Tribochemical oxidation of KBr by transition metal ferricyanides

Bertrán, José Fernández; Pascual, José Blanco; Hernández, Miriam Mesa; Rodríguez, R. Cordón

doi:10.1016/0168-7336(88)80079-2

Cited by 23 publications

(12 citation statements)

References 18 publications

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“…Indeed, all spectra show a double peak structure (red colored lines), with vibrations at 2156 and 2165 cm −1 , which are ascribed to the A 1 and E normal modes of the Fe III -CN-Mn II (HT phase) moieties. These peaks are observed in the expected frequency range (see ta-ble II) and are consistent with IR-data 12,36,37 and previous Raman measurements. 20,23,41 Also, the spectra of all samples show some additional Raman intensity at lower wavenumbers (blue colored lines), consistent with the presence of LT-configuration moieties (Fe II -CN-Mn III , table II), as was observed in the XPS data.…”

Section: Intensity (Arbunits)supporting

confidence: 91%

“…The given frequency ranges are estimates based on literature and experimental data of materials containing the specific or closely related CN-environments (varying the N-bound Intensity (arb.units) metal ion). 12,23,34,35,36,37 Across the thermal phase transition, in addition to the intervalence charge transfer, the Rb x Mn[Fe(CN) 6 ] (2+x) 3…”

Section: Intensity (Arbunits)mentioning

confidence: 99%

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Bulk and Surface Switching in Mn−Fe-Based Prussian Blue Analogues

et al. 2008

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Many Prussian Blue Analogues are known to show a thermally induced phase transition close to room temperature and a reversible, photo-induced phase transition at low temperatures. This work reports on magnetic measurements, X-ray photoemission and Raman spectroscopy on a particular class of these molecular heterobimetallic systems, specifically on Rb0.97Mn[Fe(CN)6]0.98·1.03H2O, Rb0.81Mn[Fe(CN)6]0.95·1.24H2O and Rb0.70Cu0.22Mn0.78[Fe(CN)6]0.86·2.05H2O, to investigate these transition phenomena both in the bulk of the material and at the sample surface. Results indicate a high degree of charge transfer in the bulk, while a substantially reduced conversion is found at the sample surface, even in case of a near perfect (Rb:Mn:Fe=1:1:1) stoichiometry. Thus, the intrinsic incompleteness of the charge transfer transition in these materials is found to be primarily due to surface reconstruction. Substitution of a large fraction of charge transfer active Mn ions by charge transfer inactive Cu ions leads to a proportional conversion reduction with respect to the maximum conversion that is still stoichiometrically possible and shows the charge transfer capability of metal centers to be quite robust upon inclusion of a neighboring impurity. Additionally, a 532 nm photoinduced metastable state, reminiscent of the high temperature Fe III Mn II ground state, is found at temperatures 50-100 K. The efficiency of photo-excitation to the metastable state is found to be maximized 90 K. The photo-induced state is observed to relax to the low temperature Fe II Mn III ground state at a temperature of approximately 123 K.

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Section: Intensity (Arbunits)supporting

confidence: 91%

Section: Intensity (Arbunits)mentioning

confidence: 99%

Bulk and Surface Switching in Mn−Fe-Based Prussian Blue Analogues

et al. 2008

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“…It was observed that changing the fractions of the two metals also affected the incipient oxidation state of the as‐made hybrid material, with a higher nickel mole fraction resulting in greater oxidation, as seen by the increased presence of the Fe III CNM II bond at ≈2165 cm −1 over the Fe II CNM II bond at ≈2101 cm −1 (Figure 3c) from infrared spectroscopy. [ 48,58 ] The mode assignments arise because the decrease in the electronegativity of the low‐spin iron heightens the iron‐carbon σ‐bonding, shifting the wavenumber to higher values. [ 29a ] Open‐circuit voltage measurements of the as‐made [Cu/Ni]HCF‐CB electrodes (Figure S13, Supporting Information) revealed that their initial oxidation states varied based on the amount of nickel in the [Cu/Ni]HCF crystal structure.…”

Section: Resultsmentioning

confidence: 99%

An Asymmetric Iron‐Based Redox‐Active System for Electrochemical Separation of Ions in Aqueous Media

Tan

Hatton

2020

Adv Funct Materials

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Electrochemically mediated redox-active processes are gaining momentum as a promising liquid-phase separation technology. Compared to conventional systems, they offer potential benefits, such as smaller energy footprints, nondestructive operation, reversibility, and tunability for specific analyte removal, with clear applications to societal and industrial challenges like water treatment and chemical synthesis. An asymmetric Faradaic cell heterogeneously functionalized with a metallopolymer at the anode and a hexacyanoferrate material at the cathode is presented for the first time. The redox-active species' iron centers enhance the electrosorption of heavy metal oxyanions with up to 98% removal in the ppb range, and offer tunable operating windows as low as ≈0.1 V at ≈1 A m −2 . By avoiding water splitting, the hexacyanoferrate cathode imparts additional advantages, namely a fourfold reduction in adsorption energy requirements, full suppression of solution pH increase, and the ability to capture redox-active catalytic anions such as polyoxometalates without altering their bulk oxidation state. This hybrid framework of a polymeric ferrocene anode and crystalline hexacyanoferrate cathode allows for simultaneous and synergistic uptake of anions and cations, respectively, creating a new asymmetric scheme for water-based separations, with foreseeable future extension to fields such as ion-sensing, energy storage, and electrocatalysis.

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“…The reason why the tetraalkylammonium cations trigger the dehydration of Fe-CN-Co MCNPs, which follows the introduction of the anions in place of the lattice water molecules, is under investigation. Presumably, a bulky tetraalkylammonium might act as a steric solvent molecule, because Co ions in M 1 -CN-M 2 are known to prefer to the Td geometry by the ligand substitution from H 2 O to another steric solvent, e.g., diether ether, ethanol, n-propanol, or THF [14,51]. It is also plausible that the selection of alcohol introduced as cosolvent (here n-petanol) has a profound effect on the kinetics of the structural change of Fe-CN-Co MCNPs.…”

Section: Formation Mechanismmentioning

confidence: 99%

“…This electronic state is consistent with the results of UV-vis spectra and FT-IR spectra. However, with increasing reaction time, Fe III sites are reduced by the CN-bridged Co II , and the ferromagnetic exchange pathway is broken as a result of the diamagnetic nature of low-spin Fe II (t 6 2g e 0 g , S = 0) and the paramagnetic nature of high-spin Co III (Td, t 3 2g e 3 g , S = 2) [51].…”

Section: Magnetic Properties Of Fe-cn-co Mcnpsmentioning

confidence: 99%