Siqi Yu of the Vicic Group

Graduate student Siqi Yu will be presenting a research seminar on November 8, 2016 at 4:10 PM in Neville Hall, Room 3.

"Synthesis of Novel Aminophenolate Complexes of Nickel and Accessing Nickel(II), (III), (IV) Complexes Bearing a Readily Attached [C4F8] Ligand"

The development of efficient alkyl-alkyl cross-coupling reactions remains challenging due to two significant problems: the barrier of activation of alkyl electrophiles, and the β-H elimination reaction from transition metal intermediates.  A new aminophenolate ligand was synthesized, and explored for its ability to mediate alkyl-alkyl cross-coupling reactions at nickel centers.  Nickel is also a potential catalyst for aryl-fluoroalkyl cross-coupling reactions.  However, involving nickel-mediated reductive eliminations of fluoroalkyl groups into a catalytic cycle has remained a challenging obstacle. Several very recent studies have shown the possibility of oxidatively inducing reductive eliminations of perfluoroalkyl groups with nickel. Here, we report the use of high valent terpyridyl nickel complexes bearing perfluoroalkyl ligands for stabilizing nickel centers in +2 and +3 oxidation states and providing insight into the factors influencing difficult reductive eliminations of the fluoroalkyl group. Moreover, electrochemical studies of these well-defined precursors indicate that the energy barrier of the Ni(III)/Ni(IV) redox shuttle can be significantly tuned by ligand modification.