Highly Syndioselective 3,4-Trans Polymerization of (E) 1-(4- Methylphenyl)-1,3-butadiene by Fluorenyl N Heterocyclic Carbene Ligated Lutetium Bis(alkyl) Precursor
作者：Changguang Yao, Fei Lin, Meiyan Wang, Dongtao Liu, Bo Liu, Na Liu, Zichuan Wang, Shiyu Long, Chunji
關(guān)鍵字：Wittig-type reaction; syndiotacticity; conformation; regularity; hydrogenating
論文來源：期刊
具體來源：http://pubs.acs.org/doi/pdf/10.1021/acs.macromol.5b00226
發(fā)表時間：2015年
(E)-1-(4-Methylphenyl)-1,3-butadiene
(E-1-MPBD) synthesized via the “Wittig-type” reaction was polymerized with the
ternary catalytic system (Flu-NHC)Lu(CH2SiMe3)2/Ali Bu3/[Ph3C][B(C6F5)4]
(Flu-NHC = C13H8CH2CH2(NCHCHN(C6H2Me3-2,4,6)C) to afford a new product
containing exclusively trans-3,4 (>99%) units with perfect syndiotacticity
(rrrr > 99%). The regio-3,4 tacticity was proved by the IR and NMR (1 H and
13C) spectroscopic analyses, while the 3,4-stereotacticity was confirmed by a
model polymer with lower regularity (3,4 = 90.9%, rrrr = 49.3%) prepared by the
binary catalytic system (Am-NHC)Lu- (CH2SiMe3)2/[Ph3C][B(C6F5)4] (Am-NHC =
2,6-i PrC6H3NC(C6H5)- NCH2CH2(NCHCHN(C6H2Me3-2,4,6)C). The trans-planar
conformation was uncovered through 2D-NOESY and 13C CPMAS NMR technologies.
This represents the first stereo 3,4-syndioselective polymerization of 1,3-
dienes achieved by a rare-earth metal based catalyst. Moreover, hydrogenating
the resulting polymer gave the highly syndiotactic
poly(4-methylphenyl-1-butene), which cannot be achieved by any other manner at
the present stage.
