The thermal decomposition of metal complexes—VII A thermomagnetic study of the Co(III) → Co(II) reduction in cobalt(III) ammine complexes (1)

Wendlandt, W.W.; Smith, J.P.

doi:10.1016/0022-1902(63)80392-9

Cited by 34 publications

(6 citation statements)

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“…Depending on the valences of the Co ions (2 × III, 2 × II or II + III), the charge of Co cations can neutralize {Mn 6 O 12 } n− units with six, four, or five negative charges, thus, according to this, the average valence of manganese was 18/6 (6Mn III ), 20/6 (4Mn III and 2Mn IV ), or 21/6 (3Mn III and 3Mn IV ), respectively. Although there was no sign of ammonia oxidation with Co III in this decomposition step (the lack of N 2 formation confirmed it [33]), the Co II and Mn IV centers in the oxide phase might have been formed due to the valence distribution between the Co III and Mn III . This is a hidden solid-phase quasi-intramolecular redox reaction without mass loss and the formation of other assignable redox products.…”

Section: Thermal Decomposition Of Compound 3-mnmentioning

confidence: 74%

“…Based on the N 2 O/NO (m/z = 44 and 30, respectively) peak intensity ratios, the formation of NO may be attributed not only to the fragmentation of N 2 O [35] but to another NO source as well. The formation of N 2 and ammonia as gaseous products (m/z = 28 and m/z = 17 or m/z = 16, respectively) may be attributed to the decomposition of compound 4 [33], but the mass loss showed that the [Co 2 (NH 3 ) 4 Mn 6 O 12 ] oxide phase also lost ammonia. The intensity ratio of m/z = 18 (H 2 O + ) and m/z = 17 (OH + and NH 3 + ) in this decomposition step was <1, which confirmed the ammonia evolution.…”

Section: Thermal Decomposition Of Compound 3-mnmentioning

confidence: 99%

“…The intensity ratio of m/z = 18 (H 2 O + ) and m/z = 17 (OH + and NH 3 + ) in this decomposition step was <1, which confirmed the ammonia evolution. Therefore, the decomposition product of compound 4 was NH 3 , NH 4 Cl, and N 2 [33]:…”

Section: Thermal Decomposition Of Compound 3-mnmentioning

confidence: 99%

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Multi-Centered Solid-Phase Quasi-Intramolecular Redox Reactions of [(Chlorido)Pentaamminecobalt(III)] Permanganate—An Easy Route to Prepare Phase Pure CoMn2O4 Spinel

et al. 2022

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We synthesized and structurally characterized the previously unknown [Co(NH3)5Cl](MnO4)2 complex as the precursor of CoMn2O4. The complex was also deuterated, and its FT-IR, far-IR, low-temperature Raman and UV-VIS spectra were measured as well. The structure of the complex was solved by single-crystal X-ray diffraction and the 3D-hydrogen bonds were evaluated. The N-H…O-Mn hydrogen bonds act as redox centers to initiate a solid-phase quasi-intramolecular redox reaction even at 120 °C involving the Co(III) centers. The product is an amorphous material, which transforms into [Co(NH3)5Cl]Cl2, NH4NO3, and a todorokite-like solid Co-Mn oxide on treatment with water. The insoluble residue may contain {Mn4IIIMnIV2O12}n4n-, {Mn5IIIMnIVO12}n5n- or {MnIII6O12}n6n- frameworks, which can embed 2 × n (CoII and/or CoIII) cations in their tunnels, respectively, and 4 × n ammonia ligands are coordinated to the cobalt cations. The decomposition intermediates decompose on further heating via a series of redox reactions, forming a solid CoIIMIII2O4 spinel with an average size of 16.8 nm, and gaseous N2, N2O and Cl2. The CoMn2O4 prepared in this reaction has photocatalytic activity in Congo red degradation with UV light. Its activity strongly depends on the synthesis conditions, e.g., Congo red was degraded 9 and 13 times faster in the presence of CoMn2O4 prepared at 550 °C (in air) or 420 °C (under N2), respectively.

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Section: Thermal Decomposition Of Compound 3-mnmentioning

confidence: 74%

Section: Thermal Decomposition Of Compound 3-mnmentioning

confidence: 99%

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Multi-Centered Solid-Phase Quasi-Intramolecular Redox Reactions of [(Chlorido)Pentaamminecobalt(III)] Permanganate—An Easy Route to Prepare Phase Pure CoMn2O4 Spinel

et al. 2022

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“…The reduction of Co III ions into Co II ions during the thermal decomposition of [Co(NH 3 ) 6 Cl 3 ] and its decomposition intermediate [Co(NH 3 ) 5 Cl]Cl 2 is a well-known process, similarly to other hexaamminecobalt(III) salts, with N 2 and NH 4 Cl (NH 4 X salt) formation [66,67]. Since [hexaamminecobalt(II)] complexes are thermally less stable than the analogous Co III complexes [68], and N 2 formation was detected in the thermal decomposition reaction, we performed a temperature-limited decomposition under boiling toluene.…”

Section: Isothermal Heat Treatments Of Compoundmentioning

confidence: 99%

“…The 2nd and 3rd decomposition steps of compound 1 belong to the further catalytic/ non-catalytic thermal decomposition of NH 4 3 and [Co(NH 3 ) 6 ]Cl 3 /[Co(NH 3 ) 6 ]Cl 2 precursors [66][67][68][70][71][72]. The source of N 2 O and H 2 O may be ammonium nitrate; NO can be formed via the reaction of ammonia and the oxide phases.…”

Section: Isothermal Decomposition Of Compound 1 In Boiling Toluenementioning

confidence: 99%

[Hexaamminecobalt(III)] Dichloride Permanganate—Structural Features and Heat-Induced Transformations into (CoII,MnII)(CoIII,MnIII)2O4 Spinels

et al. 2022

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We synthesized and characterized (IR, Raman, UV, SXRD) hexaamminecobalt(III) dichloride permanganate, [Co(NH3)6]Cl2(MnO4) (compound 1) as the precursor of Co–Mn–spinel composites with atomic ratios of Co:Mn = 1:1 and 1:3. The 3D−hydrogen bond network includes N–HO–Mn and N–HCl interactions responsible for solid-phase redox reactions between the permanganate anions and ammonia ligands. The temperature-limited thermal decomposition of compound 1 under the temperature of boiling toluene (110 ∘C) resulted in the formation of (NH4)4Co2Mn6O12. which contains a todorokite-like manganese oxide network (MnII4MnIII2O1210−). The heat treatment products of compounds 1 and [Co(NH3)5Cl](MnO4)2 (2) synthesized previously at 500 ∘C were a cubic and a tetragonal spinel with Co1.5Mn1.5O4 and CoMn2O4 composition, respectively. The heating of the decomposition product of compounds 1 and 2 that formed under refluxing toluene (a mixture with an atomic ratio of Co:Mn = 1:1 and 1:2) and after aqueous leaching ((NH4)4Co2Mn6O12, 1:3 Co:Mn atomic ratio in both cases) at 500 ∘C resulted in tetragonal Co0.75Mn2.25O4 spinels. The Co1.5Mn1.5O4 prepared from compound 1 at 500 ∘C during the solid-phase decomposition catalyzes the degradation of Congo red with UV light. The decomposition rate of the dye was found to be nine times faster than in the presence of the tetragonal CoMn2O4 spinel prepared in the solid-phase decomposition of compound 2. The todorokite-like intermediate prepared from compound 1 under N2 at 115 ∘C resulted in a 54 times faster degradation of Congo red, which is a great deal faster than the same todorokite-like phase that formed from compound 2 under N2.

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Thermal analysis of complex fluorides

Bukovec

Demšar

1990

Journal of Thermal Analysis

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A number of fluorometallates has been investigated by thermal analysis to establish the decomposition stoichiometry and to determine the conditions where stable intermediate phases can be isolated. The decomposition reactions of fluorovanadates depend on the atmosphere. For ammonium hexafluorometallates and potassium pentafluoroaquametallates the decomposition temperatures or enthalpies can be correlated to crystal field stabilization energies.

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The thermal decomposition of metal complexes—VII A thermomagnetic study of the Co(III) → Co(II) reduction in cobalt(III) ammine complexes (1)

Cited by 34 publications

References 5 publications

Multi-Centered Solid-Phase Quasi-Intramolecular Redox Reactions of [(Chlorido)Pentaamminecobalt(III)] Permanganate—An Easy Route to Prepare Phase Pure CoMn2O4 Spinel

Multi-Centered Solid-Phase Quasi-Intramolecular Redox Reactions of [(Chlorido)Pentaamminecobalt(III)] Permanganate—An Easy Route to Prepare Phase Pure CoMn2O4 Spinel

[Hexaamminecobalt(III)] Dichloride Permanganate—Structural Features and Heat-Induced Transformations into (CoII,MnII)(CoIII,MnIII)2O4 Spinels

Thermal analysis of complex fluorides

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