RuIII(edta) complexes as molecular redox catalysts in chemical and electrochemical reduction of dioxygen and hydrogen peroxide: inner-sphere versus outer-sphere mechanism

Debabrata Chatterjee; Marta Chrzanowska; Anna Katafias; Maria Oszajca; Rudi van Eldik

doi:10.1039/D1RA03293C

Ru^III(edta) complexes as molecular redox catalysts in chemical and electrochemical reduction of dioxygen and hydrogen peroxide: inner-sphere versus outer-sphere mechanism†

Debabrata Chatterjee,

*^ab Marta Chrzanowska,

^b Anna Katafias,

^b Maria Oszajca

^c and Rudi van Eldik

*^bcd

Author affiliations

* Corresponding authors

^a Vice-Chancellor's Research Group at Zoology Department, University of Burdwan, Burdwan-713104, India
E-mail: dchat57@hotmail.com

^b Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
E-mail: rudi.vaneldik@fau.de

^c Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland

^d Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstr. 1, 91058 Erlangen, Germany

Abstract

The reduction of molecular oxygen (O₂) and hydrogen peroxide (H₂O₂) by [Ru^II(edta)(pz)]²⁻ (edta⁴⁻ = ethylenediaminetetraacetate; pz = pyrazine) has been studied spectrophotometrically and kinetically in aqueous solution. Exposure of the aqua-analogue [Ru^II(edta)(H₂O)]²⁻ to O₂ and H₂O₂ resulted in the formation of [Ru^III(edta)(H₂O)]⁻ species, with subsequent formation of the corresponding Ru^V [double bond, length as m-dash] O complex. A working mechanism for the O₂ and H₂O₂ reduction reactions mediated by the Ru^II(edta) complexes is proposed. The role of the coordinated water molecule (by its absence or presence in the primary coordination sphere) in controlling the mechanistic pathways, outer-sphere or inner-sphere, is discussed.

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Article information

DOI: https://doi.org/10.1039/D1RA03293C
Article type: Paper
Submitted: 27 Apr 2021
Accepted: 09 Jun 2021
First published: 16 Jun 2021
This article is Open Access

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RSC Adv., 2021,11, 21359-21366

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Ru^III(edta) complexes as molecular redox catalysts in chemical and electrochemical reduction of dioxygen and hydrogen peroxide: inner-sphere versus outer-sphere mechanism

D. Chatterjee, M. Chrzanowska, A. Katafias, M. Oszajca and R. van Eldik, RSC Adv., 2021, 11, 21359 DOI: 10.1039/D1RA03293C

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