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Efficient Suppression of Chain Transfer and Branching via C_s -Type Shielding in a Neutral Nickel(II) Catalyst.

ABSTRACT: 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 (5×10⁶ ?g?mol^-1 ) are accessible, with a strictly linear microstructure (<0.1 branches/1000C). Key features of this highly active (4.3×10⁵ ?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.

SUBMITTER: Wang C

PROVIDER: S-EPMC7898505 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Efficient Suppression of Chain Transfer and Branching via Cs -Type Shielding in a Neutral Nickel(II) Catalyst.

Wang Chaoqun C Kang Xiaohui X Dai Shengyu S Cui Fengchao F Li Yunqi Y Mu Hongliang H Mecking Stefan S Jian Zhongbao Z

Angewandte Chemie (International ed. in English) 20201223 8

An effective shielding of both apical positions of a neutral NiII active site is achieved by dibenzosuberyl groups, both attached via the same donors' N-aryl group in a Cs -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 (5×106 g mol-1 ) are ac ...[more]

PMID: 33200862

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