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Béres KA, Homonnay Z, Kótai L. Hexakis(urea-O)iron Complex Salts as a Versatile Material Family: Overview of Their Properties and Applications. ACS OMEGA 2024; 9:11148-11167. [PMID: 38496982 PMCID: PMC10938395 DOI: 10.1021/acsomega.3c09635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 03/19/2024]
Abstract
Due to their Fe- and N-containing reactive urea ligand content, the hexakis(urea-O)iron(II) and hexakis(urea-O)iron(III) complexes were found to be versatile materials in various application fields of industry and environmental protection. In our present work, we have comprehensively reviewed the synthesis, structural and spectroscopic details, and thermal properties of hexakis(urea-O)iron(II) and hexakis(urea-O)iron(III) salts with different anions (NO3-, Cl-, Br- I-, I3-, ClO4-, MnO4-, SO42-, Cr2O72-, and S2O82-). We compared and evaluated the structural, spectroscopic (IR, Raman, UV-vis, Mössbauer, EPR, and X-ray), and thermogravimetric data. Based on the thermal behavior of these complexes, we evaluated the solid-phase quasi-intramolecular redox reactions of anions and urea ligands in these complexes and summarized the available information on the properties of the resulting simple and mixed iron-containing oxides. Furthermore, we give a complete overview of the application of these complexes as catalysts, reagents, absorbers, or agricultural raw materials.
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Affiliation(s)
- Kende Attila Béres
- Institute
of Materials and Environmental Chemistry, HUN-REN Research Centre for Natural Sciences, Magyar Tudósok krt. 2., H-1117 Budapest, Hungary
- Institute
of Chemistry, ELTE Eötvös
Loránd University, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
| | - Zoltán Homonnay
- Institute
of Chemistry, ELTE Eötvös
Loránd University, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
| | - László Kótai
- Institute
of Materials and Environmental Chemistry, HUN-REN Research Centre for Natural Sciences, Magyar Tudósok krt. 2., H-1117 Budapest, Hungary
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Catalytic Properties of the Spinel-Like CuxMn3−xO4 Copper Manganese Oxides—An Overview. Catalysts 2023. [DOI: 10.3390/catal13010129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Copper manganese oxide spinels and related (multiphase) materials with the formula CuxMn3−xO4 are the active catalysts in a wide variety of industrially important processes due to their great diversity in their phase relations, metal ion valence/site distribution, and chemical properties. In this review, we summarize the preparation methods and their effects on the composition, properties, and catalytic properties of various CuxMn3−xO4 catalysts with various Cu/Mn ratios. The main summarized catalytic reactions are the oxidation of carbon monoxide, nitrogen oxide, and hydrogen sulfide and the oxidative removal of organic solvents such as benzene, toluene, and xylene from the air. Some industrially important reactions (steam reforming of methanol or synthesis gas) and the manufacture of organic chemicals (methyl formate, propylene oxide, and benzyl alcohol) catalyzed by CuxMn3−xO4 spinels are also reviewed.
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[Hexaamminecobalt(III)] Dichloride Permanganate—Structural Features and Heat-Induced Transformations into (CoII,MnII)(CoIII,MnIII)2O4 Spinels. INORGANICS 2022. [DOI: 10.3390/inorganics10120252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
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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Béres KA, Homonnay Z, Kvitek L, Dürvanger Z, Kubikova M, Harmat V, Szilágyi F, Czégény Z, Németh P, Bereczki L, Petruševski VM, Pápai M, Farkas A, Kótai L. Thermally Induced Solid-Phase Quasi-Intramolecular Redox Reactions of [Hexakis(urea- O)iron(III)] Permanganate: An Easy Reaction Route to Prepare Potential (Fe,Mn)O x Catalysts for CO 2 Hydrogenation. Inorg Chem 2022; 61:14403-14418. [PMID: 36044722 PMCID: PMC9477215 DOI: 10.1021/acs.inorgchem.2c02265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Research on new reaction routes and precursors to prepare
catalysts
for CO2 hydrogenation has enormous importance. Here, we
report on the preparation of the permanganate salt of the urea-coordinated
iron(III), [hexakis(urea-O)iron(III)]permanganate
([Fe(urea-O)6](MnO4)3) via an affordable
synthesis route and preliminarily demonstrate the catalytic activity
of its (Fe,Mn)Ox thermal decomposition
products in CO2 hydrogenation. [Fe(urea-O)6](MnO4)3 contains O-coordinated urea ligands in octahedral
propeller-like arrangement around the Fe3+ cation. There
are extended hydrogen bond interactions between the permanganate ions
and the hydrogen atoms of the urea ligands. These hydrogen bonds serve
as reaction centers and have unique roles in the solid-phase quasi-intramolecular
redox reaction of the urea ligand and the permanganate anion below
the temperature of ligand loss of the complex cation. The decomposition
mechanism of the urea ligand (ammonia elimination with the formation
of isocyanuric acid and biuret) has been clarified. In an inert atmosphere,
the final thermal decomposition product was manganese-containing wuestite,
(Fe,Mn)O, at 800 °C, whereas in ambient air, two types of bixbyite
(Fe,Mn)2O3 as well as jacobsite (Fe,Mn)T-4(Fe,Mn)OC-62O4), with overall Fe to Mn stoichiometry of 1:3, were formed. These
final products were obtained regardless of the different atmospheres
applied during thermal treatments up to 350 °C. Disordered bixbyite
formed first with inhomogeneous Fe and Mn distribution and double-size
supercell and then transformed gradually into common bixbyite with
regular structure (and with 1:3 Fe to Mn ratio) upon increasing the
temperature and heating time. The (Fe,Mn)Ox intermediates formed under various conditions showed catalytic effect
in the CO2 hydrogenation reaction with <57.6% CO2 conversions and <39.3% hydrocarbon yields. As a mild solid-phase
oxidant, hexakis(urea-O)iron(III) permanganate, was
found to be selective in the transformation of (un)substituted benzylic
alcohols into benzaldehydes and benzonitriles. [Fe(urea-O)6](MnO4)3 is a selective solid-phase oxidant
of benzylic alcohols
into benzaldehydes and precursor in the preparation of (Fe,Mn)Ox catalysts for CO2 hydrogenation
into hydrocarbons. The urea ligands are in octahedral propeller-like
arrangement around the Fe3+ cation, and there are hydrogen
bonds between the permanganate anions and the urea ligands. A solid-phase
quasi-intramolecular redox reaction of the urea and the permanganate
resulted in (Fe,Mn)O, (Fe,Mn)2O3, and (Fe,Mn)T-4(Fe,Mn)OC-62O4 with an overall Fe to Mn stoichiometry of 1:3.
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Affiliation(s)
- Kende Attila Béres
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary.,György Hevesy PhD School of Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
| | - Zoltán Homonnay
- György Hevesy PhD School of Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
| | - Libor Kvitek
- Faculty of Science, Department of Physical Chemistry, Palacky University Olomouc, 17. Listopadu 12, Olomouc 77146, Czech Republic
| | - Zsolt Dürvanger
- Structural Chemistry and Biology Laboratory, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
| | - Martina Kubikova
- Faculty of Science, Department of Physical Chemistry, Palacky University Olomouc, 17. Listopadu 12, Olomouc 77146, Czech Republic
| | - Veronika Harmat
- Structural Chemistry and Biology Laboratory, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary.,ELKH-ELTE Protein eModelling Research Group, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
| | - Fanni Szilágyi
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary.,Bay Zoltan Ltd. for Applied Research, Production Division (BAY-PROD), 1 Kondorfa, H-1116 Budapest, Hungary
| | - Zsuzsanna Czégény
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary
| | - Péter Németh
- Institute for Geological and Geochemical Research, Research Centre for Astronomy and Earth Sciences, ELKH, Budaörsi street 45, H-1112 Budapest, Hungary
| | - Laura Bereczki
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary
| | - Vladimir M Petruševski
- Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje MK-1000, North Macedonia
| | - Mátyás Pápai
- Wigner Research Centre for Physics, H-1525 Budapest, P.O. Box 49, Hungary
| | - Attila Farkas
- Department of Organic Chemistry, Budapest University of Technology and Economics, Műegyetem rakpart 3, H-1111 Budapest, Hungary
| | - László Kótai
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary.,Deuton-X Ltd., Selmeci u. 89, H-2030, Érd, Hungary
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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. INORGANICS 2022. [DOI: 10.3390/inorganics10020018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
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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13C CPMAS NMR as a Tool for Full Structural Description of 2-Phenyl Substituted Imidazoles That Overcomes the Effects of Fast Tautomerization. Molecules 2020; 25:molecules25173770. [PMID: 32825018 PMCID: PMC7504167 DOI: 10.3390/molecules25173770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 11/21/2022] Open
Abstract
Tautomerization of 2-phenylimidazolecarbaldehydes has not been studied in detail so far, although this process is a well-known phenomenon for imidazole derivatives. That is why we focus our study on a series of 2-phenylimidazolecarbaldehydes and their parent alcohols that were synthesized and studied by detailed 1H and 13C NMR in solution and in the solid state. The apparent problem is that the fast tautomerization impedes the full structural description of the compounds by conventional 13C NMR measurements. Indeed, the 13C NMR spectra in solution exhibit poor resolution, and in most cases, signals from the imidazole ring are not detectable. To avoid this problem, we used 13C CP-MAS NMR as an alternative spectroscopic method for unambiguous spectroscopic characterization of the studied series of 2-phenylimidazoles. The data were analyzed in combination with quantum chemical DFT-GIAO methods by considering the tautomerization process and the intermolecular interactions. The DFT (B3LYP/6-31G(d,p)) calculations allowed to identify and suggest the preferred tautomer in the gas phase and in DMSO solvent, which for alcohols are (2-phenyl-1H-imidazol-4-yl)methanol and its analogs, and for the aldehydes are the 2-phenyl-1H-imidazole-5-carbaldehydes. The gas-phase calculated energy differences between the two possible tautomeric forms are in the range 0.645–1.415 kcal/mol for the alcohols and 2.510–3.059 kcal/mol for the aldehydes. In the DMSO solvent, however, for all compounds, the calculated energy differences go below 1.20 kcal/mol. These data suggest that both tautomeric forms of the studied 2-phenylimidazoles can be present in solution at room temperature. Our data from detailed 2D NMR measurements in the solid state (1H-13C HETCOR and 1H-1H double-quantum coherence MAS NMR) suggested that also in the solid state both tautomers coexist in different crystalline domains. This fact does not obscure the 13C CP-MAS NMR spectra of the studied 2-phenyl substituted imidazoles and suggests this spectroscopic method as a powerful tool for a complete structural description of tautomeric systems with aromatic conjugation.
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