Bifunctional Approaches to Catalysis

Learn more about how we are leveraging metal-ligand cooperativity to carry out challenging catalytic reactions.

Variable Coordination, Redox, and Protonation States

Our approach to metal-ligand cooperativity uses a pyrrole-based scaffold with imines or hydrazones at the 2 and 5 positions of the pyrrole ring. In this scaffold, the nitrogens of the imine or hydrazone can function as pendant bases while the pyrrole ring can undergo a 2-electron redox couple. This allows for the net storage and transfer H-atoms or H2. Shown above are complexes that demonstrate these variable redox and protonation states.

Using Bifunctionality of Ligand to Move H-atoms around: In and Out of Catalysis

A wealth of unusual reactivity and catalysis has been unleashed through the storage of both protons and electrons in the same scaffold. We have observed oxidative chemistry to form catalytically active superoxos, reductive chemistry to hydrogenate quinones and olefins with ligand-derived H-atom equivalents, and redox-neutral H-atom shuffling. We are currently studying complexes of Fe, Co, Ni, and Cu to discover what other rich chemistry this ligand system has in store.

Leveraging Redox-Active Ligands in Electrosynthesis

While electrocatalysis has been utilized to transform feedstock chemicals, we are interested in targeting mid-size, organic modifications with a potential (instead of light or heat) as a driving force. So far, we have observed oxidative formation of hydrogen peroxide and reductive alkyne semi-hydrogenation. With an acid or base as proton-source or acceptor, we are focusing on utilizing the ligand-based storage of these equivalents to retain high and modular selectivity within an electrochemical cell.

 

Selected publications:

“Leveraging Ligand-Based Proton and Electron Transfer for Aerobic Reactivity and Catalysis” Jesse, K. A.;* Anderson, J. S.* Chem. Sci. 2024, Accepted. Read it!

“Synthesis of a Potassium Capped Terminal Cobalt Oxido” Anferov, S. W.;* Krupinski, A.;* Anderson, J. S. Chem. Comm. 202460, 9562-9565. Read it!

“Selective Cobalt Mediated Formation of Hydrogen Peroxide from Water Under Mild Conditions Via Ligand Redox Non-Innocence” Anferov, S. W.; Boyn, J-N.; Mazziotti, D. A.; Anderson, J. S. J. Am. Chem. Soc., 2024146, 9, 5855–5863. Read it!

“Metal-Ligand Cooperativity in Chemical Electrosynthesis” Czaikowski, M. E.;* Anferov, S. W.;* Anderson, J. S. ChemCatalysis, 2024, 100922, 2667-1093. Read it!

“Electrocatalytic Semi-Hydrogenation of Terminal Alkynes using Ligand-Based Transfer of Protons and Electrons” Czaikowski, M. E.; Anferov, S. W.; Tascher, A. P.; Anderson, J. S. J. Am. Chem. Soc. 2024, 146, 1, 476–486. Read it!

“A Cobalt Adduct of an N-hydroxy-piperidinium Cation” Anferov, S. W.; Anderson, J. S. J. Coord. Chem. 2022, 75, 11-14, 1853-1864. Read it!

“Generation and Aerobic Oxidative Catalysis of a Cu(II) Superoxo Complex Supported by a Redox-Active Ligand” Czaikowski, M. E.; McNeece, A. J.; Boyn, J-N.; Jesse, K. A.; Anferov, S. W.; Filatov, A. S.; Mazziotti, D. A.; Anderson, J. S. J. Am. Chem. Soc. 2022144, 34, 15569–15580. Read it!

“Cobalt-Catalyzed Hydrogenation Reactions Enabled by Ligand-Based Storage of Dihydrogen” Anferov, S. W.; Filatov, A. S.; Anderson, J. S. ACS Catal. 2022, 12, 16, 9933–9943. Read it!

“Metal-Ligand Cooperative Transfer of Protons and Electrons” *Anferov, S. W.; *Czaikowski, M. E.; Anderson, J. S. Tre. Chem. 20213, 993-996. Read it!

“Direct Aerobic Generation of a Ferric Hydroperoxo Intermediate via a Preorganized Secondary Coordination Sphere” Jesse, K. A.; Anferov, S. W.; Collins, K. A.; Valdez-Moriera, J. A.; Czaikowski, M. E.; Filatov, A. S.; Anderson, J. S. J. Am. Chem. Soc. 2021143, 18121-18130. Read it!

“Iron(II) Complexes Featuring a Redox-Active Dihydrazonopyrrole Ligand” Jesse, K. A.; Chang, M.-C.; Filatov, A. S.; Anderson, J. S. Z. anorg. allg. Chem. 2021647, 1415-1420. Read it!

“Catalytic Hydrogenation Enabled by Ligand-Based Storage of Hydrogen” *McNeece, A. J.; *Jesse, K. A.;  Filatov, A. S.; Schneider, J. E.; Anderson, J. S. Chem. Commun. 202157, 3869-3872. Read it!

“Generation and Oxidative Reactivity of a Ni(II) Superoxo Complex via Ligand-Based Redox Non-Innocence” McNeece, A. J.; Jesse, K. A.; Xie, J.; Filatov, A. S.; Anderson, J. S. J. Am. Chem. Soc. 2020, ASAP. Read it!

“Nickel-Mediated Dehydrogenative Aryl-Aryl Homocoupling of a Bulky Phosphino-Pyridine” Mannava, V.; Jesse, K. A.; Anderson, J. S. Organometallics 2019, 38, 4554-4559. Read it!

“Neocuproine as a Redox-Active Ligand Platform on Iron and Cobalt” Jesse, K. A.; Filatov, A. S.; Xie, J.; Anderson, J. S. Inorg. Chem. 201958, 9057-9066. Read it!

“Reversible Homolytic Activation of Water via Metal-Ligand Cooperativity in a T-shaped Ni(II) Complex” Chang, M-C; Jesse, K. A.; Filatov, A. S.; Anderson, J. S. Chem. Sci. 201910, 1360-1367. Read it!

“Redox-Activity, Ligand Protonation, and Variable Coordination Modes of Diimino-Pyrrole Complexes of Palladium” McNeece, A. J.; Chang, M-C.; Filatov, A. S.; Anderson, J. S. Inorg. Chem., 201857, 7044-7050. Read it!

“Ligand-Based Storage of Protons and Electrons in Dihydrozonopyrrole Complexes of Nickel” Chang, M-C.; McNeece, A. J.; Hill, E. A.; Filatov, A. S.; Anderson, J. S. Chem. Eur. J.201824, 8001-8008. Read it!