Palladium-Catalyzed Polymerization of Propene: DFT Model Studies
Palladium-Catalyzed Polymerization of Propene: DFT Model Studies
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DOI：
10.1021/om990134p
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发表时间：
1999-08
期刊：
影响因子：
2.8
通讯作者：
Andrzej Michalak;T. Ziegler
中科院分区：
文献类型：
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作者：
Andrzej Michalak;T. Ziegler
用梯度校正密度泛函理论研究了以N∧N = - nhchchnhh -为模型配体的N∧N−PdII二亚胺配合物催化乙烯和丙烯的聚合反应。计算了[N∧N−PdIIR{η - 2- ch2chr '}]+聚合前驱体烯烃配合物（1;R ' = H, CH3）和烷基插入产物[N∧N−PdIIR ' ']+(2)，其中烷基链R含有一个伯、仲、叔α-碳。对于丙烯，1,2-和2,1-插入都被考虑过。测定了每个插入过程的过渡态TS（1,2）和相应的活化能。发现丙烯在所有情况下都更倾向于2,1-而不是1,2-插入。丙烯的插入势垒比乙烯的高，并且从含有伯α-碳的1增加到含有叔α-碳的R。同时考虑了N∧N−PdIIR ' '(2)→N∧N−PdIIR ' '(2)由初始插入产物(2)的β-氢转移过程。一个链…
Gradient-corrected density functional theory has been used to study ethylene and propene polymerization catalyzed by N∧N−PdII diimine complexes with N∧N = −NHCHCHNH− as a model ligand. Calculations have been carried out on the [N∧N−PdIIR{η2-CH2CHR‘}]+ polymerization precursor olefin complex (1; R‘ = H, CH3) as well as the alkyl insertion product [N∧N−PdIIR‘ ‘]+ (2) with the alkyl chain R containing a primary, secondary, or tertiary α-carbon. Both 1,2- and 2,1-insertions were considered for propene. The transition state TS (1,2) and the corresponding activation energies were determined for each investigated insertion process. Propene was found to prefer 2,1- over 1,2-insertion in all cases. The propene insertion barriers are higher than those of ethene and increase from 1 with R containing a primary α-carbon to R containing a tertiary α-carbon. Also considered was the isomerization process N∧N−PdIIR‘ ‘ (2) → N∧N−PdIIR‘ ‘‘ (2‘) by a β-hydrogen transfer process of the initial insertion product (2). A chain-s...