水杨亚胺基钯催化聚合丙烯的密度泛函理论研究

Grubbs水杨亚胺基镍/钯催化剂是一类新型含氮、氧配位杂原子的中性单组分 烯烃聚合催化剂。以不带取代基的水杨亚胺钯为模型催化剂，采用密度泛函理论 在B2LYP/LANL2DZ水平上对其催化聚合丙烯的链增长机理进行了研究。与催化剂配 位原子氮的对位进攻相比，丙烯从氧的对位进攻的复合能大、插入能低。当烷基链 在配位原子O的对位时1，2-插入速率低于2，1-插入；当烷基链在配位原子N对位时 ，1，2-插入速率高于2，1-插生产方式。能量量低的插入路径是烷基链在N对位是 的1，2-插入。2，1-插入路径中的γ-氢桥键烷基配合物能异构化得三个β-氢桥键 的烷基配合物，空间位阻最小的最稳定。1，2-插往前只生成一个β-氢桥键烷基配 合物。与氮原子对位的配合物相比，所有在配位原子氧对位的β-氢桥键的烷基配 合物都是更稳定的配合物构型。

Density Functional Theory Study on Salicyladiminato-Pd(II) Model Complexes as Propene Polymerization Catalyst

Grubbs' novel salicyladiminato-Ni/Pd( II ) catalyst is a neutral and single-site catalyst with heteroatoms N, O for olefin polymerization. With a model catalyst of salicyladiminato-Pd( II ) , the chain propagation mechanism of propene polymerization was investigated using density functional theory at the B3LYP/LANL2DZ level. The results show that the complex energy is larger and the insert barrier is lower for a propene molecule attacking the trans -O position of the catalyst than the complex energy and the insert barrier respectively for the propene molecule attacking the trans-N position. It was found that the 2,1-insertion was preferred over the 1, 2-insertion when the alkyl group in the catalyst is trans to 0, and 1,2- insertion was preferred over 2,1-insertion when the alkyl group is trans to N. The lowest insertion path is the 1,2-insertion where the alkyl group is trans to N. After 2, 1-insertion, the γ-agostic complex can be isomerized to three β-agostic complexes in which the one with two methyl groups trans to each other is the most stable species. But after 1,2-insertion, the γ-agostic complex can be isomerized to only one β-agostic complex. Finally, all the β-agostic complexes with the alkyl group trans to 0 in the catalyst are more stable than those with the alkyl group trans to N.