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Chemoselectivity in 4‐methyl‐1,3‐pentadiene polymerization in the presence of homogeneous Ti‐based catalysts
Author(s) -
Longo Pasquale,
Grisi Fabia,
Proto Antonio,
Zambelli Adolfo
Publication year - 1997
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.1997.030180217
Subject(s) - chemoselectivity , copolymer , monomer , ethylene , polymer chemistry , tacticity , homogeneous , catalysis , polymerization , materials science , homogeneous catalysis , chemistry , organic chemistry , polymer , physics , thermodynamics
The homogeneous catalyst CpTiCl 3 ‐MAO is able to produce a random copolymer of 4‐methyl‐1,3‐pentadiene with ethylene. 13 C NMR analysis of the copolymers shows that after insertion of ethylene units, the next 4‐ymethyl‐1,3‐pentadiene unit can be inserted in either 1,2 or 1,4 arrangement. The high chemoselectivity observed in the 1,2‐syndiotactic homopolymerization of 4‐methyl‐1,3‐pentadiene with respect to the lower one observed in the copolymerization with ethylene is attributed to a back‐biting coordination to the Ti of the active species of the penultimate monomer unit of the growing chain.