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Pacchioni G, Freund HJ. Controlling the charge state of supported nanoparticles in catalysis: lessons from model systems. Chem Soc Rev 2018; 47:8474-8502. [DOI: 10.1039/c8cs00152a] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Model systems are very important to identify the working principles of real catalysts, and to develop concepts that can be used in the design of new catalytic materials.
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Affiliation(s)
| | - Hans-Joachim Freund
- Fritz-Haber-Institut der Max-Planck-Gesellschaft
- Department of Chemical Physics
- 14195 Berlin
- Germany
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Stout HD, Kleespies ST, Chiang CW, Lee WZ, Que L, Münck E, Bominaar EL. Spectroscopic and Theoretical Study of Spin-Dependent Electron Transfer in an Iron(III) Superoxo Complex. Inorg Chem 2016; 55:5215-26. [PMID: 27159412 DOI: 10.1021/acs.inorgchem.6b00134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It was shown previously (J. Am. Chem. Soc. 2014, 136, 10846) that bubbling of O2 into a solution of Fe(II)(BDPP) (H2BDPP = 2,6-bis[[(S)-2-(diphenylhydroxymethyl)-1-pyrrolidinyl]methyl]pyridine) in tetrahydrofuran at -80 °C generates a high-spin (SFe = (5)/2) iron(III) superoxo adduct, 1. Mössbauer studies revealed that 1 is an exchange-coupled system, [Formula: see text], where SR = (1)/2 is the spin of the superoxo radical, of which the spectra were not well enough resolved to determine whether the coupling was ferromagnetic (S = 3 ground state) or antiferromagnetic (S = 2). The glass-forming 2-methyltetrahydrofuran solvent yields highly resolved Mössbauer spectra from which the following data have been extracted: (i) the ground state of 1 has S = 3 (J < 0); (ii) |J| > 15 cm(-1); (iii) the zero-field-splitting parameters are D = -1.1 cm(-1) and E/D = 0.02; (iv) the major component of the electric-field-gradient tensor is tilted ≈7° relative to the easy axis of magnetization determined by the MS = ±3 and ±2 doublets. The excited-state MS = ±2 doublet yields a narrow parallel-mode electron paramagnetic resonance signal at g = 8.03, which was used to probe the magnetic hyperfine splitting of (17)O-enriched O2. A theoretical model that considers spin-dependent electron transfer for the cases where the doubly occupied π* orbital of the superoxo ligand is either "in" or "out" of the plane defined by the bent Fe-OO moiety correctly predicts that 1 has an S = 3 ground state, in contrast to the density functional theory calculations for 1, which give a ground state with both the wrong spin and orbital configuration. This failure has been traced to a basis set superposition error in the interactions between the superoxo moiety and the adjacent five-membered rings of the BDPP ligand and signals a fundamental problem in the quantum chemistry of O2 activation.
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Affiliation(s)
- Heather D Stout
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Scott T Kleespies
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Chien-Wei Chiang
- Department of Chemistry, National Taiwan Normal University , 88, Section 4, Ting-Chow Road, Taipei 11677, Taiwan (R.O.C.)
| | - Way-Zen Lee
- Department of Chemistry, National Taiwan Normal University , 88, Section 4, Ting-Chow Road, Taipei 11677, Taiwan (R.O.C.)
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors. Top Catal 2015. [DOI: 10.1007/s11244-015-0420-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Morra E, Giamello E, Van Doorslaer S, Antinucci G, D'Amore M, Busico V, Chiesa M. Probing the Coordinative Unsaturation and Local Environment of Ti3+ Sites in an Activated High-Yield Ziegler-Natta Catalyst. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201412052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Morra E, Giamello E, Van Doorslaer S, Antinucci G, D'Amore M, Busico V, Chiesa M. Probing the Coordinative Unsaturation and Local Environment of Ti3+ Sites in an Activated High-Yield Ziegler-Natta Catalyst. Angew Chem Int Ed Engl 2015; 54:4857-60. [DOI: 10.1002/anie.201412052] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/30/2015] [Indexed: 11/12/2022]
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Dikanov SA. Resolving protein-semiquinone interactions by two-dimensional ESEEM spectroscopy. ELECTRON PARAMAGNETIC RESONANCE 2012. [DOI: 10.1039/9781849734837-00103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- S. A. Dikanov
- University of Illinois at Urbana-Champaign, Department of Veterinary Clinical Medicine 190 MSB, 506 S. Mathews Ave., Urbana IL 61801 USA
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Pacchioni G, Freund H. Electron Transfer at Oxide Surfaces. The MgO Paradigm: from Defects to Ultrathin Films. Chem Rev 2012; 113:4035-72. [DOI: 10.1021/cr3002017] [Citation(s) in RCA: 241] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei
Materiali, Università di Milano-Bicocca, Via R. Cozzi, 53−20125,
Milano, Italy
| | - Hajo Freund
- Fritz-Haber-Insitut
der MPG,
Department of Chemical Physics, Faradayweg 4-6, 14195 Berlin, Germany
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Abstract
When the superoxide radical O(2)(•-) is generated on reaction of KO(2) with water in dimethyl sulfoxide, the decay of the radical is dramatically accelerated by inclusion of quinones in the reaction mix. For quinones with no or short hydrophobic tails, the radical product is a semiquinone at much lower yield, likely indicating reduction of quinone by superoxide and loss of most of the semiquinone product by disproportionation. In the presence of ubiquinone-10, a different species (I) is generated, which has the EPR spectrum of superoxide radical. However, pulsed EPR shows spin interaction with protons in fully deuterated solvent, indicating close proximity to the ubinquinone-10. We discuss the nature of species I, and possible roles in the physiological reactions through which ubisemiquinone generates superoxide by reduction of O(2) through bypass reactions in electron transfer chains.
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Gonchar A, Risse T, Freund HJ, Giordano L, Di Valentin C, Pacchioni G. Aktivierung von molekularem Sauerstoff auf MgO: Bildung von O2.− auf dünnen, trägerfixierten MgO(001)-Filmen. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201005729] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gonchar A, Risse T, Freund HJ, Giordano L, Di Valentin C, Pacchioni G. Activation of Oxygen on MgO: O2.− Radical Ion Formation on Thin, Metal-Supported MgO(001) Films. Angew Chem Int Ed Engl 2011; 50:2635-8. [DOI: 10.1002/anie.201005729] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 11/10/2010] [Indexed: 11/07/2022]
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