Rethinking Catalyst Trapping in Ni-Catalyzed Thieno[3,2-b]thiophene Polymerization.
Rethinking Catalyst Trapping in Ni-Catalyzed Thieno[3,2-b]thiophene Polymerization.
复制标题
DOI：
10.1021/acs.macromol.2c01521
复制
发表时间：
2022-12
期刊：
影响因子：
5.5
通讯作者：
Matthew D. Hannigan;J. Tami;P. Zimmerman;A. McNeil
中科院分区：
文献类型：
--
作者：
Matthew D. Hannigan;J. Tami;P. Zimmerman;A. McNeil
催化剂转移聚合(CTP)是一种用于合成共轭聚合物的链生长方法。虽然CTP对大多数给体类型的单体都很有效，但当使用镍催化剂时，硫代[3，2-b]噻吩类单体的聚合反应停滞不前。以前的报告通过暗示催化剂被困在高度富含电子的芳烃与Ni0的π-络合物中，从而对这一结果进行了合理化。在这项研究中，提供的证据表明，催化剂陷阱更有可能是NiII络合物，它是由于Ni0氧化插入到噻吩环[3，2-b]噻吩环的C-S键上而产生的。这一结果与已知的NiO络合物对S杂芳烃的反应性是一致的，并得到了现场获得的31P核磁共振谱以及从小分子模型反应和聚合的密度泛函理论模拟中收集的数据的支持。我们认为，这种C-S插入途径和相关的非循环反应可能与理解或使其他单体与融合的噻吩类化合物的CTP有关。
Catalyst-transfer polymerization (CTP) is a chain-growth method used to synthesize conjugated polymers. Although CTP works well for most donor-type monomers, the polymerization stalls with thieno[3,2-b]thiophene when using Ni catalysts. Previous reports have rationalized this result by suggesting that the catalyst is trapped in a Ni0 π-complex with the highly electron-rich arene. In this study, evidence is provided that the catalyst trap is more likely a NiII complex that arises from oxidative insertion of Ni0 into the C-S bonds of thieno[3,2-b]thiophene. This result is consistent with the known reactivity of Ni0 complexes toward S-heteroarenes and is supported herein by 31P nuclear magnetic resonance spectra acquired in situ, as well as data collected from small-molecule model reactions and density-functional theory simulations of the polymerization. We propose that this C-S insertion pathway and related off-cycle reactions may be relevant to understanding or enabling the CTP of other monomers with fused thiophenes.