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Lanthanides have seen rapid growth in the pharmaceutical and biomedical field, thus necessitating the development of hybrid metal–organic materials capable of exerting defined biological activities. Ternary hybrid lanthanide compounds were synthesized through reaction systems of Ln(III) (Ln = La, Nd, Eu) involving the antioxidant flavonoid chrysin (Chr) and 1,10-phenanhtroline (phen) under solvothermal conditions, thus leading to pure crystalline materials. The so-derived compounds were characterized physicochemically in the solid state through analytical (elemental analysis), spectroscopic (FT-IR, UV-visible, luminescence, ESI-MS, circular dichroism, 151Eu Mössbauer), magnetic susceptibility, and X-ray crystallographic techniques. The analytical and spectroscopic data corroborate the 3D structure of the mononuclear complex assemblies and are in line with theoretical calculations (Bond Valence Sum and Hirshfeld analysis), with their luminescence suggesting quenching on the flavonoid-phen electronic signature. Magnetic susceptibility data suggest potential correlations, which could be envisioned, supporting future functional sensors. At the biological level, the title compounds were investigated for their (a) ability to interact with bovine serum albumin and (b) antibacterial efficacy against Gram(−) (E. coli) and Gram(+) (S. aureus) bacteria, collectively revealing distinctly configured biological profiles and suggesting analogous applications in cellular (patho)physiologies. [ABSTRACT FROM AUTHOR]

N,O-hybrid donor ligands are promising compounds for the isolation and separation of actinides and lanthanides from process solutions of spent nuclear fuel reprocessing. Newly synthesized N,O-hybrid donor ligands – derivatives of 2,6-pyridinedicarboxylic acid were studied as extractants and membrane components for potentiometric sensors. The extraction ability of solutions of these compounds in meta-nitrobenzotrifluoride towards d- and f-elements from nitric and perchloric acid solutions was investigated. It was shown that the replacement of amide groups with ester groups reduces the extraction ability of the ligands. Switching from nitric acid to perchloric acid gives a dramatic increase in extraction capacity due to the perchlorate effect. Also, a significant increase in extraction capacity is observed when chlorinated cobalt dicarbolide is added to the organic phase: the highest distribution coefficient is observed at a 1 : 1 ratio of extractant and additive concentrations. Potentiometric membrane sensors based on the new ligands showed significant sensitivity to Cd2+. Correlations between extraction and sensing behavior of new ligands were studied. [ABSTRACT FROM AUTHOR]

We evaluated the effects of neodymium (0.000, 2.885, 5.770 and 8.655 mg · L−1) and zinc (0.1, 0.2 and 0.3 mg · L−1), as well as their interaction on lettuce plants in hydroponics. Applications of 2.885 mg Nd · L−1 and 5.770 mg Nd · L−1 increased plant height, number of leaves and leaf area, as well as fresh and dry stem, root and total biomasses. Root volume was greater in plants treated with 2.885 mg Nd · L−1. With 0.1 mg Zn · L−1, plant height, leaf area and fresh stem, root and total biomass were greater, while applying 0.3 mg Zn · L−1 increased the ratio of dry biomass of stems and roots. Plants exposed to 5.770 mg Nd · L−1 + 0.3 mg Zn · L−1 exhibited greater leaf length. The ratios of fresh and dry biomass of stems and roots increased in plants treated with 8.655 mg · L−1 Nd + 0.3 mg Zn · L−1. Dry biomass weights of stems, roots and total were the highest in plants treated with 20 mg Nd · L−1 + 0.1 mg Zn · L−1. Nd significantly increased foliar concentration of N, P and K. Hence, Nd and Zn improve growth and nutrition. [ABSTRACT FROM AUTHOR]

By combining ErIII and YbIII ions with 3,6-dithiophene-anilate (Th2An) and scorpionate hydrotris(pyrazol-1-yl)borate (HBpz3−) ligands new luminescent dinuclear complexes are obtained. The two materials formulated as [((HB(pz)3)2Yb)2(μ-th2An)]·4DCM·1.3H2O 1Yb and [((HB(pz)3)2Er)2(μ-th2An)]·4DCM·1.8H2O 1Er, respectively, have been structurally characterized by SC-XRD and PXRD studies. This study presents a comprehensive investigation of the photophysical properties of the Th2An ligand for the first time. Our findings reveal the crucial role of the thiophene anilate as an effective optical antenna, which sensitizes near-infrared (NIR)-emitting lanthanide ions, specifically ErIII and YbIII. The significant impact of vibrational quenching on the LnIII NIR emission efficiency has been also highlighted. [ABSTRACT FROM AUTHOR]

We report here the synthesis of a series of nine coordinated mononuclear LnIII complexes [LnL1Cl2(DMF)]Cl·2.5DMF and [LnL1(L2)2]Cl·4CH3OH (LnIII = GdIII, DyIII, ErIII and YbIII, HL2 = 9-anthracenecarboxylic acid), where L1 is a hexadentate N4O2 Schiff base ligand prepared from the condensation of 1,10-phenanthroline-2,9-dicarbaldehyde and semicarbazone. The X-ray crystal structures of these complexes show the LnIII ions to possess LnN4O2Cl2 and LnN4O4 coordination spheres, which can be considered to be derived from a hexagonal bipyramidal geometry, with the ligand in the equatorial plane and the anions (chloride or 9-antracenecarboxylate) in axial positions, which undergo distortion after coordination of either a molecule of DMF or a bidentate coordination of the 9-anthracenecarboxxylate ligand. All these compounds exhibit field-induced slow magnetization relaxation (SMR). The absence of SMR at zero field due to QTM, as well as the processes involved in the magnetic relaxation under a field of 0.1 T, have been justified on the basis of theoretical calculations and the distortion of the respective coordination spheres. The severe discrepancy between the calculated and experimental thermal energy barriers for the DyIII complexes seems to indicate that the relaxation occurs with the contribution of spin–vibrational coupling, which is favored by the flexibility of the ligand. [ABSTRACT FROM AUTHOR]

Hydrogels have a wide range of medical applications, including use within implantable systems. However, when used in implants, their visibility under conventional medical imaging techniques is limited, creating safety risks for patients. In the current work, we assessed the possibility of enhancing hydrogels using Ln-based contrasting agents to facilitate their visualization in photon-counting computed tomography (PCCT). The contrast enhancement of gelatin, polyacrylamide (PAM), and silicone shells of implants was assessed. A novel synthetic route for producing cross-linked nanosized Ln2O3 with polyacrylamide was proposed and discussed in detail. Several prototypes of silicone implants, including silicone shell and gelatin or PAM filling with different combinations of contrasting agents, were produced and assessed in phantom PCCT studies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Prior to soil formation, phosphate liberated by rock weathering is often sequestered into highly insoluble lanthanide phosphate minerals. Dissolution of these minerals releases phosphate and lanthanides to the biosphere. Currently, the microorganisms involved in phosphate mineral dissolution and the role of lanthanides in microbial metabolism are poorly understood. RESULTS: Although there have been many studies of soil microbiology, very little research has investigated microbiomes of weathered rock. Here, we sampled weathered granite and associated soil to identify the zones of lanthanide phosphate mineral solubilisation and genomically define the organisms implicated in lanthanide utilisation. We reconstructed 136 genomes from 11 bacterial phyla and found that gene clusters implicated in lanthanide-based metabolism of methanol (primarily xoxF3 and xoxF5) are surprisingly common in microbial communities in moderately weathered granite. Notably, xoxF3 systems were found in Verrucomicrobia for the first time, and in Acidobacteria, Gemmatimonadetes and Alphaproteobacteria. The xoxF-containing gene clusters are shared by diverse Acidobacteria and Gemmatimonadetes, and include conserved hypothetical proteins and transporters not associated with the few well studied xoxF systems. Given that siderophore-like molecules that strongly bind lanthanides may be required to solubilise lanthanide phosphates, it is notable that candidate metallophore biosynthesis systems were most prevalent in bacteria in moderately weathered rock, especially in Acidobacteria with lanthanide-based systems. CONCLUSIONS: Phosphate mineral dissolution, putative metallophore production and lanthanide utilisation by enzymes involved in methanol oxidation linked to carbonic acid production co-occur in the zone of moderate granite weathering. In combination, these microbial processes likely accelerate the conversion of granitic rock to soil.

Reacting the antibiotic drug succinylsulfathiazole (abbreviated as SST) with the lanthanide metal ions La(III), Sm(III), and Tb(III) generated thermal stable metal-based complexes. The temperature of the reaction was 70 °C, at a pH of ~ 8.5, using stoichiometry of 2:1 (SST ligand to metal ion). Spectral and analytical characterizations of the SST metal-based complexes were obtained using ultraviolet/visible (UV-visible), Fouriertransform infrared (FT-IR) spectroscopies, X-ray diffractometry (XRD), and CHN elemental analysis. The microscopic pictures of the SST complexes were captured by a high-resolution scanning electron microscope with environmental mode (ESEM). Experimental data suggested that the general composition of La(III) complex is [La(SST)2(H2O)Cl].6H2O with a gross formula of C26H38N6O17S4ClLa, the general composition of Sm(III) complex is [Sm(SST)2(H2O)(NO3)].5H2O with a gross formula of C26H36N7O19S4Sm, whereas the general composition of Tb(III) complex is [Tb(SST)2(H2O)(NO3)].4H2O with a gross formula of C26H34N7O18S4Tb. In the manufactured complexes, two deprotonated SST molecules were captured the La(III), Sm(III), and Tb(III) ions by their bidentate carboxylate groups (COO-). The microscopic pictures clearly revealed different surface topography between SST metal-based complexes. [ABSTRACT FROM AUTHOR]

Developing highly stable and efficient catalysts for oxygen evolution reaction (OER) is extremely important to sustainable energy conversion and storage, but improved efficiency is largely hindered by sluggish reaction kinetics. Dense and bimetal ruthenates have emerged as one of the promising substitutes to replace single-metal ruthenium or iridium oxides, but the fundamental understanding the role of A-site cations is still blurring. Herein, a family of lanthanides (Ln = all the lanthanides except Pm) are applied to synthesize pyrochlore lanthanide ruthenates (Ln2Ru2O7), and only Ln2Ru2O7 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu) with pure phase can be obtained by the ambient-pressure calcination. Compared with the perovskite ruthenates (SrRuO3) and rutile RuO2, the [RuO6] units in these Ln2Ru2O7 present the largely distorted configurations and different energy level splitting to prevent the excessive Ru oxidation and dissolution, which leads the primary improvement in the electrocatalytic OER performance. In the similar crystalline field split states, the charge transfer between [RuO6] units and Ln3+ cations also affect catalytic activities, even in the Ln2Ru2O7 surface reconstruction during the OER process. Consequently, Tb2Ru2O7 showed the highest OER performance among all the prepared Ln2Ru2O7 with similar morphologies and crystallization. This systematic work gives fundamental cognition to rational design of high-performance OER electrocatalysts in proper water electrolysis technologies.

Abstract Background Rare-earth sulfide nanoparticles (NPs) could harness the optical and magnetic features of rare-earth ions for applications in nanotechnology. However, reports of their synthesis are scarce and typically require high temperatures and long synthesis times. Results Here we present a biosynthesis of terbium sulfide (TbS) NPs using microorganisms, identifying conditions that allow Escherichia coli to extracellularly produce TbS NPs in aqueous media at 37 °C by controlling cellular sulfur metabolism to produce a high concentration of sulfide ions. Electron microscopy revealed ultrasmall spherical NPs with a mean diameter of 4.1 ± 1.3 nm. Electron diffraction indicated a high degree of crystallinity, while elemental mapping confirmed colocalization of terbium and sulfur. The NPs exhibit characteristic absorbance and luminescence of terbium, with downshifting quantum yield (QY) reaching 28.3% and an emission lifetime of ~ 2 ms. Conclusions This high QY and long emission lifetime is unusual in a neat rare-earth compound; it is typically associated with rare-earth ions doped into another crystalline lattice to avoid non-radiative cross relaxation. This suggests a reduced role of nonradiative processes in these terbium-based NPs. This is, to our knowledge, the first report revealing the advantage of biosynthesis over chemical synthesis for Rare Earth Element (REE) based NPs, opening routes to new REE-based nanocrystals.

Applying the orthogonal principle for distinguishable second near‐infrared (NIR‐II) emissions has brought new dimensions for ratio fluorescence imaging (RFI) detection and information encryption, deepening the tissue detection depth and improving signal‐to‐noise ratio and information security. However, the orthogonal NIR‐II emissions underlying these advanced optical applications have been reported only in heterogeneous structures and mixtures, limiting their practicality and potential impact. Herein, NIR‐I‐activated orthogonal NIR‐IIb/c (1530/1825 nm) emissions nanoparticles (ONNPs) are developed by spatially separated doping of Tm3+ and Er3+ emitter upon switching 808 and 980 nm excitations. RFI techniques and orthogonal NIR‐II emission ONNPs are used to demonstrate vessel depth detection based on wavelength‐dependent optical attenuation properties in tissue. The superiority of the optical coding and encoding process in a 4 × 1 binary matrix is demonstrated for anticounterfeiting and decryption imaging of quick‐response (QR) code for information storage. The research progress of this NIR‐II orthogonal emissions probe will drive the development of biomedical sensing, imaging safety, and future biophotonics technologies. [ABSTRACT FROM AUTHOR]

The coordination environment of magneto-luminescent Dy3+-based Single-Molecule Magnets (SMM) is a crucial factor influencing both magnetic and luminescent properties. In this work, we explore how triphenylmethanolate (Ph3CO−), in combination with other ligands, can modulate the structure and, therefore, the magnetic properties of Dy3+-based SMM. Using triphenylmethanolate in combination with THF and pyridine (Py) as co-ligands, we synthesized a series of mononuclear cis-[Dy(OCPh3)2(THF)4][BPh4]·(2,6-Me2C5H3N) (1), trans-Dy(OCPh3)3(THF)2 (2), fac-Dy(OCPh3)3(py)3 (3) and dinuclear [(Ph3CO)Dy(THF){(μ2–Cl)2Li(THF)2}μ2–Cl]2 (4) complexes where the Dy3+ ion presents five- or six-coordinate geometries. Dinuclear compound 4 exhibits a genuine SMM behavior with a relatively high energy barrier of 421 cm−1, while mononuclear complexes 1–3 are field-induced SMM. These complexes also present Dy3+-characteristic luminescence, highlighting their multifunctional character. [ABSTRACT FROM AUTHOR]

We compare trends in experimental observations reported by Zhou et al. to relevant results from numerous previously published studies. Based on these comparisons, we question the reliability of the gibbsite titration data and consider the cation uptake curves to be incomplete and questionable as well. The adsorption edges in Zhou et al. are too flat compared to the typical adsorption edges reported in hundreds of studies. Finally, we are convinced that trends of cation adsorption with NaNO3 content not only disagree with relevant, previously published results, but are even opposite to trends expected with increasing ionic strength, whenever such effects are observed. Finally, we discuss other inconsistencies in the experimental data. [ABSTRACT FROM AUTHOR]

The introduction of the cerium(III) analogue (1‐Ce, Ln = Ce) of (tert‐butoxido)chloridopentakis(tetrahydrofuran)lanthanide(III) tetraphenylborate tetrahydrofuran disolvate, [Ln{OC(CH3)3}Cl(C4H8O)5][B(C6H5)4]·2C4H8O or [Ln(OtBu)Cl(THF)5](BPh4)·2THF (1‐Ln) has been achieved with a structural comparison between the existing solid‐state structures of other rare earth analogues and the title compound at 100 and 180 K. The cation in 1‐Ce is targeted as the cerium(III) ion possesses the criteria to exhibit slow magnetic relaxation in axial point‐charge crystal fields, akin to the dysprosium(III) ion in 1‐Dy. AC magnetic susceptibility experiments reveal no such behaviour for 1‐Ce, putting the viability of cerium‐based SMMs into question. [ABSTRACT FROM AUTHOR]

Background: Rare-earth sulfide nanoparticles (NPs) could harness the optical and magnetic features of rare-earth ions for applications in nanotechnology. However, reports of their synthesis are scarce and typically require high temperatures and long synthesis times. Results: Here we present a biosynthesis of terbium sulfide (TbS) NPs using microorganisms, identifying conditions that allow Escherichia coli to extracellularly produce TbS NPs in aqueous media at 37 °C by controlling cellular sulfur metabolism to produce a high concentration of sulfide ions. Electron microscopy revealed ultrasmall spherical NPs with a mean diameter of 4.1 ± 1.3 nm. Electron diffraction indicated a high degree of crystallinity, while elemental mapping confirmed colocalization of terbium and sulfur. The NPs exhibit characteristic absorbance and luminescence of terbium, with downshifting quantum yield (QY) reaching 28.3% and an emission lifetime of ~ 2 ms. Conclusions: This high QY and long emission lifetime is unusual in a neat rare-earth compound; it is typically associated with rare-earth ions doped into another crystalline lattice to avoid non-radiative cross relaxation. This suggests a reduced role of nonradiative processes in these terbium-based NPs. This is, to our knowledge, the first report revealing the advantage of biosynthesis over chemical synthesis for Rare Earth Element (REE) based NPs, opening routes to new REE-based nanocrystals. [ABSTRACT FROM AUTHOR]

Hybrid compounds have a significant impact on agriculture as slow macro- and micronutrient administration systems. This study aimed to evaluate the synthesis and effect of the hybrid compound Nd(NO3)3@Zn-MOF in different concentrations on the in vitro growth of vanilla (Vanilla planifolia Jacks. ex Andrews). A total of 13 vanilla plantlets per treatment were cultivated in test tubes with semi-solid Murashige and Skoog (MS) medium and without growth regulators and treated with 0, 5, 10, 15, and 30 mg L−1 of Nd(NO3)3@Zn-MOF. After 60 days of culture, we evaluated different morphological and biochemical parameters, such as shoot length, root length, the number of roots, the number of leaves, total chlorophyll and carotenoid content, antioxidant capacity, and phenolic compound content. Our results showed that the Nd(NO3)3@Zn-MOF at 10 mg L−1 concentration increased plantlet length. Furthermore, we observed an increase in root length and number with the 5 and 10 mg L−1 concentrations, and a decrease in these same parameters with the 15 and 30 mg L−1 Nd(NO3)3@Zn-MOF concentrations. There were no significant differences regarding the number of leaves or total chlorophyll content. As for the antioxidant capacity, we observed an increase with 5, 10, and 15 mg L−1 of Nd(NO3)3@Zn-MOF and a decrease with the highest concentration. Finally, the phenolic and carotenoid content decreased with the 15 and 30 mg L−1 Nd(NO3)3@Zn-MOF concentrations compared to the control. In conclusion, the hybrid compound Nd(NO3)3@Zn-MOF showed beneficial effects on the growth, physiology, and biochemistry of V. planifolia in vitro when plants were treated at low concentrations. Additionally, the high concentrations used in this study did not induce toxicity. Our findings suggest that Nd(NO3)3@Zn-MOF could be used as a biostimulant in vanilla during its in vitro culture. However, due to the hormetic effect and the possible different reactions of different genotypes, this requires further detailed research. [ABSTRACT FROM AUTHOR]

Lanthanides (Lns) have been increasingly used in different fields, raising some concerns due to potential adverse effects to human life. In this work, it is proposed a laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) method for Lns determination in tea. Cellulose powder, leave powder and filter paper were evaluated as matrix matched standards and 13C, 103Rh, 115In, 197Au and 205Tl as internal standards (IS). Operating conditions of the LA-ICP-MS system, sample preparation procedures, and spiking samples with IS and standards were optimized. Better conditions of IS mixed with powdered standards or samples was achieved when the powder particles size was lower than 50 μm and 2 mL of IS or standard solutions were added to 500 mg of sample. Best results were obtained using Au as IS and filter paper. The method was applied to Lns determination in mint tea, where Ce, La and Nd concentrations were 580 ± 50, 282 ± 15 and 340 ± 60 ng g–1, respectively. The concentrations of the other Lns were below their limit of quantification (LOQ). The Lns concentrations determined by LA-ICP-MS were in good agreement (95% confidence level, t-test) with those found using ultrasonic nebulization-ICP-MS with a precision better than 20%.

Phosphate fertilizers actively used in agriculture can serve as a source of various impurities in the soil, which can have a negative impact on environmental components. In this work, the content of rare earth elements (REEs) in phosphate fertilizers marketed in Russia was evaluated. REEs are a group of elements that are actively studied due to possible negative and positive effects on living organisms. Currently, there are no standards for the content of REEs in soil and fertilizers. Also, in the literature there are no data on REEs content in phosphate fertilizers marketed on the territory of Russia and assessment of the significance of fertilizer application as a factor of REEs input into agricultural soils. Using the method of optical emission spectrometry with inductively coupled plasma, we obtained data on the REEs content in samples of phosphate rock, single and double superphosphate (22 samples). It is shown that phosphate fertilizers can differ significantly in REEs content, high REEs content (over 1000 mg/kg) was observed in some samples of single and double superphosphate. The group of phosphate rock samples is the most homogeneous in terms of REE content in the samples. Light REEs predominate over heavy REEs in the composition of fertilizers. According to the results of the study, it can be concluded that there is potentially no significant effect of the application of the studied phosphate fertilizers on the REEs content in the soil. However, the high REEs content in some fertilizer samples requires monitoring of REEs content in soils of agrocenoses, as well as the development of standards for REE content in mineral fertilizers. Funding. This work was supported by Russian Science Foundation grant No. 22-74-00003, https://rscf.ru/project/22-74-00003/.

Sandwich d/f heterometallic complexes [(Ln(hfac)3)2M(acac)3] (Ln = La, Pr, Sm, Dy and M = Co; Ln = La and M = Ru) were prepared in strictly anhydrous conditions reacting the formally unsaturated fragment [Ln(hfac)3] and [M(acac)3] in a 2-to-1 molar ratio. These heterometallic complexes are highly sensitive to moisture. Spectroscopic observation revealed that on hydrolysis, these compounds yield dinuclear heterometallic compounds [Ln(hfac)3M(acac)3], prepared here for comparison purposes only. Quantum mechanical calculations supported, on the one hand, the hypothesis on the geometrical arrangement obtained from ATR-IR and NMR spectra and, on the other hand, helped to rationalize the spontaneous hydrolysis reaction. [ABSTRACT FROM AUTHOR]

Eu/Tb metal–organic frameworks (Eu/Tb-MOFs), exhibiting Eu3+ and Tb3+ emissions, stand out as some of the most fascinating luminescent thermometers. As the relative thermal sensitivity model is limited to its lack of precision for fitting ratio of Eu3+ and Tb3+ emissions, accurately predicting the sensing performance of Eu/Tb-MOFs remains a significant challenge. Herein, we report a series of luminescent Eu/Tb-MOF thermometers, EuxTb1−xL, with excellent thermal sensitivity around physiological levels, achieved through the tuning energy transfer from ligands to Eu3+ and Tb3+ and between the Ln ions. It was found that the singlet lowest-energy excited state (S1) of the ligand and the higher triplet energy level (Tn) are crucial in the energy transfer processes of ligand→Tb3+ and ligand→Eu3+. This enables EuxTb1−xL to serve as an effective platform for exploring the impact of these energy transfer processes on the temperature-sensing properties of luminescent Eu/Tb-MOF thermometers. The relative thermal sensitivity is comparable to that of dual-center MOF-based luminescent thermometers operating at physiological levels. This study provides valuable insights into the design of new Eu/Tb thermometers and the accurate prediction of their sensing performance. [ABSTRACT FROM AUTHOR]

The Mandorla di Avola is recognized all over the world as one of the best almond varieties. It is cultivated in a small area inside the provinces of Siracusa and Ragusa (Sicily, southern Italy). It is used in traditional Sicilian cuisine for both salty and sweet foods and of course in artisan pastry, apart from being consumed as a fruit. Due to its extraordinary organoleptic and beneficial features, the Mandorla di Avola is frequently counterfeit with almond varieties of lower quality coming from other countries. While its nutraceutical features have been studied, the possibility of authenticating it with respect to other varieties has not been explored. In this work, we used microelements determined with ICP-OES and ICP-MS as chemical descriptors to distinguish samples of Mandorla di Avola almonds from almonds coming from California and Spain, which are usually employed as substitutes in pastry. Among the different elements determined, Mn and P were found to be the best descriptors for authentication. [ABSTRACT FROM AUTHOR]

Many bacteria secrete metallophores, low-molecular-weight organic compounds that bind ions with high selectivity and affinity, in order to access essential metals from the environment. Previous work has elucidated the structures and biosynthetic machinery of metallophores specific for iron, zinc, nickel, molybdenum, and copper. No physiologically relevant lanthanide-binding metallophore has been discovered despite the knowledge that lanthanide metals (Ln) have been revealed to be essential cofactors for certain alcohol dehydrogenases across a diverse range of phyla. Here, we report the biosynthetic machinery, the structure, and the physiological relevance of a lanthanophore, methylolanthanin. The structure of methylolanthanin exhibits a unique 4-hydroxybenzoate moiety which has not previously been described in other metallophores. We find that production of methylolanthanin is required for normal levels of Ln accumulation in the methylotrophic bacterium Methylobacterium extorquens AM1, while overexpression of the molecule greatly increases bioaccumulation and adsorption. Our results provide a clearer understanding of how Ln-utilizing bacteria sense, scavenge, and store Ln; essential processes in the environment where Ln are poorly bioavailable. More broadly, the identification of this lanthanophore opens doors for study of how biosynthetic gene clusters are repurposed for additional functions and the complex relationship between metal homeostasis and fitness. [ABSTRACT FROM AUTHOR]

Lanthanides and actinides are emerging contaminants, but little is known about their uptake and distribution by plants and their interactions in the rhizosphere. To better understand the fate of these metals in plants, the bioassociation of 2, 20 and 200 µM Eu(III) by five hydroponically grown crops endemic to Europe was assessed. The metal's concentration and its speciation were monitored by inductively coupled plasma mass spectrometry and laser spectroscopy, whereas root exudation was investigated by chromatographic methods. It has been shown, that Eu(III) bioassociation is a two-stage process, involving rapid biosorption followed by accumulation in root tissue and distribution to the stem and leaves. Within 96 h of exposure time, the plant induces a change of Eu(III) speciation in the liquid medium, from a predominant Eu(III)aquo species, as calculated by thermodynamic modelling, to a species with longer luminescence lifetime. Root exudates such as citric, malic, and fumaric acid were identified in the cultivation medium and affect Eu(III) speciation in solution, as was shown by a change in the thermodynamic model. These results contribute to a comprehensive understanding of the fate of lanthanides in the biosphere and provide a basis for further investigations with the chemical analogues Cm(III) and Am(III). [ABSTRACT FROM AUTHOR]

The presence of the olive tree in Tuscany, Italy, in its forms that have survived to the present day as an essential component of the landscape dates back many centuries. Global change is now threatening it. Therefore, it is important to find markers to enhance the olive tree environment in terms of its resilience. The aim of the research was to investigate the composition of soil bacteriomes in contrasting geochemical environments using a geochemistry approach based on the behavior of the REEs, inherited from parent rock material. Bacteriome assemblages and REE content were analyzed in 48 topsoils developed in six geochemical Tuscan environments. Combined geochemical, geoinformatic, and bioinformatic techniques highlighted the existence of four bacteriome assemblages depending on Light-REEs. Further results showed that the soil bioavailable fraction of REEs was related to parent rock materials, pH, and bacteriome composition. The most abundant bacteria were Microlunatus in graded fluvio-lacustrine soils, Gaiella in graded arenaceous soils, Bradyrizhobium in pyroclastic soils, and Rubrobacter in soils on gentle slopes of calcareous and carbonatic lithologies. This research represents a starting point to define new indicators able to assess the resilience of the olive trees in the Mediterranean landscape and characterize the territory of extra virgin olive oils. [ABSTRACT FROM AUTHOR]

The synthesis of lanthanide‐based organometallic sandwich compounds is very appealing regarding their potential for single‐molecule magnetism. Here, it is exploited by on‐surface synthesis to design unprecedented lanthanide‐directed organometallic sandwich complexes on Au(111). The reported compounds consist of Dy or Er atoms sandwiched between partially deprotonated hexahydroxybenzene molecules, thus introducing a distinct family of homoleptic organometallic sandwiches based on six‐membered ring ligands. Their structural, electronic, and magnetic properties are investigated by scanning tunneling microscopy and spectroscopy, X‐ray absorption spectroscopy, X‐ray linear and circular magnetic dichroism, and X‐ray photoelectron spectroscopy, complemented by density functional theory‐based calculations. Both lanthanide complexes self‐assemble in close‐packed islands featuring a hexagonal lattice. It is unveiled that, despite exhibiting analogous self‐assembly, the erbium‐based species is magnetically isotropic, whereas the dysprosium‐based compound features an in‐plane magnetization. [ABSTRACT FROM AUTHOR]

A new series of [Fe3−xLnx]O4 nanoparticles, with Ln = Gd; Dy; Lu and x = 0.05; 0.1; 0.15, was synthesized using the coprecipitation method. Analyses by X-ray diffraction (XRD), Rietveld refinement, and high-resolution transmission electron microscopy (HRTEM) indicate that all phases crystallized in space group F d 3 ¯ m , characteristic of spinels. The XRD patterns, HRTEM, scanning electron microscopy analysis (SEM-EDS), and Raman spectra showed single phases. Transmission electron microscopy (TEM), Rietveld analysis, and Scherrer's calculations confirm that these materials are nanoparticles with sizes in the range of ~6 nm to ~13 nm. Magnetic measurements reveal that the saturation magnetization (Ms) of the as-prepared ferrites increases with lanthanide chemical substitution (x), while the coercivity (Hc) has low values. The Raman analysis confirms that the compounds are ferrites and the Ms behavior can be explained by the relationship between the areas of the signals. The magnetic measurements indicate superparamagnetic behavior. The blocking temperatures (TB) were estimated from ZFC-FC measurements, and the use of the Néel equation enabled the magnetic anisotropy to be estimated. [ABSTRACT FROM AUTHOR]

Photochromic luminescent glass-ceramics attract lots of attention as an optical storage medium owing to their large storage capacity, reversible luminescence modulation, simple operation, etc. Herein, a kind of phosphosilicate glass containing AgBr nanoparticles was designed and prepared, which can realize the color reversible transformation between light yellowish-green and brown by alternating 365 nm light illumination and thermal treatment at 300 °C. The mechanism of photochromism and bleaching of the glass is related to the generation and decomposition of Ag0 clusters. Relying on the re-absorption effect, the emission intensity of Eu3+ ions could be reversibly regulated, showing the maximum luminescence contrast of 74 %. A good fatigue resistance and reproducibility of transmittance and luminescence modulation could be observed in cycle measurements, demonstrating its potential in the optical memory field. [ABSTRACT FROM AUTHOR]

A comprehensive study of the thermoelectric properties of CuCr0.99Ln0.01S2 (Ln = La...Lu) disulfides was carried out in a temperature range of 300 to 740 K. The temperature dependencies of the Seebeck coefficient, electrical resistivity, and thermal conductivity were analyzed. It was found that the cationic substitution of chromium with lanthanides in the crystal structure of layered copper–chromium disulfide, CuCrS2 resulted in notable changes in the thermoelectric performance of CuCr0.99Ln0.01S2. The cationic substitution led to an increase in the Seebeck coefficient and electrical resistivity and a thermal conductivity decrease. The highest values of the thermoelectric figure of merit and power factor corresponded to the praseodymium-doped sample and an initial CuCrS2-matrix at 700–740 K. The cationic substitution with lanthanum, cerium, praseodymium, samarium, and terbium allowed for an enhancement of the thermoelectric performance of the initial matrix at a temperature range below 600 K. The cationic substitution of CuCrS2 with lanthanum and praseodymium ions appeared to be the most promising approach for increasing the thermoelectric performance of the initial matrix. [ABSTRACT FROM AUTHOR]

Artisanal mining is intensely carried out in developing countries, including Brazil and especially in the Amazon. This method of mineral exploration generally does not employ mitigation techniques for potential damages and can lead to various environmental problems and risks to human health. The objectives of this study were to quantify the concentrations of rare earth elements (REEs) and estimate the environmental and human health risks in cassiterite and monazite artisanal mining areas in the southeastern Amazon, as well as to understand the dynamics of this risk over time after exploitation. A total of 35 samples of wastes classified as overburden and tailings in active areas, as well as in areas deactivated for one and ten years were collected. Samples were also collected in a forest area considered as a reference site. The concentrations of REEs were quantified using alkaline fusion and ICP-MS. The results were used to calculate pollution indices and environmental and human health risks. REEs showed higher concentrations in anthropized areas. Pollution and environmental risk levels were higher in areas deactivated for one year, with considerable contamination factors for Gd and Sm and significant to extreme enrichment factors for Sc. Human health risks were low (< 1) in all studied areas. The results indicate that artisanal mining of cassiterite and monazite has the potential to promote contamination and enrichment by REEs. Highlights: REEs were first assessed in artisanal mines of monazite and cassiterite in the Brazilian Amazon. All anthropized areas showed higher concentrations of REEs. The gratest risk occurred in areas exploited a year ago. REEs pose risks to the environment and human health. [ABSTRACT FROM AUTHOR]

Relevance. Negative impact of waste from mining enterprises on the ecological state of the surrounding areas. Aim. To determine the migration ability of toxic chemical elements from waste storage sites of the Ermakovskoe beryllium deposit in the air. Object. Ermakovskoe fluorite-bertrandite-phenacite deposit and the surrounding area. Methods. Inductively coupled plasma mass spectrometry, laser diffraction, inductively coupled plasma atomic emission spectrometry. Results and conclusions. The paper introduces the experimental studies of surface atmospheric pollution by mining waste from the Ermakovskoe fluorite-bertrandite-phenakite deposit are presented using an installation for collecting aerosols above the sand surface. It was established that toxic components formed during the decomposition of residual sulfide mineralization and products of the interaction of acidic waters with rocks move from the sand thickness to the surface along with water vapor. The moisture condensed over the sand contains high contents of aluminum, iron, manganese, zinc, and phosphorus. These elements form a halo of air pollution over mining waste and are then dispersed by air currents into the surrounding area. In winter, due to wind dispersion of aerosols, the snow cover becomes contaminated over a vast area. Among the toxic elements found were beryllium, lead, cadmium, and molybdenum, which belong to the second hazard class. The solid residue of the snow cover contains a fine fraction of dust, the size of which is less than 10 microns. The halo of snow contamination with toxic chemical elements and dust extends several kilometers away from the disturbed lands.

Abstract We are reporting on the use of a low‐coordinate YbIII amide with near‐ideal planar trigonal [Yb{N(SiMe3)2}3] (1) and on a bipyramidal trigonal derivative [Yb{N(SiMe2H)2}3 ⋅ (thf)2] (2) that constitute quintessential cases to investigate luminescent and magnetic properties otherwise usually blurred on less symmetrical compounds. These compounds represent the first experimental objects that allow for the confirmation of the recent conjecture about best‐performing SMM built on the archetypal prolate lanthanide ion. We have performed a combined theoretical, luminescent, and magnetic study on these molecules. For 1, a spectacular split of the 2F7/2 ground state of 1312 cm−1 is measured by low‐temperature near‐infra‐red luminescence as well as the calculated pure wavefunction composition of the low‐lying Kramers doublets, making this complex a textbook example of a prolate SMM. These results are corroborated by comparison with 2, that exhibits as expected a 50 % decrease of the ground state splitting compared to 1. Yet, we show that these remarkable features are insufficient to promote SMM behavior, and Orbach relaxation is unlikely to occur even on such an ideal low‐coordinate SMM without control of spin‐phonon coupling.

ABSTRACT Pseudomonas alloputida KT2440 is a ubiquitous, soil-dwelling bacterium that metabolizes recalcitrant and volatile carbon sources. The latter is utilized by two redundant, Ca- and lanthanide (Ln)-dependent, pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ ADH), PedE and PedH, whose expression is regulated by Ln availability. P. alloputida KT2440 is the best-studied non-methylotroph in the context of Ln-utilization. Combined with microfluidic cultivation and single-cell elemental analysis, we studied the impact of light and heavy Ln on transcriptome-wide gene expression when growing P. alloputida KT2440 with 2-phenylethanol as the carbon and energy source. Light Ln (La, Ce, and Nd) and a mixture of light and heavy Ln (La, Ce, Nd, Dy, Ho, Er, and Yb) had a positive effect on growth, whereas supplementation with heavy Ln (Dy, Ho, Er, and Yb) exerted fitness costs. These were likely a consequence of mismetallation and non-utilizable Ln interfering with Ln sensing and signaling. The measured amounts of cell-associated Ln varied between elements. Gene expression analysis suggested that the Ln sensing and signaling machinery, the two-component system PedS2R2 and PedH, responds differently to (non-)utilizable Ln. We expanded our understanding of the lanthanide (Ln) switch in P. alloputida KT2440, demonstrating that it adjusts the levels of pedE and pedH transcripts based on the availability of Ln. We propose that the usability of Ln influences the bacterium’s response to different Ln elements.IMPORTANCEThe Ln switch, the inverse regulation of Ca- and Ln-dependent PQQ ADH in response to Ln availability in organisms featuring both, is central to our understanding of Ln utilization. Although the preference of bacteria for light Ln is well known, the effect of different Ln, light and heavy, on growth and gene expression has rarely been studied. We provide evidence for a fine-tuning mechanism of Ca- and Ln-dependent PQQ ADH in P. alloputida KT2440 on the transcriptome level. The response to (non-)utilizable Ln differs depending on the element. Ln commonly co-occur in nature. Our findings underline that Ln-utilizing microbes must be able to discriminate between Ln to use them effectively. Considering the prevalence of Ln-dependent proteins in many microbial taxa, more work addressing Ln sensing and signaling is needed. Ln availability likely necessitates different adaptations regarding Ln utilization.

We show hereby that recycling of NdFeB permanent magnets by selective leaching and precipitation is possible, using an electrolyte as hydrotrope, thus avoiding the need of any specific extractant molecules. We analyse the yield of the extractant-free process and show that the non toxic formulation of Sodium Salicylate and ethylacetate used as diluent and choosing the optimal tie-line in a ternary phase diagram allows extraction using any type of acid in the aqueous phase. Iron is well separated from rare earths and the product can be recovered directly form the fluid used in separation by oxalic acid precipitation.