Spectroscopic Evidence of Hyponitrite Radical Intermediate in NO Disproportionation at a MOF-Supported Mononuclear Copper Site

Chenyue Sun; Luming Yang; Manuel A Ortuño; Ashley M Wright; Tianyang Chen; Ashley R Head; Núria López; Mircea Dincă

doi:10.1002/anie.202015359

Spectroscopic Evidence of Hyponitrite Radical Intermediate in NO Disproportionation at a MOF-Supported Mononuclear Copper Site

Angew Chem Int Ed Engl. 2021 Mar 29;60(14):7845-7850. doi: 10.1002/anie.202015359. Epub 2021 Mar 1.

Authors

Chenyue Sun¹, Luming Yang¹, Manuel A Ortuño², Ashley M Wright¹, Tianyang Chen¹, Ashley R Head³, Núria López², Mircea Dincă¹

Affiliations

¹ Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
² Institute of Chemical Research of Catalonia, The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain.
³ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA.

PMID: 33645907
DOI: 10.1002/anie.202015359

Abstract

Dianionic hyponitrite (N₂ O₂^2- ) is often proposed, based on model complexes, as the key intermediate in reductive coupling of nitric oxide to nitrous oxide at the bimetallic active sites of heme-copper oxidases and nitric oxide reductases. In this work, we examine the gas-solid reaction of nitric oxide with the metal-organic framework Cu^I -ZrTpmC* with a suite of in situ spectroscopies and density functional theory simulations, and identify an unusual chelating N₂ O₂^.- intermediate. These results highlight the advantage provided by site-isolation in metal-organic frameworks (MOFs) for studying important reaction intermediates, and provide a mechanistic scenario compatible with the proposed one-electron couple in these enzymes.

Keywords: bioinorganic chemistry; metal-organic frameworks (MOFs); nitrogen oxides.

Publication types

Research Support, Non-U.S. Gov't