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Living 3,4‐(Co)Polymerization of Isoprene/Myrcene and One‐Pot Synthesis of a Polyisoprene Blend Catalyzed by Binuclear Rare‐Earth Metal Amidinate Complexes
Author(s) -
Yu Xiaying,
Li Meng,
Hong Jianquan,
Zhou Xigeng,
Zhang Lixin
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804944
Subject(s) - isoprene , polymerization , catalysis , chemistry , polymer chemistry , yttrium , selectivity , medicinal chemistry , organic chemistry , polymer , copolymer , oxide
Mononuclear amidinate yttrium complex C 4 H 9 C(NR) 2 Y( o ‐CH 2 C 6 H 4 NMe 2 ) 2 (R=2,6‐ i Pr 2 C 6 H 3 ) and a series of binuclear rare‐earth metal complexes bearing a bridged amidinate ligand [(RN) 2 C(CH 2 ) 4 C(NR) 2 ][RE{CH 2 C 6 H 4 ( o ‐NMe 2 )} 2 ] 2 (R=2,6‐ i Pr 2 C 6 H 3 , RE=Y, Lu, Sc) were synthesized and fully characterized. The catalytic behavior of these complexes for (co)polymerization of conjugated dienes such as isoprene and myrcene in the presence of co‐catalyst [Ph 3 C][B(C 6 F 5 ) 4 ] was investigated. These catalytic systems show impressively high activity and 3,4‐regioselectivity in living (co)polymerization. The binuclear bridged amidinate yttrium catalytic system not only exhibits the highest activity among the reported catalytic systems for 3,4‐polymerization of isoprene but also allows the steady polymerization in a living manner from −20 to 80 °C. Compared with the dramatic drop of 3,4‐selectivity for the mononuclear analogue, the binuclear catalytic system still shows moderate 3,4‐selectivity at 80 °C. Moreover, a facile one‐pot synthetic strategy for a polymer blend containing 3,4‐ and 1,4‐polyisoprene (PIP) was established through the in situ modification of the active amidinate yttrium species by addition of an excess amount of AlMe 3 .