The optical spectra and EPR spectra (characterized by the spin-Hamiltonian parameters g(//), g(perpendicular), A(//) and A(perpendicular)) for the molecular ion VO2+ in LiKSO4 crystals are calculated from two microscopic theory methods, one of which is the complete diagonalization (of energy matrix) method (CDM) and the other is the perturbation theory method (PTM). The calculated three optical absorption bands and four spin-Hamiltonian parameters from the two methods are not only close to each other, but also in reasonable agreement with the experimental values. It appears that both theoretical methods are effective in the explanation of optical and EPR spectra for 3d1 ions in crystals. The negative signs of hyperfine structure constants A(//) and A(perpendicular) for VO2+ in LiKSO4 crystals are also suggested from the calculations.
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http://dx.doi.org/10.1016/j.saa.2007.12.035 | DOI Listing |
J Hazard Mater
January 2025
College of Environmental and Safety Engineering, Shenyang University of Chemical Technology, Shenyang 110142, China; Shenyang Key Laboratory of Chemical Pollution Control, Shenyang University of Chemical Technology, Shenyang 110142, China. Electronic address:
Here, a quenching strategy was developed to create oxygen vacancies in Cu doped α-MnO. The evolutions of oxygen vacancies were directly followed by means of XRD refinement, EPR and XPS. In combination with DFT calculations and detailed characterizations, evidence is captured that oxygen vacancies not only act as direct sites for the adsorption and activation of gaseous oxygen and toluene, but also accelerate the consumption and replenishment cycle of lattice oxygen species by weakening the strength of metal-oxygen bonds.
View Article and Find Full Text PDFMolecules
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 PDFInt J Mol Sci
January 2025
Departamento de Micro y Nanotecnologías, Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Cto. Exterior S/N, C.U., Coyoacán, Ciudad de México C.P. 04510, Mexico.
Thermus thermophilus HB27 laccase (Tth-Lac) is a thermostable enzyme that contains a β-hairpin (Ala292-Gln307) covering the substrate entrance. We analyzed the role of this β-hairpin in the enzymatic activity of Tth-Lac through three β-hairpin mutants: two variants without the β-hairpin (C1Tth-Lac and C2Tth-Lac) and one with a partially modified β-hairpin (P1Tth-Lac). Enzymatic activity was assayed with different substrates with and without copper.
View Article and Find Full Text PDFJ Trace Elem Med Biol
January 2025
Center for Global Health Research (CGHR), Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, India. Electronic address:
[CuL(tmen)] is a sequence of four ternary mononuclear Schiff base copper(II) complexes that are derived from L-valine, suitable 5'-substituted-2'-hydroxyacetophenones (where the substituents are -Cl for L, -Me for L, -OMe for L, and -H for L), and tmen (where tmen-N,N,N',N' tetramethyl ethylenediamine). Without isolating the Schiff base ligand or producing any other intermediate products, all of the complexes were synthesised. These compounds were identified using elemental analysis, molar conductance, UV-Vis, FTIR, EPR, VSM-RT, and CD spectra.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Engineering Research Center of Forestry Biomass Materials and Bioenergy (Ministry of Education), National Forest and Grass Administration Woody Spices (East China) Engineering Technology Research Center, Beijing Forestry University, Beijing 100083, China. Electronic address:
Bio-based conductive hydrogels are catching a widespread attention in the field of flexible sensors and human-machine interface interaction. Here, an enhanced autocatalytic system constructed from dopamine-encapsulated cellulose nanofibers (DA@CNF) and Cu in a glycerol-water binary solvent achieved fast auto-polymerization of hydrogels within 60 s. X-ray photoelectron spectra (XPS), UV-vis spectrum (UV), Cyclic Voltammetry (CV) and electron paramagnetic resonance (EPR) were used to characterize the autocatalytic system.
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