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Updated: May 15, 2025

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes
Published on: February 27, 2017
Novel High-Efficiency Single-Site Rare Earth (RE) Catalyst System for Isoprene Polymerization
Di Kang1, Rongqing Ma2, Hongfan Hu3
1Provincial Key Laboratory of Polyolefin New Materials, College of Chemical Engineering, Northeast Petroleum University, Daqing 163318, China.
Abstract:
Bis-(o-dipheylphosphinophenyl)amine, a tridentate (PNP) chelating ligand, and several of their Rare Earth (RE) metal complexes, [bis-(o-dipheylphosphinophenyl)amido]-RER2, {[(C6H5)2P-o-(C6H4)]2NMR2 (R = -CH2-o-(C6H4)NMe2: M = Y, 1; Nd, 2; Gd, 3;), are prepared in high yields. When activated with the strong Lewis acid MMAO-7, all these complexes exhibit catalytic activity toward the polymerization of isoprene (IP) in non-protic hydrocarbons. While the Nd complex (2) showed moderate activity and stereoselectivity, the Y and Gd complexes (1 and 3) exhibited extremely high catalytic efficiency in IP homo-polymerization, and produced polyisoprene rubber (PI) with 95% to over 99% cis-1,4 stereoselectivity and narrow polydispersity indices (<2.0). Moreover, under industrially relevant conditions, complex 3 can catalyze IP to produce ultrahigh molecular weight PI (UHMW-PI, MW up to 1200-2600 kg/mol) rubber with a very narrow polydispersity index (PDI ca. 1.1-1.6), a high-performance elastomeric material mimic of natural rubber (NR).
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