Thiophenic compounds adsorption on Na(I)Y and rare earth exchanged Y zeolites: a density functional theory study

We have theoretically investigated the adsorption of thiophene, benzothiophene, dibenzothiophene on Na(I)Y and rare earth exchanged La(III)Y, Ce(III)Y, Pr(III)Y Nd(III)Y zeolites by density functional theory calculations. The calculated results show that except benzothiophene adsorbed on Na(I)Y with a stand configuration, the stable adsorption structures of other thiophenic compounds on zeolites exhibit lying configurations. Adsorption energies of thiophenic compounds on the Na(I)Y are very low, and decrease with the increase of the number of benzene rings in thiophenic compounds. All rare earth exchanged zeolites exhibit strong interaction with thiophene. La(III)Y and Nd(III)Y zeolites are found to show enhanced adsorption energies to benzothiophene and Pr(III)Y zeolites are favorable for dibenzothiophene adsorption. The analysis of the electronic total charge density and electron orbital overlaps show that the thiophenic compounds interact with zeolites by π-electrons of thiophene ring and exchanged metal atom. Mulliken charge populations analysis reveals that adsorption energies are strongly dependent on the charge transfer of thiophenic molecule and exchanged metal atom.     

Mössbauer spectroscopy and perturbed angular correlation studies of the rare-and alkaline-earth bone uptake

Emission Mössbauer spectra and Perturbed Angular Correlation measurements have been performed on samples of mineral bone powder labelled with ¹⁶¹Tb ou ³⁺ or ¹³³Ba²⁺ ions after either in vitro absorption or uptake by metabolic pathway. The study of these hyperfine spectra, compared with those carried out when ¹⁶¹Tb or ¹³³Ba are situated in either hydroxyde lattice or phosphate one, shows that the uptake modes of rare-and alkaline-earth ions on the bone matrix are different. The rare earth ion seems to be adsorbed on the surface bone in an environment of hydroxyl groups similar to the structure of a rare earth hydroxyde. The alkaline earth ion bone uptake appears more complicated and would make according to the following process: at first, surface adsorption on the hydroxylapatite in a hydroxyde environment and then cationic exchange with the calcium phosphate groups into bone crystals.     

Synthesis and luminescent properties of lanthanide homoleptic mercaptothi(ox)azolate complexes: Molecular structure of Ln(mbt)3 (Ln = Eu, Er)

The thiolate complexes of rare earth metals Ln(SR)₃ (La, HSR = 2-mercaptothiazoline (1); La, HSR = 2-mercaptobenzoxazole (2); Y, La, Sm, Eu, Tb, Gd, Er, Tm, HSR = 2-mercaptobenzothiazole (3)) were synthesized in 84-97% yield by the reactions of silylamides Ln[N(SiMe₃)₂]₃ with respective thiols. The products were characterized by elemental analysis, IR and UV/Vis spectroscopy. The structures of 3(Eu) and 3(Er) were determined by single-crystal X-ray diffraction. All obtained compounds revealed efficient luminescence in the region 400-550 nm at 293 K assigned to the ligands emission. Besides, the luminescent spectra of thiolates 3 at 77 K displayed the phosphorescent band of the ligand at 550 nm and in the cases of 3(Eu) and 3(Tb) the sets of emissions bands characteristic for Eu³⁺ and Tb³⁺ ions.     

Assessment the Exposure Level of Rare Earth Elements in Workers Producing Cerium,Lanthanum Oxide Ultrafine and Nanoparticles

In order to assess occupational exposure level of 15 rare earth elements (REEs) and identify the associated influence, we used inductively coupled plasma mass spectrometry (ICP-MS) based on closed-vessel microwave-assisted wet digestion procedure to determinate the concentration of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in urinary samples obtained from workers producing ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggest that La and Ce were the primary component, together accounting for 97 % of total REEs in workers. The urinary levels of La, and Ce among the workers (6.36, 15.32 μg.g^?1 creatinine, respectively) were significantly enriched compared to those levels measured in the control subjects (1.52, 4.04 μg.g^?1 creatinine, respectively) (p < 0.05). This study simultaneously identified the associated individual factors, the results indicate that the concentrations in over 5 years group (11.64 ± 10.93 for La, 27.83 ± 24.38 for Ce) were significantly elevated compared to 1–5 years group (2.58 ± 1.51 for La, 6.87 ± 3.90 for Ce) (p < 0.05). Compared the urinary levels of La and Ce at the separation and packaging locations (9.10 ± 9.51 for La, 22.29 ± 21.01 for Ce) with the other locations (2.85 ± 0.98 for La, 6.37 ± 2.12 for Ce), the results show urinary concentrations were significantly higher in workers at separation and packaging locations (p < 0.01). Inter-individual variation in levels of La and Ce in urine is the result of multi-factorial comprehensive action. Further researches should focus on the multiple factors contributing to the REEs levels of the occupationally exposed workers.     

Heteroleptic phthalocyaninato-[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth(III) triple-deckers: synthesis and spectroscopic characterization

The homo-dinuclear heteroleptic phthalocyaninato-[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth(III) triple-decker complexes (Pc)M[Pc(OC₈H₁₇)₈]M[Pc(OC₈H₁₇)₈] (M=Pr, Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm) (1a–10a) and (Pc)M[Pc(OC₈H₁₇)₈]M(Pc) (M=Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm) (2b–10b) were obtained by condensation of bis(phthalocyaninato) rare earths M[Pc(OC₈H₁₇)₈]₂ (M=Pr, Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm), Li₂(Pc) and M(acac)₃·nH₂O (M=Pr, Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm). These novel compounds were characterized by ¹H NMR, mass, electronic absorption (UV–Vis), and IR spectroscopic methods.     

New complexes of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) ions with morin

New solid complex compounds of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) ions with morin were synthesized. The molecular formula of the complexes is Ln(C₁₅H₉O₇)₃ · nH₂O, where Ln is the cation of lanthanide and n = 6 for La(III), Sm(III), Gd(III) or n = 8 for Ce(III), Pr(III), Nd(III) and Eu(III). Thermogravimetric studies and the values of dehydration enthalpy indicate that water occurring in the compounds is not present in the inner coordination sphere of the complex. The structure of the complexes was determined on the basis of UV-visible, IR, MS, ¹H NMR and ¹³C NMR analyses. It was found that in binding the lanthanide ions the following groups of morin take part: 3OH and 4CO in the case of complexes of La, Pr, Nd, Sm and Eu, or 5OH and 4CO in the case of complexes of Ce and Gd. The complexes are five- and six-membered chelate compounds.     

Effects of rare earth elements on telomerase activity and apoptosis of human peripheral blood mononuclear cells

To study the effects of rare earth exposure on human telomerase and apoptosis of mononuclear cells from human peripheral blood (PBMNCs). The blood contents of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, were measured by inductively coupled plasma-mass spectrometry. Telomeric repeat amplification protocol assay and flow cytometer analysis were carried out to analyze the telomerase activity and apoptosis of PBMNCs, respectively. The total content of rare earth elements in the blood showed significant differences between the exposed group and the control group. The rare earth exposure increased the telomerase activity and the percentages of cells in the S-phase and the G₂/M phase in PBMNCs, but it had no effect on the apoptotic rate of PBMNCs. Under the exposure to lower concentrations of rare earth elements, the telomerase activity of PBMNCs in the exposed group was higher than that of the control group, and there was no effect on the apoptotic rate of PBMNCs, but promoted the diploid DNA replication and increased the percentages of G₂/M- and S-phase cells.     

Rare earth metal ions for unprecedentedly fast RNA hydrolysis.

Adenylyl(3'-5')adenosine (ApA) and uridyl(3'-5')uridine (UpU) are hydrolyzed at unprecedentedly large rates by rare earth metal ions at pH 8, 30 degrees C. With 0.01 M Tm(III), the half-lives are 10 min and 51 min, respectively. Potentiality of these ions as catalytic center of artificial ribonuclease is proposed.     

Synthesis and luminescence properties of polymer–rare earth complexes containing salicylaldehyde‐type bidentate Schiff base ligand

Using molecular design and polymer reactions, two types of bidentate Schiff base ligands, salicylaldehyde–aniline (SAN) and salicylaldehyde–cyclohexylamine (SCA), were synchronously synthesized and bonded onto the side chain of polysulfone (PSF), giving two bidentate Schiff base ligand‐functionalized PSFs, PSF–SAN and PSF–SCA, referred to as macromolecular ligands. Following coordination reactions between the macromolecular ligands and Eu(III) and Tb(III) ions (the reaction occurred between the bonded ligands SAN or SCA and the lanthanide ion), two series of luminescent polymer–rare earth complexes, PSF–SAN–Eu(III) and PSF–SCA–Tb(III), were obtained. The two macromolecular ligands were fully characterized by Fourier transform infrared (FTIR), ¹H NMR and UV absorption spectroscopy, and the prepared complexes were also characterized by FTIR, UV absorption spectroscopy and thermo‐gravity analysis. On this basis, the photoluminescence properties of these complexes and the relationships between their structure and luminescence were investigated in depth. The results show that the bonded bidentate Schiff base ligands, SAN and SCA, can effectively sensitize the fluorescence emission of Eu(III) and Tb(III) ions, respectively. PSF–SAN–Eu(III) series complexes, namely the binary complex PSF–(SAN)₃–Eu(III) and the ternary complex PSF–(SAN)₃–Eu(III)–(Phen)₁ (Phen is the small‐molecule ligand 1,10‐phenanthroline), produce strong red luminescence, suggesting that the triplet state energy level of SAN is lower and well matched with the resonant energy level of the Eu(III) ion. By contrast, PSF–SAN–Eu(III) series complexes, namely the binary complex PSF–(SCA)₃–Tb(III) and the ternary complex PSF–(SCA)₃–Tb(III)–(Phen)₁, display strong green luminescence, suggesting that the triplet state energy level of SCA is higher and is well matched with the resonant energy level of Tb(III).     

Simultaneous production of propionic acid and vitamin B12 from corn stalk hydrolysates by Propionibacterium freudenreichii in an expanded bed adsorption bioreactor

Abstract

Vitamin B12 and propionic acid that were simultaneous produced by Propionibacterium freudenreichii are both favorable chemicals widely used in food preservatives, medicine, and nutrition. While the carbon source and propionic acid accumulation reflected fermentation efficiency. In this study, using corn stalk as a carbon source and fed-batch fermentation process in an expanded bed adsorption bioreactor was studied for efficient and economic biosynthesis of acid vitamin B12 and propionic. With liquid hot water pretreated corn stalk hydrolysates as carbon source, 28.65?mg L^?1 of vitamin B12 and 17.05?g L^?1 of propionic acid were attained at 168?h in batch fermentation. In order to optimize the fermentation outcomes, fed-batch fermentation was performed with hydrolyzed corn stalk in expanded bed adsorption bioreactor (EBAB), giving 47.6?mg L^?1 vitamin B12 and 91.4?g L^?1 of propionic acid at 258?h, which correspond to product yields of 0.37?mg g^?1 and 0.75?g g^?1, respectively. The present study provided a promising strategy for economically sustainable production of vitamin B12 and propionic acid by P. freudenreichii fermentation using biomass cornstalk as carbon source and expanded bed adsorption bioreactor.     

The Physical and Morphological Characteristics of Mango Powder (<Emphasis Type="Italic">Mangifera indica</Emphasis> L. cv Tommy Atkins) Produced by Foam Mat Drying

The thermal behavior, moisture adsorption properties and structural and morphological characteristics of mango powders were evaluated. The powders were obtained by foam mat drying methodology using albumin (ALB), mixture (EB) of monoglycerides of fatty acids, sorbitan monostearate and polyoxyethylene sorbitan monostearate and a combination of the two (EB-ALB) as foaming agents. The evaluation was done by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the moisture adsorption isotherms were also determined. The powder with EB had a glass transition temperature (T_g) of ?4.2 °C. The denaturation temperature of pure albumin (82.2 °C) increased in the powders with ALB to 117 °C and in those with EB-ALB to 102 °C, due to the thermal stability provided by the pulp sugars. The moisture sorption isotherm of the EB-powder showed a higher water equilibrium content than the other powders. All the powders were in the amorphous state. The morphology of the powder with EB showed corrugated particles, whereas those with ALB and EB-ALB showed particles with a less porous aspect and more compact surfaces than the powders with EB.     

The Combined Effects of Iron Excess in the Diet and Chromium(III) Supplementation on the Iron and Chromium Status in Female Rats

Inadequate iron supply has significant consequences to health. There are some relations between the metabolism of different trace elements, such as iron, zinc, copper and chromium. However, the direction of these interactions can be antagonistic or synergistic, and it depends on many factors. The aim of the study was to evaluate the combined effects of supplementary of chromium(III) propionate complex (Cr3) with iron excess on the Cr and Fe status in healthy female rats. The 36 healthy female Wistar rats were divided into six experimental groups (six animals in each) with different Fe levels—adequate (45 mg kg^?1—100% RDA) and high (excessive—180 mg kg^?1—400% RDA). At the same time, they were supplemented with Cr(III) at doses of 1, 50 and 500 mg kg^?1 of diet: C1—control (Fe 45 mg kg^?1, Cr 1 mg kg^?1); C50 (Fe 45 mg kg^?1, Cr 50 mg kg^?1); C500 (Fe 45 mg kg^?1, Cr 500 mg kg^?1); H1 (Fe 180 mg kg^?1, Cr 1 mg kg^?1); H50 (Fe 180 mg kg^?1, Cr 50 mg kg^?1); H500 (Fe 180 mg kg^?1, Cr 500 mg kg^?1). The serum iron level and total iron binding capacity (TIBC) were measured with colorimetric methods. The serum ferritin level was measured by means of electrochemiluminescence immunoassay. The serum transferrin level was measured with the ELISA method. Haematological measurements were made with an automated blood analyser. The Cr and Fe tissular levels were measured with the AAS method. The exposure to a high level of Fe(III) alone or in combination with Cr caused Fe accumulation in tissues, especially in the liver and kidneys, but there were no significant changes in the TIBC, transferrin, ferritin concentration in the serum and most haematological parameters. Moreover, the serum, hepatic and renal Cr concentrations decreased. The doses of supplementary Cr(III) given separately or in combination with high level of Fe(III) disturbed the Cr content in the liver and kidneys of healthy female rats. However, they did not change most of the parameters of Fe metabolism, except the Fe kidney concentration. Supplementary Cr3 decreased the renal Fe level in groups with adequate Fe content in the diet. However, the renal Fe levels increased along with a higher Cr level in the diet in groups with high Fe content. The findings proved a relationship between Fe(III) and Cr(III) metabolism in healthy female rats. However, the direction of change varied and depended on relative amounts of these elements in the diet.     

P(M) and P(R) forms of cytochrome c oxidase have different spectral properties

This work presents the study of the interaction between zidovudine (AZT) and rare earth (RE) ions with thenoyltrifluoroacetonate (TTA). The complexes [RE(TTA)(3) x (AZT)(2)] (where RE(III)=Eu and Gd) were prepared by reaction between the [RE(TTA)(3) x (H(2)O)(2)] precursors and AZT dissolved in acetone in the molar ratio 1:2. The obtained luminescent materials were characterized by microanalyses (C, H, N), complexometric titration, IR spectroscopy, X-ray powder diffraction and thermal analysis (DSC and TG/DTG). The luminescence data indicate that the substitution of the two water molecules by AZT in the europium complex causes an intensification of luminescence corresponding to the (5)D(0) -->(7)F(J) (J=0-4) transitions associated with one of the site symmetries. Based on the luminescence spectrum of the Eu(III)-compound the Omega(lambda) experimental intensity parameters (lambda=2 and 4) were calculated for the electronic transitions (5)D(0)-->(7)F(2, 4). The Omega(2) intensity parameter for this new compound is higher than for the precursor compound, suggesting an effective interaction between the AZT and the chemical environment of the Eu(III) ion. Luminescence data confirm that the AZT complex and precursor compound have a comparable emission quantum efficiency.     

Toxic metal biosorption by macrocolonies of cyanobacterium <Emphasis Type="Italic">Nostoc sphaeroides</Emphasis> Kützing

The cyanobacterium Nostoc sphaeroides Kützing is expected to be effective in toxic metal adsorption as it produces abundant exopolysaccharides with functional groups. Therefore, the adsorption properties of Cu²⁺, Cd²⁺, Cr³⁺, Pb²⁺, Ni²⁺, and Mn²⁺ on fresh macrocolonies and algal powder of N. sphaeroides were compared at pH 5 and 25 °C. The adsorption capacity of fresh biomass for Pb²⁺ and of algal powder for Pb²⁺ and Cr³⁺ were highest in single metal solutions. Compared to the fresh biomass, the metal adsorption capacities of algal powder were similar for Ni²⁺, Cd²⁺, and Pb²⁺ and slightly greater for Cr³⁺, but they were markedly smaller for Mn²⁺ and Cu²⁺. Coexisting ions (in tap water or in multiple solutions) significantly decreased the metal adsorption capacity, except for Cr³⁺ in tap water. The Pb²⁺ and Cr³⁺ adsorption dynamic process fitted the pseudo-second-order model well, showing fast adsorption at the first stage in 10 and 20 min, respectively. Higher pH in acidic ranges favored the adsorption greatly. The Langmuir isotherm model was suitable for explaining the adsorption, and the maximum adsorption capacities were 116.28 and 22.37 mg g^?1 for Pb²⁺ and Cr³⁺, respectively. The adsorption process was endothermic, confirmed by the significantly higher adsorption capability at higher temperature. Hydroxyl, amino, and carboxyl groups were the main functional groups based on Fourier transform infrared spectroscopy analysis, and they bind to metal ions via ion exchange. The results suggest that fresh macrocolonies of N. sphaeroides can be used as an effective biosorbent for metal ion removal, especially for Pb²⁺ and Cr³⁺.     

Synthesis, characterization, and DNA-binding properties of the Ln(III) complexes with 6-hydroxy chromone-3-carbaldehyde-(2'-hydroxy) benzoyl hydrazone

A new ligand, 6-hydroxy chromone-3-carbaldehyde-(2'-hydroxy) benzoyl hydrazone (L), was prepared by condensation of 6-hydroxy-3-carbaldehyde chromone (CDC) with 2-hydroxy benzoyl hydrazine. Its four rare earth complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, mass spectra, 1H NMR, thermogravimetry/differential thermal analysis (TG-DTA), UV-vis spectra, fluorescence spectra, and IR spectra. The general formula of the complexes is [LnL2.(NO3)2].NO3 [Ln=La(1), Sm(2), Dy(3), Eu(4)]. Spectrometric titration, ethidium bromide displacement experiments, and viscosity measurements indicate that Eu(III) complex and ligand, especially the Eu(III) complex, strongly bind with calf-thymus DNA, presumably via an intercalation mechanism. The intrinsic binding constants of Eu(III) complex and ligand with DNA were 3.55 x 10(6) and 1.33 x 10(6)M(-1) through fluorescence titration data, respectively. In addition, the suppression ratio for O2-* and OH* of the ligand and its complexes was studied by spectrophotometric methods. The experimental results show that La (1), Sm (2), and Eu (4) complexes are better effective inhibitor for OH* than that of mannitol. It indicates that the complexes have the activity to suppress O2-* and OH* and exhibit more effective antioxidants than ligand alone.     

Studies of the coordination of rare earth and transition metal nucleotide complexes by an electron spin echo method

Titrations of the paramagnetic rate earth ions Ce(III), Nd(III), Er(III), and Yb(III) with ATP, ADP, adenosine, and the hexametaphosphate ligands have been performed in order to establish the conditions required to form saturated complexes. These titrations have been made by recording the decay envelope of electron spin echoes for a range of different concentrations of the species concerned and observing the ‘nuclear modulation effect’ in the echo envelope. This novel method can be used when optical titrations are not feasible. It also yields additional information concerning changes in the number and nature of the coordinating groups, in the distances of these groups from the paramagnetic ion, and in the degree of water coordination in the primary sphere. It was shown that: (a) ATP has a greater affinity than ADP for rate earth ions; (b) Ce(III) has a greater affinity than Nd(III) for ATP; (c) the interaction between rate earth ions and ³¹P nuclei in the added phosphates is greatest for cations with the smallest radii; (d) more phosphate groups are bound in hexametaphosphate complexes of rate earth ions than in the corresponding ATP complexes; (e) some of the coordination sites in rare earth ATP complexes are occupied by water. In othe studies performed with paramagnetic transition metal ions, it was shown that Co(II) can, under certain conditions, bind to the adenine moiety of ATP.     

Accumulation of rare earth elements in maize plants (Zea mays L.) after application of mixtures of rare earth elements and lanthanum

Rare earth elements are applied in China to improve crop production, and the distribution patterns of individual rare earth elements in native plants have widely been reported. But our knowledge is still limited about the dose-dependent accumulation of individual rare earth elements in agricultural crops after application of rare earth elements. Effects of lanthanum and mixtures of rare earth elements were studied in pot experiments on the accumulation of individual rare earth elements in maize plants. All plant samples were divided into plant tops and roots. On addition of mixtures of rare earth elements and lanthanum to the soil, a significant dose-dependent accumulation of individual rare earth element(s) was found in the roots and in the plant tops. Application of mixtures of rare earth elements at >10 mg kg^–1 soil, resulted in a significant increase in contents of light rare earth elements in the roots, and at a dose of 50 mg kg^–1 soil, a similar phenomenon was found in the plant tops. When mixtures of rare earth elements were replaced by lanthanum alone, at a dose higher than 10 mg La kg^–1 soil, a significant increase in La content occurred in the roots and in the plant tops. The content ratio of La to Ce in maize plants appeared to increase as the application doses of rare earth element(s) increased. At a highest dose (50 mg kg^–1soil), the transport of the absorbed La from the roots to the plant tops might be substantially reduced after treatment with lanthanum alone, compared with mixtures of rare earth elements. Increasing the application doses of rare earth element(s) appeared to cause a positive Gd and negative Ce anomaly in the roots and in the plant tops, and the anomaly was more obvious in the plant tops than in the roots. The results indicated that the Gd and Ce anomaly in corns might be considered as important parameters for the safety assessment of agricultural application of rare earth elements.     

Characterization of a Lactobacillus gasseri JCM 1131T Lipoteichoic Acid with a Novel Glycolipid Anchor Structure

We determined the chemical structure of lipoteichoic acid (LTA) from Lactobacillus gasseri JCM 1131^T. The repeating unit was comprised of glycerolphosphate and 2-alanylglycerolphosphate. The glycolipid anchor was tetrahexosylglycerol with two or three acyl groups. To our knowledge, this is the first demonstration of a tetrahexose structure in an LTA glycolipid anchor.     

Presence and possible origin of positive Eu anomaly in shoot samples of Juncus effusus L

BackgroundThe rare earth elements (REE) are non-essential elements for plants. They stimulate plant growth at low doses, but at high levels are phytotoxic. There are differences in concentrations of REE in various organs of the same plant species, but the normalized REE patterns can be very similar in samples of the same species collected in different locations. Here we compare normalized REE curves in above-ground samples of Juncus effusus L. (common rush, soft rush) collected from sites with different land-use types.MethodsThe concentrations of rare earth elements were measured in 55 shoot samples of J. effusus L. The samples were collected from 15 sampling sites located in the Holy Cross Mts., south-central Poland and analyzed with the use of inductively coupled plasma mass spectrometry (ICP-MS). The results were normalized to the North American Shale Composite and anomalies of different elements were calculated.ResultsTotal REE concentrations varied from 0.028 mg/kg to 2.7 mg/kg. The samples were enriched in the light REE (from La to Eu) with the highest concentrations of La and Ce. The North American Shale Composite (NASC)-normalized REE curves were roughly similar in all samples except for two samples collected in the acid mine drainageaffected areas.ConclusionAll samples showed positive europium anomalies in NASC-normalized REE concentration patterns. The most probable explanation of this is that the uptake and translocation of Eu in J. effusus (and possibly in other wetland plants) is caused by a short-term decrease of the redox potential in a rhizosphere favoring reduction of Eu³⁺ to Eu²⁺ and thus enhancing Eu mobility in the soil-plant environment.     

EXAFS studies and gaussian view energy calculations of the complexation of europium with 1,3,5-trideoxy-1,3,5-tris((2-hydroxybenzyl)amino)-cis-inositol

Complexation of 1,3,5-trideoxy-1,3,5-tris((2-hydroxybenzyl)amino)-cis-inositol (thci) in I = 1.00 M (NaClO₄) with Eu(III) and La(III) was studied by EXAFS measurements and gaussian view energy calculations.EXAFS studies indicated that two complexes Eu(thci)²⁺ and are formed with thci and Eu(III). At lower pH, Eu(III) is bonded to thci via two hydroxyl groups (cyclohexanetriol or 2-hydroxybenzylamino moieties) and 7 H₂O molecules, for a total of 9 Eu–O bonds. However, at higher pH there are two hydroxyl groups (cyclohexanetriol or 2-hydroxybenzylamino moieties), two amino groups, and five water molecules for a total Eu(III) coordination number of 9. gaussian view energy calculations indicate that in the Eu(thci)²⁺, thci bonds to Eu(III) in a similar manner and is in good correlation with the EXAFS data.