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Polymerization via Insertion of Ethylene into Al−C bond under Mild Conditions: Mechanistic Studies on the Promotion Exerted by a Catalytic Amount of Cationic Gadolinium Metallocene
Author(s) -
Fukushima Rika,
Tardif Olivier,
Kaita Shojiro,
Wakatsuki Yasuo,
Koga Nobuaki
Publication year - 2021
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202100193
Subject(s) - cationic polymerization , ethylene , metallocene , polyethylene , polymerization , polymer chemistry , gadolinium , chemistry , alkyl , quenching (fluorescence) , catalysis , photochemistry , materials science , organic chemistry , polymer , fluorescence , physics , quantum mechanics
The cationic gadolinium metallocene [(C 5 Me 5 ) 2 Gd][B(C 6 F 5 ) 4 ], when combined with an excess amount of Al( i Bu) 3 , efficiently produces polyethylene at 80 °C under 0.8 MPa pressure of ethylene. After quenching, the resulting polyethylene has ethyl group at one end and isobutyl group at the other terminal. Because no Gd‐alkyl species appears to be involved, a mechanism with conventional coordinative chain transfer polymerization (CCTP) is not feasible. Density functional theory (DFT) analyses indicate a novel mechanism in which the cationic Gd plays a crucial role by coordinating ethylene and assists the insertion of the coordinated ethylene into Al−C bond.