单酚取代氮杂环卡宾稀土配合物的合成、表征及其催化性能的研究

发布时间：2018-04-28 18:56

本文选题：氮杂环卡宾 + 稀土配合物　；参考：《浙江大学》2017年硕士论文

【摘要】：本文制备了一系列单酚取代的氮杂环卡宾类配体前体,并用核磁共振谱和元素分析方法表征了配位体前体的结构。选取了其中两种四氢嘧啶配体前体与六甲基硅胺基稀土化合物进行配位反应,成功制备了四种结构新颖的氮杂环卡宾胺基稀土配合物,并用单晶X-射线衍射分析、核磁共振谱表征了配合物的精确结构。将所得配合物用于催化ε-已内酯开环聚合,发现此类配合物无论是单组份体系或是与异丙醇组成双组份体系,都能有效地催化ε-已内酯开环聚合。通过萘酚取代的氮杂环卡宾配体前体3-((2-hydroxynaphthalenyl)methyl)-1-mesityl-3,4,5,6-tetrahydropyrimidinium chloride H2L1 与六甲基硅胺基稀土Ln[N(SiMe3)2]3反应,合成了含有卡宾-钾结构的胺基稀土配合物L1KLnN”3(Ln=Y,1a;Nd,1b)。选取苯酚取代的氮杂环卡宾类配体前体3-(2-hydroxybenzyl)-1-mesityl-3,4,5,6-tetrahydropyrimidinium chloride H2L2 以同样的方式与胺基稀土反应,也得到了结构类似的胺基稀土配合物L2KLnN"3(Ln=Y,2a;Nd,2b)。单晶X-射线衍射分析表明这四种配合物均为单个甲苯溶剂分子配位的单分子配合物结构,配合物中存在金属钾和稀土元素两种金属离子。其中钾离子与配体上的卡宾结构成键,稀土金属带着三个六甲基二硅胺基基团与配体上的酚氧基相连,不同的稀土金属钇和钕均可以得到相同结构的配合物。同时,对于含有钇离子的配合物1a、2a做了核磁共振表征,且用DFT方法模拟了它们的结构,由NBO计算结果得到了两种结构的电荷分布和成键轨道构成。通过原位核磁的方式表征了在不同加料顺序时,制备配合物1a和1b可能发生的不同的反应过程。单酚取代氮杂环卡宾胺基稀土配合物1a-2b可以单组份有效催化ε-已内酯开环聚合反应,得到高分子量的聚合产物。在异丙醇存在下催化ε-已内酯聚合反应,聚合过程与异丙醇的加入量有关,当加入10倍当量的异丙醇参与聚合反应时,聚合体系呈现出可控聚合的特征。
[Abstract]:A series of monophenol-substituted carbene ligand precursors were prepared and their structures were characterized by nuclear magnetic resonance spectroscopy (NMR) and elemental analysis. Two kinds of tetrahydropyrimidine ligand precursors were selected to coordinate with hexamethylamino rare earth compounds. Four novel aza-heterocyclic carbenamine rare earth complexes were prepared and analyzed by single crystal X-ray diffraction. The exact structure of the complex was characterized by nuclear magnetic resonance spectroscopy. The complexes were used to catalyze the ring-opening polymerization of 蔚 -caprolactone. It was found that these complexes could effectively catalyze the ring-opening polymerization of 蔚 -caprolactone, either in a one-component system or in a two-component system composed of isopropanol. The amino rare earth complex (L1KLnN "3LNNNX Y1a NdNdN) containing the structure of carbene and potassium was synthesized by the reaction of naphthol substituted N-heterocyclic carbene ligands 3-hexamethylenyl-methyl-1-mesityl-3-tetrahydropyrimidinium chloride H2L1 with hexamethylsilymidinium Ln [N(SiMe3)2] 3. In the same way, the phenol-substituted N-heterocyclic carbene ligand precursor 3-trichloro-2-hydroxybenzyl-1-mesityl-3azyl-3-tetrahydropyrimidinium chloride H2L2 reacted with amino rare earth elements in the same way, and a similar Amino rare earth complex L2KLnN "3 LnnCY _ 2a Nd2b" was obtained. The single crystal X-ray diffraction analysis shows that the four complexes are monomolecular complexes coordinated by a single toluene solvent, and there are two metal ions, potassium metal and rare earth elements, in the complexes. Potassium ions bond with carbene structure on ligands, rare earth metals with three hexamethyldisilylamino groups are linked to phenoxy groups on ligands, and different rare earth metal yttrium and neodymium can all get the same structure complexes. At the same time, the complex 1a ~ 2a containing yttrium ion was characterized by NMR, and their structures were simulated by DFT method. The charge distribution and bonding orbitals of the two structures were obtained by NBO calculation. The different reaction processes of 1a and 1b were characterized by in situ NMR. Monophenol substituted aza-heterocyclic carbenamine rare earth complex 1a-2b can effectively catalyze ring-opening polymerization of 蔚 -caprolactone and obtain high molecular weight polymerization products. The polymerization process of 蔚 -caprolactone in the presence of isopropanol is related to the amount of isopropanol added. When isopropanol of 10 times equivalent is added to the polymerization, the polymerization system exhibits the characteristics of controllable polymerization.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4

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