View in EDS

Design of hybrid steric α-diimine nickel precatalysts with intramolecular π–π interactions for the synthesis of polyethylene elastomers.

Saved in:
Bibliographic Details
Title: Design of hybrid steric α-diimine nickel precatalysts with intramolecular π–π interactions for the synthesis of polyethylene elastomers.
Authors: Hu, Xiaoqiang1 (AUTHOR), Yue, Jingfeng2,3 (AUTHOR), Zhang, Yuxing2 (AUTHOR), Jian, Zhongbao2,3 (AUTHOR) zbjian@ciac.ac.cn
Source: Dalton Transactions: An International Journal of Inorganic Chemistry. 4/21/2026, Vol. 55 Issue 15, p6182-6190. 9p.
Subjects: Nickel catalysts, Stacking interactions, Thermoplastic elastomers, Catalytic activity, Thermal stability, Addition polymerization
Abstract: A series of hybrid steric α-diimine Ni(II) precatalysts incorporating a rigid diarylmethyl group and a flexible isopropyl substituent were designed and synthesized for ethylene polymerization. Single-crystal X-ray diffraction analyses revealed intramolecular offset π–π stacking between the electron-deficient acenaphthene-based backbone and the electron-rich aryl rings of the diarylmethyl group. This non-covalent interaction rigidified the ligand framework, suppressed N-aryl rotation, and conferred exceptional thermal stability to the precatalysts, particularly at lower temperatures where enhanced π–π interactions further stabilize the structure. Upon activation with MAO, these precatalysts exhibited high activities (up to 2.31 × 107 g mol−1 h−1), which were largely retained even at 110 °C. They produced high-molecular-weight polyethylene elastomers with tunable branching densities (54–96/1000C). The catalytic performance was critically influenced by remote para-substituents on the diarylmethyl moiety, with electron-donating groups (–OCH3) yielding both the highest activity and molecular weight. Notably, the "ABAB"-type hybrid steric precatalysts exhibited superior activity and branching density compared to their unsymmetric "AABB"-type counterparts. The resulting polymers demonstrated excellent elastomeric properties, including high elongation at break (up to 1329%) and outstanding strain recovery (up to 86%), thereby demonstrating the efficacy of this synergistic design for the direct synthesis of high-performance thermoplastic elastomers. [ABSTRACT FROM AUTHOR]
Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:A series of hybrid steric α-diimine Ni(II) precatalysts incorporating a rigid diarylmethyl group and a flexible isopropyl substituent were designed and synthesized for ethylene polymerization. Single-crystal X-ray diffraction analyses revealed intramolecular offset π–π stacking between the electron-deficient acenaphthene-based backbone and the electron-rich aryl rings of the diarylmethyl group. This non-covalent interaction rigidified the ligand framework, suppressed N-aryl rotation, and conferred exceptional thermal stability to the precatalysts, particularly at lower temperatures where enhanced π–π interactions further stabilize the structure. Upon activation with MAO, these precatalysts exhibited high activities (up to 2.31 × 107 g mol−1 h−1), which were largely retained even at 110 °C. They produced high-molecular-weight polyethylene elastomers with tunable branching densities (54–96/1000C). The catalytic performance was critically influenced by remote para-substituents on the diarylmethyl moiety, with electron-donating groups (–OCH3) yielding both the highest activity and molecular weight. Notably, the "ABAB"-type hybrid steric precatalysts exhibited superior activity and branching density compared to their unsymmetric "AABB"-type counterparts. The resulting polymers demonstrated excellent elastomeric properties, including high elongation at break (up to 1329%) and outstanding strain recovery (up to 86%), thereby demonstrating the efficacy of this synergistic design for the direct synthesis of high-performance thermoplastic elastomers. [ABSTRACT FROM AUTHOR]
ISSN:14779226
DOI:10.1039/d6dt00369a