Formation of Red Elemental Selenium from Seleniferous Oxyanions: Deoxygenation by a Homogeneous Iron Catalyst

Kelly L Gullett; Courtney L Ford; Ian J Garvey; Tabitha J Miller; Clare A Leahy; Lisa N Awaitey; Daniel M Hofmann; Toby J Woods; Alison R Fout

doi:10.1021/jacs.3c05981

Formation of Red Elemental Selenium from Seleniferous Oxyanions: Deoxygenation by a Homogeneous Iron Catalyst

J Am Chem Soc. 2023 Sep 27;145(38):20868-20873. doi: 10.1021/jacs.3c05981. Epub 2023 Sep 15.

Authors

Kelly L Gullett¹, Courtney L Ford¹, Ian J Garvey¹, Tabitha J Miller¹, Clare A Leahy¹, Lisa N Awaitey², Daniel M Hofmann¹, Toby J Woods¹, Alison R Fout³

Affiliations

¹ School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, United States.
² Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.
³ Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.

PMID: 37712762
DOI: 10.1021/jacs.3c05981

Abstract

Seleniferous oxyanions are groundwater contaminants from both anthropogenic and natural sources, while pure amorphous selenium nanoparticles have a variety of industrial applications. Biology can achieve the multicomponent 6 e^-/8 H⁺ reduction of selenate to amorphous selenium using multiple metalloenzymes, like selenate and selenite reductase. Inspired by biology, we developed a new homogeneous system that can generate pure elemental selenium with no caustic waste. The stoichiometric reductions of selenate, selenite, and selenium dioxide with an iron(II) complex produced an iron(III)-oxo and red elemental selenium, the latter of which has been characterized by a variety of spectroscopic techniques. The catalytic reduction of SeO₄^2- and SeO₃^2- directly to amorphous Se and isolated as Se=PPh₃ is reported with a turnover number of 12 and 7, respectively.