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Reactivities of endo versus exo Isomers of Ester‐Substituted Norbornenes in their Addition Copolymerizations Catalyzed by Cyclopentadienyl Nickel Complexes
Author(s) -
Shikada Chie,
Kaita Shojiro,
Maruyama Yooichiroh,
Takei Masayuki,
Wakatsuki Yasuo
Publication year - 2008
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200700612
Subject(s) - norbornene , reactivity (psychology) , copolymer , cyclopentadienyl complex , chemistry , catalysis , polymer chemistry , medicinal chemistry , monomer , stereochemistry , organic chemistry , polymer , medicine , alternative medicine , pathology
Abstract The addition copolymerization of 5‐norbornene‐2‐carboxylic acid methyl ester (NBCM) with norbornene (NB) catalyzed by CpNi‐based (Cp = η 5 ‐C 5 H 5 ) systems, i.e., CpNi(PPh 3 )Me/B(C 6 F 5 ) 3 and CpNi(PPh 3 )Cl/AlMe 3 /B(C 6 F 5 ) 3 , was studied with particular focus on the reactivities of the endo ‐ versus exo ‐isomers of NBCM. Unlike the well‐known higher reactivity of the exo ‐isomer in Pd II ‐catalyzed polymerizations, the CpNi system showed a small but noticeable preference for the endo‐ isomer. The better reactivity of the endo ‐isomer is more pronounced in the copolymerization of cis ‐5‐norbornene‐2,3‐dicarboxylic acid dimethyl ester (NBCD) with NB, where only the endo ‐isomer gave the copolymer when the NB/NBCD feed ratio was 6/4.