Interaction Of Lanthanides Research Articles

Lanthanum fixation by Myxococcus xanthus: cellular location and extracellular polysaccharide observation

Myxococcus xanthus is a soil bacterium of the myxobacteria group and is abundant in almost all soils. Its role in soil ecology is considered significant. One noteworthy characteristic of the bacterium is that it produces large quantities of extracellular polymeric substances (EPS). It is also known that its biomass has the capacity to fix heavy metals. Here it is reported that M. xanthus was able to accumulate 0.6 mmol of La per g of wet biomass and/or 0.99 mmol per g of dry biomass. Transmission Electron Microscopy (TEM) observation of M. xanthus cells treated with La showed that a substantial amount of this cation was fixed in the EPS and in the cell wall. Smaller amounts were also observed in the cytoplasm. Fixed La appeared as phosphate in all cellular locations. The results given here also show that the use of La enables TEM observation of the M. xanthus EPS as a dense fibrillar net surrounding the cells. This technique is relatively easy and prevents EPS collapse, which occurs frequently during the fixation and dehydration procedures commonly used in preparations for TEM observations. Since antibodies are no longer required, the La stain can be carried out without delaying bacterial cell cultivation or isolation. In addition, the presence of La in cell cytoplasm without cell degeneration suggests that this microorganism could be used as a model in the study of bacteria–lanthanide interactions.

Trivalent Lanthanide Interactions with a Terdentate Bis(dialkyltriazinyl)pyridine Ligand Studied by Electrospray Ionization Mass Spectrometry

The 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridines (DATPs) belong to a new family of extracting agents recently developed in the framework of nuclear fuel reprocessing. These molecules exhibit exceptional properties to separate actinides(III) from lanthanides(III) in nitric acid solutions. A previous work showed that electrospray ionization mass spectrometry (ESI-MS) is a reliable technique to provide solution data such as stoichiometries and conditional stability constants of various DATP complexes with europium and evidenced the unusual capability of DiPTP [bis(di-iso-propyltriazinyl)pyridine] ligand to form 1:3 complexes in nitric acid solution. This latter result is further investigated by considering DiPTP complexation features with the complete lanthanide family. As a starting point of the experimental procedure used for stability constant evaluation, the intensity distribution of ions detected by ESI-MS is studied for solutions containing Ln(NO(3))(3) in water/methanol (1:1 v/v) with the pH value set at 2.8 and 4.6 by HNO(3) additions. At pH 2.8, the nitrate anions are found to prevent lanthanides from processes occurring within the ion source: redox phenomena or gas-phase reactions with methanol which give species such as [Ln(MeO)(2)](+). Thus, the total intensity of MS signals from [Ln(NO(3))(2)(H(2)O)(p)(MeOH)(n)](+) ions is found proportional to the metal ion concentration. At pH 4.6, with lower nitrate concentration, the nature of the species identified on mass spectra depends on the electronic properties of the lanthanide elements. It is shown that Ln(III) complexation with DiPTP leads to the exclusive formation of 1:3 complexes with the whole lanthanide series which may be due not only to the hydrophobic exterior of the ligand but also to the unusual electronic density distribution in DATP ligands as compared with other aza-aromatic ligands. The conditional stability constants of the 1:3 lanthanide(III) complexes with DiPTP have been determined at pH 2.8 and are found to increase almost regularly from La (log beta(3)(app) = 11.7 +/- 0.1) to Lu (log beta(3)(app) = 16.7 +/- 0.8). Moreover, the kinetic stability of the gas-phase 1:3 complexes obtained by electrospray has been investigated by energy-resolved collision-induced dissociation and provides useful information on the bonding and structure.

Absorption Spectral Studies Involving 4f–4f Transitions as Structural Probe in Chemical and Biochemical Reactions and Compositional Dependence of Intensity Parameters

Absorption spectral studies on lanthanides are described, dealing with 4f–4f transitions as structural probe in chemical and biochemical reactions, and compositional dependence of intensity parameters in order to understand the structure and nature of lanthanide bimolecular interaction. This review is basically addressed to the suitable application of solution absorptional spectral spectroscopy: (i) in probing the binding characteristics and multimetal simultaneous coordination of biomolecules, (ii) following the different steps involved n complex sol-gel processes involving heterometallic alkoxides as precursors fore generation of suitable materials for future computing devices, and (iii) in pursuing the progress of some organic synthesis, specially Meerwin-Ponndorf-Verley reaction and Diels-Alder cycloaddition reaction, homogeneously catalysed by lanthanides. Solution kinetics of interactions of lanthanides involved in the reactions is presented.

Crystal chemistry of clay-Mn oxide associations in soils, fractures, and matrix of the Bandelier Tuff, Pajarito Mesa, New Mexico

The upper 25 m of Bandelier Tuff at Pajarito Mesa, New Mexico, include soils, shallow fractures, deeper fractures, and tuff matrices in which clays provide a record of transport and alteration. The principal pathways within this system are fractures that penetrate the tuff. Large fractures that host deep root penetration provide a setting in which clay deposits accumulate through particulate or colloidal migration from the soil zone. Clays throughout the system are predominantly expandable interstratified illite/smectites (I/S), but clays of the tuff matrix at depth are distinctly Fe-rich and are not mixed with clays transported from the surface into fractures. Chemical alteration superimposed on clay particles transported into fractures results in clays with lower Al : Si ratios, higher Na, and higher lanthanide content with increasingly negative Eu anomalies with depth. These changes are accompanied by invasion and precipitation of Mn oxides, principally birnessite, within clay bodies. Investigation of the Mn oxides by synchrotron X-ray fluorescence (SXRF) shows that Mn is associated with Ba, Ce, Ni, and Pb. In addition, synchrotron X-ray absorption near-edge structure (XANES) spectra show that Ce in Mn oxides occurs as Ce3+ and Ce4+, with average Ce oxidation state of ∼3.75. The Mn oxides intergrown with clays actively participate in removal of Ce from solution, accompanied by oxidation of Ce3+ to Ce4+. Other lanthanides are accumulated by the clays but are not concentrated along with Ce in the Mn oxides. Extraction of Ce from solution by Mn oxides is more effective than lanthanide accumulation in clay, a process that is variable and likely influenced by defects, extent of recrystallization, and particle sizes. This dichotomy in lanthanide interaction results in locally constant Ce content but either negative or positive Ce anomalies in the clay-Mn oxide system as a consequence of variability in the abundance of the other lanthanides. Nevertheless, the net lanthanide pattern for the sum of all clay-Mn oxide samples in either shallow or deep fractures has no Ce anomaly, indicating that other lanthanides segregated from Ce are not transported beyond the range of either the shallow or deep fracture systems. Evidence from Eu anomalies indicates that lanthanides accumulated in the fracture clays are acquired from the local tuff. The clay-Mn oxide assemblage is more effective than clay alone in accumulating of a wide variety of heavy metals.

Lanthanide(III) perchlorate complexes of two 24 membered N 3O 4-donor macrocycles

Two novel macrocycles, L 1 and L 2, containing a N 3O 4-donor set, have been synthesised, and their complexation potential towards Ln(III) ions have been investigated. The cyclocondensation reaction between 2,6-bis(2-formylphenoxymethyl)pyridine and 1,2-bis(2-aminophenoxy)butane in the absence of metal ions, yields the macrocycle L 1 as the main product. The diamine macrocycle L 2 is formed by reaction of the diamine and dicarbonyl precursors followed by an in situ reduction with NaBH 4. The interaction of lanthanide(III) ions with both ligands has been investigated.

The Synergistic Extraction of Lanthanide Ions by a Mixture of Calix[4]resorcinarene or its Dimethylamino-, Piperidyl- or Trimethylammoniummethylated Derivatives and 1,10-Phenanthroline in n-Heptanol

The alkylaminomethylatedcalix[4]resorcinarene derivatives, modified bydimethylamino-, piperidyl- and trimethylammoniummoieties, have been synthesised to investigate theirextractability towards lanthanide ions and to comparewith the extractability of calix[4]resorcinarene. Both calix[4]resorcinarene and its derivatives have beenshown to synergistically affect lanthanide ionextraction from neutral aqueous solutions by1,10-phenanthroline through outer-sphere interactionof lanthanide bis-phenanthrolinate cations withdeprotonated forms of calix[4]resorcinarene. Thederivatives with dimethylamino- andpiperidylmethylated moieties are shown to be moreeffective extractants in comparison with theunsubstituted one.

Lanthanide(III) Nitrate Complexes of Two 17 Membered N3O2-Donor Macrocycles

The interaction of lanthanide(III) ions with two N3O3-macrocycles, L1 and L2, derived from 2,6-bis(2-formylphenoxymethyl)pyridine and 1,2-diaminoethane has been investigated. Schiff-base macrocyclic lanthanide(III) complexes LnL1(NO3)3 · xH2O (Ln = Nd, Sm, Eu or Lu) have been prepared by direct reaction of L1 and the appropriate hydrated lanthanide nitrate. The direct reaction between the diamine macrocycle L2 and the hydrated lanthanide(III) nitrates yields complexes LnL2(NO3)3· H2O only for Ln = Dy or Lu. The reduction of the Schiff-base macrocycle decreases the complexation capacity of the ligand towards the Ln(III) ions. The complexes have been characterised by elemental analysis, molar conductivity data, FAB mass spectrometry, IR and, in the case of the lutetium complexes, 1H NMR spectroscopy.

Spectral Studies of Lanthanide Interactions with Membrane Surfaces

We have monitored the interactions of the series of trivalent lanthanide cations with the thylakoid membrane surface of spinach chloroplasts using two complementary spectral techniques. Measurements of the fluorescence emission of the extrinsic probe 2-p-toluidinonaphthalene-6-sulfonate (TNS) and the absorbance of the intrinsic chromophore chlorophyll provide two sensitive means of characterizing the dependence of the cation-membrane interaction on the nature of the cation. In these systems, added lanthanide cations adsorb onto the membrane surface to neutralize exposed segments of membrane-embedded protein complexes. The lanthanide-induced charge neutralization increases the proximity of added TNS anion to the membrane surface as evidenced by variations in the TNS fluorescence level and wavelength of maximum emission. Our results reveal a strong dependence of TNS fluorescence parameters on both lanthanide size and total orbital angular momentum L value. Lanthanides with greater charge density (small size and/or low L value) enhance the TNS fluorescence level to a greater extent. A possible origin for the lanthanide-dependent TNS fluorescence levels is suggested in terms of a heterogeneity in the number and type of TNS binding sites. The data are consistent with the proposal that larger lanthanides with smaller enthalpies of hydration induce more significant membrane appression. 59 refs., 9 figs.,more » 2 tabs.« less

Interdiffusion of cerium in Fe-base alloys with Ni or Cr

Isothermal interdiffusion studies relevant to lanthanide interactions with cladding alloys in the Integral Fast Reactor program were carried out at 425°C by employing solid-solid diffusion couples assembled with disks of Ce and disks of Fe, Ni, and Fe-10.1Ni, and Fe-20.1Cr, binary alloys (composition in at%). The diffusion structures and intermetallic layers which developed in the various couples during the diffusion anneal were metallographically examined and analyzed by SEM-EDS techniques for concentration profiles. Computer programs were developed to construct profiles of concentrations and to evaluate interdiffusion fluxes and effective interdiffusion coefficients for the individual components over selected regions of the diffusion zones of the various couples. Intrinsic diffusion data were calculated at marker planes in the Ni 3Ce 7 and Fe 2Ce phases developed in the Ni vs Ce and Fe vs Ce couples, respectively. The intermetallic phases and diffusion layers observed in the various couples are discussed in the light of phase diagrams and experimental diffusion paths.

Infrared spectra of carbon monoxide adsorbed on SiO 2-supported lanthanide-Ni bimetallic catalysts and their catalytic properties

Recently the surface properties of the lanthanide (rare earth) - transition metal intermetallics and lanthanide metal overlayers have attracted a growing interest from the point of view of technical applications in catalyst and hydrogen storage. However, despite the intrinsic interest and considerable potential of these novel materials, very little detailed work has been carried out with a view to unveiling the specific properties upon interactions of lanthanides with transition metals. It has been shown that Eu and Yb metals dissolve in liquid ammonia to yield homogeneous solutions containing the ammoniated electrons. When the transition metal powders are added to this solution, the metal powders react with the dissolved lanthanide metals in liquid ammonia to form novel bimetallic catalysts. Such a system can be used as a catalyst probe for studying the catalytic actions induced by interactions between the lanthanide and transition metals. The present investigation was extended to include a SiO{sub 2}-supported bimetallic systems obtained when Eu or Yb dissolved in liquid ammonia reacts with silica-supported Ni. Using Fourier transform (FT)-IR studies of adsorbed carbon monoxide the authors provided information about the way the surface components were disposed in this bimetallic system. Adsorbed carbon monoxide was used as a molecularmore » probe for the nature of bimetallic surface since the IR spectra of adsorbed probe molecules directly reflected variations in the surface.« less

Characterization of lanthanides as competitors of Na+ and K+ in occlusion sites of renal (Na+,K+)-ATPase

Lanthanides are useful probes in Ca2+ binding proteins, including sarcoplasmic reticulum (Ca2+,Mg2+)-ATPase. Here, we report that lanthanides compete with Rb+ and Na+ for occlusion in renal (Na+,K+)-ATPase. The lanthanides appear to bind at a single site and act as competitive antagonists, without themselves becoming occluded. All lanthanides tested are effective with the order of potencies Pr greater than Nd greater than La greater than Eu greater than Tb greater than Ho greater than Er, but differences are small. The presence of Mg2+ ions does not affect competition of La3+ with Na+ or K+ suggesting that the effects are not exerted via divalent metal sites. Lanthanides compete with Rb+ and Na+ in membranes digested with trypsin so as to produce 19-kDa and smaller fragments of the alpha-chain (Karlish, S.J.D., Goldshleger, R., and Stein, W. D. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 4566-4570), also suggestive of a direct interaction of lanthanides with Na+ and K+ sites. Effects of lanthanides on conformational changes of fluorescein-labeled (Na+,K+)-ATPase are Na(+)-like. They stabilize the E1 state and compete with K+ ions. The Ki for La3+ is 0.445 microM. The apparent affinity in fluorescence assays is proportional to enzyme concentration (Ki = 32.4*[protein] + 0.445 microM La3+), suggesting that lanthanides are also bound nonspecifically (possibly to phospholipids). Direct assays confirm that Tb3+ binding is nonspecific. Measurements of the rate of various conformational transitions show that the rate of E2(K+)----E1(X) (X = Na+ or La3+) is significantly inhibited by La3+ compared to Na+. La3+ ions also slightly accelerate the rate of the E1----E2(K+) conformational transition. The dissociation rate of La3+ has been measured by monitoring the rate of E1(La3+)----E2(K+). It is 1.741 s-1 at 25 degrees C. Based on this value, it is unlikely that La3+ ions are stably occluded, consistent with the conclusion from occlusion experiments. In the future, lanthanides bound to monovalent cation sites with high affinity may become useful probes for location and characterization of sites, although it will be necessary to take into account the large amount of nonspecific binding.

Kinetic Studies of Lanthanide Interactions with Humic Substances by Time Resolved Laser Induced Fluorescence

Article Kinetic Studies of Lanthanide Interactions with Humic Substances by Time Resolved Laser Induced Fluorescence was published on January 1, 1991 in the journal Radiochimica Acta (volume 52-53, issue 1).

Reactivity of (C5Me5)2Sm with aryl-substituted alkenes: synthesis and structure of a bimetallic styrene complex that contains an .eta.2-arene lanthanide interaction

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactivity of (C5Me5)2Sm with aryl-substituted alkenes: synthesis and structure of a bimetallic styrene complex that contains an .eta.2-arene lanthanide interactionWilliam J. Evans, Tamara A. Ulibarri, and Joseph W. ZillerCite this: J. Am. Chem. Soc. 1990, 112, 1, 219–223Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://doi.org/10.1021/ja00157a035RIGHTS & PERMISSIONSArticle Views407Altmetric-Citations120LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (757 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Influence of solvent and of cation size on the conformations of lasalocid A-lanthanide(III) ion complexes: circular dichroism and fluorescence studies.

The interaction of lanthanide(III) nitrates (La3+ to Lu3+) with the carboxylic ionophore lasalocid A (LS) has been studied by circular dichroism (CD) and fluorescence spectroscopic techniques in acetonitrile and in methanol. Analysis of the CD data in acetonitrile has revealed the coexistence of both 1:1 (ionophore:cation) and 2:1 complexes in solution. For 1.22 A greater than ionic radius greater than 1.13 A, 1:1 complexes are preferred, and for 1.13 A greater than ionic radius greater than 1.03 A, 2:1 complexes are preferred. Induced CD bands for Ln3+ ions have been observed upon binding to LS in acetonitrile. The LS-Ln3+ complexes are less stable in methanol than in acetonitrile. CD spectral changes showed that the conformations of the complexes in methanol are different from those in acetonitrile. The complexes have rather open conformations in methanol compared to those in acetonitrile. The results underscore the importance of ionic radius, solvent environment, and ionization state of LS in determining the conformations of the ionophore-cation complexes.

Acyclic and macrocyclic schiff base complexes of lanthanides and actinides

The work reviewed here is the result of a collaborative project designed to explore the interaction of lanthanides and actinides with acyclic and macrocyclic Schiff base ligands. The ligands are penta- and hexa-dentate in character and have present arrays of donors drawn from oxygen, nitrogen and sulphur atoms. The acyclic ligands are capable of allowing binuclear incorporation to occur; this feature was included in the study as is the area of selective metal extraction. A single ligand capable of removing two cations simultaneously would have cost benefit advantage over a ligand capable only of removing a single cation.

Acyclic and macrocyclic schiff base complexes of lanthanides and actinides

Acyclic and macrocyclic schiff base complexes of lanthanides and actinides

Interaction of lanthanide(III) ions with bovine prothrombin fragment. 1. A luminescence and nuclear magnetic resonance study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction of lanthanide(III) ions with bovine prothrombin fragment. 1. A luminescence and nuclear magnetic resonance studyMary E. Scott, Martha M. Sarasua, Henry C. Marsh, David L. Harris, Richard G. Hiskey, and Karl A. KoehlerCite this: J. Am. Chem. Soc. 1980, 102, 10, 3413–3419Publication Date (Print):May 1, 1980Publication History Published online1 May 2002Published inissue 1 May 1980https://doi.org/10.1021/ja00530a018RIGHTS & PERMISSIONSArticle Views58Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (948 KB) Get e-Alerts Get e-Alerts

The interaction of lanthanides with isolated sarcoplasmic reticulum vesicles from rabbit skeletal muscle.

The interaction of lanthanides with isolated sarcoplasmic reticulum (SR) vesicles from rabbit skeletal muscle and the effects of lanthanides on 45Ca2+ uptake by the vesicles were studied. 153Gd3+ was taken up by the vesicles in the absence of ATP and oxalate in a time-dependent manner, reaching a maximum total accumulation of 380 nmol 153Gd3+/mg protein after 20 min with 200 microM 153Gd3+. This 153Gd3+ accumulation was not washed out by 1 mM EGTA. The addition of ATP induced the release of 87% of the bound 153Gd3+, leaving behind irreversibly-accumulated 153Gd3+. Pre-incubation of the vesicles with lanthanides in the absence of ATP and oxalate inhibited 45Ca2+ uptake without affecting Ca2+-ATPase activity. The percent inhibition of 45Ca2+ uptake increased with length of pre-incubation of the vesicles with lanthanides, reaching 33% after 20 min of pre-incubation. Increasing the 45Ca2+ concentration or adding ATP or oxalate to the preincubation medium abolished these inhibitory effects on 45Ca2+ uptake.

The interaction of ions with phosphatidylcholine bilayers

The interaction of lanthanides and other cations with phosphatidylcholine bilayers present as single bilayer vesicles in 2H 2O has been investigated in terms of stoichiometry, apparent binding constants and environmental conditions. Lanthanides are shown to form 2 : 1 (molar ratio) phosphatidylcholine to metal ion complexes. The apparent binding constant K b varies as a function of the quantity of metal ion bound and as a function of the Cl − concentration. The apparent binding constant at “zero loading” is K 0 = 1.25 · 10 4 L 2 · M − at 0.15 M KCl . It decreases exponentially with increased “loading” expressed as the molar ratio of metal ion bound to effective phosphatidylcholine concentration and increases exponential with Cl − concentration. The interaction of lanthanides and divalent cations such as Ca 2+ and Mg 2+ is independent of pH in the pH range 3–7 + and 3–10 respectively, but is sensitive to the nature of the anion. The presence of anions enhances the interaction with polyvalent cations, the chaotropic anions showing the largest effect. The order of enhancement is Cl − < Br − < NO 3 − < SCN − < I − < ClO 4 − . The nature of the monovalent counterion (cation) has little effect on the enhanced binding of lanthanides in the presence of the above anions. The affinity of other polyvalent cations for phosphatidylcholine bilayers has been determined by competition with lanthanides. The physiologically important divalent cations Ca 2+ and Mg 2+ both bind less strongly (by about an order of magnitude) to the lipid surface. The order of binding of cations reflects direct binding to the phosphodiester group, with UO 2 2+ showing the highest affinity.

The interaction of lanthanide and calcium salts with phospholipid bilayer vesicles: The validity of the nuclear magnetic resonance method for determination of vesicle bilayer phospholipid surface ratios

Contrary to a recent report (B. Sears et al., Biochemistry 15 (1976) 1635), it has been determined that the ratio of the number of phospholipids on the inner and outer surfaces of phospholipid bilayer vesicles can be accurately determined by NMR paramagnetic ion shift reagent studies of vesicles. It is concluded that the metal interacts with all of the phospholipid on the exposed bilayer surface. A ratio of outer phospholipid to inner surface phospholipid of 2.1 ± 0.1 is obtained regardless of the nucleus studies, position of the nucleus relative to the metal ion binding site, molar ratio of metal to phospholipid over three orders of magnitude, or location of the metal ion on the inside or outside of the vesicle. Additionally, P-31 NMR studies using LaCl 3 and CaCl 2 indicate that Ca 2+ weakly interacts with egg PC vesicles and than the lanthanides are adequate substitutes for Ca 2+ since neither metal is found to perturb measurably the average polar head group conformation.