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Updated: May 12, 2025

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Cis-Chelating Diphosphanes for Intracavity Nickel(II)-Catalyzed Ethylene Oligomerization
Yang Li1, Sara Figueirêdo de Alcântara Morais2, Mingyang Han1
1Équipe Confinement Moléculaire et Catalyse, Institut de Chimie de Strasbourg, UMR 7177 CNRS, Université de Strasbourg, 4, rue Blaise Pascal, CS90032, 67081 Strasbourg cedex, France.
Abstract:
Four cis-chelating diphosphanes derived from cyclodextrins (CDs), each featuring a distinct intracavity environment, compel NiII or PdII metal centers to reside within α- or β-CD cavities. Nickel(II) complexes of these metal-confining ligands act as active catalysts in ethylene oligomerization upon activation with modified methylaluminoxane (MMAO). The size of the cavity and the position of the P2Ni fragment relative to the cavity affect both the activity and selectivity of the reaction. In all instances, 1-butene is the major product (up to 98% C4 products and 90% 1-butene within the C4 fraction). Extensive theoretical studies with state-of-the-art methods carried out on the most selective system suggest that the CD cavity restricts isomerization pathways by limiting the mobility of the coordinated olefin in this constrained supramolecular environment, thereby enhancing α-olefin formation.
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