Theoretical Study on the Photochemical Decomposition Reaction of Permanganate Ion, MnO4-

Nakai, Hiromi; Ohmori, Yasuya; Nakatsuji, Hiroshi

doi:10.1021/j100021a016

Cited by 22 publications

(20 citation statements)

References 4 publications

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“…Assuming that the electronic excitation energy is converted into vibrational energy on the electronic ground‐state surface, dissociation of a hot ion should therefore be fast. Finally, we note that photodecomposition of permanganate in solution mainly leads to evolution of O 2 , not production of O 9. This suggests that solvent caging effects prevent the loss of atomic oxygen.…”

Section: Resultsmentioning

confidence: 70%

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

et al. 2013

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We report electronic spectra of mass-selected MnO4(-) and MnO4(-)⋅H2O using electronic photodissociation spectroscopy. Bare MnO4(-) fragments by formation of MnO3(-) and MnO2(-), while the hydrated complex predominantly decays by loss of the water molecule. The band in the visible spectral region shows a well-resolved vibrational progression consistent with the excitation of a Mn-O stretching mode. The presence of a single water molecule does not significantly perturb the spectrum of MnO4(-). Comparison with the UV/Vis absorption spectrum of permanganate in aqueous solution shows that complete hydration causes a small blueshift, while theoretical models including a dielectric medium have predicted a redshift. The experimental data can be used as benchmarks for electronic structure theory methods, which usually predict electronic spectra in the absence of a chemical environment.

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Section: Resultsmentioning

confidence: 70%

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

et al. 2013

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“…This configuration favors formation of an intramolecular O-O bond, shown as the peroxo intermediate S 4b in Figure 4. The peroxo intermediate that forms at Mn4 in our mechanism is formally similar to the peroxo intermediate that forms during O 2 release from permanganate (MnO 4 − ) following photoexcitation in the gas phase (100,101). Based on DFT calculations and assuming the high oxidation state assignment, Siegbahn (67,102) found that an oxo-oxyl radical coupling mechanism for O-O P 680 : reaction center Chl a dimer bond formation in S 4 has significantly lower energy than the nucleophilic attack mechanisms preferred by Brudvig and coworkers (103).…”

Section: Flash #3: S 3 → S 4 → S 0 + Omentioning

confidence: 64%

Photosystem II: The Reaction Center of Oxygenic Photosynthesis

Vinyard

Ananyev

Dismukes

2013

Annu. Rev. Biochem.

359

298

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Photosystem II (PSII) uses light energy to split water into chemical products that power the planet. The stripped protons contribute to a membrane electrochemical potential before combining with the stripped electrons to make chemical bonds and releasing O2 for powering respiratory metabolisms. In this review, we provide an overview of the kinetics and thermodynamics of water oxidation that highlights the conserved performance of PSIIs across species. We discuss recent advances in our understanding of the site of water oxidation based upon the improved (1.9-Å resolution) atomic structure of the Mn4CaO5 water-oxidizing complex (WOC) within cyanobacterial PSII. We combine these insights with recent knowledge gained from studies of the biogenesis and assembly of the WOC (called photoassembly) to arrive at a proposed chemical mechanism for water oxidation.

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“…Note that decomposition along route 5 cannot proceed with light of 578 nm (2.14 eV) wavelength, as the second step requires 3.2 eV of energy. In addition, Nakai et al 8 have obtained a linear geometry for MnO 2 -with their SAC/SAC-CI approach, which is in contradiction with experimental observations 9 of a bent MnO 2 -anion. Using the density functional theory and the generalized gradient approximation (DFT-GGA) for the exchange correlation potential, we had earlier studied the energetics of neutral and anionic clusters of FeO n (n ) 1-4).…”

Section: Introductionmentioning

confidence: 84%

Photodecomposition of MnO₄^-: A Theoretical Study

1999

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The electronic and geometrical structures of the ground states and low-lying isomers of MnO 4 and MnO 4 -have been calculated as a function of spin-multiplicities by using the molecular orbital theory based on generalized gradient approximation to the density functional formalism. Total energies of isomers are used for evaluating the energetics of the MnO 4 -decay through various fragmentation channels. Two primary channels were found depending on the energy of photons. The preferred photofragmentation channel, accessible with ≈2 eV photons, is found to involve an initial excitation of the ground-state MnO 4 -anion into its peroxo isomer followed by subsequent excitations into a superoxo form. Photodetachment of an extra electron from this superoxo isomer anion leads to the formation of a neutral superoxo isomer of MnO 4 , which, in turn, dissociates to MnO 2 + O 2 . Excitations of the anion peroxo isomer into biperoxo isomer are also possible with 3.7 eV, photons and the latter could dissociate spontaneously to MnO 2 -+ O 2 . A number of other decay channels are accessible with low-energy photons, but their intensities are expected to be low because these require flipping the spin of one or more electrons.

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Theoretical Study on the Photochemical Decomposition Reaction of Permanganate Ion, MnO4-

Cited by 22 publications

References 4 publications

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

Photosystem II: The Reaction Center of Oxygenic Photosynthesis

Photodecomposition of MnO₄^-: A Theoretical Study

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Theoretical Study on the Photochemical Decomposition Reaction of Permanganate Ion, MnO4-

Cited by 22 publications

References 4 publications

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

Photosystem II: The Reaction Center of Oxygenic Photosynthesis

Photodecomposition of MnO4-: A Theoretical Study

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Photodecomposition of MnO₄^-: A Theoretical Study