The stoichiometric reaction of the salicylaldimine derivatives (L1–L12) with trimethylaluminium afforded the corresponding dimethylaluminium aldiminophenolates (C1–C12), which were fully characterized by NMR spectroscopy and elemental analysis. The molecular structures of the representative complexes C1, C6, and C8 were determined by the single-crystal X-ray diffraction, which revealed distorted tetrahedral geometry at aluminium. Activation of the dimethylaluminium aldiminophenolates for the ring-opening polymerization required one equivalent of BnOH. On the basis of the polymerization results for L-lactide, D-lactide or rac-lactide, higher efficiency was observed for the ROP of D-lactide, and the nature of the ligands present significantly affected the observed catalytic activities and the properties of the resultant polylactides.
水杨醛亚胺衍
生物(L1–L12)与
三甲基铝的
化学计量反应生成相应的
二甲基铝醛亚宝系(C1–C12),这些化合物通过核磁共振光谱和元素分析进行了充分表征。代表性络合物C1、C6和C8的分子结构通过单晶X射线衍射确定,显示出铝呈扭曲的四面体几何结构。激活
二甲基铝醛亚宝系用于开环聚合需要一个当量的BnOH。根据
L-乳酸、D-
乳酸或外消旋
乳酸的聚合结果,D-
乳酸的开环聚合效率较高,并且
配体的性质显著影响了观察到的催化活性以及所得到的聚
乳酸的性质。