98%
921
2 minutes
20
Due to the different Cu centers, the [CuCu(HO)LCl] MOF has been widely studied using electron paramagnetic resonance (EPR) spectra, particularly regarding its capacity for gas molecule adsorption. In the present work, based on the occupation sites of Cu in [CuCu(HO)LCl], three corresponding fragments, dimer [CuO]-[CuO] (C), defective [CuO] (C), and [CuN] (C), are established to investigate the two different EPR signals (S and S) and the local environment of Cu. By applying the order perturbation formulas of the spin-Hamiltonian parameters, C and C can be excluded because of the EPR silence of the antiferromagnetically coupled Cu pair at low (7 K) temperatures and the silent signal of Cu. Thus, two mononuclear Cu ion defect species (C and C) in [CuCu(HO)LCl] can account for signals S and S, indicating two distinct surrounding environments of Cu. When the results from the density functional theory calculations are combined, the defective copper paddle wheel units are superior to the pristine ones in the adsorption of HO, which is beneficial to the electrochemical hydrogen evolution reaction (HER) and oxygen evolution reactions (OER). Therefore, the reliability of the perturbation method to investigate the EPR spectra and the adsorption behavior of MOFs is powerfully demonstrated, which can reduce the time consumed by current first-principles calculations.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.inorgchem.4c04694 | DOI Listing |
Dalton Trans
September 2025
CEQUINOR (UNLP, CCT-CONICET La Plata, asociado a CIC), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Blvd. 120 No. 1465, 1900 La Plata, Argentina.
This study details the synthesis of a novel ligand, ()-5-chloro-'-(2-hydroxy-3-methoxybenzylidene) thiophene-2-carbohydrazide ligand (for short, H2L), and its tetranuclear Cu(II) complex (Cu4L4), together with their X-ray crystal structures and the magnetic properties and EPR spectra of Cu4L4 within the 4-300 K temperature range. Furthermore, we report the spectroscopic characterization (FTIR and UV-Vis) of the compounds and perform a Hirshfeld analysis of their non-covalent interactions, along with certain quantum chemical calculations. H2L crystallizes in the monoclinic space group with = 8 molecules per unit cell and the Cu4L4 complex crystallizes in the tetragonal space group 4/ with = 4.
View Article and Find Full Text PDFJ Hazard Mater
August 2025
Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China. Electronic address:
Peracetic acid (PAA)-driven advanced oxidation processes (AOPs) are increasing favored for water treatment due to their environmentally benignity and ease of activation. However, the development of low-cost and high-performance activators is still a primary challenge. In this study, Fe-doped g-CN (Fe-N-C) was fabricated as an efficient peracetic acid (PAA) activator for sustainable degradation of emerging contaminants (ECs) like bisphenol A (BPA) with a removal efficiency of 97.
View Article and Find Full Text PDFInt J Biol Macromol
August 2025
Advanced Polymer Laboratory, Department of Polymer Science and Technology, Government College of Engineering and Leather Technology (Post-Graduate), Maulana Abul Kalam Azad University of Technology, Salt Lake City, Kolkata 700106, West Bengal, India.
This study was designed to develop a chemically modified chitosan-based sustainable adsorption system for soluble metal pollutants. Here, chitosan hydrogel beads modified with sulphate-sulphuric acid presented a high adsorption capacity toward copper ions and higher reusability due to enhanced low pH tolerance. Though the adsorption process was independent of incubation temperature, it varied with the pH of solution.
View Article and Find Full Text PDFJ Magn Reson
August 2025
Institute of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, Zurich, 8093 Switzerland.
Dynamic nuclear polarization (DNP) relies on the transfer of electron polarization to nuclei through microwave irradiation and is typically performed under cryogenic magic-angle spinning (MAS) at high magnetic fields. Gyrotrons are commonly used microwave sources in DNP because of their ability to produce high-power microwaves over a broad frequency range. An important step towards a more in-depth understanding of DNP mechanisms and rational optimization of DNP performance is the access to instrumentation, which can provide information about the DNP process.
View Article and Find Full Text PDFJ Phys Chem Lett
August 2025
Shanghai Key Laboratory of Magnetic Resonance, Institute of Magnetic Resonance and Molecular Imaging in Medicine, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, P. R. China.
Accurate theoretical prediction of EPR (electron paramagnetic resonance) spectra is crucial for elucidating reaction mechanisms, identifying unknown radicals, and guiding chemical transformations. This study introduces near-DFT (nuclear electron spin density approximation via radial functions for DFT), a novel computational approach that synthesizes two fundamental physical principles into a new predictive framework for the isotropic hyperfine coupling constant (). First, it systematically applies the Kato cusp condition to correctly describe electron spin density near the nucleus.
View Article and Find Full Text PDF