@article{MTMT:34753165, title = {Insight into the Structure and Redox Chemistry of [Carbonatotetraamminecobalt(III)] Permanganate and Its Monohydrate as Co-Mn-Oxide Catalyst Precursors of the Fischer-Tropsch Synthesis}, url = {https://m2.mtmt.hu/api/publication/34753165}, author = {Béres, Kende Attila and Dürvanger, Zsolt and Homonnay, Zoltán and Nagyné Bereczki, Laura and Barta Holló, Berta and Farkas, Attila and Petruševski, Vladimir M. and Kótai, László}, doi = {10.3390/inorganics12040094}, journal-iso = {INORGANICS}, journal = {INORGANICS}, volume = {12}, unique-id = {34753165}, abstract = {[Carbonatotetraamminecobalt(III)] permanganate monohydrate was synthesized first in the metathesis reaction of [Co(NH3)4CO3]NO3 and NaMnO4 in aqueous solution. Its thermal dehydration at 100 °C resulted in phase-pure [Co(NH3)4CO3]MnO4 (compound 1). Compounds 1 and 2 (i.e., the hydrated form) were studied with IR, far-IR, and low-temperature Raman spectroscopies, and their vibrational modes were assigned. The lattice parameters were determined by powder X-ray diffraction (PXRD) and single crystal X-ray diffraction (SXRD) methods for the triclinic and orthorhombic compounds 1 and 2, respectively. The detailed structure of compound 2 was determined, and the role of hydrogen bonds in the structural motifs was clarified. UV studies on compounds 1 and 2 showed the distortion of the octahedral geometry of the complex cation during dehydration because of the partial loss of the hydrogen bonds between the crystal water and the ligands of the complex cation. The thermal decomposition consists of a solid phase quasi-intramolecular redox reaction between the ammonia ligands and permanganate anions with the formation of ammonia oxidation products (H2O, NO, N2O, and CO2). The solid phase reaction product is amorphous cobalt manganese oxide containing ammonium, carbonate (and nitrate) anions. The temperature-controlled thermal decomposition of compound 2 in toluene at 110 °C showed that one of the decomposition intermediates is ammonium nitrate. The decomposition intermediates are transformed into Co1.5Mn1.5O4 spinel with MnCo2O4 structure upon further heating. Solid compound 2 gave the spinel at 500 °C both in an inert and air atmosphere, whereas the sample pre-treated in toluene at 110 °C without and with the removal of ammonium nitrate by aqueous washing, gave the spinel already at 300 and 400 °C, respectively. The molten NH4NO3 is a medium to start spinel crystallization, but its decomposition stops further crystal growth of the spinel phase. By this procedure, the particle size of the spinel product as low as ~4.0 nm could be achieved for the treatments at 300 and 400 °C, and it increased only to 5.7 nm at 500 °C. The nano-sized mixed cobalt manganese oxides are potential candidates as Fischer-Tropsch catalysts.}, year = {2024}, eissn = {2304-6740}, orcid-numbers = {Béres, Kende Attila/0000-0003-4257-0581; Dürvanger, Zsolt/0000-0002-2652-4916; Homonnay, Zoltán/0000-0001-5299-5394; Barta Holló, Berta/0000-0002-5786-442X; Farkas, Attila/0000-0002-8877-2587} } @article{MTMT:34718662, title = {Hexakis(urea-O)iron Complex Salts as a Versatile Material Family: Overview of Their Properties and Applications}, url = {https://m2.mtmt.hu/api/publication/34718662}, author = {Béres, Kende Attila and Homonnay, Zoltán and Kótai, László}, doi = {10.1021/acsomega.3c09635}, journal-iso = {ACS OMEGA}, journal = {ACS OMEGA}, volume = {9}, unique-id = {34718662}, issn = {2470-1343}, year = {2024}, eissn = {2470-1343}, pages = {11148-11167}, orcid-numbers = {Béres, Kende Attila/0000-0003-4257-0581; Homonnay, Zoltán/0000-0001-5299-5394} } @article{MTMT:34643365, title = {Reaction of Partially Methylated Polygalacturonic Acid with Iron(III) Chloride and Characterization of a New Mixed Chloride–Polygalacturonate Complex}, url = {https://m2.mtmt.hu/api/publication/34643365}, author = {Kótai, László and Lázár, Károly and Kiss, László Ferenc and Szentmihályi, Klára}, doi = {10.3390/molecules29040890}, journal-iso = {MOLECULES}, journal = {MOLECULES}, volume = {29}, unique-id = {34643365}, issn = {1420-3049}, year = {2024}, eissn = {1420-3049} } @article{MTMT:34316828, title = {Spectroscopic and structural characterization of hexaamminecobalt(III) dibromide permanganate}, url = {https://m2.mtmt.hu/api/publication/34316828}, author = {Barta Holló, Berta and Bayat, Niloofar and Nagyné Bereczki, Laura and Petrusevski, Vladimir and Béres, Kende Attila and Farkas, Attila and Szilágyi, Imre Miklós and Kótai, László}, doi = {10.2298/JSC230702062B}, journal-iso = {J SERB CHEM SOC}, journal = {JOURNAL OF THE SERBIAN CHEMICAL SOCIETY}, volume = {88}, unique-id = {34316828}, issn = {0352-5139}, abstract = {Structural and spectroscopic characterization (SXRD, IR, liq. N2 temperature Raman, UV) of hexaamminecobalt(III) dibromide permanganate, [Co(NH3)6]Br2(MnO4) (compound 1) are described. There is a 3D hydrogen bond network including N-H???O-Mn and N-H???Br interactions, which could serve as potential reaction centers for solid-phase redox reactions between the ammonia ligands and/or bromide ions as reductants and permanganate ions as oxidant agents. The effect of the nature of halogen ions on the structural and spectroscopic properties of [Co(NH3)6]Br2(MnO4) and the analogous chloride compound, [Co(NH3)6]Cl2(MnO4) (compound 2) are discussed in detail.}, year = {2023}, eissn = {1820-7421}, pages = {1237-1252}, orcid-numbers = {Barta Holló, Berta/0000-0002-5786-442X; Béres, Kende Attila/0000-0003-4257-0581; Farkas, Attila/0000-0002-8877-2587} } @article{MTMT:34077482, title = {Carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers: An easy was to synthesize Nano-ZrO2@C and Nano-(ZrC, ZrO2)@C composites}, url = {https://m2.mtmt.hu/api/publication/34077482}, author = {Martiz Chalen, Jose Alejandro and Károly, Zoltán and Nagyné Bereczki, Laura and Trif, László and Farkas, Attila and Kállay-Menyhárd, Alfréd and Kótai, László}, doi = {10.3390/jcs7080306}, journal-iso = {J COMPOSITES SCI}, journal = {JOURNAL OF COMPOSITES SCIENCE}, volume = {7}, unique-id = {34077482}, year = {2023}, eissn = {2504-477X}, orcid-numbers = {Trif, László/0000-0002-3960-1829; Farkas, Attila/0000-0002-8877-2587} } @article{MTMT:34037505, title = {Crystal Nanoarchitectonics and Characterization of the Octahedral Iron(III)–Nitrate Complexes with Isomer Dimethylurea Ligands}, url = {https://m2.mtmt.hu/api/publication/34037505}, author = {Béres, Kende Attila and Homonnay, Zoltán and Nagyné Bereczki, Laura and Dürvanger, Zsolt and Petruševski, Vladimir M. and Farkas, Attila and Kótai, László}, doi = {10.3390/cryst13071019}, journal-iso = {CRYSTALS}, journal = {CRYSTALS}, volume = {13}, unique-id = {34037505}, abstract = {Three octahedral iron(III) nitrate complexes with dimethylated urea ligand isomers, [hexakis(N,N’-dimethylurea-O)iron(III)] nitrate (compound 1), trans-[diaquatetrakis(N,N-dimethylurea-O)iron(III)] nitrate (compound 2), and [hexakis(N,N-dimethylurea-O)iron(III)] nitrate trihydrate (compound 3) were prepared and characterized with single crystal X-ray diffraction, IR, Raman and UV–Vis methods. In compounds 1 and 3, six dimethylurea ligands coordinate to the central FeIII ion via the oxygen in octahedral geometry and the ligands are arranged in a propeller-like manner, dividing the complex cations into two sides. In compound 1, the dimethylurea propellers screw in the opposite direction on the two sides of the complex and in compound 3, they are arranged with the same handedness on the two sides. The complexes have helical chirality. The two sides of the complex cations differ not only in the rotation direction of the ligands but also in the hydrogen bond formation. On one side of the complex cation, the ligands form intermolecular hydrogen bonds only with the crystal waters, meanwhile on the other side of the complex, the ligands form hydrogen bonds only with the nitrate ions. In compound 2, [Fe(N,N-dimethylurea)4(H2O)2]3+ cations form layers that are separated by interconnected NO3− ions forming a hydrogen bonding system and connecting the complex cations A-s and B-s. The three crystallographically different nitrate ions each form four hydrogen bonds in a way that they have one bidentate O atom and two monodentate O atoms; however, the anions differ in their hydrogen bonding. The spectroscopic characteristics of compound 2 were determined by IR measurements on the deuterated compound 2 as well.}, year = {2023}, eissn = {2073-4352}, orcid-numbers = {Béres, Kende Attila/0000-0003-4257-0581; Homonnay, Zoltán/0000-0001-5299-5394; Dürvanger, Zsolt/0000-0002-2652-4916; Petruševski, Vladimir M./0000-0002-4796-4929; Farkas, Attila/0000-0002-8877-2587} } @article{MTMT:33834200, title = {Three ammonium-iron-sulfite phases from a burning dump of the Vasas abandoned opencast coal mine (Pécs, Mecsek Mountains, Hungary) and the new mineral kollerite}, url = {https://m2.mtmt.hu/api/publication/33834200}, author = {Fehér, Béla and Szakáll, Sándor and Ende, M. and Effenberger, H.S. and Mihály, Judith and Sajó, István and Kótai, László and Szabó, D.}, doi = {10.1007/s00710-023-00818-1}, journal-iso = {MINER PETROL}, journal = {MINERALOGY AND PETROLOGY}, volume = {117}, unique-id = {33834200}, issn = {0930-0708}, year = {2023}, eissn = {1438-1168}, pages = {231-245}, orcid-numbers = {Sajó, István/0000-0002-1228-1407} } @article{MTMT:33628427, title = {Synthesis, structure, and Mössbauer spectroscopic studies on the heat-induced solid-phase redox reactions of hexakis(urea-O)iron(III) peroxodisulfate}, url = {https://m2.mtmt.hu/api/publication/33628427}, author = {Béres, Kende Attila and Homonnay, Zoltán and Barta Holló, B. and Gracheva, Maria and Petruševski, V.M. and Farkas, Attila and Dürvanger, Zsolt and Kótai, László}, doi = {10.1557/s43578-022-00794-w}, journal-iso = {J MATER RES}, journal = {JOURNAL OF MATERIALS RESEARCH}, volume = {38}, unique-id = {33628427}, issn = {0884-2914}, abstract = {Anhydrous hexakis(urea-O)iron(III)]peroxydisulfate ([Fe(urea-O) 6 ] 2 (S 2 O 8 ) 3 (compound 1 ), and its deuterated form were prepared and characterized with single-crystal X-ray diffraction and spectroscopic (IR, Raman, UV, and Mössbauer) methods. Six crystallographically different urea ligands coordinate via their oxygen in a propeller-like arrangement to iron(III) forming a distorted octahedral complex cation. The octahedral arrangement of the complex cation and its packing with two crystallographically different persulfate anions is stabilized by extended intramolecular (N–H⋯O = C) and intermolecular (N–H⋯O–S) hydrogen bonds. The two types of peroxydisulfate anions form different kinds and numbers of hydrogen bonds with the neighboring [hexakis(urea-O) 6 iron(III)] 3+ cations. There are spectroscopically six kinds of urea and three kinds (2 + 1) of persulfate ions in compound 1 , thus to distinguish the overlapping bands belonging to internal and external vibrational modes, deuteration of compound 1 and low-temperature Raman measurements were also carried out, and the bands belonging to the vibrational modes of urea and persulfate ions have been assigned. The thermal decomposition of compound 1 was followed by TG-MS and DSC methods in oxidative and inert atmospheres as well. The decomposition starts at 130 °C in inert atmosphere with oxidation of a small part of urea (~ 1 molecule), which supports the heat demand of the transformation of the remaining urea into ammonia and biuret/isocyanate. The next step of decomposition is the oxidation of ammonia into N 2 along with the formation of SO 2 (from sulfite). The main solid product proved to be (NH 4 ) 3 Fe(SO 4 ) 3 in air. In inert atmosphere, some iron(II) compound also formed. The thermal decomposition of (NH 4 ) 3 Fe(SO 4 ) 3 via NH 4 Fe(SO 4 ) 2 formation resulted in α -Fe 2 O 3 . The decomposition pathway of NH 4 Fe(SO 4 ) 2 , however, depends on the experimental conditions. NH 4 Fe(SO 4 ) 2 transforms into Fe 2 (SO 4 ) 3 , N 2 , H 2 O, and SO 2 at 400 °C, thus the precursor of α -Fe 2 O 3 is Fe 2 (SO 4 ) 3 . Above 400 °C (at isotherm heating), however, the reduction of iron(III) centers was also observed. FeSO 4 formed in 27 and 75% at 420 and 490 °C, respectively. FeSO 4 also turns into α -Fe 2 O 3 and SO 2 on further heating.}, year = {2023}, eissn = {2044-5326}, pages = {1102-1118}, orcid-numbers = {Béres, Kende Attila/0000-0003-4257-0581; Homonnay, Zoltán/0000-0001-5299-5394; Gracheva, Maria/0000-0001-5245-8425; Farkas, Attila/0000-0002-8877-2587; Dürvanger, Zsolt/0000-0002-2652-4916} } @{MTMT:33620312, title = {Eljárás mikroméretű nikkel-cink-ferrit (NixZn1-xFe2O4, 0 < x < 1) előállítására}, url = {https://m2.mtmt.hu/api/publication/33620312}, author = {Bódis, Eszter and Fazekas, Péter and Károly, Zoltán and Keszler, Anna Mária and Klébert, Szilvia and Kótai, László and Szépvölgyi, János}, unique-id = {33620312}, abstract = {Jelen találmány tárgya eljárás nikkel-cink-ferrit (NixZn1-xFe2O4, 0