摘要
Four lanthanum alkoxides stabilized by a carbon-bridged bis(phenolate) ligand were synthesized and their catalytic behavior for the ring-opening polymerization of L-lactide was explored. Reactions of [(MBMP)LaCp(THF) 2 ] (MBMP 2 = 2,2′-methylene-bis(6-tert-butyl-4-methyl phenoxo)) with HOCH 2 Ph, HOCH 2 CF 3 , HOCH(CH 3 ) 2 , and HOCH 2 CH 2 N(CH 3 ) 2 , respectively, in a 1:1 molar ratio in THF gave the dimeric lanthanum alkoxo complexes [(MBMP)Ln(μ-OR)(THF) 2 ] 2 (OR = OCH 2 Ph(1), OCH 2 CF 3 (2), OCH(CH 3 ) 2 (3), OCH 2 CH 2 N(CH 3 ) 2 (4)]. These complexes were well characterized, and the definitive molecular structure of complex 1 was determined. It was found that complexes 1 to 4 are efficient initiators for the ring-opening polymerization of L-lactide. The structure of the alkoxo groups has a significant effect on the catalytic behavior, and complex 2 can initiate L-lactide polymerization in a controlled manner.
Four lanthanum alkoxides stabilized by a carbon-bridged bis（phenolate） ligand were synthesized and their catalytic behavior for the ring-opening polymerization of L-lactide was explored. Reactions of [（MBMP）LaCp（THF）2] （MBMP2- = 2,2＇-methylene- bis（6-tert-butyl-4-methyl phenoxo）） with HOCH2Ph, HOCH2CF3, HOCH（CH3）〉 and HOCH2CH2N（CH3）2, respectively, in a 1 ： 1 molar ratio in THF gave the dimeric lanthanum alkoxo complexes [（MBMP）Ln（gt-OR）（THF）2]2 （OR = OCH2Ph （1）, OCHzCF3 （2）, OCH（CH3）2 （3）, OCH2CHzN（CH3）2 （4）]. These complexes were well characterized, and the definitive molecular structure of complex 1 was determined. It was found that complexes 1 to 4 are efficient initiators for the ring-opening polymerization of L-lactide. The structure of the alkoxo groups has a significant effect on the catalytic behavior, and complex 2 can initiate L-lactide polymerization in a controlled manner.
基金
supported by the National Natural Science Foundation of China (20972108, 21174095 and 21132002)
the Priority Academic Program Developement of Jiangsu Higher Education Institutions, and the Qing Lan Project
关键词
L-丙交酯
催化行为
聚合反应
合成
醇盐
桥连
定碳
表征
organolanthanide complex
bis（phenolate） ligands
alkoxide
lactide
synthesis
polymerization
