The Role of Co-Activation and Ligand Functionalization in Neutral Methallyl Nickel(II) Catalysts for Ethylene Oligomerization and Polymerization

Daniela E. Ortega, Diego Cortés-Arriagada, Oleksandra S. Trofymchuk, Diana Yepes, Soledad Gutiérrez-Oliva, René S. Rojas, Alejandro Toro-Labbé

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

11 Citas (Scopus)

Resumen

A detailed quantum chemical study that analyzed the mechanism of ethylene oligomerization and polymerization by means of a family of four neutral methallyl NiII catalysts is presented. The role of the boron co-activators, BF3 and B(C6F5)3, and the position of ligand functionalization (ortho or para position of the N-arylcyano moiety of the catalysts) were investigated to explain the chain length of the obtained polymers. The chain initialization proceeded with higher activation barriers for the ortho-functionalized complexes (≈19 kcal mol−1) than the para-substituted isomers (17–18 kcal mol−1). Two main pathways were revealed for the chain propagation: The first pathway was favored when using the B(C6F5)3 co-activated catalyst, and it produced long-chain polymers. A second pathway led to the β-hydrogen complexes, which resulted in chain oligomerization; this pathway was preferred when the BF3 co-activated catalysts were used. Otherwise, the termination of longer chains occurred via a stable hydride intermediate, which was formed with an energy barrier of about 14 kcal mol−1 for the B(C6F5)3 co-activated catalysts. Significant new insights were made into the reaction mechanism, whereby neutral methallyl NiII catalysts act in oligomerization and polymerization processes. Specifically, the role of co-activation and ligand functionalization, which are key information for the further design of related catalysts, were revealed.

Idioma originalInglés
Páginas (desde-hasta)10167-10176
Número de páginas10
PublicaciónChemistry - A European Journal
Volumen23
N.º42
DOI
EstadoPublicada - 26 jul. 2017

Áreas temáticas de ASJC Scopus

  • Química (todo)

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