Electron-transfer studies of a peroxide dianion

Andrew M. Ullman; Xianru Sun; Daniel J. Graham; Nazario Lopez; Matthew Nava; Rebecca De Las Cuevas; Peter Müller; Elena V. Rybak-Akimova; Christopher C. Cummins; Daniel G. Nocera

doi:10.1021/ic500759g

Electron-transfer studies of a peroxide dianion

Andrew M. Ullman, Xianru Sun, Daniel J. Graham, Nazario Lopez, Matthew Nava, Rebecca De Las Cuevas, Peter Müller, Elena V. Rybak-Akimova, Christopher C. Cummins, Daniel G. Nocera

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

A peroxide dianion (O₂^2-) can be isolated within the cavity of hexacarboxamide cryptand, [(O₂)∪mBDCA-5t-H ₆]^2-, stabilized by hydrogen bonding but otherwise free of proton or metal-ion association. This feature has allowed the electron-transfer (ET) kinetics of isolated peroxide to be examined chemically and electrochemically. The ET of [(O₂)∪mBDCA-5t-H₆] ^2- with a series of seven quinones, with reduction potentials spanning 1 V, has been examined by stopped-flow spectroscopy. The kinetics of the homogeneous ET reaction has been correlated to heterogeneous ET kinetics as measured electrochemically to provide a unified description of ET between the Butler-Volmer and Marcus models. The chemical and electrochemical oxidation kinetics together indicate that the oxidative ET of O₂^2- occurs by an outer-sphere mechanism that exhibits significant nonadiabatic character, suggesting that the highest occupied molecular orbital of O ₂^2- within the cryptand is sterically shielded from the oxidizing species. An understanding of the ET chemistry of a free peroxide dianion will be useful in studies of metal-air batteries and the use of [(O ₂)∪mBDCA-5t-H₆]^2- as a chemical reagent.

Original language	English
Pages (from-to)	5384-5391
Number of pages	8
Journal	Inorganic Chemistry
Volume	53
Issue number	10
DOIs	https://doi.org/10.1021/ic500759g
State	Published - May 19 2014
Externally published	Yes

Funding

Funders	Funder number
U.S. Department of Energy	DE-FG02-06ER15799
National Science Foundation	0750140
National Science Foundation

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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@article{a60d74f2336d414e9db684017c9f9a13,

title = "Electron-transfer studies of a peroxide dianion",

abstract = "A peroxide dianion (O22-) can be isolated within the cavity of hexacarboxamide cryptand, [(O2)∪mBDCA-5t-H 6]2-, stabilized by hydrogen bonding but otherwise free of proton or metal-ion association. This feature has allowed the electron-transfer (ET) kinetics of isolated peroxide to be examined chemically and electrochemically. The ET of [(O2)∪mBDCA-5t-H6] 2- with a series of seven quinones, with reduction potentials spanning 1 V, has been examined by stopped-flow spectroscopy. The kinetics of the homogeneous ET reaction has been correlated to heterogeneous ET kinetics as measured electrochemically to provide a unified description of ET between the Butler-Volmer and Marcus models. The chemical and electrochemical oxidation kinetics together indicate that the oxidative ET of O22- occurs by an outer-sphere mechanism that exhibits significant nonadiabatic character, suggesting that the highest occupied molecular orbital of O 22- within the cryptand is sterically shielded from the oxidizing species. An understanding of the ET chemistry of a free peroxide dianion will be useful in studies of metal-air batteries and the use of [(O 2)∪mBDCA-5t-H6]2- as a chemical reagent.",

author = "Ullman, {Andrew M.} and Xianru Sun and Graham, {Daniel J.} and Nazario Lopez and Matthew Nava and {De Las Cuevas}, Rebecca and Peter M{\"u}ller and Rybak-Akimova, {Elena V.} and Cummins, {Christopher C.} and Nocera, {Daniel G.}",

year = "2014",

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doi = "10.1021/ic500759g",

language = "English",

volume = "53",

pages = "5384--5391",

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T1 - Electron-transfer studies of a peroxide dianion

AU - Ullman, Andrew M.

AU - Sun, Xianru

AU - Graham, Daniel J.

AU - Lopez, Nazario

AU - Nava, Matthew

AU - De Las Cuevas, Rebecca

AU - Müller, Peter

AU - Rybak-Akimova, Elena V.

AU - Cummins, Christopher C.

AU - Nocera, Daniel G.

PY - 2014/5/19

Y1 - 2014/5/19

N2 - A peroxide dianion (O22-) can be isolated within the cavity of hexacarboxamide cryptand, [(O2)∪mBDCA-5t-H 6]2-, stabilized by hydrogen bonding but otherwise free of proton or metal-ion association. This feature has allowed the electron-transfer (ET) kinetics of isolated peroxide to be examined chemically and electrochemically. The ET of [(O2)∪mBDCA-5t-H6] 2- with a series of seven quinones, with reduction potentials spanning 1 V, has been examined by stopped-flow spectroscopy. The kinetics of the homogeneous ET reaction has been correlated to heterogeneous ET kinetics as measured electrochemically to provide a unified description of ET between the Butler-Volmer and Marcus models. The chemical and electrochemical oxidation kinetics together indicate that the oxidative ET of O22- occurs by an outer-sphere mechanism that exhibits significant nonadiabatic character, suggesting that the highest occupied molecular orbital of O 22- within the cryptand is sterically shielded from the oxidizing species. An understanding of the ET chemistry of a free peroxide dianion will be useful in studies of metal-air batteries and the use of [(O 2)∪mBDCA-5t-H6]2- as a chemical reagent.

AB - A peroxide dianion (O22-) can be isolated within the cavity of hexacarboxamide cryptand, [(O2)∪mBDCA-5t-H 6]2-, stabilized by hydrogen bonding but otherwise free of proton or metal-ion association. This feature has allowed the electron-transfer (ET) kinetics of isolated peroxide to be examined chemically and electrochemically. The ET of [(O2)∪mBDCA-5t-H6] 2- with a series of seven quinones, with reduction potentials spanning 1 V, has been examined by stopped-flow spectroscopy. The kinetics of the homogeneous ET reaction has been correlated to heterogeneous ET kinetics as measured electrochemically to provide a unified description of ET between the Butler-Volmer and Marcus models. The chemical and electrochemical oxidation kinetics together indicate that the oxidative ET of O22- occurs by an outer-sphere mechanism that exhibits significant nonadiabatic character, suggesting that the highest occupied molecular orbital of O 22- within the cryptand is sterically shielded from the oxidizing species. An understanding of the ET chemistry of a free peroxide dianion will be useful in studies of metal-air batteries and the use of [(O 2)∪mBDCA-5t-H6]2- as a chemical reagent.

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DO - 10.1021/ic500759g

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SP - 5384

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JO - Inorganic Chemistry

JF - Inorganic Chemistry

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ER -

Electron-transfer studies of a peroxide dianion

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