The phosphate KCoCr(PO) and iron-substituted variants KCoCrFe(PO) ( = 0.25, 0.5, and 0.75) were synthesized by a solid-state reaction route, while a high substitution level of Fe was achieved. Their structures were refined using powder X-ray diffraction and indexed in a monoclinic system with a 2/ space group. A 3D framework with six-sided tunnels parallel to the [101] direction was formed in which the K atoms are located. Mössbauer spectroscopy confirms the exclusive presence of octahedral paramagnetic Fe ions, with isomer shifts increasing slightly with substitution. Electron paramagnetic resonance spectroscopy confirmed the presence of paramagnetic Cr ions. The activation energy, determined by dielectric measurements, shows that the iron-containing samples present higher ionic activity. Relative to the electrochemical activity of K, these materials could be good candidates for positive and/or negative electrode materials for energy storage applications.
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http://dx.doi.org/10.1021/acs.inorgchem.2c04389 | DOI Listing |
Molecules
January 2025
N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russia.
The interaction of sodium phytate hydrate CHOP·xNa·yHO (phytNa) with Cu(OAc)·HO and 1,10-phenanthroline (phen) led to the anionic tetranuclear complex [Cu(HO)(phen)(phyt)]·2Na·2NH·32HO (), the structure of the latter was determined by X-ray diffraction analysis. The phytate is completely deprotonated; six phosphate fragments (with atoms P1-P6) are characterized by different spatial arrangements relative to the cyclohexane ring (1a5e conformation), which determines two different types of coordination to the complexing agents-P1 and P3, P4, and P6 have monodentate, while P2 and P5 are bidentately bound to Cu cations. The molecular structure of the anion complex is stabilized by a set of strong intramolecular hydrogen bonds involving coordinated water molecules.
View Article and Find Full Text PDFMetabolites
December 2024
Leicester School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK.
Since the biological activities and toxicities of 'foreign' and/or excess levels of metal ions are predominantly determined by their precise molecular nature, here we have employed high-resolution H NMR analysis to explore the 'speciation' of paramagnetic Ni(II) ions in human saliva, a potentially rich source of biomolecular Ni(II)-complexants/chelators. These studies are of relevance to the corrosion of nickel-containing metal alloy dental prostheses (NiC-MADPs) in addition to the dietary or adverse toxicological intake of Ni(II) ions by humans. Unstimulated whole-mouth human saliva samples were obtained from n = 12 pre-fasted (≥8 h) healthy participants, and clear whole-mouth salivary supernatants (WMSSs) were obtained from these via centrifugation.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Attaining sub-Kelvin temperatures remains technologically challenging and often relies on the scarce resource He, unless employing adiabatic demagnetization refrigeration. Herein, the active coolant typically consists of weakly coupled paramagnetic ions, whose magnetic interaction strengths are comparable in energy to the relevant temperature regime of cooling. Such interactions depend strongly on inter-ion distances, fundamentally hindering the realization of dense coolants for sub-Kelvin refrigeration.
View Article and Find Full Text PDFACS Mater Au
January 2025
Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States.
Lanthanide materials with a 4f electron configuration (S) offer an exciting system for realizing multiple addressable spin states for qubit design. While the S ground state of 4f free ions displays an isotropic character, breaking degeneracy of this ground state and excited states can be achieved through local symmetry of the lanthanide and the choice of ligands. This makes Eu attractive as it mirrors Gd in exhibiting the S ground state, capable of seven spin-allowed transitions.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2025
State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of China, Nanjing, Jiangsu, 210042, China. Electronic address:
In this study, manganese oxide supported biochar (MBC) was used as a catalyst of periodate (PI) for the oxidative degradation of sulfonamide antibiotic sulfamethazine (SMZ). The degradation rate of 10 mg/L SMZ reached 99 % in 60 min in the MBC/PI system, and the optimal condition was pH 3.5, 0.
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