Mechanistic Studies on the Role of [Cu(CO3)n]2-2n as a Water Oxidation Catalyst

Amir Mizrahi, Chemistry, Nuclear Research Center Negev, Beer Sheva, Israel
Israel Zilbermann, Chemistry, Nuclear Research Center Negev, Beer Sheva, Israel

Recent interest in the field of water oxidation has triggered the discovery of a wide variety of catalytic systems, both homogeneous and heterogeneous. Identification and direct observation of the key intermediates is vital for unraveling the mechanism of water oxidation in a particular system⁽¹⁾.

Recently it was reported⁽²⁾ that [Cu(CO₃)_n]^2-2nacts as a electro-catalyst for the oxidation of water. The detailed mechanism was discussed but the question whether a Cu^III or a Cu^IVintermediate is the key oxidizing agent was not elucidated.

Pulse radiolysis is known as a mechanistic tool for elucidating the mechanisms of single-electron redox processes. Under the same conditions described in the electro-catalytic study⁽²⁾ pulse radiolysis measurements revealed that [Cu^III(CO₃)_n]^3-2n has a UV-vis spectrum similar to that observed electrochemically. Furthermore the kinetics of disappearance of [Cu^III(CO₃)_n]^3-2n obey a second order rate law. DFT calculations reveal a significant charge transfer from the coordinated carbonate to Cu(III), suggesting that the coordinated carbonate has a radical character.

1. D. Polyansky; J. Hurst; S. Lymar. Eur. J. Inorg. Chem. 619–634 (2014).

2. Z. Chen; T. J. Meyer. Angewandte communications. 52, 700-703 (2013).


Mechanistic Studies on the Role of [Cu(CO3)n]2-2n as a Water Oxidation Catalyst Amir Mizrahi, Chemistry, Nuclear Research Center Negev, Beer Sheva, Israel Israel Zilbermann, Chemistry, Nuclear Research Center Negev, Beer Sheva, Israel Recent interest in the field of water oxidation has triggered the discovery of a wide variety of catalytic systems, both homogeneous and heterogeneous. Identification and direct observation of the key intermediates is vital for unraveling the mechanism of water oxidation in a particular system⁽¹⁾. Recently it was reported⁽²⁾ that [Cu(CO₃)_n]^2-2nacts as a electro-catalyst for the oxidation of water. The detailed mechanism was discussed but the question whether a Cu^III or a Cu^IVintermediate is the key oxidizing agent was not elucidated. Pulse radiolysis is known as a mechanistic tool for elucidating the mechanisms of single-electron redox processes. Under the same conditions described in the electro-catalytic study⁽²⁾ pulse radiolysis measurements revealed that [Cu^III(CO₃)_n]^3-2n has a UV-vis spectrum similar to that observed electrochemically. Furthermore the kinetics of disappearance of [Cu^III(CO₃)_n]^3-2n obey a second order rate law. DFT calculations reveal a significant charge transfer from the coordinated carbonate to Cu(III), suggesting that the coordinated carbonate has a radical character. 1. D. Polyansky; J. Hurst; S. Lymar. Eur. J. Inorg. Chem. 619–634 (2014). 2. Z. Chen; T. J. Meyer. Angewandte communications. 52, 700-703 (2013).

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