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Efficient Suppression of Chain Transfer and Branching via C (s)‐Type Shielding in a Neutral Nickel(II) Catalyst

An effective shielding of both apical positions of a neutral Ni(II) active site is achieved by dibenzosuberyl groups, both attached via the same donors’ N‐aryl group in a C (s)‐type arrangement. The key aniline building block is accessible in a single step from commercially available dibenzosuberol....

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Detalles Bibliográficos
Autores principales: Wang, Chaoqun, Kang, Xiaohui, Dai, Shengyu, Cui, Fengchao, Li, Yunqi, Mu, Hongliang, Mecking, Stefan, Jian, Zhongbao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7898505/
https://www.ncbi.nlm.nih.gov/pubmed/33200862
http://dx.doi.org/10.1002/anie.202013069
Descripción
Sumario:An effective shielding of both apical positions of a neutral Ni(II) active site is achieved by dibenzosuberyl groups, both attached via the same donors’ N‐aryl group in a C (s)‐type arrangement. The key aniline building block is accessible in a single step from commercially available dibenzosuberol. This shielding approach suppresses chain transfer and branch formation to such an extent that ultrahigh molecular weight polyethylenes (5×10(6) g mol(−1)) are accessible, with a strictly linear microstructure (<0.1 branches/1000C). Key features of this highly active (4.3×10(5) turnovers h(−1)) catalyst are an exceptionally facile preparation, thermal robustness (up to 90 °C polymerization temperature), ability for living polymerization and compatibility with THF as a polar reaction medium.