PROJECT 2

Metal-Ligand Cooperation of the PPP and PSiP Systems

Metal-ligand cooperation is recently emphasized as a unique synthetic methodology to expand the role of transition metal ions in multi-electron catalytic reactions. Various ligand types such as salicylaldimine (salen) equipped with phenolate groups, catecholate and phenylenediamine along with their derivatives were reported as redox-active ligands. In most of the non-innocent ligands, a π-conjugated system is employed in which the reasonable ligand activity can be coupled with the metal’s redox change.In our group, we study an unusual metal-ligand cooperation employing a (PPP)Ni scaffold in which various intramolecular group transfer occurs between a phosphide moiety of the ligand and the nickel ion. This cooperation involves a two-electron Ni(0/II) redox process, coupled with reversible P-E bond formation, E = O, N, S. More recently, we also found that a single electron redox can occur at (PPP)Ni and (PPP)Co systems via the reversible formation of a P-P bond.

Selected Publications

"Metal-Ligand Cooperativity of a Co–P Moiety” Kim, S. and Lee, Y.* Inorg. Chem. Front. 2020, 7, 1172-1181.
“A P-P Bond as a Redox Reservoir and an Active Reaction Site” Kim, Y.-E. and Lee, Y.* Angew. Chem., Int. Ed. 2018, 57, 14159-14163.
“Alkoxide Migration at a Nickel(II) Center induced by a π–Acidic Ligand: Migratory Insertion versus Metal-Ligand Cooperation” Oh, S., Kim, S., Lee, D., Gwak, J. and Lee, Y.* Inorg. Chem. 2016, 55, 12863-12871.
“Reversible P-S Bond Formation via Thiolate Group Transfer Coupled with a Ni(0)/Ni(II) Redox Process” Oh, S. and Lee, Y.* Organometallics 2016, 35, 1586-1592.
“Phosphinite-Ni(0) Mediated Formation of a Phosphide-Ni(II)-OCOOMe Species via Uncommon Metal-Ligand Cooperation.” Kim, Y.-E., Kim, O., Oh, S., Kim, S., Kim, J., Han, S. W. and Lee, Y.* J. Am. Chem. Soc. 2015, 137, 4280-4283.

We have a particular interest in using M− Si bonding because the M−Si moiety possesses a weaker Si−C bond compared to the C−C and C−N bonds and thus can be actively involved in the reaction. To utilize a M−Si moiety as a cooperative motif, we have employed an anionic silyl group in part of the ancillary ligand as a selective group-transfer site.

Selected Publications

“A Silyl-Nickel Moiety as a Metal-Ligand Cooperative Site” Kim, J., Kim, Y.-E., Park, K. and Lee, Y.* Inorg. Chem. 2019, 58, 11534-11545.
“Unusual Hydridicity of a Cobalt Bound Si-H Moiety” Kim, J., Kim, Y., Sinha, I., Park, K., Kim, S. and Lee, Y.* Chem. Commun. 2016, 52, 9367-9370. Selected as a back cover.