Electron transfer with organometals. Steric effects as probes for outer-sphere and inner-sphere oxidations of homoleptic alkylmetals with iron(III) and iridate(IV) complexes

1979 ◽  
Vol 101 (19) ◽  
pp. 5593-5603 ◽  
Author(s):  
C. L. Wong ◽  
J. K. Kochi
Keyword(s):  
Electron Transfer ◽  
Outer Sphere ◽  
Steric Effects ◽  
Inner Sphere

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

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21359-21366
Author(s):  
Debabrata Chatterjee ◽  
Marta Chrzanowska ◽  
Anna Katafias ◽  
Maria Oszajca ◽  
Rudi van Eldik
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Electrochemical Reduction ◽  
Molecular Oxygen ◽  
Outer Sphere ◽  
Transfer Processes ◽  
Edta Complexes ◽  
Inner Sphere ◽  
Electron Transfer Processes ◽  
Sphere Mechanism

[RuII(edta)(L)]2–, where edta4– =ethylenediaminetetraacetate; L = pyrazine (pz) and H2O, can reduce molecular oxygen sequentially to hydrogen peroxide and further to water by involving both outer-sphere and inner-sphere electron transfer processes.

Electron transfer kinetics of cobaloxime complexes

1996 ◽  
Vol 74 (5) ◽  
pp. 658-665 ◽  
Author(s):  
Kefei Wang ◽  
R.B. Jordan
Keyword(s):  
Electron Transfer ◽  
Exchange Rate ◽  
Rate Constants ◽  
Ph Dependence ◽  
Outer Sphere ◽  
The Self ◽  
Oxidation Of Co ◽  
Reduction Potentials ◽  
Inner Sphere ◽  
Kinetics Of

The rates of oxidation of CoII(dmgBF2)2(OH2)2 by CoIII(NH3)5X2+ (X = Br−, Cl−, and N3−) have been studied at 25 °C in 0.10 M LiClO4. The rate constants are 50 ± 9, 2.6 ± 0.2, and 5.9 ± 1.0 M−1 s−1 for X = Br−, Cl−, and N3−, respectively, in 0.01 M acetate buffer at pH 4.7. The relative rates are consistent with the inner-sphere bridging mechanism established earlier by Adin and Espenson for the analogous reactions of CoII(dmgH)2(OH2)2. The rate constants with CoII(dmgBF2)2(OH2)2 typically are ~103 times smaller and this is attributed largely to the smaller driving force for the CoII(dmgBF2)2(OH2)2 complex. The outer-sphere oxidations of cobalt(II) sepulchrate by CoIII(dmgH)2(OH2)2+ (pH 4.76–7.35, acetate, MES, and PIPES buffers) and CoIII(dmgBF2)2(OH2)2+ (pH 3.3–7.42, chloroacetate, acetate, MES, and PIPES buffers) have been studied. The pH dependence gives the following rate constants (M−1 s−1) for the species indicated: (1.55 ± 0.09) × 105 (CoIII(dmgBF2)2(OH2)2+); (5.5 ± 0.3) × 103 (CoII(dmgH)2(OH2)2+); (3.1 ± 0.5) × 102 (CoIII(dmgH)2(OH2)(OH)); (2.5 ± 0.3) × 102 (CoIII(dmgBF2)2(OH2)(OH)). The known reduction potentials for cobalt(III) sepulchrate and the diaqua complexes, and the self-exchange rate for cobalt(II/III) sepulchrate, are used to estimate the self-exchange rate constants for the dioximate complexes. Comparisons to other reactions with cobalt sepulchrate indicates best estimates of the self-exchange rate constants are ~2.4 × 10−2 M−1 s−1 for CoII/III(dmgH)2(OH2)2and ~5.7 × 10−3 M−1 s−1 for CoII/III(dmgBF2)2(OH2)2. Key words: electron transfer, cobaloxime, inner sphere, outer sphere, self-exchange.

scholarly journals Computational Characterization of Single-Electron Transfer Steps in Water Oxidation

Inorganics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 32 ◽  
Author(s):  
Adiran de Aguirre ◽  
Ignacio Funes-Ardoiz ◽  
Feliu Maseras
Keyword(s):  
Electron Transfer ◽  
Water Oxidation ◽  
Density Functional ◽  
Outer Sphere ◽  
Oxidation Catalysis ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Inner Sphere ◽  
Water Oxidation Catalysis

The presence of single-electron transfer (SET) steps in water oxidation processes catalyzed by first-row transition metal complexes has been recently recognized, but the computational characterization of this type of process is not trivial. We report a systematic theoretical study based on density functional theory (DFT) calculations on the reactivity of a specific copper complex active in water oxidation that reacts through two consecutive single-electron transfers. Both inner-sphere (through transition state location) and outer-sphere (through Marcus theory) mechanisms are analyzed. The first electron transfer is found to operate through outer-sphere, and the second one through inner-sphere. The current work proposes a scheme for the systematic study of single-electron transfer in water oxidation catalysis and beyond.

Applications of the Marcus cross relation to inner sphere O2 reduction: Implications in Small-Molecule Activation

2019 ◽  
Author(s):  
David Lacy
Keyword(s):  
Electron Transfer ◽  
Small Molecule ◽  
Rate Constants ◽  
Outer Sphere ◽  
Catalyst Design ◽  
Small Molecule Activation ◽  
Proton Coupled Electron Transfer ◽  
O2 Reduction ◽  
Inner Sphere ◽  
Mechanistic Probe

The Marcus cross relation has been used for outer sphere electron transfer, proton transfer, hydride transfer, and proton-coupled electron transfer. This work shows that the same Marcus cross relation is useful in determining rate constants for inner sphere reduction of molecular oxygen. This has many implications in the field of small molecule activation in the form of catalyst design and as an indirect mechanistic probe.

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