摘要
通过稀土氯化物与席夫碱钠盐的交换反应制备了一系列以3,5-二叔丁基水杨醛缩苯胺为配体的稀土席夫碱配合物.对其中的钕席夫碱配合物进行了X射线单晶衍射分析,发现其单晶结构为五角双锥构型,所得席夫碱稀土配合物可以单组分催化ε-己内酯开环聚合.深入研究了钕席夫碱配合物催化己内酯的开环聚合机理,考察了不同聚合条件对单体转化率、产物分子量及分子量分布的影响.结果表明,该聚合反应速率为一级,聚合反应具有较好的可控性.聚合物端基分析表明,聚合反应以配位-插入机理进行.
Lanthanide Schiff-base complexes with the formula [3,5-tBu2-2-（O）C6H2CH=NC6H5]3Ln（THF） （Ln=Sc,Y,La,Nd,and Gd） were synthesized by the metathesis reaction of anhydrous LnCl3 with a Schiff-base sodium salt in good yields （ 〉80%）.The complex containing a neodymium center was characterized by X-ray diffraction and the structure around the neodymium atom could be described as a pentagonal bipyramid.The ring-opening polymerization （ROP） of ε-caprolactone （CL） was successfully carried out using the lanthanide Schiff-base complexes as catalysts,and the neodymium complex leads to a controlled ROP of CL.The influence of the reaction conditions on the monomer conversion,molecular weight,and molecular weight distribution of the resultant polymers was investigated.The polymerization rate was first-order with respect to the monomer concentration.End-group analyses of the oligomer of CL showed that the polymerization underwent a coordination-insertion mechanism.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第8期965-971,共7页
基金
Supported by the National Natural Science Foundation of China (20774078)
the Special Funds for National Basic Research Program of China (973 Program,G2005CB623802)
the Scientific Research Foundation for Returned Scholars,Ministry of Education of China
关键词
己内酯
开环聚合
稀土催化剂
席夫碱
晶体结构
ε-caprolactone
ring-opening polymerization
rare-earth catalyst
Schiff-base
crystal structure
