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Magnetochemistry
Volume 11
Issue 4
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Magnetochemistry, Volume 11, Issue 4 (April 2025) – 13 articles

Cover Story (view full-size image): A series of isostructural lanthanoid coordination polymers based on a ditopic bis-picolinate ligand were synthesized. The compounds contain lanthanoid cations in a tricapped trigonal prismatic nonacoordinated geometry, bridged by segmented bischelating ligands to yield an extended orthorhombic crystal structure with triangular cavities. The magnetic measurements show that the Dy derivative exhibits slow relaxation properties in the absence of an external field, following quantum tunneling and the Orbach mechanisms of relaxation. This compound, together with the Gd and Tb analogues, also exhibits slow relaxation properties under an applied DC magnetic field. The Gd derivative is one of the few reported Gd(III) compounds exhibiting slow relaxation of magnetization. View this paper
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25 pages, 6174 KiB  
Article
Copper(II)-Promoted Reactions of α-Pyridoin Oxime: A Dodecanuclear Cluster and a 2D Coordination Polymer
by Konstantina H. Baka, Luís Cunha-Silva, Catherine P. Raptopoulou, Vassilis Psycharis, Dionissios Papaioannou, Mark M. Turnbull, Zoi G. Lada, Spyros P. Perlepes and Theocharis C. Stamatatos
Magnetochemistry 2025, 11(4), 35; https://doi.org/10.3390/magnetochemistry11040035 - 18 Apr 2025
Viewed by 132
Abstract
The reaction of CuCl2∙2H2O, (E)-2-hydroxy-1,2-di(pyridin-2-yl)ethanone oxime (α-pyroxH2) and Et3N in refluxing MeOH gave complex [Cu12Cl12(mpydol)4(pydox)2(MeOH)4] (1), where mpydol2− is the [...] Read more.
The reaction of CuCl2∙2H2O, (E)-2-hydroxy-1,2-di(pyridin-2-yl)ethanone oxime (α-pyroxH2) and Et3N in refluxing MeOH gave complex [Cu12Cl12(mpydol)4(pydox)2(MeOH)4] (1), where mpydol2− is the dianion of 1,2-dimethoxy-1,2-di(pyridin-2-yl)ethane-1,2-diol and pydox2− is the dianion of (E,E)-1,2-di(pyridin-2-yl)ethanedione dioxime. “Blind” experiments have proven that the transformation of α-pyroxH2 is copper(II)-assisted. By changing the solvent from MeOH to MeCN, the polymeric compound {[Cu4Cl4(pic)4]}n (2) was isolated; pic− is the pyridine-2-carboxylato(-1) ligand. The observed α-pyroxH2 → pic− transformation is also copper(II)-assisted. The topology of the metal ions in 1 can be described as consisting of four consecutive isosceles triangles in a zigzag configuration. Complex 2 is a 2D coordination polymer consisting of CuII4 squares. Complete mechanistic views for the α-pyroxH2 → mpydol2−, pydox2− and pic− transformations are critically discussed. In 1, the six CuII ions of the “central” triangles seem to be strongly antiferromagnetically coupled, thus cancelling out their spins (SCu6 = 0). The two local spins of S = 1/2 for each of the antiferromagnetically coupled “terminal” CuII3 triangles result in an overall S = 1 ground state spin value for 1. In 2, the four CuII ions within each tetrameric unit are practically isolated and ferromagnetic interactions occur between these units through CuII–(μ-Cl)–CuII bridges. Full article
(This article belongs to the Special Issue Latest Research on the Magnetic Properties of Coordination Compounds)
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18 pages, 2772 KiB  
Article
Cobalt(II) and Nickel(II) Cubane {M4O4} Complexes Derived from Di-2-pyridyl Ketone and Benzoate: Syntheses, Structure and Magnetic Properties
by Carolina Pejo, Santiago Valiero, Carlos Rojas-Dotti, Guilherme P. Guedes, Joan Cano, Miguel A. Novak, Raúl Chiozzone, Maria G. F. Vaz and Ricardo González
Magnetochemistry 2025, 11(4), 34; https://doi.org/10.3390/magnetochemistry11040034 - 15 Apr 2025
Viewed by 259
Abstract
Two tetranuclear complexes were obtained by a self-assembly process employing di-2-pyridyl ketone ((py)2CO), benzoate and M(NO3)2 (M = Co and Ni). The compounds [M4{(py)2C(OH)O}4(O2CPh)4], where {(py)2C(OH)O} [...] Read more.
Two tetranuclear complexes were obtained by a self-assembly process employing di-2-pyridyl ketone ((py)2CO), benzoate and M(NO3)2 (M = Co and Ni). The compounds [M4{(py)2C(OH)O}4(O2CPh)4], where {(py)2C(OH)O}− is the monoanion of the gem-diol form of (py)2CO, were characterized through single-crystal X-ray diffraction and magnetic measurements. Structural analysis revealed that both complexes possess a [M4O4] cubane-like core. A two-J model and magnetic anisotropy were employed to analyze the magnetic properties of both compounds. These studies indicate the presence of dominant ferromagnetic interactions within both tetranuclear cores. DFT and CASSCF/NEVPT2 calculations were also performed to support the fitting of experimental magnetic data. Full article
(This article belongs to the Special Issue Magnetic Coordination Compounds and More... a Long and Successful Story: A Tribute to M. Julve and F. Lloret)
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16 pages, 6463 KiB  
Article
Decaying Oscillating Pulsed Magnetic Field Induces Lysosome-Dependent Cell Death in A375 Melanoma via Magneto-Mechanical Force
by Yan Mi, Jianli Wang, Sifan Tang, Chi Ma, Wei Zheng and Jiayu Chen
Magnetochemistry 2025, 11(4), 33; https://doi.org/10.3390/magnetochemistry11040033 - 14 Apr 2025
Viewed by 233
Abstract
The synergistic application of magnetic fields and iron oxide nanorod particles (IONPs) presents a novel therapeutic approach for inducing lysosome-dependent cell death (LDCL) via magneto-mechanical force (MMF). This study demonstrates the efficacy of decaying oscillating pulsed magnetic fields (DOPMFs) to propel IONPs to [...] Read more.
The synergistic application of magnetic fields and iron oxide nanorod particles (IONPs) presents a novel therapeutic approach for inducing lysosome-dependent cell death (LDCL) via magneto-mechanical force (MMF). This study demonstrates the efficacy of decaying oscillating pulsed magnetic fields (DOPMFs) to propel IONPs to induce rapid tumor regression via lysosomal membrane permeabilization (LMP). The systematic evaluation of dose-dependent parameters revealed that DOPMF intensity and pulse number critically determine A375 melanoma cell viability reduction. Mechanistic investigations identified two hallmark biomarkers of LMP: increased cytosolic cathepsin B activity and downregulated LAMP-2 expression. Crucially, in vivo experiments using A375 melanoma-bearing mouse models corroborated the therapeutic potential of this approach, showing significant tumor growth inhibition without systemic toxicity or invasive procedures. Collectively, our findings demonstrate that MMF by IONPs under DOPMF stimulation exhibits significant efficacy in suppressing melanoma proliferation, offering a non-invasive, targeted approach for oncological intervention. Full article
(This article belongs to the Section Applications of Magnetism and Magnetic Materials)
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12 pages, 5831 KiB  
Article
The Impact of Ho Addition on the Microstructural Features and Magnetic Performances of Sintered NdFeB Magnets
by Xin-De Zhu, Wei-Ming Liu, Fei Wang, Zhao-Pu Xu, Qian Wang, Xiao-Qian Gu, Meng Li, Ya Jiang, Feng-Sheng Xue and Mei Wang
Magnetochemistry 2025, 11(4), 32; https://doi.org/10.3390/magnetochemistry11040032 - 14 Apr 2025
Viewed by 178
Abstract
Two NdFeB magnets with distinct compositions were fabricated via an identical process. One magnet was doped with 2.5 wt.% of Ho, whereas the other remained undoped. Subsequently, grain boundary diffusion was performed on both magnets using metallic Tb, adopting the same set of [...] Read more.
Two NdFeB magnets with distinct compositions were fabricated via an identical process. One magnet was doped with 2.5 wt.% of Ho, whereas the other remained undoped. Subsequently, grain boundary diffusion was performed on both magnets using metallic Tb, adopting the same set of technological parameters. A comprehensive analysis was conducted on the magnetic properties, phase compositions, microstructures, and elemental distributions of these two magnets. The findings indicate that the incorporation of Ho enhances the utilization efficiency of Tb. As a result, the magnets can achieve higher coercivity across different temperatures, with only a minor reduction in remanence. During the sintering process of the Ho-doped magnet, fine precipitated particles of Ho2Fe14B are generated inside the magnet. This phenomenon causes the refinement of the main grains of the magnet. The refined main grains facilitate the effective diffusion of Tb within the magnet, eliminating the formation of the anti-shell structure. Furthermore, when Ho substitutes for Nd, it leads to a more homogeneous distribution of the Nd-rich phase. Additionally, it increases the densification degree of the sintered NdFeB magnets. These effects contribute to a further enhancement of the magnets’ coercivity. Full article
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17 pages, 3303 KiB  
Article
Lanthanoid Coordination Polymers Based on Homoditopic Picolinate Ligands: Synthesis, Structure and Magnetic Properties
by Verónica Jornet-Mollá, Carlos J. Gómez-García, Miquel J. Dolz-Lozano and Francisco M. Romero
Magnetochemistry 2025, 11(4), 31; https://doi.org/10.3390/magnetochemistry11040031 - 7 Apr 2025
Viewed by 163
Abstract
A ditopic ligand (H2L1), containing picolinate subunits segmented by ethynylene bridges, has been used in the synthesis of a series of isostructural coordination polymers, formulated as [(CH3)2NH2][Ln(L1)2]·H2 [...] Read more.
A ditopic ligand (H2L1), containing picolinate subunits segmented by ethynylene bridges, has been used in the synthesis of a series of isostructural coordination polymers, formulated as [(CH3)2NH2][Ln(L1)2]·H2O·CH3COOH, where Ln = Eu (1), Gd (2), Tb (3), Dy (4) and Ho (5). The single-crystal structures show that these compounds crystallise in the orthorhombic Pna21 space group and form 3D anionic lattices with triangular cavities. AC magnetic susceptibility measurements show that the Gd, Tb and Dy derivatives (2–4) present a slow relaxation in their magnetisation under an applied DC magnetic field. The detailed study of the AC susceptibility in compounds 2 and 4 shows that they relax following direct and Orbach mechanisms under these conditions. The Dy derivative (4) retains this behaviour in the absence of an external field, relaxing via quantum tunnelling and Orbach mechanisms. Compound 2 is one of the very few reported Gd(III) compounds showing slow relaxation in its magnetisation. Full article
(This article belongs to the Special Issue Magnetic Coordination Compounds and More... a Long and Successful Story: A Tribute to M. Julve and F. Lloret)
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19 pages, 13794 KiB  
Article
Experimental Study on Thermal Conductivity of Hybrid Magnetic Fluids Under External Magnetic Field
by Licong Jin, Jixian Yang, Qian Li, Xin Tian and Decai Li
Magnetochemistry 2025, 11(4), 30; https://doi.org/10.3390/magnetochemistry11040030 - 3 Apr 2025
Viewed by 191
Abstract
In the paper, a hybrid magnetic fluid is prepared by adding carbon nanotubes to pure ferrofluid to improve its thermal conductivity. Furthermore, an electromagnet is used as magnetic source equipment, and the magnetic field strength in the air gap of the electromagnet is [...] Read more.
In the paper, a hybrid magnetic fluid is prepared by adding carbon nanotubes to pure ferrofluid to improve its thermal conductivity. Furthermore, an electromagnet is used as magnetic source equipment, and the magnetic field strength in the air gap of the electromagnet is analyzed in theory, simulations, and experiments. A thermal conductivity measurement apparatus for magnetic fluid is established according to the transient hot-wire method. The effects of weight fraction and the length of carbon nanotubes, the external magnetic field strength, and the magnetic field duration time on the thermal conductivity of hybrid magnetic fluid are experimentally investigated. The results show that the thermal conductivity of the hybrid magnetic fluid is significantly improved by adding long carbon nanotubes (10–30 μm), and the thermal conductivity could be enhanced by 23.39% when its weight fraction is 1%. The magnetic field strength (41, 81, 122, 162 mT) and magnetic field duration time have little influence on the thermal conductivity of the hybrid magnetic fluid. The thermal conductivity of the hybrid magnetic fluid has good stability. Full article
(This article belongs to the Special Issue Ferrofluids: Electromagnetic Properties and Applications)
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15 pages, 4711 KiB  
Article
Impact of Compaction Pressure and Heat Treatment Temperature on the Performance of FeSiBCuNb/FeNi Soft Magnetic Composites
by Yanyan Song, Zhi Zhang, Shaoxiong Zhou, Ruibiao Zhang, Xiantao Li and Haichen Yu
Magnetochemistry 2025, 11(4), 29; https://doi.org/10.3390/magnetochemistry11040029 - 3 Apr 2025
Viewed by 140
Abstract
FeSiBCuNb powders, produced via the gas–water atomization method, typically exhibit a broad particle size distribution and high sphericity. Nanocrystalline soft magnetic composites derived from these powders demonstrate exceptional service stability. In this study, a series of FeSiBCuNb/FeNi nanocrystalline magnetic powder cores (NMPCs) were [...] Read more.
FeSiBCuNb powders, produced via the gas–water atomization method, typically exhibit a broad particle size distribution and high sphericity. Nanocrystalline soft magnetic composites derived from these powders demonstrate exceptional service stability. In this study, a series of FeSiBCuNb/FeNi nanocrystalline magnetic powder cores (NMPCs) were fabricated under varying compaction pressures and heat treatment temperatures. The effects of these parameters on the soft magnetic properties were systematically analyzed. The findings reveal that optimizing compaction pressure and heat treatment temperature significantly enhances the density of the composite powders, leading to improved magnetic permeability and reduced core loss; when compaction pressure is 1800 MPa and heat treatment temperature is 550 °C, the NMPCs display outstanding magnetic properties with a low Hc of 6.32 Oe, high μe of 71.9, a low Pcv of 86.3 kW/m3 at 50 mT and 100 kHz, and 351.5 kW/m3 at 20 mT and 1000 kHz. Therefore, tailoring these processing conditions can enhance the soft magnetic performance of FeSiBCuNb nanocrystalline composites. Full article
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17 pages, 3070 KiB  
Article
Impact of Magnetic Field on ROS Generation in Cu-g-C3N4 Against E. coli Disinfection Process
by Elkin Darío C. Castrillon, Santiago Correa and Yenny P. Ávila-Torres
Magnetochemistry 2025, 11(4), 28; https://doi.org/10.3390/magnetochemistry11040028 - 3 Apr 2025
Viewed by 186
Abstract
The antibacterial activity of g-C3N4 and Cu-g-C3N4 was evaluated against E. coli, with their disinfection capabilities influenced by structural characteristics, photocatalytic properties, and modulation under a static magnetic field. The incorporation of Cu2+ does not [...] Read more.
The antibacterial activity of g-C3N4 and Cu-g-C3N4 was evaluated against E. coli, with their disinfection capabilities influenced by structural characteristics, photocatalytic properties, and modulation under a static magnetic field. The incorporation of Cu2+ does not significantly affect the (210) reflection in XRD analysis, indicating that the alignment of aromatic layers remains stable. However, the presence of copper enables complete disinfection, in contrast to graphitic carbon nitride, which achieves only partial disinfection. Cu2+ is likely positioned at N-aliphatic sites and coexists with hydroxylated species, which may influence photocatalytic performance by modifying reactant adsorption and ROS generation. SEM-EDS analysis confirmed that Cu2+ modification did not significantly alter the material’s morphology, although a 3% copper content was detected, suggesting a heterogeneous surface distribution. Thermodynamic analysis showed that exposure to a magnetic field increased the Gibbs free energy of adsorption from 6.34 J/m2 to 10.52 J/m2, reducing interactions with key reactants essential for ROS formation. As a result, both disinfection and photodegradation efficiency were significantly diminished. Additionally, the presence of a magnetic field was found to modify the surface properties of the material, affecting its photocatalytic performance. In Cu-C3N4 materials, a decrease in the contact angle suggests enhanced hydrophilicity, while an increase in surface tension may influence the adsorption of water and hydroxyl radicals. This study underscores the effect of a magnetic field on the photocatalytic behavior of materials deposited on polymeric substrates with intrinsic electronic properties, ultimately impacting overall disinfection efficiency. Full article
(This article belongs to the Special Issue Recent Progress of Magnetic Field Effect on Catalysts)
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16 pages, 4352 KiB  
Article
Sustainable Phosphate Remediation via Hierarchical Mg-Fe Layered Double Hydroxides on Magnetic Biochar from Agricultural Waste
by Xiuling Li, Lei Xin, Yuhan Peng, Shihao Zhang, Delong Guan and Jing Song
Magnetochemistry 2025, 11(4), 27; https://doi.org/10.3390/magnetochemistry11040027 - 1 Apr 2025
Viewed by 203
Abstract
Addressing aquatic phosphate pollution requires advanced materials that combine high selectivity with recyclability. Here, we present a hierarchically structured composite integrating Mg-Fe layered double hydroxides (LDHs) with magnetic biochar derived from mulberry branches—an abundant agricultural byproduct. Through hydrothermal synthesis, the composite achieves a [...] Read more.
Addressing aquatic phosphate pollution requires advanced materials that combine high selectivity with recyclability. Here, we present a hierarchically structured composite integrating Mg-Fe layered double hydroxides (LDHs) with magnetic biochar derived from mulberry branches—an abundant agricultural byproduct. Through hydrothermal synthesis, the composite achieves a unique architecture combining Fe3O4-enabled magnetic recovery (2.63 emu·g−1 saturation) with LDHs’ anion exchange capacity and biochar’s porous network. Systematic characterization reveals phosphate capture mechanisms dominated by hydrogen bonding through deprotonated carboxyl groups, inner-sphere complexation with metal oxides, and interlayer anion exchange, enabling 99.22% phosphate removal at optimal conditions (pH 6, 25 °C). Crucially, the material demonstrates exceptional selectivity over competing Cl− and NO3− ions while maintaining 87.83% efficiency after three regeneration cycles via alkaline treatment. Kinetic and thermodynamic analyses confirm chemisorption-driven uptake aligned with pseudo-second-order kinetics (R2 > 0.9998) and Langmuir monolayer adsorption (7.72 mg·g−1 capacity). This waste-derived magnetic composite establishes a sustainable paradigm for eutrophication control, merging selective phosphate sequestration with energy-efficient recovery for circular water treatment applications. Full article
(This article belongs to the Special Issue Applications of Magnetic Materials in Water Treatment)
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9 pages, 2043 KiB  
Article
Magnetic Relaxation in a Heterolanthanide Binuclear Complex Involving a Nitronyl Nitroxide Biradical
by Yan Zhou, Junfang Xie, Chaoyi Jin, Yue Ma and Licun Li
Magnetochemistry 2025, 11(4), 26; https://doi.org/10.3390/magnetochemistry11040026 - 31 Mar 2025
Viewed by 257
Abstract
The reaction of nitronyl nitroxide biradical NITPhMeImbis(5-(2-methylimidazole)-1,3-bis(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)-benzene) with Dy(hfac)3 and La(hfac)3 (hfac = hexafluoroacetylacetonate) afforded a heterolanthanide complex [Dy0.56La1.44(hfac)7(NITPhMeImbisH)] (1). In this complex, the biradical NITPhMeImbis ligand chelates one Ln(III) ion [...] Read more.
The reaction of nitronyl nitroxide biradical NITPhMeImbis(5-(2-methylimidazole)-1,3-bis(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)-benzene) with Dy(hfac)3 and La(hfac)3 (hfac = hexafluoroacetylacetonate) afforded a heterolanthanide complex [Dy0.56La1.44(hfac)7(NITPhMeImbisH)] (1). In this complex, the biradical NITPhMeImbis ligand chelates one Ln(III) ion via its two neighboring NO units and simultaneously binds the La(III) ion through another NO group to form a dinuclear structure. Direct current (dc) magnetic measurement shows the dominant ferromagnetic couplings in Complex 1. Spin dynamics studies exhibit visible frequency-dependent peaks of χ″ signals under a dc field evidenced by field-induced magnetic relaxation behavior, which is a combination of Orbach and QTM processes, giving the Ueff, τ0 and τQTM values of 15.14 K, 3.04 × 10−7 s and 3.61 × 10−4 s, respectively. Full article
(This article belongs to the Special Issue Molecular Magnetism: A Themed Issue in Honor of Professor Dai-Zheng Liao on the Occasion of His 85th Birthday)
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14 pages, 7361 KiB  
Article
Improving the Soft Magnetic Characteristics of Nanocrystalline Soft Magnetic Composites Through the Incorporation of Ultrafine FeSiAl Powders
by Yanyan Song, Zhi Zhang, Shaoxiong Zhou, Ruibiao Zhang, Haichen Yu and Xiantao Li
Magnetochemistry 2025, 11(4), 25; https://doi.org/10.3390/magnetochemistry11040025 - 30 Mar 2025
Viewed by 356
Abstract
Nanocrystalline powders, characterized by a biphasic amorphous nanocrystalline structure, demonstrate outstanding soft magnetic characteristics, including reduced coercivity (Hc), enhanced effective permeability (μe), and increased resistivity. However, their high hardness, poor formability, and significant core loss (P [...] Read more.
Nanocrystalline powders, characterized by a biphasic amorphous nanocrystalline structure, demonstrate outstanding soft magnetic characteristics, including reduced coercivity (Hc), enhanced effective permeability (μe), and increased resistivity. However, their high hardness, poor formability, and significant core loss (Pcv) restrict their use in high-performance molded inductors. In this study, FeSiBCuNb/FeSiAl nanocrystalline soft magnetic composites (NSMCs) were fabricated, and the influence of varying the FeSiAl concentration on the microstructure, density, and soft magnetic characteristics of NSMCs was investigated. Then, the underlying mechanisms of these effects were explained. The results demonstrate that FeSiAl exhibits apparent deformation following compression, effectively filling the air gap between the FeSiBCuNb powder particles, thereby enhancing coupling among the magnetic particles. Consequently, the density of the NSMCs was enhanced, leading to a significant improvement in their overall soft magnetic properties. When 50 wt.% FeSiAl is added, the NSMCs display outstanding magnetic properties, including a low Hc of 4.36 Oe, a high μe of 48.7, a low Pcv of 119.35 kW/m3 at 50 mT and 100 kHz, and a high DC-bias performance of 73.29% at 100 Oe. Compared to NSMCs without FeSiAl, μe increased by 59.4% and Pcv decreased by 66.1%. Meanwhile, the incorporation of ultrafine FeSiAl powder was found to significantly improve the material properties, as the deformable FeSiAl particles effectively fill interparticle gaps during compaction, enhancing density and magnetic coupling. The 50 wt.% FeSiAl composition demonstrated exceptional properties. These advances address critical challenges in high-frequency power electronic applications and provide a practical material solution for next-generation power electronics. Full article
(This article belongs to the Section Magnetic Materials)
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19 pages, 3964 KiB  
Article
Preparation, Characterization, and Application of Citrate-Functionalized Cobalt-Doped Iron Oxide Nanoparticles for Rhodamine Dye and Lead Ion Sequestration
by Sangeetha Jayakumar, Barid Baran Lahiri and Arup Dasgupta
Magnetochemistry 2025, 11(4), 24; https://doi.org/10.3390/magnetochemistry11040024 - 29 Mar 2025
Viewed by 228
Abstract
The toxicity of hazardous dyes like rhodamine B and heavy metal ions like lead warrants the need for wastewater remediation. We describe here the functionalization of cobalt-doped iron oxide (Co0.1Fe2.9O4) magnetic nanoparticles (MNPs) with citrate moieties for [...] Read more.
The toxicity of hazardous dyes like rhodamine B and heavy metal ions like lead warrants the need for wastewater remediation. We describe here the functionalization of cobalt-doped iron oxide (Co0.1Fe2.9O4) magnetic nanoparticles (MNPs) with citrate moieties for the effective sequestration of rhodamine B dye and lead ions from contaminated water. Citrate-functionalized MNPs are prepared using a co-precipitation technique. For the uncoated MNPs, the hydrodynamic diameter and zeta potential are found to be 21 nm and ~45 ± 3.1 mV, respectively. The hydrodynamic diameters are found to increase to ~51, ~59, and ~68 nm for the MNPs functionalized with ~20, ~40, and ~60 mg/mL of citrate, respectively, whereas the corresponding zeta potentials are found to be ~−27.95 ± 3.5 mV, ~−32.5 ± 3.6 mV, and ~−33.9 ± 3.5 mV, respectively. The chemisorption of the citrate moieties over the MNPs cause the zeta potential to be negative, a phenomenon which is further verified from the citrate-specific absorption bands in the Fourier transform infrared (FTIR) spectra of the surface-functionalized MNPs. UV-visible spectrophotometry is employed to probe the MNP-aided elimination of rhodamine B dye and lead ions from aqueous media, where the absorption bands at ~554 nm and ~375 nm (for lead (II)-5-dimercapto-1,3,4-thiadiazole chelate) are utilized for quantitative analyses. These citrate-functionalized nanoparticles are found to successfully remove the toxic rhodamine B dye and lead ions from water, with removal efficiencies of ~93.7 ± 2.6% and ~90 ± 2.4%, respectively. The unbound -COO− functional groups of the citrate-functionalized MNPs electrostatically interact with the cationic rhodamine B dye or lead (II) ions, thereby leading to the adsorption onto the surface-functionalized MNPs and the subsequent magnetic-field-assisted removal. The experimental findings show the efficacy of the citrate-functionalized cobalt-doped iron oxide MNPs for the sequestration of dye pollutants and lead ions from contaminated water. Full article
(This article belongs to the Special Issue Applications of Magnetic Materials in Water Treatment)
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14 pages, 4754 KiB  
Article
Slow Relaxation of Magnetization and Magnetocaloric Effects in One-Dimensional Oxamato-Based Lanthanide(III) Coordination Polymers
by Jhonny W. Maciel, Lucas H. G. Kalinke, Renato Rabelo, Meiry E. Alvarenga, Felipe Terra Martins, Nicolás Moliner and Danielle Cangussu
Magnetochemistry 2025, 11(4), 23; https://doi.org/10.3390/magnetochemistry11040023 - 24 Mar 2025
Viewed by 359
Abstract
Herein, we present the synthesis and characterization of a series of isostructural lanthanide(III) compounds with the N-(4-carboxyphenyl)oxamic acid (H3pcpa) ligand of the general formula as {[Ln2(Hpcpa)3(H2O)5]}n [Ln = Dy(III) 1, [...] Read more.
Herein, we present the synthesis and characterization of a series of isostructural lanthanide(III) compounds with the N-(4-carboxyphenyl)oxamic acid (H3pcpa) ligand of the general formula as {[Ln2(Hpcpa)3(H2O)5]}n [Ln = Dy(III) 1, Ho(III) 2, Er(III) 3]. The structure of 3 consists of neutral zig–zag chains of Er(III) ions, with Hpcpa2– ligands acting as bridges in a bidentate/monodentate coordination mode with five water molecules achieving the eight-coordination around the two Er(III) ions within the repeating bis(carboxylate)-bridged dinuclear units along the chain. The magnetic and magnetocaloric properties were studied for 1–3. Compound 1 presents a field-induced slow relaxation of the magnetization with a “reciprocating thermal behavior” below 5 K for H = 0.25 T, while 2 shows maxima of the magnetic entropy from 3 up to 6 K for ΔH > 2 T. Full article
(This article belongs to the Special Issue Magnetic Coordination Compounds and More... a Long and Successful Story: A Tribute to M. Julve and F. Lloret)
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