Search Results (352)

Metallogels, three-dimensional supramolecular networks formed through metal–ligand coordination, have emerged as a new generation of adaptive soft materials with promising biomedical potential. By integrating the structural stability and tuneable functionality of metal centres with the dynamic self-assembly of organic gelators, these systems exhibit exceptional mechanical strength, responsiveness, and multifunctionality. Recent studies demonstrate their diverse applications in drug delivery, anticancer therapy, antimicrobial and wound healing treatments, biosensing, bioimaging, and tissue engineering. Interestingly, the coordination of metal ions such as Ru(II), Zn(II), Fe(III), and lanthanides enables the creation of self-healing, thixotropic, and stimuli-responsive gels capable of controlled release and therapeutic action. Moreover, the incorporation of luminescent or redox-active metals adds optical and electronic properties suitable for diagnostic and monitoring purposes. This collection summarizes the most recent advances in the field, highlighting how rational molecular design and coordination chemistry contribute to the development of multifunctional, biocompatible, and responsive metallogels that bridge the gap between materials science and medicine. Full article

The synthesis, characterization, and equilibrium studies of complexes of selected lanthanide ions Eu(III), Gd(III), and Tb(III) with the ligand 1,3-bis(3-bromo-5-chlorosalicylideneamino)-2-propanol (H₃L) are reported. It was found that in the solid state, the complexes with the formulas [Eu(H₃L)₂(NO₃)₃], [Gd(H₃L)₂(NO₃)₃], and [Tb(H₃L)₂(NO₃)₃] are formed. In solution, complexes with stoichiometries of Ln(III):H₃L 1:1 and 1:2 were obtained. The ligand H₃L was isolated in crystalline form, and its molecular structure and conformation were determined by single-crystal X-ray diffraction analysis. The compounds were further characterized by elemental analysis, infrared spectroscopy, ¹H NMR, ¹³C NMR techniques, and mass spectrometry (ESI), confirming the formation of the Schiff base group. Stability constants of the complexes in solution were determined using potentiometric titration, providing insights into the metal-ligand binding equilibria. In addition, the spectroscopic properties of the ligand and its lanthanide(III) ion complexes were investigated by UV-Vis spectroscopy, which confirmed ligand-to-metal charge transfer interactions, as well as by luminescence measurements. The luminescence studies revealed inefficient energy transfer in [Eu(H₃L)₂(NO₃)₃] complexes, while no transfer was observed in [Tb(H₃L)₂(NO₃)₃] systems at any pH value. This behavior is attributed to the large energy gap between the ligand triplet state and the lowest resonant levels of the studied lanthanide ions. Full article

Precise remote temperature sensing at the micro- and nanoscale is a growing necessity in modern science and technology. We report a series of luminescent tris-acetylacetonate lanthanide complexes, Ln(acac)₃(H₂O)₂ (Ln = Eu (1Eu), Tb (1Tb), Yb (1Yb)); acac⁻ = acetylacetonate), operating as self-referenced thermometers in the 290–350 K range, both in the solid state and when embedded in hybrid nanoparticles. Among the investigated systems, the Eu³⁺ complex exhibits excellent lifetime-based thermometric performance, achieving a maximum relative sensitivity (S_rmax) of 2.9%·K⁻¹ at 340 K with a temperature uncertainty (δT) as low as 0.02 K and an average temperature uncertainty ($\overline{\delta T}$) of 0.5 K, placing it among the most effective ratiometric lanthanide-based luminescent thermometers reported to date. The Yb³⁺ analog enables intensity-based thermometry in the near-infrared domain with a good sensitivity S_rmax = 0.5%·K⁻¹ at 293 K, δT = 0.5 K at 303 K, and $\overline{\delta T}$ = 1.6 K. These molecular thermometers were further incorporated into the shell of Prussian Blue@SiO₂ core–shell nanoparticles. Among the resulting hybrids, PB@SiO₂-acac/(1Tb/1Eu) (with a Tb/Eu ratio of 2/8) stood out by enabling ratiometric temperature sensing based on the Eu³⁺⁵D₀ → ⁷F₂ lifetime, with satisfactory parameters (S_rmax = 0.9%·K⁻¹, δT = 0.21 K at 303 K, and $\overline{\delta T}$ = 1.1 K). These results highlight the potential of simple coordination complexes and their nanohybrids for advanced luminescent thermometry applications. Full article

The paper reports on obtaining visually appealing images from opal matrices to artificial samples comprising regular packing of monodisperse silica globules. We show the images of iridescence, photoluminescence, and both of them simultaneously, exciting upconversion luminescence of Er³⁺ ions from BaTiO₃ xerogel/opal matrix. Opal matrix with BaTiO₃ xerogel doped with Er³⁺ and Yb³⁺ ions demonstrates upconversion luminescence under excitation with the wavelength 980 nm of the laser with the main bands ranging from 500 to 570 nm and 640–700 nm, corresponding to the transitions from the excited states ²H_11/2, ⁴S_3/2, ⁴F_9/2, ⁴I_9/2 to the ground state ⁴I_15/2 of trivalent Er ions. In our view, the synthesis of opal matrices along with the generation of luminescent xerogels doped, for example, with trivalent lanthanides, is a promising approach for obtaining colorful images, always very individual and often very attractive, bringing joy and pleasure at concerts and other show business events. Full article

Lanthanide-doped inorganic luminescent materials have been extensively studied and applied in X-ray detection and imaging, anti-counterfeiting, and optical information storage. However, many reported rare-earth-based luminescent materials show only single-mode optical responses, which limits their applications in complex scenarios. Here, we report a novel Na₃KMg₇(PO₄)₆:Eu phosphor synthesized by a simple high-temperature solid-state method. The multi-color luminescence of Eu²⁺ and Eu³⁺ ions in a single matrix of Na₃KMg₇(PO₄)₆:Eu, known as radio-photoluminescence, is achieved through X-ray-induced ion reduction. It demonstrated a good linear response (R² = 0.9897) and stable signal storage (storage days > 50 days) over a wide range of X-ray doses (maximum dose > 200 Gy). In addition, after X-ray irradiation, this material exhibits photochromic properties ranging from white to brown in a bright field and shows remarkable bleaching and recovery capabilities under 254 nm ultraviolet light or thermal stimulation. This dual-modal luminescent phosphor Na₃KMg₇(PO₄)₆:Eu, which combines photochromism and radio-photoluminescence, presents a dual-mode X-ray detection and imaging strategy and offers a comprehensive and novel solution for applications in anti-counterfeiting and optical information encryption. Full article

The Gabal Um Samra (GUS) compound intrusion in the Eastern Desert of Egypt consists of a co-magmatic series of syenogranite and alkali feldspar granite. Accessory minerals (e.g., zircon, monazite, allanite) are abundant. Geochemically, the GUS intrusion is a classic A-type granite. It is extensively fractionated, enriched in large ion lithophile elements and high field strength elements, and depleted in Ba, Sr, K, and Ti. Normalized rare earth element patterns are nearly flat, without any lanthanide tetrad anomalies, but with distinct negative Eu anomalies (Eu/Eu* = 0.14–0.22) due to feldspar fractionation. Paired Zr-Hf and Y-Ho element systematics indicate igneous rather than hydrothermal processes. The petrogenesis of the comparatively unaltered GUS intrusion offers an opportunity to refine the standard model for post-collisional felsic magmatism in the Neoproterozoic Arabian–Nubian Shield. It is explained by the partial melting of juvenile crust induced by lithospheric delamination, followed by extensive fractional crystallization. A quantitative mass-balance model shows that the granite varieties of the GUS intrusion plausibly represent liquids along a single liquid line of descent; but, if so, the more evolved, later pulses display anomalous enrichment in Rb, Nb, Ta, U, and REE. The most plausible source for this enrichment is the extraction of small-degree residual melts from earlier pulses and the mixing of the melts into the later pulses, an energetically favorable process we call “auto-assimilation”. A quantitative model shows that the residual liquid after 97.5% crystallization of the syenogranite can fit the major oxide and trace element data in the alkali feldspar granite if 0.07% by mass of this melt is added to the evolving system for each 1% crystal fractionation by mass. The GUS intrusion represents an example of moderate rare metal enrichment and concentration to sub-economic grade by auto-assimilation. Similar processes may affect intrusions that feature higher grade mineralization, but the evidence is often obscured by the extensive alteration of those deposits. Full article

Lanthanide/transition metal-doped luminescent materials are advanced materials with broad application potential. This type of material achieves control and optimization of luminescence performance by introducing lanthanide/transition metal ions into the host material and utilizing its unique electronic structure and optical properties. Luminescent materials are suitable for optical communication devices, biological imaging, and photodetectors. The combination of lanthanide/transition metals with various matrix materials provides a new platform for creating new chemical and physical properties in materials science and device applications. In this paper, we summarize the latest progress in the research of lanthanide/transition metal-doped luminescent materials and explain their roles in biological imaging, sensing, and optoelectronic applications. It starts with various synthesis techniques and explores how to cleverly incorporate rare earth/transition metals into various matrices, thereby endowing them with unique properties. Then, the advantages and disadvantages of each synthesis technique are discussed. Subsequently, the focus will be on functional strategies and their applications. Finally, strategies for lanthanide/transition metal ion-doped luminescent materials to address challenges are proposed, and insights from each section are summarized. Full article

Scandium(III) (Sc(III)) is the smallest among the trivalent ions in Group 3, which includes yttrium(III) and lanthanides (III) with a hydration number of 8 and 8–9, respectively. The hydration number of Sc(III) in aqueous solutions reported so far varies from six to ten and remains an open question. In general, applying pressure and temperature to aqueous solutions perturbs the water structure and ion solvation, providing insight into the nature of ion solvation. In the present study, we perform neutron scattering measurements of a 1 m (mol/kg) ScCl₃ aqueous solution in D₂O (hereafter H is used to symbolize the hydrogen atom instead of D) under the thermodynamic conditions from 0.1 MPa/298 K to 4 GPa/523 K. Using the empirical potential structure refinement (EPSR) method, the neutron scattering data are analyzed to extract the site–site pair distribution functions, coordination number distributions, angle distributions, and spatial density functions (3D structure). A predominant Sc(III) species is [Sc(OH₂)₇]³⁺ with a distorted pentagonal bipyramidal geometry together with appreciable amounts of contact ion pair species [ScCl_n(OH₂)_(6−n)]⁽³⁻ⁿ⁾⁺ (n = 1–3) and [Sc(OH₂)₈]³⁺ with mean Sc–Cl and Sc–OH₂ distances of 2.42 and 2.11 Å, respectively. An aqua chloride ion is surrounded on average by 7.8 and 10.9 water molecules with a Cl–H₂O distance of 3.10 Å at 0.1 MPa/298 K and 4 GPa/523 K, respectively. Applying GPa pressure transforms the tetrahedral network structure of water under ambient conditions to a dense, randomly packed structure with a mean coordination number of 12.6, resulting in an increase in the first-neighbor distance from 2.77 to 2.89 Å. The hydrogen bonds between water molecules remain linear but are largely distorted at high temperatures and high pressures. The present results provide a hint for understanding the underlying mechanism of high-pressure and temperature coordination chemistry and in applied fields, such as processes in geochemistry of the Earth’s upper mantle and pressure-induced protein denaturation. Full article

The experimental IR and Raman vibrational spectra of a hydrated La(III) complex with a 1,2,3-triazole ligand were characterized by using four different Density Functional Theory (DFT) levels and two accurate scaling procedures. In the theoretical calculations, the hydration water in the experimental sample was considered under the Discrete Model (DM) with different numbers of explicit water molecules and different positions around the La(III) ion and the carboxylate groups. The predicted IR spectra at the M06-2X/Lanl2dz level appear to be the closest to the experimental ones. Based on the optimized structures, molecular properties and global chemical descriptors were also calculated, and the findings obtained are discussed in detail herein. Additionally, several photophysical properties were determined in both the free ligand and in several lanthanide complexes, and with the sample in the solid state and in DMSO solution. A blue shift in the fluorescence of the complexes was observed compared to the free ligand, as well as in the solid-state sample compared to the solution. Full article

Given the outstanding magnetic characteristics of lanthanide ions, the development of mononuclear or multinuclear lanthanide complexes becomes imperative. Previous research showed that a series of mononuclear Dy(III) complexes of rhodamine benzoyl hydrazone Schiff base ligands exhibit remarkable single-molecule magnetic properties and fluorescence. In this study, we used analogous ligands to synthesize lanthanide complexes [Dy(HL¹-o)(NO₃)₂(CH₃OH)₂]NO₃·CH₃OH (complex 1·MeOH) and tetranuclear complexes [Ln₄(L¹-c)₂(L²)₂(μ₃-OH)₂(NO₃)₂(CH₃OH)₄](NO₃)₂·2CH₃CN·5CH₃OH·2H₂O (Ln = Dy, complex 2; Ln = Gd, complex 3). Magnetic susceptibility measurements show that 1·2H₂O is a single-molecule magnet, 2 shows slow magnetic relaxation and 3 is a magnetic cooling material with the magnetic entropy change of 9.81 J kg⁻¹ K⁻¹ at 2 K and 5 T. The theoretical calculations on 1·MeOH indicate that it shows good magnetic anisotropy with the calculated energy barrier of 194.6 cm⁻¹. Full article

Lanthanide rare earth elements possess significant promise for material applications owing to their distinctive optical and magnetic characteristics, as well as their versatile coordination capabilities. This study introduced a lanthanide-functionalized magnetic nanocellulose composite (NNC@Fe₃O₄@La(OH)₃) for effective phosphorus/nitrogen (P/N) ligand separation. The hybrid material employs the adaptable coordination geometry and strong affinity for oxygen of La³⁺ ions to show enhanced DNA-binding capacity via multi-site coordination with phosphate backbones and bases. This study utilized cellulose as a carrier, which was modified through carboxylation and amination processes employing deep eutectic solvents (DES) and polyethyleneimine. Magnetic nanoparticles and La(OH)₃ were subsequently incorporated into the cellulose via in situ growth. NNC@Fe₃O₄@La(OH)₃ showed a specific surface area of 36.2 m²·g⁻¹ and a magnetic saturation intensity of 37 emu/g, facilitating the formation of ligands with accessible La³⁺ active sites, hence creating mesoporous interfaces that allow for fast separation. NNC@Fe₃O₄@La(OH)₃ showed a significant affinity for DNA, with adsorption capacities reaching 243 mg/g, mostly due to the multistage coordination binding of La³⁺ to the phosphate groups and bases of DNA. Simultaneously, kinetic experiments indicated that the binding process adhered to a pseudo-secondary kinetic model, predominantly dependent on chemisorption. This study developed a unique rare-earth coordination-driven functional hybrid material, which is highly significant for constructing selective separation platforms for P/N-containing ligands. Full article

Incorporation of lanthanide (Ln) and actinide (An) ions into the human body poses significant chemotoxic and radiotoxic risks, necessitating effective decorporation strategies. This study investigates the displacement of biologically relevant ligands from trivalent ions of europium, Eu(III), and curium, Cm(III), in artificial biofluids by various complexing agents, i.e., ethylenediaminetetraacetic acid (EDTA), ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), and spermine-based hydroxypyridonate chelator 3,4,3-LI(1,2-HOPO) (HOPO). Utilizing a modified unified bioaccessibility method (UBM) to simulate gastrointestinal conditions, we conducted concentration-dependent displacement experiments at both room and body temperatures. Time-resolved laser-induced fluorescence spectroscopy (TRLFS) supported by ²H nuclear magnetic resonance (NMR) spectroscopy and thermodynamic modelling revealed the complexation efficacy of the agents under physiological conditions. Results demonstrate that high affinity, governed by complex stability constants and ligand pK_a values, is critical to overcome cation and anion competition and leads to effective decorporation. Additionally, there is evidence that cyclic ligands are inferior to linear ligands for this application. HOPO and DTPA exhibited superior displacement efficacy, particularly in the complete gastrointestinal tract simulation. This study highlights the utility of in vitro workflows for evaluating decorporation agents and emphasizes the need for ligands with optimal binding characteristics for enhanced chelation therapies. Full article

Lanthanide perovskite materials are promising candidates for supercapacitor applications. In this study, a series of La_1−xCa_xCrO₃ (x = 0–0.2) materials were prepared by sol-gel method, incorporating bivalent ions calcium at A-site. La_0.85Ca_0.15CrO₃ exhibited the lowest charge transfer resistance and highest specific surface area. At 1 A/g, La_0.85Ca_0.15CrO₃ achieved a maximum specific capacitance of 306 F/g, about 2.3 times higher than that of the LaCrO₃ (133 F/g). Based on the observed data, a mechanism involving oxygen anion charge storage during the charging-discharging process is proposed. After 5000 long cycle, the coulomb efficiency of the electrode remains above 94%. These results demonstrate that Ca-substituted compounds exhibit significant potential for A-site engineering in supercapacitor applications. Full article

Photoacoustic imaging (PAI) merges the high spatial resolution of optical methods with the deep tissue penetration provided by ultrasound, making it a valuable tool in biomedical imaging. In recent years, a diverse array of photoacoustic contrast agents, spanning both organic and inorganic materials, has been developed. Among them, upconversion nanoparticles (UCNPs) stand out as promising candidates due to their unique optical features, tunable absorption in the near-infrared I (NIR-I, 750–1350 nm) region, and strong potential for both imaging and treatment-related uses. This review discusses the growing significance of UCNPs in the field of PAI, focusing on their structural characteristics, strengths, and existing challenges. Then, we talk about an up-to-date account of the current literature on the use of UCNPs as contrast agents for PAI. Lastly, we discuss the challenges and perspectives of UCNPs as a contrast agent for PAI in preclinical research and clinical diagnosis. Full article

We present high-precision multi-configuration Dirac–Hartree–Fock (MCDHF) calculations for the metastable states of ${\mathrm{Pr}}^{9+}$ and ${\mathrm{Nd}}^{10+}$ ions, systematically investigating their energy levels, transition properties, Landé $g_J$ factors, and hyperfine interaction constants. Our results show excellent agreement with available experimental data and theoretical benchmarks, while resolving critical configuration assignment discrepancies through detailed angular momentum coupling analysis. The calculations highlight the significant role of Breit interaction and provide the first theoretical predictions of electric quadrupole hyperfine constants ($B_{\mathrm{hfs}}$). These findings deliver essential atomic data for the development of next-generation optical clocks and establish lanthanide highly charged ions as exceptional candidates for precision tests of fundamental physics. Full article