Outer-Sphere Reactivity Shift of Secondary Phosphine Oxide-Based Nickel Complexes: From Ethylene Hydrophosphinylation to Oligomerization
Résumé
A new dimension for secondary phosphine
oxide (SPOs) ligands is described in this article. Demonstrated
on original p-allylic nickel structures, these self-assembled
complexes trigger catalytic hydrophosphinylation
reactions. Addition of a Lewis acid B(C6F5)3 switches the reactivity
towards migratory insertion and thus ethylene oligomerization
through an unprecedented outer-sphere interaction
with the coordinated SPO ligand. NMR experiments
and X-ray analyses allowed for the observation of
the formation of zwitterionic active species as well as their
degradation pathway.