Electrochemical C-N Bond Formation within Boron Imidazolate Cages Featuring Single Copper Sites

Carter S Gerke; Yuting Xu; Yuwei Yang; Gregory D Foley; Briana Zhang; Ethan Shi; Nicholas M Bedford; Fanglin Che; V Sara Thoi

doi:10.1021/jacs.3c08359

Electrochemical C-N Bond Formation within Boron Imidazolate Cages Featuring Single Copper Sites

J Am Chem Soc. 2023 Dec 6;145(48):26144-26151. doi: 10.1021/jacs.3c08359. Epub 2023 Nov 27.

Authors

Carter S Gerke¹, Yuting Xu², Yuwei Yang³, Gregory D Foley¹, Briana Zhang¹, Ethan Shi¹, Nicholas M Bedford³, Fanglin Che², V Sara Thoi^{1

4}

Affiliations

¹ Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
² Department of Chemical Engineering, University of Massachusetts, Lowell, Massachusetts 01854, United States.
³ School of Chemical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.
⁴ Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States.

PMID: 38053495
DOI: 10.1021/jacs.3c08359

Abstract

Electrocatalysis expands the ability to generate industrially relevant chemicals locally and on-demand with intermittent renewable energy, thereby improving grid resiliency and reducing supply logistics. Herein, we report the feasibility of using molecular copper boron-imidazolate cages, BIF-29(Cu), to enable coupling between the electroreduction reaction of CO₂ (CO₂RR) with NO₃^- reduction (NO₃RR) to produce urea with high selectivity of 68.5% and activity of 424 μA cm^-2. Remarkably, BIF-29(Cu) is among the most selective systems for this multistep C-N coupling to-date, despite possessing isolated single-metal sites. The mechanism for C-N bond formation was probed with a combination of electrochemical analysis, in situ spectroscopy, and atomic-scale simulations. We found that NO₃RR and CO₂RR occur in tandem at separate copper sites with the most favorable C-N coupling pathway following the condensation between *CO and NH₂OH to produce urea. This work highlights the utility of supramolecular metal-organic cages with atomically discrete active sites to enable highly efficient coupling reactions.