Balancing steric and electronic effects of bidentate, mixed P,N ligands to control Kumada catalyst transfer polycondensation of a sterically hindered thiophene†,Polymer Chemistry

当前位置： X-MOL 学术 › Polym. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Balancing steric and electronic effects of bidentate, mixed P,N ligands to control Kumada catalyst transfer polycondensation of a sterically hindered thiophene†
Polymer Chemistry ( IF 4.1 ) Pub Date : 2018-06-08 00:00:00 , DOI: 10.1039/c8py00452h
S. Hameury _{1,

2,

3,

4,

5} , C. Gourlaouen _{6,

7,

8,

9,

10} , M. Sommer _{1,

2,

3,

4,

5}

Affiliation

The polymerization of sterically hindered thiophenes via Kumada catalyst transfer polycondensation (KCTP) has been shown to be challenging to control using catalysts with bidentate diphosphine ligands but promising with mixed P,N ligands. Herein we present a broad range of Ni^II and Pd^II complexes bearing either diphosphines or hybrid P,N ligands for catalyzing the KCTP of 2-bromo-3-(2,5-dioctylphenyl)-5-iodothiophene. Among these, catalytic activity and control over the reaction was optimized by a subtle balance of sterics and electronics of the mixed P,N ligand. The best performance was obtained with an oxazoline-based P,N ligand. Density functional theory calculations indicate that the association energies between Ni⁰ and the polythiophene backbone are higher for hybrid P,N ligands compared to diphosphines and highest for the oxazoline-based P,N ligand. This explains the reduced tendency for dissociation, resulting in decreased chain termination and higher conversion. This study broadens the range of available catalysts for KCTP useful for the polymerization of sterically hindered thiophene monomers.

中文翻译：

平衡双齿，混合的P，N配体的空间和电子效应，以控制空间受阻噻吩的Kumada催化剂转移缩聚†

已经显示，通过使用熊田催化剂转移缩聚（KCTP）进行的位阻噻吩的聚合对于使用具有双齿二膦配体的催化剂来控制是有挑战性的，但是对于混合的P，N配体来说是有希望的。在本文中，我们提出了广泛的带有二膦或杂化P，N配体的Ni ^II和Pd ^II配合物，用于催化2-溴-3-（2,5-二辛基苯基）-5-碘噻吩的KCTP。其中，通过混合的P，N配体在空间和电子方面的微妙平衡，优化了催化活性和对反应的控制。使用基于恶唑啉的P，N配体可获得最佳性能。密度泛函理论计算表明，Ni ⁰之间的缔合能与二膦相比，杂合P，N配体的聚噻吩主链和聚噻吩主链更高，而基于恶唑啉的P，N配体的聚噻吩主链最高。这解释了解离趋势的降低，导致链终止的减少和更高的转化率。这项研究拓宽了可用于空间位阻噻吩单体聚合的KCTP催化剂的范围。

更新日期：2018-06-08

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11