非碳环配体的钍（IV）三烷基配合物作为高活性异戊二烯聚合催化剂。

Thorium(iv) trialkyl complexes of non-carbocyclic ligands as highly active isoprene polymerisation catalysts.

作者信息

Qin Guorui, Cheng Jianhua

机构信息

State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, No. 5625, Renmin Street, Changchun, 130022 China.

出版信息

Dalton Trans. 2019 Aug 6;48(31):11706-11714. doi: 10.1039/c9dt01617a.

DOI:10.1039/c9dt01617a

PMID:31274141

Abstract

A series of mono-anionic non-carbocyclic ligands, including bidentate benzamidinate [PhC(NDipp)2] (Dipp = C6H3-2,6-iPr2), iminophosphinamide [Ph2P(NDipp)2] and phosphinoamide [Ph2PNDipp], and tridentate hydrotris(3,5-dimethyl-1-pyrazolyl)borate (TpMe2) were used to stabilize the corresponding thorium(iv) trialkyl complexes [PhC(NDipp)2]Th(CH2SiMe3)3 (1), [Ph2P(NDipp)2]Th(CH2SiMe3)3 (2), [Ph2P(NDipp)]Th(p-CH2-C6H4-Me)3 (3) and (TpMe2)Th(CH2SiMe3)3 (4), which were characterized by NMR spectroscopy and single-crystal X-ray analysis. Complexes 1-4 in combination with [Ph3C][B(C6F5)4] and AliBu3 form non-Cp-ligated actinide catalyst systems to show high activity and high cis-1,4-selectivity (89.9%) or trans-1,4-selectivity (91.4%) for the polymerization of isoprene. The reaction rate and selectivity of complexes 1 and 2 were controlled by the crowded space around the thorium centre, corroborated by the kinetics of the polymerization and the steric maps.

摘要

一系列单阴离子非碳环配体，包括双齿苯甲脒[PhC(NDipp)₂]（Dipp = C₆H₃ - 2,6 - iPr₂）、亚氨基磷酰胺[Ph₂P(NDipp)₂]和磷酰氨基[Ph₂PNDipp]，以及三齿氢三(3,5 - 二甲基 - 1 - 吡唑基)硼酸盐（TpMe₂），用于稳定相应的钍(IV)三烷基配合物[PhC(NDipp)₂]Th(CH₂SiMe₃)₃（1）、[Ph₂P(NDipp)₂]Th(CH₂SiMe₃)₃（2）、[Ph₂P(NDipp)]Th(p - CH₂ - C₆H₄ - Me)₃（3）和（TpMe₂）Th(CH₂SiMe₃)₃（4），这些配合物通过核磁共振光谱和单晶X射线分析进行了表征。配合物1 - 4与[Ph₃C][B(C₆F₅)₄]和三异丁基铝组合形成非茂金属镧系催化剂体系，对异戊二烯聚合表现出高活性和高顺式 - 1,4 - 选择性（89.9%）或反式 - 1,4 - 选择性（91.4%）。配合物1和2的反应速率和选择性受钍中心周围拥挤空间的控制，这一点通过聚合动力学和空间映射得到了证实。