enriched (Pm = 0.97). The nature and steric hindrance of the ligands coordinated to the central metal ions remarkably influenced the polymer properties. Kinetic studies revealed that the polymerization was first order with respect to each of these compounds and lactide/caprolactone monomers. All the polymerizations were living, with good molecular weight control and relatively narrow molar mass distributions.
我们合成了一系列含有双
金属
配体和两个铝中心的希夫碱化合物,并通过 1H、13C NMR 和元素分析对其进行了表征。这些化合物可成功用作 rac-
LActide 和 ε-capro
LActone 聚合反应的催化剂。用这些化合物制备的聚
乳酸(P
LA)具有很高的同素异形富集度(Pm = 0.97)。与中心
金属离子配位的
配体的性质和立体阻碍显著影响了聚合物的特性。动力学研究表明,这些化合物和内酯/
己内酯单体的聚合均为一阶聚合。所有聚合反应都是活的,分子量控制良好,摩尔质量分布相对较窄。