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1.
Int J Mol Sci ; 25(15)2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-39125638

RESUMEN

The oxidation of tetraselenatetracene (TSeT) by tetracyanoquinodimethane in the presence of dysprosium(III) tris(hexafluoroacetylacetonate), DyIII(hfac)3, produces black crystals of {TSeT1.5}●+[DyIII(hfac)4]- (1) salt, which combines conducting and magnetic sublattices. It contains one-dimensional stacks composed of partially oxidized TSeT molecules (formal averaged charge is +2/3). Dimers and monomers can be outlined within these stacks with charge and spin density redistribution. The spin triplet state of the dimers is populated above 128 K with an estimated singlet-triplet energy gap of 542 K, whereas spins localized on the monomers show paramagnetic behavior. A semiconducting behavior is observed for 1 with the activation energy of 91 meV (measured by the four-probe technique for an oriented single crystal). The DyIII ions coordinate four hfac- anions in [DyIII(hfac)4]-, providing D2d symmetry. Slow magnetic relaxation is observed for DyIII under an applied static magnetic field of 1000 Oe, and 1 is a single-ion magnet (SIM) with spin reversal barrier Ueff = 40.2 K and magnetic hysteresis at 2 K. Contributions from DyIII and TSeT●+ paramagnetic species are seen in EPR. The DyIII ion rarely manifests EPR signals, but such signal is observed in 1. It appears due to narrowing below 30 K and has g4 = 6.1871 and g5 = 2.1778 at 5.4 K.


Asunto(s)
Disprosio , Semiconductores , Disprosio/química , Aniones/química , Dimerización , Modelos Moleculares , Fenómenos Magnéticos , Magnetismo
2.
Luminescence ; 39(8): e4862, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39129445

RESUMEN

The present work investigates the structural and luminescence behaviour of Dy3+-Sm3+ co-doped glass ceramics obtained through heat treatment of precursor glasses. The growth of SiO2 polycrystalline particles and evolution of these crystallites in the glass domain are witnessed via XRD and FESEM study. The presence of network vibrational bands, hydroxyl groups and the increased quantity of bridging oxygens (BOs) in glass ceramics are analysed through FTIR spectroscopy study. The absorption study (UV-Visible-NIR) showed the possible electronic transitions of Dy3+ and Sm3+ ions. The red shift in the absorption band edges and the lower bandgap values are obtained as a result of improved heat treatment in glass ceramics. Emission studies show the enhanced luminescence intensity of glass ceramics under 350 and 402 nm excitations. Decay measurement of glass ceramics showed the improved lifetimes of Dy3+ and Sm3+ ions to have appeared in microseconds (×10-6 s). The colour characteristics of glass ceramics analysed using CIE colour chromaticity diagram and correlated colour temperature (CCT) values suggest the neutral to cool white light emissions. Therefore, prepared glass ceramics with SiO2 polycrystalline phase are considered to be suitable materials in cool white LEDs applications.


Asunto(s)
Cerámica , Cristalización , Disprosio , Luminiscencia , Samario , Dióxido de Silicio , Cerámica/química , Dióxido de Silicio/química , Disprosio/química , Samario/química , Luz , Vidrio/química
3.
Nat Commun ; 15(1): 5876, 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38997277

RESUMEN

Biological ion channels exhibit high selectivity and permeability of ions because of their asymmetrical pore structures and surface chemistries. Here, we demonstrate a biomimetic nanofluidic channel (BNC) with an asymmetrical structure and glycyl-L-proline (GLP) -functionalization for ultrafast, selective, and unidirectional Dy3+ extraction over other lanthanide (Ln3+) ions with very similar electronic configurations. The selective extraction mainly depends on the amplified chemical affinity differences between the Ln3+ ions and GLPs in nanoconfinement. In particular, the conductivities of Ln3+ ions across the BNC even reach up to two orders of magnitude higher than in a bulk solution, and a high Dy3+/Nd3+ selectivity of approximately 60 could be achieved. The designed BNC can effectively extract Dy3+ ions with ultralow concentrations and thereby purify Nd3+ ions to an ultimate content of 99.8 wt.%, which contribute to the recycling of rare earth resources and environmental protection. Theoretical simulations reveal that the BNC preferentially binds to Dy3+ ion due to its highest affinity among Ln3+ ions in nanoconfinement, which attributes to the coupling of ion radius and coordination matching. These findings suggest that BNC-based ion selectivity system provides alternative routes to achieving highly efficient lanthanide separation.


Asunto(s)
Disprosio , Disprosio/química , Iones , Biomimética/métodos , Nanotecnología/métodos , Neodimio/química
4.
Radiat Prot Dosimetry ; 200(10): 890-900, 2024 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-38847419

RESUMEN

The metrological quality of a measurement is characterised by evaluating the uncertainty in the measurement. In this paper, uncertainty in personal dose measured using individual monitoring CaSO4:Dy-based thermoluminescence dosimeter badge is evaluated by application of the guide to the expression of uncertainty in measurement method. The present dose reporting quantity, whole body dose (WBD) and the proposed quantity, personal dose equivalent, Hp(10) has been used as measurands. The influence of various input quantities on the measurement were analyzed through tests that conform to the requirements of the International Electrotechnical Commission IEC 62387. The study found that the expanded uncertainties for WBD and Hp(10) measurements were 63.4% and 41.4%, respectively, corresponding to a 95% coverage probability for workplace fields covering a wide photon energy range (33-1250 keV). However, the uncertainty estimates were quite lower for the type of workplaces that are identified using the dose evaluation algorithm. The input quantities, namely, the response to a mixture of photon beam qualities and photon energy and angular dependence contribute the most to the total uncertainty.


Asunto(s)
Exposición Profesional , Dosis de Radiación , Dosimetría Termoluminiscente , Lugar de Trabajo , Dosimetría Termoluminiscente/instrumentación , Dosimetría Termoluminiscente/métodos , Humanos , Exposición Profesional/análisis , Incertidumbre , Monitoreo de Radiación/métodos , Algoritmos , Disprosio/química , Fotones , Protección Radiológica/métodos , Protección Radiológica/normas , Dosímetros de Radiación
5.
Int J Biol Macromol ; 267(Pt 1): 131449, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38599422

RESUMEN

The depleting supply of natural sources of rare earth elements (REE) is a concern to many nations as demand for advanced technology is becoming vital for national security. In this communication, the recovery of dysprosium(III) from aqueous systems was exemplified by a modified phosphorylated chitosan (PCs/MB) prepared by the C-Mannich reaction of phosphorylated chitosan, glutaraldehyde, and 4-hydroxycoumarin in ethanolic solution. Batch adsorption studies achieved a maximum adsorption capacity (qmax) of 34 mg/g at 25 °C and pH = 5.4 for 2 h. Fourier Transform-Infrared Spectroscopy, elemental mapping, and quantitative analyses revealed ion-exchange mechanism with C6-phosphate and a synergistic complexation with the amino group between two hexose units of the chitosan chain confirming the correlation provided by the pseudo-second order kinetics (R2 = 0.9996), extrapolated mean free energy of adsorption (Eads) of 12.9 kJ/mol from the corrected Dubinin-Radushkevich isotherm, and the extrapolated enthalpy of adsorption (ΔH0ads) of -42.4 kJ/mol from the linearized Van't Hoff plot. Competitive adsorption with iron(II), cerium(III), and neodymium(III) demonstrated preferential removal of dysprosium(III) and complete exclusion of iron(II), which illustrates potential application in the separation of REE from electronic wastes.


Asunto(s)
Quitosano , Disprosio , Hidrogeles , Quitosano/química , Disprosio/química , Adsorción , Hidrogeles/química , Fosforilación , Cinética , Tecnología Química Verde , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Concentración de Iones de Hidrógeno , Purificación del Agua/métodos , Espectroscopía Infrarroja por Transformada de Fourier , Termodinámica
6.
Adv Sci (Weinh) ; 11(13): e2307812, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38243646

RESUMEN

Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.


Asunto(s)
Aleaciones , Osteogénesis , Implantes Absorbibles , Aleaciones/química , Aleaciones/farmacología , Ensayo de Materiales , Mitocondrias/efectos de los fármacos , Zinc/química , Disprosio/química , Disprosio/farmacología , Osteogénesis/efectos de los fármacos , Sirtuinas/efectos de los fármacos , Humanos , Fracturas Óseas/tratamiento farmacológico
7.
Luminescence ; 39(1): e4582, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37655429

RESUMEN

Eu3+ ,Dy3+ co-doped Sr2 LaZrO5.5 -based phosphors were prepared through a sol-gel method. Through characterization, it was found that the Sr2 LaZrO5.5 -based fluorescent powder co-doped with Eu3+ and Dy3+ had a cubic structure. At an excitation wavelength of 290 nm, the substrate Sr2 LaZrO5.5 exhibited strong blue emission at 468 nm, and the Sr2 LaZrO5.5 :18%Eu3+ phosphor exhibited a strong red emission peak at 612 nm. When the doping amount of Dy3+ was 5, 8, 12, 15, or 18%, the Sr2 LaZrO5.5 :18%Eu3+ phosphor changed from an orange-red light, to a warm white light, and to a cold white light. According to the emission spectra, the emission intensities of the substrates Sr2 LaZrO5.5 and Sr2 LaZrO5.5 :Eu3+ decreased with increasing Dy3+ concentration, confirming the energy transfer between the host Sr2 LaZrO5.5 -Eu3+ ,Dy3+ , and resulting in a lower CCT value, with significantly improved white light emission.


Asunto(s)
Disprosio , Luminiscencia , Disprosio/química , Luz , Transferencia de Energía , Luz Roja
8.
Molecules ; 28(13)2023 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-37446628

RESUMEN

To reduce the issue of tri-primary color reabsorption, a new approach for single-phase phosphors as light-emitting diodes (LEDs) has been recommended. The structures, morphology, photoluminescence, thermal stability, and luminescence mechanism of a variety of Ca3Bi (PO4)3 (CBPO): Ce3+/Dy3+ phosphors were investigated. XRD characterization showed that all CBPO samples were eulytite structures. Furthermore, the energy transfer process from Ce3+ to Dy3+ in CBPO is systematically investigated in this work, and the color of light can be adjusted by changing the ratio of doped ions. Under UV light, energy is transferred from Ce3+-Dy3+ mainly through quadrupole-quadrupole interactions in the CBPO host, and doping with different Dy3+ concentrations tunes the emission color from blue to white. The thermal stability of the CBPO: 0.04Ce3+, 0.08Dy3+ samples is outstanding, and the CIE coordinates of the samples after emission have little effect with temperature, while their emission intensity at 423 K is as strong as that at room temperature, reaching 90%. The above results indicate that this CBPO material has great potential as a white light phosphor under near-UV excitation at the optimized concentration of Ce3+ and Dy3+.


Asunto(s)
Disprosio , Luminiscencia , Disprosio/química , Rayos Ultravioleta , Transferencia de Energía , Temperatura
9.
Luminescence ; 38(10): 1814-1824, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37522552

RESUMEN

The CaAlBO4 :RE (RE = Dy3+ , Eu3+ , Sm3+ ) phosphor were prepared via combustion synthesis and studied by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), photoluminescence (PL) spectra and CIE coordinates. The phase formation of the obtained phosphor was analyzed by XRD and the result was confirmed by standard PDF Card No. 1539083. XRD data successfully indicated pure phase of CaAlBO4 phosphor. The crystal structure of CaAlBO4 phosphor is orthorhombic with space group Ccc2 (37). The SEM image of CaAlBO4 phosphor reveals an agglomerated morphology and non-uniform particle size. The EDS image provides evidence of the elements present and the chemical makeup of the materials. Under the 350 nm excitation, the emission spectrum of Dy3+ activated CaAlBO4 phosphor consists of two main groups of characteristic peaks located at 484 and 577 nm which are ascribed to 4 F9/2 → 6 H15/2 and 4 F9/2 → 6 H13/2 transition of Dy3+ respectively. The PL emission spectra of CaAlBO4 :Eu3+ phosphor shows characteristics bands observed around 591 and 613 nm, which corresponds to 5 D0 → 7 F1 and 5 D0 → 7 F2 transition of Eu3+ respectively, upon 395 nm excitation wavelength. The emission spectra of Sm3+ activated CaAlBO4 phosphor shows three characteristic bands observed at 565, 601 and 648 nm which emits yellow, orange and red color. The prominent emission peak at the wavelength 601 nm, which is attributed to 4 G5/2 → 6 H7/2 transition, displays an orange emission. The CIE color coordinates of CaAlBO4 :RE (RE = Dy3+ , Eu3+ , Sm3+ ) phosphor are calculated to be (0.631, 0.368), (0.674, 0.325) and (0.073, 0.185). As per the obtained results, CaAlBO4 :RE (RE = Dy3+ , Eu3+ , Sm3+ ) phosphor may be applicable in eco-friendly lightning technology.


Asunto(s)
Europio , Sustancias Luminiscentes , Europio/química , Sustancias Luminiscentes/química , Disprosio/química , Microscopía Electrónica de Rastreo , Difracción de Rayos X , Luminiscencia
10.
Appl Radiat Isot ; 198: 110840, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37156063

RESUMEN

The production possibility of 161Tb and 155Tb by irradiating of natural dysprosium with gamma rays obtained by decelerating an electron beam with an energy of 55 MeV has been demonstrated experimentally. The yield of 161Tb was 14.4 × 103 Bq × µA-1 × h-1 × cm2 × gDy2O3-1. Simultaneously, upon irradiation, 155Dy is formed with the yield of 25 × 103 Bq × µA-1 × h-1 × cm2 × gDy2O3-1, which leads to the formation of 1.6 × 103 Bq × µA-1 × h-1 × cm2 × gDy2O3-1 of 155Tb. It has been shown that the isolation of terbium radioisotopes from tens of mg of dysprosium target can be achieved by extraction chromatography, and final separation yield was 39%. The impurity of 160Tb is 7.3% of the 161Tb activity at EOB.


Asunto(s)
Disprosio , Radioisótopos , Disprosio/química , Terbio/química
11.
Nature ; 618(7963): 87-93, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37259003

RESUMEN

Technologically critical rare-earth elements are notoriously difficult to separate, owing to their subtle differences in ionic radius and coordination number1-3. The natural lanthanide-binding protein lanmodulin (LanM)4,5 is a sustainable alternative to conventional solvent-extraction-based separation6. Here we characterize a new LanM, from Hansschlegelia quercus (Hans-LanM), with an oligomeric state sensitive to rare-earth ionic radius, the lanthanum(III)-induced dimer being >100-fold tighter than the dysprosium(III)-induced dimer. X-ray crystal structures illustrate how picometre-scale differences in radius between lanthanum(III) and dysprosium(III) are propagated to Hans-LanM's quaternary structure through a carboxylate shift that rearranges a second-sphere hydrogen-bonding network. Comparison to the prototypal LanM from Methylorubrum extorquens reveals distinct metal coordination strategies, rationalizing Hans-LanM's greater selectivity within the rare-earth elements. Finally, structure-guided mutagenesis of a key residue at the Hans-LanM dimer interface modulates dimerization in solution and enables single-stage, column-based separation of a neodymium(III)/dysprosium(III) mixture to >98% individual element purities. This work showcases the natural diversity of selective lanthanide recognition motifs, and it reveals rare-earth-sensitive dimerization as a biological principle by which to tune the performance of biomolecule-based separation processes.


Asunto(s)
Proteínas Bacterianas , Elementos de la Serie de los Lantanoides , Lantano , Multimerización de Proteína , Disprosio/química , Disprosio/aislamiento & purificación , Iones/química , Elementos de la Serie de los Lantanoides/química , Elementos de la Serie de los Lantanoides/aislamiento & purificación , Lantano/química , Neodimio/química , Neodimio/aislamiento & purificación , Methylocystaceae , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Cristalografía por Rayos X , Estructura Cuaternaria de Proteína
12.
Luminescence ; 37(9): 1563-1574, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35816364

RESUMEN

Samples of microcrystalline rare earth-doped magnesium borate materials were synthesized via modified solid-state diffusion and were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Photoluminescence (PL) results for the MgB4 O7 :Dy sample depicts blue emission that resulted from a 4 F9/2 -6 H15/2 transition that peaked at 484 nm, which was much stronger than the yellow emission arising due to the 4 F9/2 -6 H13/2 transition at 576 nm. From the emission spectra for MgB4 O7 :Tb, it seems that at higher concentrations of Tb3+ ion, the green emission becomes strong and directly relates to the energy transfer from the 5 D3 excited state to the 5 D4 excited state through a cross-relaxation, whereas the blue emission is suppressed in MgB4 O7 phosphors. The thermoluminescence (TL) of the samples was measured immediately after irradiation and compared by TL curve with CaSO4 :Dy. MgB4 O7 :Dy showed very good TL sensitivity for the desirable dosimetric curve at ~218°C and the best glow curve structure. In comparison with the dosimetric peaks for MgB4 O7 :Ce and MgB4 O7 :Tb, the MgB4 O7 :Dy phosphor is equally sensitive to CaSO4 :Dy. MgB4 O7 :Dy and MgB4 O7 :Tb showed linearity for a 1-5 kGy dose. The activation energies and frequency factors were also calculated for samples MgB4 O7 :RE (where RE = Dy, Tb, Ce) using the peak shape method.


Asunto(s)
Disprosio , Metales de Tierras Raras , Disprosio/química , Transferencia de Energía , Luminiscencia , Metales de Tierras Raras/química , Difracción de Rayos X
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 278: 121309, 2022 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-35550991

RESUMEN

White-light-emitting La10W22O81 (LWO): xDy3+ (0.5 ≤ x ≤ 10 mol%) nanocrystalline phosphors were developed by a facile hydrothermal assisted solid-state reaction. X-ray diffraction (XRD) pattern indicated that the prepared samples adopted orthorhombic crystal structures. The agglomeration of uniform nanorods was identified from the FE-SEM analysis of the optimized LWO: 1.5 mol% Dy3+ nanocrystalline phosphors. Additionally, transmission electron microscope, scanning transmission electron microscopy, selected area electron diffraction, and X-ray photoelectron spectroscopy were employed to explore the surface morphology, size, interplanar distance, and chemical composition with valence states of the LWO: 1.5 mol% Dy3+ phosphors, respectively. By exciting with 387 nm, the LWO: Dy3+ emission spectra showed two intense peaks at 476 nm (4F9/2→6H15/2) and 571 nm (4F9/2→6H13/2) and a shoulder peak at 659 nm (4F9/2→6H11/2). Optimum emission intensity was achieved for 1.5 mol% Dy3+ in the LWO host lattice. The luminescence quenching beyond 1.5 mol% Dy3+ is attributed to the dipole-dipole interactions when the Dy3+ (donor) and Dy3+ (acceptor) ions are at a critical distance of 58.53 Å. Photometric studies were conducted to evaluate the performance and practical applicability of the phosphors. The CIE chromaticity diagram suggests that the LWO: 1.5 mol% Dy3+ nanophosphor conspicuously exhibits cool white light. Therefore, this material could be a promising and potential white light-emitting nanocrystalline phosphor material for white light emitting diodes (LEDs) under near-UV excitation. In addition, the toxicity of the optimized nanophosphor in normal WI-38 lung fibroblast cells and MCF-7 breast cancer cells was examined. Surprisingly, LWO: 1.5 mol% Dy3+ nanophosphor was found to be non-cytotoxic to normal cells, but extremely toxic to cancer cells. Therefore, the nanophosphor materials can be considered potential candidates for biomedical applications, particularly for cancer treatment.


Asunto(s)
Disprosio , Luminiscencia , Disprosio/química , Luz , Transición de Fase , Difracción de Rayos X
14.
Dalton Trans ; 51(13): 5195-5202, 2022 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-35274652

RESUMEN

Due to the small differences in the chemical properties of facial (fac) and meridional (mer) stereoisomers, selective synthesis of one of the isomers is challenging, especially for lanthanide complexes. By using a flexible bidentate phosphine oxide ligand, we managed to isolate three stereoisomeric 2D and 3D coordination polymers, in which six-coordinate Dy(III) ions possess fac- or mer-Cl3O3 coordination environments. Structural studies indicate that the stereochemistry differences result from their various supramolecular interactions (e.g., hydrogen bonding and π⋯π stacking). Magnetic property measurements reveal the different static and dynamic magnetic behaviours of the three stereoisomers. Ab initio CASSCF calculations were then performed which indicated that their distinct magnetic behaviours arise from their fac/mer configurations. Compared to fac-Dy(III), mer-Dy(III) possesses more axial ground-state KDs and higher first excited KDs.


Asunto(s)
Disprosio , Elementos de la Serie de los Lantanoides , Cristalografía por Rayos X , Disprosio/química , Elementos de la Serie de los Lantanoides/química , Polímeros/química , Estereoisomerismo
15.
Luminescence ; 37(5): 758-765, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35199460

RESUMEN

In this work, the hydroxyapatite nanoparticles doped with trivalent dysprosium ions were synthesized by a co-precipitation method. The characterization techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) were carried out to determine the crystalline and structural properties. The Rietveld structural refinement of the XRD patterns confirmed the purity of the phase formation of the synthesized nanoparticles. The photoluminescence emission spectra exhibited intense emissions in the blue region at 450 nm and 476 nm along with less intense yellow emission at 573 nm which can be attributed to the magnetic dipole and electric dipole transitions of dysprosium respectively. In order to evaluate the colour tunability of the emitted light CIE chromaticity coordinate values were calculated. The intense blue emissions from the synthesized sample were found to be favourable for bioimaging. The images obtained from the fluorescence microscopy revealed that the dysprosium-doped hydroxyapatite nanoparticles are potential bioimaging probes in human cells.


Asunto(s)
Disprosio , Nanopartículas , Durapatita , Disprosio/química , Humanos , Luminiscencia , Nanopartículas/química , Difracción de Rayos X
16.
J Mater Chem B ; 10(2): 302-305, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34914815

RESUMEN

Contrast agents retaining high relaxivities at ultrahigh magnetic fields underpin an enhanced image sensitivity within derived MRI scans. By varying the Dy3+ loading density inside a mesoporous silica architecture the dominant Curie effect can be effectively tuned so as to optimise T2 contrast at magnetic fields as high as 11.7 T.


Asunto(s)
Medios de Contraste/química , Radiofármacos/química , Dióxido de Silicio/química , Disprosio/química , Campos Magnéticos , Porosidad , Temperatura
17.
Molecules ; 26(14)2021 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-34299654

RESUMEN

A tripodal Schiff base ligand, 2,4,6-Tris(4-carboxybenzimino)-1,3,5-triazine (MT) and its trinuclear Dy(III), Er(III), and Gd(III) complexes were synthesized. These were characterized using UV-visible, IR, 1H, and 13C NMR spectroscopies, elemental analysis, and molar conductivity measurements. The spectral studies indicate that the ligand is hexadentate and coordinates to the Ln(III) ions through the oxygen atoms of the carboxylic group. The trinuclear complexes were characterized as being bridged by carboxylate anions to the Dy(III), Er(III), and Gd(III) salen centers and displaying a coordination number of six. Biological studies revealed that MT is more active against the test micro-organisms relative to the trinuclear complexes. Acute toxicity studies revealed that MT is safe and has a wide range of effective doses (ED50). In vivo antimalarial studies indicate that MT could serve as an effective antimalarial agent since it has parasitemia inhibition of 84.02% at 50 mg/kg and 65.81% at 25 mg/kg, close to the value (87.22%) of the standard drug-Artesunate. Molecular docking simulation studies on the compounds against SARS-CoV-2 (6Y84) and E. coli DNA gyrase (5MMN) revealed effective binding interactions through multiple bonding modes. The binding energy calculated for Er(III)MT-6Y84 and Er(III)MT-5MMN complexes showed active molecules with the ability to inhibit SARS-CoV-2 and E. coli DNA gyrase.


Asunto(s)
Triazinas/química , Triazinas/farmacología , Aniones/química , Ácidos Carboxílicos/química , Simulación por Computador , Complejos de Coordinación/química , Cristalografía por Rayos X/métodos , Disprosio/química , Erbio/química , Gadolinio/química , Elementos de la Serie de los Lantanoides/química , Ligandos , Espectroscopía de Resonancia Magnética/métodos , Simulación del Acoplamiento Molecular , Estructura Molecular , Bases de Schiff/química , Triazinas/síntesis química
18.
Chem Commun (Camb) ; 57(63): 7818-7821, 2021 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-34278395

RESUMEN

Tapping into the secondary coordination environment of mononuclear DyIII-complexes leads to drastic changes in luminescence and magnetism. Visualization of effects induced by stereoelectronics on the opto-magnetic properties was achieved through subtle modifications in the ligand framework.


Asunto(s)
Complejos de Coordinación/química , Disprosio/química , Campos Magnéticos , Estructura Molecular , Imagen Óptica , Estereoisomerismo
19.
Bioorg Chem ; 115: 105204, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34325217

RESUMEN

In this study for the first time, high efficient, eco-friendly and novel Dy2O3/ZnO-Au ternary nanocomposites (Dy/ZnO-AuNCs) were prepared in presence of pomegranate fruit (PF) extract as capping and reducing agents (Dy/ZnO-AuNCs@PF). The influence of various parameters such as basic agents, reducing agents, sonication power, and sonication time were performed to reach the optimum condition. The formation of the products was characterized by FT-IR, HRTEM, XRD, FE-SEM, TEM, EDX and DRS techniques. The XRD and TEM analysis showed that the morphology and crystallite size of nanocomposites were spherical morphology and 85-90 nm, respectively. The obtained Dy/ZnO-AuNCs@PF were investigated as a nanocatalyst for degradation of erythrosine (ES) as anionic dye and basic violet 10 (BV10) as cationic dye under UV and visible light irradiations. The Dy/ZnO-AuNCs@PF exhibited higher photodegradation against ES (89.6%) and BV10 (91.3%) than pure Dy2O3 (63.1% for ES, 66.5% for BV10) and Dy2O3/ZnO (64.5% for ES, 70.8% for BV10) under UV irradiation. It was found that gold nanoparticles have significant effect on Dy/ZnO-AuNCs@PF catalytic performance for decomposition of organic pollutants. In addition, Dy/ZnO-AuNCs@PF showed excellent in-vitro antibacterial activity against A. baumannii, S. aureus and P. mirabilis with MIC and MBC values of (5, 80 mg/ml), (5, 40 mg/ml) and (2.5, 20 mg/ml), respectively. Generally, according to its excellent antibacterial and catalytic activity, Dy/ZnO-AuNCs@PF can be used in biomedical and environmental applications.


Asunto(s)
Antibacterianos/farmacología , Disprosio/farmacología , Oro/farmacología , Nanocompuestos/química , Extractos Vegetales/farmacología , Óxido de Zinc/farmacología , Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Catálisis , Relación Dosis-Respuesta a Droga , Disprosio/química , Frutas/química , Oro/química , Tecnología Química Verde , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Procesos Fotoquímicos , Extractos Vegetales/síntesis química , Extractos Vegetales/química , Granada (Fruta)/química , Proteus mirabilis/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Relación Estructura-Actividad , Óxido de Zinc/química
20.
Molecules ; 26(4)2021 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-33672166

RESUMEN

The search for two- and three-dimensional materials with slow relaxation of the magnetization (single-ion magnets, SIM and single-molecule magnets, SMM) has become a very active area in recent years. Here we show how it is possible to prepare two-dimensional SIMs by combining Dy(III) with two different anilato-type ligands (dianions of the 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone: C6O4X22-, with X = H and Cl) in dimethyl sulfoxide (dmso). The two compounds prepared, formulated as: [Dy2(C6O4H2)3(dmso)2(H2O)2]·2dmso·18H2O (1) and [Dy2(C6O4Cl2)3(dmso)4]·2dmso·2H2O (2) show distorted hexagonal honeycomb layers with the solvent molecules (dmso and H2O) located in the interlayer space and in the hexagonal channels that run perpendicular to the layers. The magnetic measurements of compounds 1, 2 and [Dy2(C6O4(CN)Cl)3(dmso)6] (3), a recently reported related compound, show that the three compounds present slow relaxation of the magnetization. In compound 1 the SIM behaviour does not need the application of a DC field whereas 2 and 3 are field-induced SIM (FI-SIM) since they show slow relaxation of the magnetization when a DC field is applied. We discuss the differences observed in the crystal structures and magnetic properties based on the X group of the anilato ligands (H, Cl and Cl/CN) in 1-3 and in the recently reported derivative [Dy2(C6O4Br2)3(dmso)4]·2dmso·2H2O (4) with X = Br, that is also a FI-SIM.


Asunto(s)
Benzoquinonas/química , Complejos de Coordinación/química , Disprosio/química , Modelos Moleculares , Estructura Molecular
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