Stereoselectivity and chemoselectivity in Ziegler-Natta polymerizations of conjugated dienes. 1. Monomers with low-energy s-Cis η4 coordination

C. Costabile, G. Milano, Luigi Cavallo, G. Guerra*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

The mechanisms of stereoselectivity and chemoselectivity in the Ziegler-Natta polymerizations of conjugated dienes have been investigated by density functional methods, in the framework of the widely accepted polymerization scheme involving anti-allyl coordination of the growing chain. Most insertions would occur through intermediates with the diene monomer s-cis η4 coordinated to the metal and with the monomer concavity oriented toward the terminal allyl group of the growing chain. Monomer coordinated intermediates presenting a backbiting of the anti-allyl coordinated growing chain (η3η2) would essentially lead to 1,4-unlike insertions only, while monomer coordinated intermediates simply presenting an anti-allyl coordination of the growing chain would lead to 1,4-like and/or 1,2-unlike insertions. These models are able to rationalize several experimental data relative to stereoselectivity and chemoselectivity in Ziegler-Natta polymerizations of conjugated dienes.

Original languageEnglish (US)
Pages (from-to)7952-7960
Number of pages9
JournalMacromolecules
Volume34
Issue number23
DOIs
StatePublished - Nov 6 2001

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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