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Sample records for chelating coordinated oxo-anions

  1. Bowl adamanzanes-bicyclic tetraamines: syntheses and crystal structures of complexes with cobalt(III) and chelating coordinated oxo-anions

    DEFF Research Database (Denmark)

    Broge, Louise; Søtofte, Inger; Jensen, Kristian

    2007-01-01

    complex is provided. Four of the seven complexes contain a chelate coordinating oxo-anion ( sulfate, formiate, nitrate, carbonate). Equilibration of these species with the corresponding diaqua complex is generally slow. The rates of equilibration in 5 mol dm(-3) perchloric acid at 25 degrees C have been...

  2. Bowl adamanzanes--bicyclic tetraamines: syntheses and crystal structures of complexes with cobalt(III) and chelating coordinated oxo-anions.

    Science.gov (United States)

    Broge, Louise; Søtofte, Inger; Jensen, Kristian; Jensen, Nicolai; Pretzmann, Ulla; Springborg, Johan

    2007-09-14

    Seven cobalt(III) complexes of the macrobicyclic tetraamine ligand [2(4).3(1)]adamanzane ([2(4).3(1)]adz) are reported along with the crystal structure of six of these complexes. The solid state and solution structures are discussed, and a detailed assignment of the NMR spectra of the sulfato complex is provided. Four of the seven complexes contain a chelate coordinating oxo-anion (sulfate, formiate, nitrate, carbonate). Equilibration of these species with the corresponding diaqua complex is generally slow. The rates of equilibration in 5 mol dm(-3) perchloric acid at 25 degrees C have been measured, yielding half lives of 20 min, 10 min and 3 h for the sulfato, formiato and carbonato species respectively. The corresponding reaction for the nitrato complex occurs with a half life of less than 3 min. The concentration acid dissociation constant for the Co([2(4).3(1)]adz)(HCO(3))(2+) ion has been measured to K(a) = 0.33 mol dm(-3) [25 degrees C, I = 2 mol dm(-3)] and K(a) = 0.15 mol dm(-3) [25 degrees C, I = 5 mol dm(-3)]. The propensity for coordination of sulfate was found to be large enough for a quantitative conversion of the carbonato complex to the sulfato complex to occur in 3 mol dm(-3) triflic acid containing a small sulfate contamination. On this basis the decarboxylation in 5 mol dm(-3) triflic acid of the corresponding cobalt(III) carbonato complex of the larger macrobicyclic tetraamine ligand [3(5)]adz was reinvestigated and found to lead to the sulfato complex as well. The difference in exchange rate of the oxo-anion ligands for the cobalt(III) complexes of the two adamanzane ligands is discussed and attributed to fundamental differences in the molecular structure where an inverted configuration of the secondary non-bridged amine groups is seen for the complexes of the larger [3(5)]adz ligand. The high affinity for chelating coordination of oxo-anions for these two cobalt(iii)-adamanzane-moieties is rationalised on basis of the N-Co-N angles. N

  3. Uranyl oxo activation and functionalization by metal cation coordination

    International Nuclear Information System (INIS)

    Arnold Polly, L.; Pecharman, A. F.; Hollis, E.; Parsons, S.; Love, J. B.; Yahia, A.; Maron, L.; Yahia, A.; Maron, L.

    2010-01-01

    The oxo groups in the uranyl ion [UO 2 ] 2+ - one of many oxo cations formed by metals from across the periodic table - are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a 'Pacman' environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C-H bond activation reactions are occurring. (authors)

  4. Uranyl oxo activation and functionalization by metal cation coordination

    Energy Technology Data Exchange (ETDEWEB)

    Arnold Polly, L; Pecharman, A F; Hollis, E; Parsons, S; Love, J B [Univ Edinburgh, EaStCHEM Sch Chem, Edinburgh EH9 3JJ, Midlothian (United Kingdom); Yahia, A; Maron, L [Univ Toulouse 3, LPCNO, UMR 5215, INSA, CNRS, F-31077 Toulouse 4 (France); Yahia, A; Maron, L [Univ Montpellier 2, ENSCM, CNRS, ICSM, UMR 5257, CEA, Ctr Marcoule, F-30207 Bagnols Sur Ceze (France)

    2010-07-01

    The oxo groups in the uranyl ion [UO{sub 2}]{sup 2+} - one of many oxo cations formed by metals from across the periodic table - are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a 'Pacman' environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C-H bond activation reactions are occurring. (authors)

  5. Hydrothermal synthesis and crystal structure of a europium(III) coordination polymer with 5-sulfoisophthalate trivalent anions and free 4, 4'-bipyridine molecules

    International Nuclear Information System (INIS)

    Lin Humao; Qing Caixiao; Qian Miao; Ping Xiaohong

    2005-01-01

    A novel europium(III) coordination polymer [Eu(Sip)(H 2 O) 5 ] n · nH 2 O · 1.5 n(Bipy) (I) (Sip is 5-sulfoisophthalate trivalent anion and Bipy is 4,4'-bipyridine) is hydrothermally synthesized and determined by the single crystal X-ray diffraction method. Polymer I crystallizes in the monoclinic system, space group C2/c with a = 30.7515(6), b = 10.9577(2), c = 17.5545(4) A, β = 112.040(1) deg, Z = 4. In I, each Eu 3+ ion is coordinated by four oxygen atoms from two carboxylate groups of two different Sip anions and five oxygen atoms from five coordinated water molecules to complete a deformed mono-cap square antiprism. Moreover, each Sip anion acts as a tetradentate ligand to connect two adjacent Eu 3+ ions through its two chelating carboxylate groups, resulting in one-dimensional linear chains. In addition, fifteen different kinds of hydrogen-bonding interactions link the chains, lattice water molecules, and free Bipy molecules to engender a complicated hydrogen-bonding network [ru

  6. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  7. Imaging Tumor Vasculature Noninvasively with Positron Emission Tomography and RGD Peptides Labeled with Copper 64 Using the Bifunctonal Chelates DOTA, Oxo-DO3A. and PCTA

    Directory of Open Access Journals (Sweden)

    Donald T.T. Yapp

    2013-06-01

    Full Text Available Two novel bifunctional chelates, 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15,11,13-triene-3,6,9-triacetic acid (PCTA and 1-oxa-4,7,10-triazacyclododecane-4,7,10-triacetic acid (Oxo-DO3A, were found to radiolabel antibodies with copper 64 (64Cu well for positron emission tomography (PET. In this study, the same chelators were used to radiolabel peptides with 64Cu for PET imaging of angiogenesis. PCTA, Oxo-DO3A, and 1,4,7,10-tetraazacyclododecane-N,N‘,N“,N”’-tetraacetic acid (DOTA were conjugated to cyclic-(RGDyK, and their binding affinities were confirmed. Conditions for 64Cu radiolabeling were optimized for maximum yield and specific activity. The in vitro stability of the radiolabeled compounds was challenged with serum incubation. PET studies were carried out in a non-αvβ3-expressing tumor model to evaluate the compounds' specificity for proliferating tumor vasculature and their in vivo pharmacokinetics. The PCTA and Oxo-DO3A bioconjugates were labeled with 64Cu at higher effective specific activity and radiochemical yield than the DOTA bioconjugate. In the imaging studies, all the 64Cu bioconjugates could be used to visualize the tumor and the radiotracer uptake was blocked with cyclic-(RGDyK. Target uptake of each bioconjugate was similar, but differences in other tissues were observed. 64Cu-PCTA-RGD showed the best clearance from nontarget tissue and the highest tumor to nontarget ratios. PCTA was the most promising bifunctional chelate for 64Cu peptide imaging and warrants further investigation.

  8. Anion-Dependent Exocyclic Mercury(II) Coordination Polymers of Bis-dithiamacrocycle

    Energy Technology Data Exchange (ETDEWEB)

    Siewe, Arlette Deukam; Kim, Seul Gi; Choi, Kyu Seong [Kyungnam University, Changwon (Korea, Republic of); Lee, Shim Sung [Gyeongsang National University, Jinju (Korea, Republic of)

    2014-09-15

    Synthesis and structural characterization of mercury(II) halides and perchlorate complexes of bis-OS{sub 2}-Synthesis and structural characterization of mercury(II) halides and perchlorate complexes of bis-OS{sub 2}- macrocycle (L) are reported. L reacts with mercury(II) chloride and bromide to yield an isostructural 2D coordination polymers with type [Hg(L)X{sub 2}]n (1: X = Cl and 2: X = Br). In 1, each Hg atom which lies outside the cavity is six-coordinate with a distorted octahedral geometry, being bound to four adjacent ligands via monodentate Hg-S bonds and two remaining sites are occupied by two terminal chlorido ligands to form a fishnet-like 2D structure. When reacting with mercury(II) iodide, L afforded a 1D coordination polymer [Hg{sub 2}(L)I{sub 4}]·CHCl{sub 3}n in which each exocyclic Hg atom is four-coordinate, being bound to two sulfur donors from different ligands doubly bridging the ligand molecules in a head-to-tail mode. The coordination sphere in 3 is completed by two iodo terminal ligands, adopting a distorted tetrahedral geometry. On reacting with mercury(II) perchlorate, L forms solvent-coordinated 1D coordination polymer ([Hg{sub 2}(L)(DMF){sub 6}](ClO{sub 4}){sub 4}·2DMF)n instead of the anion-coordination. In 4, the Hg atom is five-coordinate, being bound to two sulfur donors from two different ligands doubly bridging the ligand molecules in a side-by-side mode to form a ribbon-like 1D structure.. The three remaining coordination sites in 4 are completed by three DMF molecules in a monodentate manner. Consequently, the different structures and connectivity patterns for the observed exocyclic coordination polymers depending on the anions used are influenced not only by the coordination ability of the anions but also by anion sizes macrocycle (L) are reported. L reacts with mercury(II) chloride and bromide to yield an isostructural 2D coordination polymers with type [Hg(L)X{sub 2}]n (1: X = Cl and 2: X = Br). In 1, each Hg atom which lies

  9. New insights into thorium and uranium oxo-arsenic (III/V) and oxo-phosphates (V) crystal chemistry

    International Nuclear Information System (INIS)

    Yu, Na

    2015-01-01

    The fundamental chemistry of actinides is of great interest owing to the diverse number of valence states and complex coordination chemistry of the actinides. The phases based on actinides and oxo-salt fragments have been under thorough investigation in the last decades. These compounds can be widely found in nature and they affect the migration process of actinides in nature. A better understanding of the fundamental coordination chemistry of actinide compounds with oxo-salts of group V elements is not only important for understanding the actinides behavior within the migration process but can also be used to understand actinide properties in phosphate ceramics. Concerning the radioactive issues, the less radioactive early actinides (i.e. U, Th) can be taken as modeling elements to study the crystal chemistry of the transuranic elements (Np, Pu) without the major handling problems. This can be done as Th(IV) has a very similar coordination chemistry with An(IV) and U(VI) can be chosen as a modeling element for transuranic elements in higher valence states. Therefore, a systematic research on the actinides (U, Th) bearing phases with tetrahedral oxo-anions such as phosphates and arsenates have been performed in this work. High temperature (HT) solid state reaction, High pressure high temperature (HP-HT) solid state reaction and the hydrothermal method were the methods of choice for synthesizing actinide bearing oxo-arsenic(III/V) and oxo- phosphorus(V) phases in the past three years. As a result, numerous novel compounds containing actinides were obtained. The structures of all compounds were determined using single crystal X-ray diffraction data. Raman spectroscopy, EDS, DSC and high temperature powder X-ray diffraction (HT-PXRD) measurements were implemented to characterize the chemical and physical properties of the obtained compounds. The core of this dissertation is a fundamental study of the crystal chemistry of actinides (Th, U) oxo-arsenic (III/V) and oxo

  10. New insights into thorium and uranium oxo-arsenic (III/V) and oxo-phosphates (V) crystal chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Na

    2015-12-11

    The fundamental chemistry of actinides is of great interest owing to the diverse number of valence states and complex coordination chemistry of the actinides. The phases based on actinides and oxo-salt fragments have been under thorough investigation in the last decades. These compounds can be widely found in nature and they affect the migration process of actinides in nature. A better understanding of the fundamental coordination chemistry of actinide compounds with oxo-salts of group V elements is not only important for understanding the actinides behavior within the migration process but can also be used to understand actinide properties in phosphate ceramics. Concerning the radioactive issues, the less radioactive early actinides (i.e. U, Th) can be taken as modeling elements to study the crystal chemistry of the transuranic elements (Np, Pu) without the major handling problems. This can be done as Th(IV) has a very similar coordination chemistry with An(IV) and U(VI) can be chosen as a modeling element for transuranic elements in higher valence states. Therefore, a systematic research on the actinides (U, Th) bearing phases with tetrahedral oxo-anions such as phosphates and arsenates have been performed in this work. High temperature (HT) solid state reaction, High pressure high temperature (HP-HT) solid state reaction and the hydrothermal method were the methods of choice for synthesizing actinide bearing oxo-arsenic(III/V) and oxo- phosphorus(V) phases in the past three years. As a result, numerous novel compounds containing actinides were obtained. The structures of all compounds were determined using single crystal X-ray diffraction data. Raman spectroscopy, EDS, DSC and high temperature powder X-ray diffraction (HT-PXRD) measurements were implemented to characterize the chemical and physical properties of the obtained compounds. The core of this dissertation is a fundamental study of the crystal chemistry of actinides (Th, U) oxo-arsenic (III/V) and oxo

  11. Design and synthesis of some polyaminopolycarboxylic acids and the structural influence of their anions on the separation of actinides and lanthanides

    International Nuclear Information System (INIS)

    Tse, P.K.

    1983-01-01

    Investigation of some methods for the preparation of four polyaminopolycarboxylic acids: thiobis(ethylenenitrilo)-N,N,N',N'-tetraacetic acid, N,N-bis(2-aminoethyl)aniline-N',N',N'',N''-tetraacetic acid, bis(3-aminopropyl)ether-N,N,N',N'-tetraacetic acid and N,N-bis[N',N'-dicarboxymethyl-3-aminopropyl]-N-methylammonioacetate are reported. The coordinating properties of their anions with regard to lanthanide ions have been examined. Polyaminopolycarboxylates form 1:1 chelate species with trivalent lanthanide ions in aqueous media. The stability constants of their metal chelate species depend upon the size of the chelating rings formed, the basicity of the middle atom in the chain, and the number of coordination points between anion and metal cation. Tracer level 241 Am- 155 Eu cation-exchange experiments explore how the relative magnitude of the chelate stability constants affects the separation of members of the lanthanide and actinide series

  12. Engaging the Terminal: Promoting Halogen Bonding Interactions with Uranyl Oxo Atoms.

    Science.gov (United States)

    Carter, Korey P; Kalaj, Mark; Surbella, Robert G; Ducati, Lucas C; Autschbach, Jochen; Cahill, Christopher L

    2017-11-02

    Engaging the nominally terminal oxo atoms of the linear uranyl (UO 2 2+ ) cation in non-covalent interactions represents both a significant challenge and opportunity within the field of actinide hybrid materials. An approach has been developed for promoting oxo atom participation in a range of non-covalent interactions, through judicious choice of electron donating equatorial ligands and appropriately polarizable halogen-donor atoms. As such, a family of uranyl hybrid materials was generated based on a combination of 2,5-dihalobenzoic acid and aromatic, chelating N-donor ligands. Delineation of criteria for oxo participation in halogen bonding interactions has been achieved by preparing materials containing 2,5-dichloro- (25diClBA) and 2,5-dibromobenzoic acid (25diBrBA) coupled with 2,2'-bipyridine (bipy) (1 and 2), 1,10-phenanthroline (phen) (3-5), 2,2':6',2''-terpyridine (terpy) (6-8), or 4'-chloro-2,2':6',2''-terpyridine (Cl-terpy) (9-10), which have been characterized through single crystal X-ray diffraction, Raman, Infrared (IR), and luminescence spectroscopy, as well as through density functional calculations of electrostatic potentials. Looking comprehensively, these results are compared with recently published analogues featuring 2,5-diiodobenzoic acid which indicate that although inclusion of a capping ligand in the uranyl first coordination sphere is important, it is the polarizability of the selected halogen atom that ultimately drives halogen bonding interactions with the uranyl oxo atoms. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Stereognostic coordination chemistry. 1. The design and synthesis of chelators for the uranyl ion

    International Nuclear Information System (INIS)

    Franczyk, T.S.; Czerwinski, K.R.; Raymond, K.N.

    1992-01-01

    A new approach to the molecular recognition of metal oxo cations is introduced based on a ligand design strategy that provides at least one hydrogen bond donor for interaction with oxo group(s) as well as conventional electron pair donor ligands for coordination to the metal center. This concept of stereognostic coordination of oxo metal ions is exemplified in the design of four tripodal ligands-tris[2-(2-carboxyphenoxy)ethyl]amine[NEB],tris[3-(2-carboxyphenoxy)propyl]amine[NPB], tris[3-(2-carboxynaphthyl-3-oxy)propyl]amine [NPN], and tris[3-(2-carboxy=4octadecylphenoxy)propyl]amine[NPodB] - for sequestration of the uranyl ion. The ligands NEB, NPB, and NPN form 1:1 complexes with UO 2 2+ . The bidentate coordination of carboxyl groups of these compounds is indicated by the infrared spectra, which offer some support for the presence of a hydrogen bond to the uranyl group. Mass spectral data corroborate CPK model predictions that more than five intervening atoms between the tertiary nitrogen atom and the carboxylate groups are required for metal ion incorporation and monomeric complex formation. Solvent extractions of aqueous UO 2 2+ into chloroform solutions of the ligands have shown them to be powerful extractants. In the case of the very hydrophobic ligand NPodB the stoichiometry of the complexation reaction is shown to be 1:1 UO 2 /ligand complex formed by the release of 3 protons. The extraction is quantitative at pH 2.5, and an effective extraction coefficient of about 10 11 is estimated for neutral aqueous solutions of UO 2 2+ . 81 refs., 13 figs., 2 tabs

  14. Crystal structure of the salt bis(triethanolamine-κ4N,O,O′,O′′cadmium bis[2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-ylacetate

    Directory of Open Access Journals (Sweden)

    Jamshid Mengnorovich Ashurov

    2016-04-01

    Full Text Available The reaction of 2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-ylacetic acid (NBTA and triethanolamine (TEA with Cd(CH3OO2 resulted in the formation of the title salt, [Cd(C6H15NO32](C9H6NO3S2. In its crystal structure, the complex cation [Cd(TEA2]2+ and two independent NBTA− units with essentially similar geometries and conformations are present. In the complex cation, each TEA molecule behaves as an N,O,O′,O′′-tetradentate ligand, giving rise to an eight-coordinate CdII ion with a bicapped trigonal–prismatic configuration. All ethanol groups of each TEA molecule form three five-membered chelate rings around the CdII ion. The Cd—O and Cd—N distances are in the ranges 2.392 (2–2.478 (2 and 2.465 (2–2.475 (3 Å, respectively. O—H...O hydrogen bonds between the TEA hydroxy groups and carboxylate O atoms connect cationic and anionic moieties into chains parallel to [110]. Each NBTA− anion is additionally linked to a symmetry-related anion through π–π stacking interactions between the benzene and thiazoline rings [minimum centroid-to-centroid separation = 3.604 (2 Å]. Together with additional C—H...O interactions, these establish a double-layer polymeric network parallel to (001.

  15. Coumarin benzothiazole derivatives as chemosensors for cyanide anions

    Science.gov (United States)

    Wang, Kangnan; Liu, Zhiqiang; Guan, Ruifang; Cao, Duxia; Chen, Hongyu; Shan, Yanyan; Wu, Qianqian; Xu, Yongxiao

    2015-06-01

    Four coumarin benzothiazole derivatives, N-(benzo[d]thiazol-2-yl)-2-oxo-2H-chromene-3-carboxamide (1), (Z)-N-(3-methylbenzo[d]thiazol-2(3H)-ylidene)-2-oxo-2H-chromene-3-carboxamide (2), 7-(diethylamino)-N-(benzo[d]thiazol-2-yl)-2-oxo-2H-chromene-3-carboxamide (3) and (Z)-7-(diethylamino)-N-(3-methylbenzo[d]thiazol-2(3H)-ylidene)-2-oxo-2H-chromene-3-carboxamide) (4), have been synthesized. Their crystal structures, photophysical properties in acetonitrile and recognition properties for cyanide anions have been investigated. All the compounds are generally planar, especially compound 1 exhibits perfect planarity with dihedral angle between benzothiazolyl group and coumarin group being only 3.63°. Coumarin benzothiazole compounds 1 and 3 can recognize cyanide anions by Michael addition reaction and compound 3 exhibits color change from yellow to colorless and green fluorescence was quenched completely, which can be observed by naked eye. Coumarin benzothiazolyliden compound 4 can recognize cyanide anions with fluorescence turn-on response based on the copper complex ensemble displacement mechanism.

  16. Anion-Controlled Architecture and Photochromism of Naphthalene Diimide-Based Coordination Polymers

    Directory of Open Access Journals (Sweden)

    Jian-Jun Liu

    2018-02-01

    Full Text Available Three new cadmium coordination polymers, namely [Cd(NO32(DPNDI(CH3OH]·CH3OH (1, [Cd(SCN2(DPNDI] (2, and [Cd(DPNDI2(DMF2]·2ClO4 (3 (DPNDI = N,N-di(4-pyridyl-1,4,5,8-naphthalene diimide, DMF = N,N-dimethylformamide have been synthesized by reactions of DPNDI with Cd(NO32, Cd(SCN2, and Cd(ClO42, respectively. Compound 1 is a one-dimensional coordination polymer with strong lone pair-π interactions between the coordinated NO3− anions and the imide ring of DPNDI; while 2 is a two-dimensional network with a (4, 4 net topology. In the case of 3, due to the presence of uncoordinated perchlorate counter ions, it exhibits a non-interpenetrated square-grid coordination polymer containing one-dimensional rhomboid channels. The structural diversity in these compounds is attributed to different coordination abilities and geometries of counter anions. Due to the presence of electron-deficient NDI moiety, the photochromic behavior of these compounds was studied. Interestingly, only compounds 1 and 3 exhibit color changes under light irradiation. The influence of the anions on the photochromism process of the NDI-based materials has been discussed.

  17. Organo-gallium and indium complexes with dithiolate and oxo ligands

    Indian Academy of Sciences (India)

    Page 1 ... of several of these com- plexes have been established by single crystal X-ray diffraction analyses. Complexes derived from oxo ligands ... diode) applications.8. Organometallic complexes derived from chelating ligands, such as substituted. 8-hydroxyqunoline and azomethine linkages, are emerging as potential ...

  18. Anion effect on the retention of recoil atom of coordination crystalline compounds

    International Nuclear Information System (INIS)

    Dimotakis, P.N.; Papadopoulos, B.P.

    1980-01-01

    The anion effect of various cobaltic crystalline compounds - having the same cation and differing in anion -on the retention of neutron activated central cobalt atom has been studied. The cation was trans-dichloro(bis)ethylenediamine cobalt(III) and the anions were simple spherical anions (Cl - , Br - , I - ), planar anions (NO 3 - ), trigonal pyramidal anions (ClO 3 - , BrO 3 - ), tetrahedral anions (SO 4 2- , CrO 4 2- , MnO 4 - ) and linear anions (SCN - ). The cobalt-60 activity after reactor irradiation either in simple Co 2+ cation or in cobaltic complex cation determined the retention values. In all irradiations at ordinary temperature and at liquid nitrogen temperature the results showed an effect of the different anions, depending on the geometry, volume and charge, on the recombination of the recoil cobalt with the ligands in the coordination sphere. (author)

  19. On flotation separation of oxo-anions of transition metals by the use of fine-emulsified solutions of cationic collector in non-polar liquids

    International Nuclear Information System (INIS)

    Skrylev, L.D.; Purich, A.N.; Babinets, S.K.

    1980-01-01

    Experimentally shown is a principle possibility of flotation separation of oxo-anions of transition metals by the use of fine-emulsified solutions of cationic collector in non-polar liquids. Ammonium vanadate and sodium tuno.state solutions have been the objects of study. Hexadezilamine has been used as collector. The collector has been introduced in the form of hexadecylamine emulsions in n-decane, in tetrachloromethane or alcohol. Optimum pH value ranges are determined for separation processes

  20. Synthesis, characterization and properties of a glycol-coordinated ε-Keggin-type Al13 chloride

    KAUST Repository

    Gu, Bin; Sun, Chenglin; Fettinger, James C.; Casey, William H.; Dikhtiarenko, Alla; Gascon, Jorge; Koichumanova, Kamila; Babu Sai Sankar Gupta, Karthick; Jan Heeres, Hero; He, Songbo

    2018-01-01

    Herein we present the first example of a glycol-coordinated ε-Keggin Al13 chloride (gl-ε-Al13), which is the first chelated version since discovery of Al13 in 1960. The molecular structure consists of [AlO4Al12(OH)12(OC2H4OH)12]Cl7·H2O units with chelating mono-anionic ethylene glycol units replacing one bridging and one terminal oxygen site.

  1. Synthesis, characterization and properties of a glycol-coordinated ε-Keggin-type Al13 chloride

    KAUST Repository

    Gu, Bin

    2018-03-29

    Herein we present the first example of a glycol-coordinated ε-Keggin Al13 chloride (gl-ε-Al13), which is the first chelated version since discovery of Al13 in 1960. The molecular structure consists of [AlO4Al12(OH)12(OC2H4OH)12]Cl7·H2O units with chelating mono-anionic ethylene glycol units replacing one bridging and one terminal oxygen site.

  2. Synthesis and thermal characterization of new ternary chelates of piroxicam and tenoxicam with glycine and DL-phenylalanine and some transition metals

    Science.gov (United States)

    Zayed, M. A.; El-Dien, F. A. Nour; Mohamed, Gehad G.; El-Gamel, Nadia E. A.

    2006-05-01

    The ternary chelates of piroxicam (Pir) and tenoxicam (Ten) with Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) in the presence of various amino acids such as glycine (Gly) or DL-phenylalanine (PhA) were prepared and characterized with different physicochemical methods. IR spectra confirm that Pir and Ten behave as a neutral bidentate ligand coordinated to the metal ions via the pyridine- N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its deprotonated carboxylic group. In addition, PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its deprotonated carboxylic and amino groups. The solid reflectance spectra and magnetic moment measurements confirm that all the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. Thermal behaviour of the complexes is extensively studied using TG and DTA techniques. TG results show that water molecules (hydrated and coordinated) and anions are removed in the first and second steps while Gly, PhA, Pir and Ten are decomposed in the next and subsequent steps. The pyrolyses of the chelates into different gases are observed in the DTA curves as exo- or endothermic peaks. Also, phase transition states are observed in some chelates. Different thermodynamic parameters are calculated using Coats-Redfern method and the results are interpreted.

  3. Preparation and physicochemical characterization of anionic uranyl. beta. -ketoenolates

    Energy Technology Data Exchange (ETDEWEB)

    Marangoni, G; Paolucci, G [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Graziani, R; Celon, E

    1978-01-01

    New classes of anionic uranyl ..beta..-ketoenolates of formula (UO/sub 2/L/sub 2/X)/sup -/ (where L = 1,3-diphenylpropane-1,3-dionate (dppd), 4,4,4-trifluoro-1-phenylbutane-1,3-dionate (tfpbd), or 1-phenylbutane-1,3-dionate (pbd); X = Cl/sup -/, Br/sup -/, I/sup -/, (NO/sub 3/)/sup -/, (O/sub 2/CMe)/sup -/, or (NCS)/sup -/) and (L/sub 2/O/sub 2/U(..mu..-X) UO/sub 2/L/sub 2/)/sup -/ (where X = F/sup -/, and also Cl/sup -/ only in the case of L = dppd) have been synthesized and characterized by a number of physical measurements. The different ability of the various anionic ligands to enter into the co-ordination sphere of the uranyl ion, their potentially different bonding modes, and the possible correlations between physical parameters and the nature of either the chelate substituents or the anionic ligand are discussed.

  4. Quantum Chemical Investigation on the Antioxidant Activity of Neutral and Anionic Forms of Juglone: Metal Chelation and Its Effect on Radical Scavenging Activity

    Directory of Open Access Journals (Sweden)

    Aymard Didier Fouegue Tamafo

    2017-01-01

    Full Text Available The chelation ability of divalent Mg, Ca, Fe, Co, Ni, Cu, Zn, and monovalent Cu ions by neutral and anionic forms of juglone has been investigated at DFT/B3LYP/6-31+G(d,p level of theory in gas and aqueous phases. It is noteworthy that only the 1 : 1 stoichiometry was considered herein. The effects of these metals on the radical scavenging activity of neutral juglone were evaluated via the usual descriptors of hydrogen atom transfer. According to our results, metal chelation by the two forms of juglone was spontaneous and exothermic in both media. Based on the binding energies, Cu(II ion showed the highest affinity for the ligands. QTAIM analyses identified the metal-ligand bonds as intermediate type interactions in all the chelates, except those of Ca and Mg. It was also found that the chelates were better radical scavengers than the ligands. In the gas phase, the scavenging activity of the compounds was found to be governed by direct hydrogen atom transfer, the Co(II chelate being the most reactive. In the aqueous phase also, the sequential proton loss electron transfer was preferred by all the molecules, while the Cu(II chelates were the most reactive.

  5. Titanium Insertion into CO Bonds in Anionic Ti-CO2 Complexes.

    Science.gov (United States)

    Dodson, Leah G; Thompson, Michael C; Weber, J Mathias

    2018-03-22

    We explore the structures of [Ti(CO 2 ) y ] - cluster anions using infrared photodissociation spectroscopy and quantum chemistry calculations. The existence of spectral signatures of metal carbonyl CO stretching modes shows that insertion of titanium atoms into C-O bonds represents an important reaction during the formation of these clusters. In addition to carbonyl groups, the infrared spectra show that the titanium center is coordinated to oxalato, carbonato, and oxo ligands, which form along with the metal carbonyls. The presence of a metal oxalato ligand promotes C-O bond insertion in these systems. These results highlight the affinity of titanium for C-O bond insertion processes.

  6. Determination of Mg(2+) Speciation in a TFSI(-)-Based Ionic Liquid With and Without Chelating Ethers Using Raman Spectroscopy.

    Science.gov (United States)

    Watkins, Tylan; Buttry, Daniel A

    2015-06-11

    Raman spectroscopy was employed to assess the complex environment of magnesium salts in the n-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyrTFSI) room-temperature ionic liquid (RTIL). At room temperature, Mg(TFSI)2 was miscible with BMPyrTFSI and formulated by [Mg(TFSI)2](x)[BMPyrTFSI](1-x) (x ≤ 0.55). Results suggest that at low concentrations of Mg(TFSI)2, anionic complexes in which Mg(2+) is surrounded by at least four TFSI(-) were formed. Above x = 0.2 an average of three TFSI(-) surround each Mg(2+). Below x = 0.12, there is a greater number of monodentate interactions between TFSI(-) oxygens and Mg(2+) cations, whereas above x = 0.12 bidentate ligands dominate. The fraction of TFSI(-) existing in the cis conformation increased with increasing Mg(2+) concentration. Mg(ClO4)2 was also studied as a Mg(2+) source. At equivalent mole fractions to those of the Mg(TFSI)2 salt, Mg(2+) from Mg(ClO4)2 was surrounded by only two TFSI(-) anions as ClO4(-) appeared to compete with TFSI(-) for coordination with Mg(2+). Similar behavior was also observed for the less soluble halide salts MgX2 (X = Cl, Br, I). Additions of chelating ligands were shown to effectively reduce the average number of TFSI(-) around Mg(2+) in a manner consistent with maintaining a sixfold oxygen coordination number around Mg(2+). Furthermore, an alternative class of ionic liquids, known as "solvate" ionic liquids, were produced. In this case glymes (Gm, m + 1 ether oxygens) were mixed with Mg(TFSI)2 so that glymes chelated Mg(2+), creating Mg(Gm)(y)(2+) complexes. The general formula was given by Mg(Gm)(y)(TFSI)2. These solvate ILs melt between 40 and 80 °C. Raman spectra clearly showed the glyme chelating ability and stronger coordination with Mg(2+) with respect to TFSI(-). Finally, linear sweep voltammograms showed the anodic stability of the glymes to improve due to coordination with Mg(2+).

  7. Binding of anions in triply interlocked coordination catenanes and dynamic allostery for dehalogenation reactions.

    Science.gov (United States)

    Yang, Linlin; Jing, Xu; An, Bowen; He, Cheng; Yang, Yang; Duan, Chunying

    2018-01-28

    By synergistic combination of multicomponent self-assembly and template-directed approaches, triply interlocked metal organic catenanes that consist of two isolated chirally identical tetrahedrons were constructed and stabilized as thermodynamic minima. In the presence of suitable template anions, the structural conversion from the isolated tetrahedral conformers into locked catenanes occurred via the cleavage of an intrinsically reversible coordination bond in each of the tetrahedrons, followed by the reengineering and interlocking of two fragments with the regeneration of the broken coordination bonds. The presence of several kinds of individual pocket that were attributed to the triply interlocked patterns enabled the possibility of encapsulating different anions, allowing the dynamic allostery between the unlocked/locked conformers to promote the dehalogenation reaction of 3-bromo-cyclohexene efficiently, as with the use of dehalogenase enzymes. The interlocked structures could be unlocked into two individual tetrahedrons through removal of the well-matched anion templates. The stability and reversibility of the locked/unlocked structures were further confirmed by the catching/releasing process that accompanied emission switching, providing opportunities for the system to be a dynamic molecular logic system.

  8. Crystal structure of a mixed-ligand terbium(III coordination polymer containing oxalate and formate ligands, having a three-dimensional fcu topology

    Directory of Open Access Journals (Sweden)

    Chainok Kittipong

    2016-01-01

    Full Text Available The title compound, poly[(μ3-formato(μ4-oxalatoterbium(III], [Tb(CHO2(C2O4]n, is a three-dimensional coordination polymer, and is isotypic with the LaIII, CeIII and SmIII analogues. The asymmetric unit contains one TbIII ion, one formate anion (CHO2− and half of an oxalate anion (C2O42−, the latter being completed by application of inversion symmetry. The TbIII ion is nine-coordinated in a distorted tricapped trigonal–prismatic manner by two chelating carboxylate groups from two C2O42− ligands, two carboxylate oxygen atoms from another two C2O42− ligands and three oxygen atoms from three CHO2− ligands, with the Tb—O bond lengths and the O—Tb—O bond angles ranging from 2.4165 (19 to 2.478 (3 Å and 64.53 (6 to 144.49 (4°, respectively. The CHO2− and C2O42− anions adopt μ3-bridging and μ4-chelating-bridging coordination modes, respectively, linking adjacent TbIII ions into a three-dimensional 12-connected fcu topology with point symbol (324.436.56. The title compound exhibits thermal stability up to 623 K, and also displays strong green photoluminescence in the solid state at room temperature.

  9. Fluoride ion recognition by chelating and cationic boranes.

    Science.gov (United States)

    Hudnall, Todd W; Chiu, Ching-Wen; Gabbaï, François P

    2009-02-17

    Because of the ubiquity of fluoride ions and their potential toxicity at high doses, researchers would like to design receptors that selectively detect this anion. Fluoride is found in drinking water, toothpaste, and osteoporosis drugs. In addition, fluoride ions also can be detected as an indicator of uranium enrichment (via hydrolysis of UF(6)) or of the chemical warfare agent sarin, which releases the ion upon hydrolysis. However, because of its high hydration enthalpy, the fluoride anion is one of the most challenging targets for anion recognition. Among the various recognition strategies that are available, researchers have focused a great deal of attention on Lewis acidic boron compounds. These molecules typically interact with fluoride anions to form the corresponding fluoroborate species. In the case of simple triarylboranes, the fluoroborates are formed in organic solvents but not in water. To overcome this limitation, this Account examines various methods we have pursued to increase the fluoride-binding properties of boron-based receptors. We first considered the use of bifunctional boranes, which chelate the fluoride anion, such as 1,8-diborylnaphthalenes or heteronuclear 1-boryl-8-mercurio-naphthalenes. In these molecules, the neighboring Lewis acidic atoms can cooperatively interact with the anionic guest. Although the fluoride binding constants of the bifunctional compounds exceed those of neutral monofunctional boranes by several orders of magnitude, the incompatibility of these systems with aqueous media limits their utility. More recently, we have examined simple triarylboranes whose ligands are decorated by cationic ammonium or phosphonium groups. These cationic groups increase the electrophilic character of these boranes, and unlike their neutral analogs, they are able to complex fluoride in aqueous media. We have also considered cationic boranes, which form chelate complexes with fluoride anions. Our work demonstrates that Coulombic and chelate

  10. Mixed ligand chelates of rare earths in aqueous solution

    International Nuclear Information System (INIS)

    Lakhani, S.U.; Thakur, G.S.; Sangal, S.P.

    1981-01-01

    Mixed ligand chelates of the 1:1 trivalent lanthanoids-EDTA, HEDTA and NTA chelates-1, 2-Dihydroxybenzene (Pyrocatechol) have been investigated at 35degC and 0.2 M ionic strength maintained by NaC10 4 . The formation of mixed ligand chelates has been found in all cases. The formation of mixed ligand chelates with EDTA shows the coordination number of lanthanoids to be eight, while the mixed ligand chelates with HEDTA and NTA shows the coordination number to be seven and six respectively. The stability constants of mixed ligand chelates are smaller than the binary complexes. The order of stability constants with respect to primary ligands follows the order NTA>HEDTA>EDTA. With respect to metal ions the stability constants increases with the decrease in ionic radii such as Gd< Er< Yb. (author)

  11. Bioinspired catalytic generation of high-valent cobalt-oxo species by the axially coordinated CoPc on pyridine-functionalized MWCNTs for the elimination of organic contaminants

    Science.gov (United States)

    Li, Nan; Wang, Ying; Wu, Chenren; Lu, Wangyang; Pei, Kemei; Chen, Wenxing

    2018-03-01

    Enzymes have always been a source of inspiration for the design and improvement of catalysts. Many examples are occurring in heme/non-heme metalloenzymes with the generation of active high-valent metal-oxo intermediates that are controlled by the surrounding amino acids/protein and axial residue ligands, facilitating the efficient oxidation of substrates in biochemical processes. Here, the high-valent cobalt-oxo species have been formed during the heterolysis of H2O2 activated by the bioinspired catalyst, axially coordinated cobalt phthalocyanine (CoPc) on pyridine-functionalized multi-walled carbon nanotubes (MWCNTs-Py), characterized by ultraviolet-visible and X-ray photoelectron spectroscopy. Formation process of the active cobalt-oxo species has been further confirmed by electrospray ionization mass spectrometry analysis and the results from the density functional theory (B3LYP/6-311G) calculations. Such high-valent cobalt-oxo species exhibit high reactivity and enough persistence for the oxidation of the target substrate, C.I. Acid Red 1. The oxidation products are nearly biodegradable small molecules identified by ultra-performance liquid chromatography/high-definition mass spectrometry. This strategy provides a foundation on developing efficient and persistent catalytic system, in particular oxidation processes based on the complex catalysts with N4 macrocycle structures.

  12. Understanding weakly coordinating anions: tetrakis(pentafluorophenyl)borate paired with inorganic and organic cations.

    Science.gov (United States)

    Andreeva, Nadezhda A; Chaban, Vitaly V

    2017-03-01

    Efficient design of ionic compounds requires a systematic understanding of cation-anion interactions. Weakening of electrostatic attraction is essential to increase the liquid range of the ionic compound and decrease its melting point. Here, we report simulations of the closest-approach cation-anion distances in a variety of ion pairs containing the tetrakis(pentafluorophenyl)borate (TFPB - ) anion. Small alkali cations (Li + , Na + ) penetrate the TFPB - core, whereas K + and larger organic cations do not. In the latter case, the shortest possible distance from the cations to the boron atom of TFPB - ranges from 0.50 nm to 0.63 nm. TFPB - was shown to be substantially rigid, providing a steric hindrance to thermodynamically efficient cation-anion coordination. Our results prove that TFPB - is more efficient for electrostatic charge confinement than the tetraoctylammonium cation, whereas the perfluorophenyl group is more efficient than linear alkyl chains. These simulations will motivate development of TFPB - -based ionic liquids with low phase transition points. Graphical Abstract Ionic configuration of the equilibrated "TFPB + K"system.

  13. Chelated Nitrogen-Sulphur-Codoped TiO2: Synthesis, Characterization, Mechanistic, and UV/Visible Photocatalytic Studies

    Directory of Open Access Journals (Sweden)

    Hayat Khan

    2017-01-01

    Full Text Available This study presents in detail the physicochemical, photoluminescent, and photocatalytic properties of carboxylic acid chelated nitrogen-sulphur-codoped TiO2. From the Fourier transform infrared spectroscopic study, it was revealed that the formate group formed bidentate bridging linkage while the acetate group coordinated in a bidentate chelating mode with a titanium precursor. In compliance with X-ray diffraction data, the anatase to rutile transformation temperature was extended due to carboxylic acid chelation and NS codoping. Raman analysis indicated four Raman peaks at 146, 392, 512, and 632 cm−1 for the precalcined chelated TiO2; on incorporation with NS dopants, an increase in Raman intensity for these peaks was recorded, indicating the structure stability of the anatase phase. Furthermore, X-ray photoelectron spectroscopic study revealed the presence of anionic doping of nitrogen and cationic doping of sulphur in the lattice of TiO2. When evaluating the UV-visible photodegradation rate of 4-chlorophenol, the modified TiO2 (NS0.06-TFA showed the highest photocatalytic activity. In connection with the activity tests, several scavenger agents were employed to elucidate the significance of the different reactive oxidizing species during the photocatalytic process. Moreover, the transfer pathways of photogenerated carriers and the photocatalytic reaction mechanism of modified TiO2 were also explained in detail.

  14. Gas-generated thermal oxidation of a coordination cluster for an anion-doped mesoporous metal oxide.

    Science.gov (United States)

    Hirai, Kenji; Isobe, Shigehito; Sada, Kazuki

    2015-12-18

    Central in material design of metal oxides is the increase of surface area and control of intrinsic electronic and optical properties, because of potential applications for energy storage, photocatalysis and photovoltaics. Here, we disclose a facile method, inspired by geochemical process, which gives rise to mesoporous anion-doped metal oxides. As a model system, we demonstrate that simple calcination of a multinuclear coordination cluster results in synchronic chemical reactions: thermal oxidation of Ti8O10(4-aminobenzoate)12 and generation of gases including amino-group fragments. The gas generation during the thermal oxidation of Ti8O10(4-aminobenzoate)12 creates mesoporosity in TiO2. Concurrently, nitrogen atoms contained in the gases are doped into TiO2, thus leading to the formation of mesoporous N-doped TiO2. The mesoporous N-doped TiO2 can be easily synthesized by calcination of the multinuclear coordination cluster, but shows better photocatalytic activity than the one prepared by a conventional sol-gel method. Owing to an intrinsic designability of coordination compounds, this facile synthetic will be applicable to a wide range of metal oxides and anion dopants.

  15. f-Element Ion Chelation in Highly Basic Media

    International Nuclear Information System (INIS)

    Paine, R.T.

    2000-01-01

    A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelators for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

  16. Syntheses, structures, and photoluminescence of lanthanide coordination polymers based on 4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Jing; Li, Lei; Peng, Jing-Wei; Qiao, Wei-Wei; Sun, Mei-Mei [College of Chemistry, Tianjin Normal University, Tianjin (China); Gu, Wen [College of Chemistry, Nankai University, Tianjin (China)

    2018-03-15

    Investigating the coordination chemistry of H{sub 2}CDA (4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid) with rare earth salts Ln(NO{sub 3}){sub 3} under hydrothermal conditions, structure transformation phenomenon was observed. The ligand, H{sub 2}CDA charged to its position isomer, enol type structure, H{sub 3}CAM (4-hydroxypyridine-2,6-dicarboxylic acid). Six new lanthanide(III) coordination polymers with the formulas [Ln(CAM)(H{sub 2}O){sub 3}]{sub n} [Ln = La (1), Pr, (2)] and {[Ln(CAM)(H_2O)_3].H_2O}{sub n} [Ln = Nd, (3), Sm, (4), Eu, (5), Y, (6)] were synthesized and characterized. The X-ray structure analyses show two kinds of coordination structures. The complexes 1 and 2 and 3-6 are isostructural. Complexes 1 and 2 crystallize in the monoclinic C{sub 2}/c space group, whereas 3-6 crystallize in the monoclinic system with space group P2{sub 1}/n. In the two kinds of structures, H{sub 3}CAM displays two different coordination modes. The Sm{sup III} and Eu{sup III} complexes exhibit the corresponding characteristic luminescence in the visible region at an excitation of 376 nm. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Dramatic Influence of an Anionic Donor on the Oxygen-Atom Transfer Reactivity of a MnV–Oxo Complex

    Science.gov (United States)

    Neu, Heather M; Quesne, Matthew G; Yang, Tzuhsiung; Prokop-Prigge, Katharine A; Lancaster, Kyle M; Donohoe, James; DeBeer, Serena; de Visser, Sam P; Goldberg, David P

    2014-01-01

    Addition of an anionic donor to an MnV(O) porphyrinoid complex causes a dramatic increase in 2-electron oxygen-atom-transfer (OAT) chemistry. The 6-coordinate [MnV(O)(TBP8Cz)(CN)]− was generated from addition of Bu4N+CN− to the 5-coordinate MnV(O) precursor. The cyanide-ligated complex was characterized for the first time by Mn K-edge X-ray absorption spectroscopy (XAS) and gives Mn–O=1.53 Å, Mn–CN=2.21 Å. In combination with computational studies these distances were shown to correlate with a singlet ground state. Reaction of the CN− complex with thioethers results in OAT to give the corresponding sulfoxide and a 2e−-reduced MnIII(CN)− complex. Kinetic measurements reveal a dramatic rate enhancement for OAT of approximately 24 000-fold versus the same reaction for the parent 5-coordinate complex. An Eyring analysis gives ΔH≠=14 kcal mol−1, ΔS≠=−10 cal mol−1 K−1. Computational studies fully support the structures, spin states, and relative reactivity of the 5- and 6-coordinate MnV(O) complexes. PMID:25256417

  18. Syntheses and structures of technetium(V) and rhenium(V) oxo complexes of peptide having KYC-sequence

    International Nuclear Information System (INIS)

    Takayama, T.; Suzuki, K.; Sekine, T.; Kudo, H.

    2000-01-01

    Technetium(V) and rhenium(V) oxo complexes of a peptide having a KYC-sequence such as KYCAR (H 3 L 5 ) and KYCAREPPTRTNAYQGQG-NH 2 (H 3 L 18 ) were synthesized, and structures of the complexes were characterized by spectroscopic techniques. All of the complexes were synthesized by the ligand exchange reaction of [(n-C 4 H 9 ) 4 N][MOCl 4 ] (M = 99 Tc, Re) with peptide in methanol or dimethylformamide solution. These complexes have a square pyramidal structure with an oxo ligand at the apical position. The peptide is coordinated to a metal atom through N amine of lysine. S thiol of cysteine, and N amide of tyrosine and cysteine in the equatorial plane. A lysine (CH 2 ) 4 NH 2 group of the L 5 ligand has the syn conformation with respect to metal-oxo bonding in the complex. The syn isomer was selectively formed in the ligand exchange reaction. The conversion of the syn isomer to the anti isomer was observed only for syn-[ReO(L 5 )], in which the coordination of water to the trans position of the oxo ligand was involved. (orig.)

  19. f-Element Ion Chelation in Highly Basic Media - Final Report

    International Nuclear Information System (INIS)

    Paine, R.T.

    2000-01-01

    A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelator s for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

  20. Anion capture and sensing with cationic boranes: on the synergy of Coulombic effects and onium ion-centred Lewis acidity.

    Science.gov (United States)

    Zhao, Haiyan; Leamer, Lauren A; Gabbaï, François P

    2013-06-21

    Stimulated by the growing importance and recognized toxicity of anions such as fluoride, cyanide and azides, we have, in the past few years, developed a family of Lewis acidic triarylboranes that can be used for the complexation of these anions in organic and protic solvents, including water. A central aspect of our approach lies in the decoration of the boranes with peripheral ammonium, phosphonium, sulfonium stibonium or telluronium groups. The presence of these cationic groups provides a Coulombic drive for the capture of the anion, leading to boranes that can be used in aqueous solutions where anion hydration and/or protonation are usually competitive. The anion affinity of these boranes can be markedly enhanced by narrowing the separation between the anion binding site (i.e. the boron atom) and the onium ion. In such systems, the latent Lewis acidity of the onium ion also plays a role as manifested by the formation of B-X→E (E = P, S, Sb, or Te; X = F, CN or N3) chelate motifs that provide additional stability to the resulting complexes. These effects, which are maximum in stibonium and telluronium boranes, show that the Lewis acidity of heavy onium ions can be exploited for anion coordination and capture. The significance of these advances is illustrated by the development of applications in anion sensing, fluorination chemistry and (18)F radiolabeling for positron emission tomography.

  1. Copper(I) coordination compounds with closododecaborate anion

    International Nuclear Information System (INIS)

    Malinina, E.A.; Drozdova, V.V.; Mustyatsa, V.N.; Goeva, L.V.; Polyakova, I.N.; Votinova, N.A.; Zhizhin, K.Yu.; Kuznetsov, N.T.

    2006-01-01

    Cu(I) Complexes with closo-dodecaborate anion Cat[CuB 12 H 12 ], where Cat= Cs + , Ph 4 P + , Ph 4 As + , R x NH 4-x + (R=Me, Et, Pr, Bu, X=3-4) are synthesized. Synthesis of complexes was conducted in the copper(II) salt-salt of dodecaborate anion-sulfur dioxide (sodium sulfite) system. Structure of the complex [Cu 2 (NCCH 3 ) 4 B 12 H 12 ] assigned by X-ray structural analysis discloses that B 12 H 12 2- anion enters into the inner sphere of metal-complexing agent, and connection of closo-borate ligand with the metal is caused by the formation of three-centric metal-hydrogen-boron bonds [ru

  2. Ultrasonically-enhanced preparation, characterization of CaFe-layered double hydroxides with various interlayer halide, azide and oxo anions (CO32-, NO3-, ClO4-).

    Science.gov (United States)

    Szabados, Márton; Varga, Gábor; Kónya, Zoltán; Kukovecz, Ákos; Carlson, Stefan; Sipos, Pál; Pálinkó, István

    2018-01-01

    An ultrasonically-enhanced mechanochemical method was developed to synthesize CaFe-layered double hydroxides (LDHs) with various interlayer anions (CO 3 2- , NO 3 - , ClO 4 - , N 3 - , F - , Cl - , Br - and I - ). The duration of pre-milling and ultrasonic irradiation and the variation of synthesis temperature in the wet chemical step were investigated to obtain the optimal parameters of preparation. The main method to characterize the products was X-ray diffractometry, but infrared and synchrotron-based X-ray absorption spectroscopies as well as thermogravimetric measurements were also used to learn about fine structural details. The synthesis method afforded successful intercalation of the anions, among others the azide anion, a rarely used counter ion providing a system, which enables safe handling the otherwise highly reactive anion. The X-ray absorption spectroscopic measurements revealed that the quality of the interlayered anions could modulate the spatial arrangement of the calcium ions around the iron(III) ions, but only in the second coordination sphere. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Two three-dimensional coordination polymers of lead(II) with iminodiacetate and naphthalene-dicarboxylate anions: Synthesis, characterization and luminescence behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hazari, Debdoot; Jana, Swapan Kumar [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721 102, West Bengal (India); Fleck, Michel [Institute of Mineralogy and Crystallography, University of Vienna, Geozentrum, Althanstr. 9, A-1090 Vienna (Austria); Zangrando, Ennio [Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste (Italy); Dalai, Sudipta, E-mail: sudipta@mail.vidyasagar.ac.in [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721 102, West Bengal (India)

    2014-11-15

    Two lead(II) compounds [Pb{sub 3}(idiac){sub 3}(phen){sub 2}(H{sub 2}O)]·2(H{sub 2}O) (1) and [Pb(ndc)]{sub n} (2), where H{sub 2}idiac=iminodiacetic acid, phen=1,10-phenanthroline and H{sub 2}ndc=naphthalene-2,6-dicarboxylic acid, have been synthesized and structurally characterized. Single crystal X-ray diffraction analysis showed that compound 1 is a discrete trinuclear complex (of two-fold symmetry) which evolves to a supramolecular 3D network via π–π interactions, while in compound 2 the naphthalene dicarboxylate anion act as a linker to form a three dimensional architecture, where the anion adopts a bis-(bidentate bridging) coordination mode connecting four Pb(II) centers. The photoluminescence property of the two complexes has been studied. - graphical abstract: Two new topologically different 1D coordination polymers formed by Pb{sub 4} clusters have been synthesized and characterized by x-ray analysis. The luminescence and thermal properties have been studied. - Highlights: • 1 is a trinuclear complex of Pb(II) growing to 3D network via weak interactions. • In 1, layers of (4,4) rhomboidal topology are identified. • In 2, the ndc anion adopts interesting bis-(bidentate bridging) coordination. • In 2, network is reinforced by C–H…π-ring interactions between the ndc rings.

  4. Syntheses and structures of technetium(V) and rhenium(V) oxo complexes of peptide having KYC-sequence

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, T.; Suzuki, K.; Sekine, T.; Kudo, H. [Dept. of Chemistry, Tohoku Univ., Sendai (Japan)

    2000-07-01

    Technetium(V) and rhenium(V) oxo complexes of a peptide having a KYC-sequence such as KYCAR (H{sub 3}L{sup 5}) and KYCAREPPTRTNAYQGQG-NH{sub 2} (H{sub 3}L{sup 18}) were synthesized, and structures of the complexes were characterized by spectroscopic techniques. All of the complexes were synthesized by the ligand exchange reaction of [(n-C{sub 4}H{sub 9}){sub 4}N][MOCl{sub 4}] (M = {sup 99}Tc, Re) with peptide in methanol or dimethylformamide solution. These complexes have a square pyramidal structure with an oxo ligand at the apical position. The peptide is coordinated to a metal atom through N{sub amine} of lysine. S{sub thiol} of cysteine, and N{sub amide} of tyrosine and cysteine in the equatorial plane. A lysine (CH{sub 2}){sub 4}NH{sub 2} group of the L{sup 5} ligand has the syn conformation with respect to metal-oxo bonding in the complex. The syn isomer was selectively formed in the ligand exchange reaction. The conversion of the syn isomer to the anti isomer was observed only for syn-[ReO(L{sup 5})], in which the coordination of water to the trans position of the oxo ligand was involved. (orig.)

  5. Peroxide coordination of tellurium in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mikhaylov, Alexey A.; Medvedev, Alexander G. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel); Churakov, Andrei V.; Grishanov, Dmitry A.; Prikhodchenko, Petr V. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Lev, Ovadia [The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel)

    2016-02-15

    Tellurium-peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH{sub 4}){sub 4}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2} (1) and (NH{sub 4}){sub 5}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH).1.28 H{sub 2}O.0.72 H{sub 2}O{sub 2} (2) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single-crystal and powder X-ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2}]{sup 4-}. The structure of 2 consists of an unsymmetrical [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH)]{sup 5-} anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te{sub 2}(μ-OO){sub 2}(μ-O) fragment with one μ-oxo- and two μ-peroxo bridging groups. {sup 125}Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3-40 %wt H{sub 2}O{sub 2} and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium-peroxide coordination in any aqueous system and the first report of inorganic tellurium-peroxo complexes. General features common to all reported p-block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Formation of nitridotechnetium(VI) μ-oxo dimer complexes with EDTA and EDDA

    International Nuclear Information System (INIS)

    Takayama, T.; Kani, Y.; Sekine, T.; Kudo, H.; Yoshihara, K.

    1995-01-01

    Reactions of [ 99 TcNCl 4 ] - with ethylenediaminetetraacetic acid 4 (ETDA) and ethylenediamine-N,N'-diacetic acid (EDDA) in a mixture of water and acetone gave Tc VI N-EDTA and Tc VI N-EDTA complexes. The infrared spectra of both reaction products showed the existence of the Tc≡N and C=O groups. The elemental analysis indicated the 1:1 TcN-ligand ratio in the EDTA and EDDA complexes. Electrophoresis showed that the Tc VI -EDTA complex was an anionic species in a perchlorate solution. For the Tc VI N-EDDA complex, neutral and anionic species were formed, depending on the pH of the solution. Formation of the μ-oxo dimer complexes was suggested from the UV-Vis absorption spectra. (author) 11 refs.; 4 figs.; 1 tab

  7. (2,4-Dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylato-κ2O4,O5(4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylato-κ2O4,O5bis(1,10-phenanthroline-κ2N,N′yttrium(III dihydrate

    Directory of Open Access Journals (Sweden)

    Zilu Chen

    2008-09-01

    Full Text Available In the title compound, [Y(C5H2N2O4(C5H3N2O4(C12H8N22]·2H2O, the YIII ion lies on a twofold rotation axis and exhibits a distorted square-antiprismatic coordination geometry. It is chelated by two 1,10-phenanthroline ligands, a 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate monoanion and a 4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylate dianion. The H atom involved in an N—H...N hydrogen bond between the 1,2-dihydropyrimidine units has half occupancy and is disordered around a twofold rotation axis.

  8. Tetraphenylborate as a non - coordinating anion in hexamethyphosphoramine (HMPA) and tetramethylurea (TMU) lanthanide complexes

    International Nuclear Information System (INIS)

    Kuya, M.K.; Serra, O.A.

    1979-01-01

    The synthesis of the HMPA and TMU complexes of rare earth ions using tetraphenylborate, a non-coordinating anion, as a precipitating agent is reported. The compounds obtained conform to the general formula LnL 6 (B PHI 4 ) 3 (Ln=Ce-Lu,Y, whe L=HMPA and Ln=nd, Sm,Eu,Er,Y when L=TMU). The characterization by conductance, infrared and visible measurements is consistent with the lack of donor capacity of tetraphenylborate ion, and with a coordination number six in a nearly octahedral site symmetry for both type of compounds. The TMU complexes seem to be more stable than the corresponding HMPA ones, indicating that the steric factor can be more important than the donor capacity of the ligands in this type of lanthanide compounds. (author) [pt

  9. Synthesis, characterization, and reactivity of a uranium(VI) carbene imido oxo complex

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Erli; Cooper, Oliver J.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [Nottingham Univ. (United Kingdom). School of Chemistry; Tuna, Floriana; McInnes, Eric J.L. [Manchester Univ. (United Kingdom). School of Chemistry and Photon Science Inst.

    2014-06-23

    We report the uranium(VI) carbene imido oxo complex [U(BIPM{sup TMS})(NMes)(O)(DMAP){sub 2}] (5, BIPM{sup TMS}=C(PPh{sub 2}NSiMe{sub 3}){sub 2}; Mes=2,4,6-Me{sub 3}C{sub 6}H{sub 2}; DMAP=4-(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two-electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T-shaped motif with respect to the carbene, which is consistent with an inverse trans-influence. Complex 5 reacts with tert-butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPM{sup TMS})(O){sub 2}(DMAP){sub 2}] (6).

  10. Electrochemically Generated cis-Carboxylato-Coordinated Iron(IV) Oxo Acid-Base Congeners as Promiscuous Oxidants of Water Pollutants

    DEFF Research Database (Denmark)

    de Sousa, David P; Miller, Christopher J; Chang, Yingyue

    2017-01-01

    The nonheme iron(IV) oxo complex [FeIV(O)(tpenaH)]2+ and its conjugate base [FeIV(O)(tpena)]+ [tpena- = N,N,N'-tris(2-pyridylmethyl)ethylenediamine-N'-acetate] have been prepared electrochemically in water by bulk electrolysis of solutions prepared from [FeIII2(μ-O)(tpenaH)2](ClO4)4 at potentials...... of the electrochemically generated iron(IV) oxo complexes, in terms of the broad range of substrates examined, represents an important step toward the goal of cost-effective electrocatalytic water purification....

  11. Structures of metal complexes with anions of di(hydroxymethyl)phosphinic and di(chloromethyl)phosphinic acids

    International Nuclear Information System (INIS)

    Sergienko, V.S.; Aleksandrov, G.G.

    2001-01-01

    The structural peculiarities of the different metals [Cu, Ni, rare earths (La, Nd, Er, Lu), Ag, Li, Na, Sr] with anions of di-substituted monophosphonic acids - di(hydroxymethyl) phosphonic acid (HOCH 2 ) 2 PO 2 - (L 1 ) and di(chloromethyl) phosphonic acid (ClCH 2 ) 2 PO 2 - (L 2 ), and the methods of coordinating ligands L 1 and L 2 with these metals were viewed. Coordination number of metal decreases from eight in the case of La, Nd to seven for Er, and further to six for Lu with decreasing size of rare earth element. M-O bond lengths decrease the same way. The LiL 2 · H 2 O structure was determined, Li atom shows tetrahedron coordination by three oxygen atoms of the three ligands L 2 and atom O(ω) of water molecule. The ligand L 1 are acting as a tetradentate chelate μ 3 -bridge function in the structure of the Sr(L 1 ) 2 compound. The interval of Sr-O distances comprises 2.521 - 2.683 A [ru

  12. Anion binding in biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Feiters, Martin C [Department of Organic Chemistry, Institute for Molecules and Materials, Faculty of Science, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Meyer-Klaucke, Wolfram [EMBL Hamburg Outstation at DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Kostenko, Alexander V; Soldatov, Alexander V [Faculty of Physics, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 (Russian Federation); Leblanc, Catherine; Michel, Gurvan; Potin, Philippe [Centre National de la Recherche Scientifique and Universite Pierre et Marie Curie Paris-VI, Station Biologique de Roscoff, Place Georges Teissier, BP 74, F-29682 Roscoff cedex, Bretagne (France); Kuepper, Frithjof C [Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland (United Kingdom); Hollenstein, Kaspar; Locher, Kaspar P [Institute of Molecular Biology and Biophysics, ETH Zuerich, Schafmattstrasse 20, Zuerich, 8093 (Switzerland); Bevers, Loes E; Hagedoorn, Peter-Leon; Hagen, Wilfred R, E-mail: m.feiters@science.ru.n [Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft (Netherlands)

    2009-11-15

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L{sub 3} (2p{sub 3/2}) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  13. Anion binding in biological systems

    International Nuclear Information System (INIS)

    Feiters, Martin C; Meyer-Klaucke, Wolfram; Kostenko, Alexander V; Soldatov, Alexander V; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Kuepper, Frithjof C; Hollenstein, Kaspar; Locher, Kaspar P; Bevers, Loes E; Hagedoorn, Peter-Leon; Hagen, Wilfred R

    2009-01-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L 3 (2p 3/2 ) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  14. Anion binding in biological systems

    Science.gov (United States)

    Feiters, Martin C.; Meyer-Klaucke, Wolfram; Kostenko, Alexander V.; Soldatov, Alexander V.; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Küpper, Frithjof C.; Hollenstein, Kaspar; Locher, Kaspar P.; Bevers, Loes E.; Hagedoorn, Peter-Leon; Hagen, Wilfred R.

    2009-11-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L3 (2p3/2) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  15. Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

    Directory of Open Access Journals (Sweden)

    Margaret E. Sears

    2013-01-01

    Full Text Available Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease.

  16. Synthesis, characterization, and reactivity of a uranium(VI) carbene imido oxo complex

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Erli; Cooper, Oliver J.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [School of Chemistry, University of Nottingham (United Kingdom); Tuna, Floriana; McInnes, Eric J.L. [School of Chemistry and Photon Science Institute, University of Manchester (United Kingdom)

    2014-06-23

    We report the uranium(VI) carbene imido oxo complex [U(BIPM{sup TMS})(NMes)(O)(DMAP){sub 2}] (5, BIPM{sup TMS}=C(PPh{sub 2}NSiMe{sub 3}){sub 2}; Mes=2,4,6-Me{sub 3}C{sub 6}H{sub 2}; DMAP=4-(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two-electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T-shaped motif with respect to the carbene, which is consistent with an inverse trans-influence. Complex 5 reacts with tert-butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPM{sup TMS})(O){sub 2}(DMAP){sub 2}] (6). (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Comparison of bifunctional chelates for {sup 64}Cu antibody imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Cara L.; Crisp, Sarah; Bensimon, Corinne [MDS Nordion, Vancouver, BC (Canada); Yapp, Donald T.T.; Ng, Sylvia S.W. [British Columbia Cancer Agency Research Centre, Vancouver, BC (Canada); University of British Columba, The Faculty of Pharmaceutical Sciences, Vancouver, BC (Canada); Sutherland, Brent W. [British Columbia Cancer Agency Research Centre, Vancouver, BC (Canada); Gleave, Martin [Prostate Centre at Vancouver General Hospital, Vancouver, BC (Canada); Jurek, Paul; Kiefer, Garry E. [Macrocyclics Inc., Dallas, TX (United States)

    2010-11-15

    Improved bifunctional chelates (BFCs) are needed to facilitate efficient {sup 64}Cu radiolabeling of monoclonal antibodies (mAbs) under mild conditions and to yield stable, target-specific agents. The utility of two novel BFCs, 1-Oxa-4,7,10-triazacyclododecane-5-S-(4-isothiocyanatobenzyl)-4,7,10-triacetic acid (p-SCN-Bn-Oxo-DO3A) and 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-4-S-(4-isothiocyanatobenzyl)-3,6,9-triacetic acid (p-SCN-Bn-PCTA), for mAb imaging with {sup 64}Cu were compared to the commonly used S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-tetraacetic acid (p-SCN-Bn-DOTA). The BFCs were conjugated to trastuzumab, which targets the HER2/neu receptor. {sup 64}Cu radiolabeling of the conjugates was optimized. Receptor binding was analyzed using flow cytometry and radioassays. Finally, PET imaging and biodistribution studies were done in mice bearing either HER2/neu-positive or HER2/neu-negative tumors. {sup 64}Cu-Oxo-DO3A- and PCTA-trastuzumab were prepared at room temperature in >95% radiochemical yield (RCY) in <30 min, compared to only 88% RCY after 2 h for the preparation of {sup 64}Cu-DOTA-trastuzumab under the same conditions. Cell studies confirmed that the immunoreactivity of the mAb was retained for each of the bioconjugates. In vivo studies showed that {sup 64}Cu-Oxo-DO3A- and PCTA-trastuzumab had higher uptake than the {sup 64}Cu-DOTA-trastuzumab at 24 h in HER2/neu-positive tumors, resulting in higher tumor to background ratios and better tumor images. By 40 h all three of the {sup 64}Cu-BFC-trastuzumab conjugates allowed for clear visualization of the HER2/neu-positive tumors but not the negative control tumor. The antibody conjugates of PCTA and Oxo-DO3A were shown to have superior {sup 64}Cu radiolabeling efficiency and stability compared to the analogous DOTA conjugate. In addition, {sup 64}Cu-PCTA and Oxo-DO3A antibody conjugates may facilitate earlier imaging with greater target to background ratios than

  18. Isotopic measurement of uranium using NP-type chelate resin beads

    International Nuclear Information System (INIS)

    Wu Lanbi; Chen Wenpo; Wang Shijun

    1994-08-01

    NP-type chelate resin beads is used as a carrier of samples in the isotopic measurements of uranium by mass spectrometry. The results show that its absorption efficiency for uranium can be greater than 50%. It is one order magnitude higher than that strong basic anion resin, however, the ionization efficiencies of both are almost the same. Therefore, the amount of uranium required for isotopic analysis can be reduced one order of magnitude. This method has been used for isotopic analysis of uranium in NP-type chelate resin beads contained 10 -9 ∼ 10 -7 g uranium. For standard sample UTB-500, the external precision of measurements are within +-0.2%, for natural uranium samples are within +- 0.5%. The application of NP-type chelate resin beads in the isotopic measurement of uranium is a new creative achievement. It has been used in the depletion test of uranium-atomic vapor laser isotope separation

  19. (Acetonitrile[bis(2-pyridylmethylamine]bis(perchloratocopper(II

    Directory of Open Access Journals (Sweden)

    Ray J. Butcher

    2008-01-01

    Full Text Available In the title compound, [Cu(ClO42(C12H13N3(C2H3N], the CuII atom is six-coordinate in a Jahn–Teller distorted octahedral geometry, with coordination by the tridentate chelating ligand, an acetonitrile molecule, and two axial perchlorate anions. The tridentate ligand bis(2-pyridylmethylamine chelates meridionally and equatorially while an acetonitrile molecule is coordinated at the fourth equatorial site. The two perchlorate anions are disordered with site occupancy factors of 0.72/0.28. The amine H is involved in intramolecular hydrogen bonding to the perchlorate O atoms and there are extensive but weak intermolecular C—H...O interactions.

  20. f-Element Ion Chelation in Highly Basic Media

    International Nuclear Information System (INIS)

    Paine, Robert T.

    1999-01-01

    High-level radioactive waste (HLW) generated in the DOE complex is stored in tanks at several sites, but predominantly it is found at the Hanford reservation. Much of the material has been exposed to high pHs, consequently the waste exists in a complex, poorly understood mixture of solids, gels and solutions. The final waste remediation plan may involve chemical separation of fractions and a suitable, well developed molecular chemistry basis for performing these separations is not available. Indeed, the fundamental chemical behavior of most radioactive nuclides in basic media is not known. The goal of this project is to undertake fundamental studies of the coordination chemistry of f-element species in basic aqueous solutions containing common waste treatment ions (e.g., NO3 -, CO3 2-, organic carboxylates, and EDTA), as well as new waste scrubbing chelators produced in this study. The experimental agenda includes: 1. Studies of the speciation of Sr and Ln ions in basic solutions wit h and without common counterions; 2. Preparations of new multifunctional ligands that may act as strong, ion-specific chelators for Sr and/or Ln ions in basic media; and 3. Studies of the coordination and dissolution behavior of oxide-hydroxide species, as well as in insoluble sols, gels, and precipitates in combination with new chelating ligands. It is anticipated that this coordination chemistry will facilitate the design of advanced separation schemes required for handling the complex waste matrices found at the Hanford HLW facility

  1. Coordination of two high-affinity hexamer peptides to copper(II) and palladium(II) models of the peptide-metal chelation site on IMAC resins.

    Science.gov (United States)

    Chen, Y; Pasquinelli, R; Ataai, M; Koepsel, R R; Kortes, R A; Shepherd, R E

    2000-03-20

    The coordination of peptides Ser-Pro-His-His-Gly-Gly (SPHHGG) and (His)6 (HHHHHH) to [PdII(mida)(D2O)] (mida2- = N-methyliminodiacetate) was studied by 1H NMR as model reactions for CuII(iminodiacetate)-immobilized metal affinity chromatography (IMAC) sites. This is the first direct physical description of peptide coordination for IMAC. A three-site coordination is observed which involves the first, third, and fourth residues along the peptide chain. The presence of proline in position 2 of SPHHGG achieves the best molecular mechanics and bonding angles in the coordinated peptide and enhances the interaction of the serine amino nitrogen. Histidine coordination of H1, H3, and H4 of (His)6 and H3 and H4 of SPHHGG was detected by 1H NMR contact shifts and H/D exchange of histidyl protons. The EPR spectra of SPHHGG and HHHHHH attached to the [CuII(mida)] unit were obtained for additional modeling of IMAC sites. EPR parameters of the parent [Cu(mida)(H2O)2] complex are representative: gzz = 2.31; gyy = 2.086; gxx = 2.053; A parallel = 161G; AN = 19G (three line, one N coupling). Increased rhombic distortion is detected relative to the starting aqua complex in the order of [Cu(mida)L] for distortion of HHHHHH > SPHHGG > (H2O)2. The lowering of symmetry is also seen in the decrease in the N-shf coupling, presumably to the imino nitrogen of mida2- in the order 19 G (H2O), 16 G (SPHHGG) and 11 G (HHHHHH). Visible spectra of the [Cu(mida)(SPHHGG)] and [Cu(mida)(HHHHHH)] as a function of pH indicate coordination of one histidyl donor at ca. 4.5, two in the range of pH 5-7, and two chelate ring attachments involving the terminal amino donor for SPHHGG or another histidyl donor of HHHHHH in the pH domain of 7-8 in agreement with the [PdII(mida)L] derivatives which form the two-chelate-ring attachment even at lower pH as shown by the 1H NMR methods.

  2. Solid-state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

    Science.gov (United States)

    Tarasov, Konstantin A; O'Hare, Dermot; Isupov, Vitaly P

    2003-03-24

    The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies. If metal chloride or nitrate salts are used in the reaction with the LDH then co-intercalation of either the Cl(-) or NO(3)(-) anions is observed. In the case of metal acetate salts the cations intercalate without the accompanying anion. This can be explained by the different intercalation selectivity of the anions in relation to the LDH. In the latter case the introduction of the positive charge into LDH structure was compensated for by the release from the solid of the equivalent quantity of lithium and hydrogen cations. Time-resolved in-situ X-ray diffraction measurements have revealed that the chelation/intercalation reactions proceed very quickly. The rate of the reaction found for nickel acetate depends on concentration as approximately k[Ni(Ac)(2)](3).

  3. Four Novel Zn (II Coordination Polymers Based on 4′-Ferrocenyl-3,2′:6′,3′′-Terpyridine: Engineering a Switch from 1D Helical Polymer Chain to 2D Network by Coordination Anion Modulation

    Directory of Open Access Journals (Sweden)

    Lufei Xiao

    2017-11-01

    Full Text Available Four novel ZnII coordination polymers, [(ZnCl22(L2]n (1, [(ZnBr22(L2]n (2, and [(ZnI22(L2]n (3 and {[Zn(SCN2]1.5(L3}n (4, have been synthesized based on 4′-ferrocenyl-3,2′:6′,3′′-terpyridine with ZnII ions and different coordination anions under similar ambient conditions. Their structures have been confirmed using single crystal X-ray diffraction analysis, showing that complexes 1–3 are one-dimensional (1D double-stranded metal ion helical polymer chains and complex 4 is of a two-dimensional (2D network. The structural transformations of them from a 1D polymer chain to a 2D network under the influence of the coordination anions has been systematic investigated. Furthermore, the optical band gaps have been measured by optical diffuse reflectance spectroscopy, revealing that the ligand and the complexes should have semiconductor properties.

  4. Two Ti13-oxo-clusters showing non-compact structures, film electrode preparation and photocurrent properties.

    Science.gov (United States)

    Hou, Jin-Le; Luo, Wen; Wu, Yin-Yin; Su, Hu-Chao; Zhang, Guang-Lin; Zhu, Qin-Yu; Dai, Jie

    2015-12-14

    Two benzene dicarboxylate (BDC) and salicylate (SAL) substituted titanium-oxo-clusters, Ti13O10(o-BDC)4(SAL)4(O(i)Pr)16 (1) and Ti13O10(o-BDC)4(SAL-Cl)4(O(i)Pr)16 (2), are prepared by one step in situ solvothermal synthesis. Single crystal analysis shows that the two Ti13 clusters take a paddle arrangement with an S4 symmetry. The non-compact (non-sphere) structure is stabilized by the coordination of BDC and SAL. Film photoelectrodes are prepared by the wet coating process using the solution of the clusters and the photocurrent response properties of the electrodes are studied. It is found that the photocurrent density and photoresponsiveness of the electrodes are related to the number of coating layers and the annealing temperature. Using ligand coordinated titanium-oxo-clusters as the molecular precursors of TiO2 anatase films is found to be effective due to their high solubility, appropriate stability in solution and hence the easy controllability.

  5. Ligand Influences on Properties of Uranium Coordination Complexes - Structure, Reactivity, and Spectroscopy

    OpenAIRE

    Kosog, Boris

    2012-01-01

    In this thesis several different aspects of uranium chemistry are presented. It was shown that terminal uranium(V) oxo and imido complexes [((RArO)3tacn)UV(O)] and [((RArO)3tacn)UV(NSiMe3)] (R = t Bu, Ad) can be oxidized by silver(I) hexafluoro-antimonate to the uranium(VI) oxo and imido complexes [((RArO)3tacn)UVI(O)]SbF6 and [((RArO)3tacn)UVI(NSiMe3)]SbF6. While for the t Bu-derivative of the oxo complex an equatorial coordination is observed due to stabilization by the inverse trans-influe...

  6. The intra-annular acylamide chelate-coordinated compound: The keto-tautomer of metal (II) milrinone complex

    Science.gov (United States)

    Gong, Yun; Liu, Jinzhi; Tang, Wang; Hu, Changwen

    2008-03-01

    In the presence of N, N'-dimethyllformamide (DMF), two isostructural metal (II)-milrinone complexes formulated as M(C 12H 8N 3O) 2 (M = Co 1 and Ni 2) have been synthesized and characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. The two compounds crystallize in the tetragonal system, chiral space group P4 32 12. They exhibit similar two dimensional (2D) square grid-like framework, in which milrinone acts as a ditopic ligand with its terminal pyridine and intra-annular acylamide groups covalently bridging different metal centers. The intra-annular acylamide ligand shows a chelate-coordinated mode. Compounds 1 and 2 are stable under 200 °C. Compound 3 formulated as (C 12H 9N 3O) 4·H 2O was obtained in the presence of water, the water molecule in the structure leads to the racemization of compound 3 and it crystallizes in the monoclinic system, non-chiral space group P2 1/ c. Milrinone exhibits a keto-form in the three compounds and compounds 1- 3 exhibit different photoluminescence properties.

  7. A New Approach to Non-Coordinating Anions: Lewis Acid Enhancement of Porphyrin Metal Centers in a Zwitterionic Metal$-$Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jacob A. [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Chemistry; Petersen, Brenna M. [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Chemistry; Kormos, Attila [Hungarian Academy of Sciences, Budapest (Hungary); Echeverría, Elena [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Physics and Astronomy; Chen, Yu-Sheng [Univ. of Chicago, Argonne, IL (United States). ChemMatCARS, Center for Advanced Radiation Sources; Zhang, Jian [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Chemistry

    2017-02-28

    Here, we describe a new strategy to generate non-coordinating anions using zwitterionic metal–organic frameworks (MOFs). By assembly of anionic inorganic secondary building blocks (SBUs) ([In(CO2)4]$-$) with cationic metalloporphyrin-based organic linkers, we prepared zwitterionic MOFs in which the complete internal charge separation effectively prevents the potential binding of the counteranion to the cationic metal center. We demonstrate the enhanced Lewis acidity of MnIII- and FeIII-porphyrins in the zwitterionic MOFs in three representative electrocyclization reactions: [2 + 1] cycloisomerization of enynes, [3 + 2] cycloaddition of aziridines and alkenes, and [4 + 2] hetero-Diels–Alder cycloaddition of aldehydes with dienes. Lastly, this work paves a new way to design functional MOFs for tunable chemical catalysis.

  8. Solid state structure of thorium(IV) complexes with common aminopoly-carboxylate ligands

    International Nuclear Information System (INIS)

    Thuery, Pierre

    2011-01-01

    The crystal structures of the complexes formed by reaction of thorium(IV) nitrate with iminodiacetic acid (H 2 IDA), nitrilotriacetic acid (H 3 NTA), and ethylenediaminetetraacetic acid (H 4 EDTA) under hydrothermal conditions are reported. In [Th(HIDA) 2 (C 2 O 4 )].H 2 O (1), the metal atom is chelated by two carboxylate groups from two HIDA - anions and by two oxalate ligands formed in situ; two additional oxygen atoms from two more HIDA - anions complete the ten-coordinate environment of bi-capped square anti-prismatic geometry. The uncoordinated nitrogen atom is protonated and involved in hydrogen bonding. Two different ligands are present in [Th(NTA)(H 2 NTA)(H 2 O)].H 2 O (2), one of them being a O 3 ,N-chelating tri-anion which acts also as a bridge toward two neighboring metal ions, and the other being a bis-monodentate bridging species with an uncoordinated carboxylic arm and a central ammonium group. An aqua ligand completes the nine-coordinated, capped square anti-prismatic metal environment. The EDTA 4- anion in [Th(EDTA)(H 2 O)].2H 2 O (3) is chelating through one oxygen atom from each carboxylate group and the two nitrogen atoms, as in a previously reported molecular complex. Two carboxylate groups are bridging, which, with the addition of an aqua ligand, gives a capped square anti-prismatic coordination polyhedron. Aminopoly-carboxylate ligands have been much investigated in relation with actinide decorporation and nuclear wastes management studies, and the present results add to the structural information available on their complexes with thorium(IV), which has mainly been obtained up to now by extended X-ray absorption fine structure (EXAFS) spectroscopy. In particular, the bridging (non-chelating) coordination mode of H 2 NTA - is a novel feature in this context. All three complexes crystallize as two-dimensional assemblies and are thus novel examples of thorium-organic coordination polymers. (author)

  9. Nomenclature on an inorganic compound

    International Nuclear Information System (INIS)

    1998-10-01

    This book contains eleven chapters : which mention nomenclature of an inorganic compound with introduction and general principle on nomenclature of compound. It gives the description of grammar for nomenclature such as brackets, diagonal line, asterisk, and affix, element, atom and groups of atom, chemical formula, naming by stoichiometry, solid, neutral molecule compound, ion, a substituent, radical and name of salt, oxo acid and anion on introduction and definition of oxo acid, coordination compound like symbol of stereochemistry , boron and hydrogen compound and related compound.

  10. Characterization of sup(99m)Tc/sup(99)Tc-hydroxycarboxylic acid chelates by high voltage electrophoresis without supporting material

    International Nuclear Information System (INIS)

    Hoffmann, I.; Muenze, R.; Dreyer, I.; Dreyer, R.

    1982-01-01

    Ion mobilities of different sup(99m)Tc- and 99 Tc chelates prepared by reduction of pertechnetate by Sn(II) in the presence of citric, malic, tartaric, gluconic, and α-hydroxyisobutyric acid as ligands have been measured by means of electrophoresis without supporting material. All the chelates investigated proved to be anions in the pH range of 2-7. Both the Tc(V)- and Tc(IV) compounds with the same ligand including the sup(99m)Tc preparation show identical ion mobilities and dissociation characteristics. (author)

  11. Extreme ultraviolet patterning of tin-oxo cages

    Science.gov (United States)

    Haitjema, Jarich; Zhang, Yu; Vockenhuber, Michaela; Kazazis, Dimitrios; Ekinci, Yasin; Brouwer, Albert M.

    2017-07-01

    We report on the extreme ultraviolet (EUV) patterning performance of tin-oxo cages. These cage molecules were already known to function as a negative tone photoresist for EUV radiation, but in this work, we significantly optimized their performance. Our results show that sensitivity and resolution are only meaningful photoresist parameters if the process conditions are optimized. We focus on contrast curves of the materials using large area EUV exposures and patterning of the cages using EUV interference lithography. It is shown that baking steps, such as postexposure baking, can significantly affect both the sensitivity and contrast in the open-frame experiments as well as the patterning experiments. A layer thickness increase reduced the necessary dose to induce a solubility change but decreased the patterning quality. The patterning experiments were affected by minor changes in processing conditions such as an increased rinsing time. In addition, we show that the anions of the cage can influence the sensitivity and quality of the patterning, probably through their effect on physical properties of the materials.

  12. Polymeric metal chelates with piperazine(bis)dithiocarbamate

    International Nuclear Information System (INIS)

    Larionov, S.V.; Kosareva, L.A.; Ikorskij, V.N.; Uskov, E.M.

    1982-01-01

    Roentgenoamorphous polymer chelates of Fe 3 , Co 2 , Ni 2 , Cu 2 , Zn 2 , Cd 2 , Pb 2 with tetradentate bridge ligand piperazine-(bis) dithiocarbamate have been synthesized. IR spectra in the region 200-400 cm - 1 point to coordination of sulphur atoms of groups CS 2- with metals. It is found that among the polymers synthesized CuLxH 2 O possesses the lowest electric resistance

  13. Detection of cyanide anion by zinc porphyrin-spiropyran dyad

    Energy Technology Data Exchange (ETDEWEB)

    Kho, Young Min; Hur, Dae Young; Shin, Eun Ju [Dept. of Chemistry, Sunchon National University, Suncheon (Korea, Republic of)

    2016-10-15

    Versatile methods of the sensitive and selective detection for cyanide anion to monitor toxic cyanide have been developed. These include colorimetric, colorimetric, chromatographic, and electrochemical analyses. Among those methods for cyanide detection, optical methods based on absorption and fluorescence spectroscopy are relatively simple, inexpensive, and sensitive. A number of organic sensors for cyanide anion have been designed and synthesized. Absorption and/or fluorescence spectra of these sensors are changed by forming coordination complex or bonding covalently with cyanide. Compared with other anions, cyanide anion has some characteristic properties, such as its strong nucleophilicity and high binding affinity toward metal ions, and is superior and useful for the development of the sensors. Both covalent bond-based sensors and coordination complex-based sensors have been developed for cyanide detection. The results indicate that ZnP-SP plays a role as a CN{sup -} selective, colorimetric sensor either without or with UV irradiation.

  14. Detection of cyanide anion by zinc porphyrin-spiropyran dyad

    International Nuclear Information System (INIS)

    Kho, Young Min; Hur, Dae Young; Shin, Eun Ju

    2016-01-01

    Versatile methods of the sensitive and selective detection for cyanide anion to monitor toxic cyanide have been developed. These include colorimetric, colorimetric, chromatographic, and electrochemical analyses. Among those methods for cyanide detection, optical methods based on absorption and fluorescence spectroscopy are relatively simple, inexpensive, and sensitive. A number of organic sensors for cyanide anion have been designed and synthesized. Absorption and/or fluorescence spectra of these sensors are changed by forming coordination complex or bonding covalently with cyanide. Compared with other anions, cyanide anion has some characteristic properties, such as its strong nucleophilicity and high binding affinity toward metal ions, and is superior and useful for the development of the sensors. Both covalent bond-based sensors and coordination complex-based sensors have been developed for cyanide detection. The results indicate that ZnP-SP plays a role as a CN"- selective, colorimetric sensor either without or with UV irradiation

  15. Comparison of the octadentate bifunctional chelator DFO*-pPhe-NCS and the clinically used hexadentate bifunctional chelator DFO-pPhe-NCS for {sup 89}Zr-immuno-PET

    Energy Technology Data Exchange (ETDEWEB)

    Vugts, Danielle J.; Klaver, Chris; Sewing, Claudia; Poot, Alex J.; Adamzek, Kevin; Visser, Gerard W.M.; Dongen, Guus A.M.S. van [VU University Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Huegli, Seraina; Mari, Cristina; Gasser, Gilles [University of Zurich, Department of Chemistry, Zurich (Switzerland); Valverde, Ibai E. [University of Basel Hospital, Division of Radiopharmaceutical Chemistry, Basel (Switzerland); Mindt, Thomas L. [Institute of Pharmaceutical Sciences, ETH Zurich, Zurich (Switzerland); General Hospital of Vienna, Ludwig Boltzmann Institute for Applied Diagnostics, Vienna (Austria)

    2017-02-15

    All clinical {sup 89}Zr-immuno-PET studies are currently performed with the chelator desferrioxamine (DFO). This chelator provides hexadentate coordination to zirconium, leaving two coordination sites available for coordination with, e.g., water molecules, which are relatively labile ligands. The unsaturated coordination of DFO to zirconium has been suggested to result in impaired stability of the complex in vivo and consequently in unwanted bone uptake of {sup 89}Zr. Aiming at clinical improvements, we report here on a bifunctional isothiocyanate variant of the octadentate chelator DFO* and the in vitro and in vivo comparison of its {sup 89}Zr-DFO*-mAb complex with {sup 89}Zr-DFO-mAb. The bifunctional chelator DFO*-pPhe-NCS was prepared from previously reported DFO* and p-phenylenediisothiocyanate. Subsequently, trastuzumab was conjugated with either DFO*-pPhe-NCS or commercial DFO-pPhe-NCS and radiolabeled with Zr-89 according to published procedures. In vitro stability experiments were carried out in saline, a histidine/sucrose buffer, and blood serum. The in vivo performance of the chelators was compared in N87 tumor-bearing mice by biodistribution studies and PET imaging. In 0.9 % NaCl {sup 89}Zr-DFO*-trastuzumab was more stable than {sup 89}Zr-DFO-trastuzumab; after 72 h incubation at 2-8 C 95 % and 58 % intact tracer were left, respectively, while in a histidine-sucrose buffer no difference was observed, both products were ≥ 92 % intact. In vivo uptake at 144 h post injection (p.i.) in tumors, blood, and most normal organs was similar for both conjugates, except for skin, liver, spleen, ileum, and bone. Tumor uptake was 32.59 ± 11.95 and 29.06 ± 8.66 % ID/g for {sup 89}Zr-DFO*-trastuzumab and {sup 89}Zr-DFO-trastuzumab, respectively. The bone uptake was significantly lower for {sup 89}Zr-DFO*-trastuzumab compared to {sup 89}Zr-DFO-trastuzumab. At 144 h p.i. for {sup 89}Zr-DFO*-trastuzumab and {sup 89}Zr-DFO-trastuzumab, the uptake in sternum was 0.92

  16. Targeted Catalytic Inactivation of Angiotensin Converting Enzyme by Lisinopril-Coupled Transition Metal Chelates

    Science.gov (United States)

    Joyner, Jeff C.; Hocharoen, Lalintip; Cowan, J. A.

    2012-01-01

    A series of compounds that target reactive transition metal chelates to somatic Angiotensin Converting Enzyme (sACE-1) have been synthesized. Half maximal inhibitory concentrations (IC50) and rate constants for both inactivation and cleavage of full length sACE-1 have been determined and evaluated in terms of metal-chelate size, charge, reduction potential, coordination unsaturation, and coreactant selectivity. Ethylenediamine-tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA), and tripeptide GGH were linked to the lysine sidechain of lisinopril by EDC/NHS coupling. The resulting amide-linked chelate-lisinopril (EDTA-lisinopril, NTA-lisinopril, DOTA-lisinopril, and GGH-lisinopril) conjugates were used to form coordination complexes with iron, cobalt, nickel and copper, such that lisinopril could mediate localization of the reactive metal chelates to sACE-1. ACE activity was assayed by monitoring cleavage of the fluorogenic substrate Mca-RPPGFSAFK(Dnp)-OH, a derivative of bradykinin, following pre-incubation with metal-chelate-lisinopril compounds. Concentration-dependent inhibition of sACE-1 by metal-chelate-lisinopril complexes revealed IC50 values ranging from 44 nM to 4,500 nM for Ni-NTA-lisinopril and Ni-DOTA-lisinopril, respectively, versus 1.9 nM for lisinopril. Stronger inhibition was correlated with smaller size and lower negative charge of the attached metal chelates. Time-dependent inactivation of sACE-1 by metal-chelate-lisinopril complexes revealed a remarkable range of catalytic activities, with second order rate constants as high as 150,000 M−1min−1 (Cu-GGH-lisinopril), while catalyst-mediated cleavage of sACE-1 typically occurred at much lower rates, indicating that inactivation arose primary from sidechain modification. Optimal inactivation of sACE-1 was observed when the reduction potential for the metal center was poised near 1000 mV, reflecting the difficulty of protein

  17. Targeted catalytic inactivation of angiotensin converting enzyme by lisinopril-coupled transition-metal chelates.

    Science.gov (United States)

    Joyner, Jeff C; Hocharoen, Lalintip; Cowan, J A

    2012-02-22

    A series of compounds that target reactive transition-metal chelates to somatic angiotensin converting enzyme (sACE-1) have been synthesized. Half-maximal inhibitory concentrations (IC(50)) and rate constants for both inactivation and cleavage of full-length sACE-1 have been determined and evaluated in terms of metal chelate size, charge, reduction potential, coordination unsaturation, and coreactant selectivity. Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), and tripeptide GGH were linked to the lysine side chain of lisinopril by 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride/N-hydroxysuccinimide coupling. The resulting amide-linked chelate-lisinopril (EDTA-lisinopril, NTA-lisinopril, DOTA-lisinopril, and GGH-lisinopril) conjugates were used to form coordination complexes with iron, cobalt, nickel, and copper, such that lisinopril could mediate localization of the reactive metal chelates to sACE-1. ACE activity was assayed by monitoring cleavage of the fluorogenic substrate Mca-RPPGFSAFK(Dnp)-OH, a derivative of bradykinin, following preincubation with metal chelate-lisinopril compounds. Concentration-dependent inhibition of sACE-1 by metal chelate-lisinopril complexes revealed IC(50) values ranging from 44 to 4500 nM for Ni-NTA-lisinopril and Ni-DOTA-lisinopril, respectively, versus 1.9 nM for lisinopril. Stronger inhibition was correlated with smaller size and lower negative charge of the attached metal chelates. Time-dependent inactivation of sACE-1 by metal chelate-lisinopril complexes revealed a remarkable range of catalytic activities, with second-order rate constants as high as 150,000 M(-1) min(-1) (Cu-GGH-lisinopril), while catalyst-mediated cleavage of sACE-1 typically occurred at much lower rates, indicating that inactivation arose primarily from side chain modification. Optimal inactivation of sACE-1 was observed when the reduction potential for the

  18. Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry

    Science.gov (United States)

    Chao, T.T.; Fishman, M. J.; Ball, J.W.

    1969-01-01

    A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969.

  19. From chelating precursors to La0.05Sr0.95CoO3-y oxide

    International Nuclear Information System (INIS)

    Hong, L.; Guo, F.; Lin, J.

    1999-01-01

    Several La 0.05 Sr 0.95 CoO 3-y (LSCO-95) powders were synthesized by means of a chelated complex-based precursor approach, which involved pyrolysis of chelating precursors and subsequent calcination of the resulting oxides. This paper focuses on the coordination effects of the precursors on the formation of the crystalline phases of the LSCO-95 oxide, showing that when the precursor is composed of EDTA-metal complexes, the perovskite-type oxide LSCO-95, an electronic-ionic mixed conducting ceramic material, can be achieved. In contrast, those LSCO-95 powders obtained initially from the pyrolysis of the precursors containing other coordination ligands possess only the undesirable hexagonal structure

  20. Rhenium(V) oxo complexes relevant to technetium renal imaging agents derived from mercaptoacetylglycylglycylaminobenzoic acid isomers. Structural and molecular mechanics studies

    International Nuclear Information System (INIS)

    Hansen, L.; Taylor, A. Jr; Marzilli, L.G.; Cini, R.

    1992-01-01

    The synthesis and characterization of three rhenium(V) oxo complexes derived from isomers of mercaptoacetylglycylglycylaminobenzoic acid (MAG 2 -ABAH 5 ) are reported. The isomers were synthesized from o-, m- and p-aminobenzoic acid and differed in the position of the terminal carboxyl group. The anions of 8-10, [ReO(MAG 2 -*ABAH)] - (* = para (8), meta (9), ortho (10)), contained the tetraanionic form of the ligands with the carboxyl group protonated. Compounds 8,9, and 10 were synthesized by exchange reactions of ReOCl 3 (Me 2 SO)(Ph 3 P) under moderate conditions and were isolated as [Ph 4 P] + , [Bu 4 N] + , and [Ph 4 P] + salts, respectively. The structures of 8 and 10 were determined by X-ray diffraction methods; except for the location of the carboxyl group, the structures are similar. The coordination geometry is pseudo square pyramidal, with nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The orientation of the carboxyl group in 10 is anti to the Re double-bond O group. Since the carboxyl groups are protonated in 8 and 10 and in other relevant structures from this class of radiopharmaceuticals including [Ph 4 As][TcO(MAG 3 H)] (MAG 3 H = tetraanionic form of mercaptoacetyltriglycine), the authors developed molecular mechanics parameters that allowed them to calculate the structures of 8, 10, and [TcO(MAG 3 H)] - . They then extended the calculations to all three isomeric complexes in their deprotonated forms and to [TcO(MAG 3 )] 2- in order to approximate their solution phase structures. They conclude that the [TcO(MAG 3 )] 2- species is conformationally flexible, and they have made an initial assessment of structures vs renal clearance

  1. Selective recovery of Ag(I) coordination anion from simulate nickel electrolyte using corn stalk based adsorbent modified by ammonia–thiosemicarbazide

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Ying, E-mail: xiongying_1977@hotmail.com; Wan, Li; Xuan, Jing; Wang, Yongwei; Xing, Zhiqing; Shan, Weijun; Lou, Zhenning

    2016-01-15

    Highlights: • We developed a “green” corn stalk adsorbent treated by thiosemicarbazide–glutaraldehyde. • Adsorption mechanism of AgCl{sub i}{sup 1−i} could be electrostatic interaction with C−SH{sup +}−N and C=SH{sup +} group. • The gel could selectively adsorb AgCl{sub i}{sup 1−i} coordination anion from the Ag(I)–Cu(II)–Ni(II) simulate nickel electrolyte. - Abstract: In nickel electrolyte, Ag(I) was present at trace level concentration (10–20 mg L{sup −1}) and existed in the form of AgCl{sub i}{sup 1−i} coordination anion, instead of Ag{sup +} positive ion usually in several sources. In the present study, TSC-NH{sub 3}-OCS adsorbent based on natural corn stalk modified by ammonia (NH{sub 3})–thiosemicarbazide (TSC) was synthesized and characterized using some instrumental techniques. The TSC-NH{sub 3}-OCS adsorbent could selectively adsorb Ag(I) as AgCl{sub i}{sup 1−i} coordination anion from the Ag(I)–Cu(II)–Ni(II) simulate nickel electrolyte, especially in the case of the very high levels of Cu(II) and Ni(II), which significantly outperforms the commercial available resins. The adsorption mechanism was believed to be electrostatic interaction of the protonated bands of AgCl{sub 4}{sup 3−} with protonated thiol form of the thioamide units by FTIR and XPS analysis. The maximum adsorption capacity in the Ag(I) single and Ag(I)–Cu(II)–Ni(II) ternary system were obtained and calculated as 153.54 and 46.69 mg g{sup −1}, respectively. The reasons that the maximum adsorption capacity of AgCl{sub i}{sup 1−i} from the single and ternary system varied widely could be explained by adsorption kinetic and thermodynamic results. In addition, three successive sorption/desorption cycle runs from ternary system were performed which indicated that the TSC-NH{sub 3}-OCS adsorbent has a good performance for recovery Ag(I) from simulate nickel electrolyte.

  2. An unprecedented extended architecture constructed from a 2-D interpenetrating cationic coordination framework templated by SiW12O404- anion

    International Nuclear Information System (INIS)

    Wang Xiuli; Lin Hongyan; Bi Yanfeng; Chen Baokuan; Liu Guocheng

    2008-01-01

    A novel inorganic-organic hybrid compound based on polyoxometalates (POMs) and organic ligand formulated as [Cu 2 (bpp) 4 (H 2 O) 2 ](SiW 12 O 40 )∼6H 2 O (1) [bpp=1,3-bis(4-pyridyl)propane], was hydrothermally synthesized and structurally characterized by elemental analysis, single-crystal X-ray diffraction analysis, IR, TG, and cyclic voltammetry. Crystal data for 1: Orthorhombic, Pbcn, a=23.0085(19) A, b=14.6379(12) A, c=23.6226(19) A, V=7956.0(11) A 3 , Z=4, Dc=3.315 g cm -3 , and R(final)=0.0826. X-ray diffraction study reveals that compound 1 was the first interpenetrating network of 2-D metal-organic cationic coordination framework [Cu 2 (bpp) 4 (H 2 O) 2 ] n 4n+ , in which Keggin-type anions SiW 12 O 40 4- has been used as a non-coordinating anionic template. The electrochemical property of 1-bulk modified carbon paste electrode (1-CPE) has been studied, and the results indicate that 1-CPE has good electrocatalytic activities toward the reduction of nitrite in 1 M H 2 SO 4 aqueous solution. - Graphical abstract: Compound [Cu 2 (bpp) 4 (H 2 O) 2 ](SiW 12 O 40 )∼6H 2 O (1) represents the first 2-D interpenetrating cationic metal-organic frameworks (MOFs) templated by Keggin-type anions. These MOF layers are stacked together along the crystallographic c axis exactly to construct large cubic-like channels (with dimensions of 12.3x13.6 A) occupied by SiW 12 O 40 4- clusters

  3. Different photoluminescent properties of binary and ternary europium chelates doped in PMMA

    International Nuclear Information System (INIS)

    Liu Hongguo; Park, Seongtae; Jang, Kiwan; Zhang Wansong; Seo, Hyo-Jin; Lee, Yong-Ill

    2003-01-01

    Two kinds of europium-β-diketone chelates, binary Eu(DBM) 3 and ternary Eu(DBM) 3 phen were doped in poly(methyl methacrylate) (PMMA). These chelates show very different photoluminescent (PL) behaviors: the hypersensitive 5 D 0 → 7 F 2 emission bands of Eu(DBM) 3 phen change slightly with the molar ratios, while those of Eu(DBM) 3 change obviously and regularly with the molar ratios. The results of the luminescent lifetimes of 5 D 0 levels show that the binary chelate exists as two kinds of species in the doped systems, and the lifetimes and contents of each species change with the molar ratios, while the ternary chelate exists as one kind of species in the doped systems. X-ray diffraction (XRD) patterns of the binary chelate doped systems give some diffraction peaks that are different from those of pure chelate and change with the molar ratios, indicating new kinds of crystal structures formed, and consequently, the first coordination sphere of Eu 3+ ion changes; while those of the ternary chelate doped systems just show amorphous diffraction halos of the host, indicating that the ternary chelate exist in an amorphous state and disperse well in the host. The FTIR spectra of PMMA also change gradually with increasing the molar ratios of the doped two kinds of chelates, and the XRD patterns show that the amorphous halos of PMMA in the doped systems are different from those of pure PMMA and change with the molar ratios, too, suggesting the interaction between the guest and the host

  4. Metal-oxo containing polymer nanobeads as potential contrast agents for magnetic resonance imaging

    Science.gov (United States)

    Pablico, Michele Huelar

    Magnetic resonance imaging (MRI) has greatly revolutionized the way diseases are detected and treated, as it is a non-invasive imaging modality solely based on the interaction of radiowaves and hydrogen nuclei in the presence of an external magnetic field. It is widely used today for the diagnosis of diseases as it offers an efficient method of mapping structure and function of soft tissues in the body. Most MRI examinations utilize paramagnetic materials known as contrast agents, which enhance the MR signal by decreasing the longitudinal (T1) and transverse (T2) relaxation times of the surrounding water protons in biological systems. This results into increased signal intensity differences thereby allowing better interpretation and analysis of pathological tissues. Contrast agents function by lowering the T1 or lowering the T2, resulting into bright and dark contrasts, respectively. The most common MRI contrast agents that are in clinical use today are gadolinium chelates and superparamagnetic iron oxide nanoparticles, both of which have their own advantages in terms of contrast enhancement properties. In the past few years, however, there has been interest in utilizing metal-containing clusters for MRI contrast enhancement as these materials bridge the gap between the constrained structure and magnetic properties of the gadolinium chelates with the superparamagnetic behavior of the iron oxide nanoparticles. Recently, metallic clusters containing Mn and Fe metal centers have received increased attention mainly because of their potential for high spin states and benign nature. In the quest to further develop novel imaging agents, this research has focused on investigating the use of metal-oxo clusters as potential contrast agents for MRI. The primary goal of this project is to identify clusters that meet the following criteria: high paramagnetic susceptibility, water-soluble, stable, cheap, contain environmentally benign metals, and easily derivatized. This work is

  5. The roles of organic anion permeases in aluminium resistance and mineral nutrition.

    Science.gov (United States)

    Delhaize, Emmanuel; Gruber, Benjamin D; Ryan, Peter R

    2007-05-25

    Soluble aluminium (Al(3+)) is the major constraint to plant growth on acid soils. Plants have evolved mechanisms to tolerate Al(3+) and one type of mechanism relies on the efflux of organic anions that protect roots by chelating the Al(3+). Al(3+) resistance genes of several species have now been isolated and found to encode membrane proteins that facilitate organic anion efflux from roots. These proteins belong to the Al(3+)-activated malate transporter (ALMT) and multi-drug and toxin extrusion (MATE) families. We review the roles of these proteins in Al(3+) resistance as well as their roles in other aspects of mineral nutrition.

  6. Toxicity of copper chelates of azomethines and amino acids for Chlorella pyrenoidosa

    Energy Technology Data Exchange (ETDEWEB)

    Barashkov, G.K.; Rukhadze, E.G.; Talyzenkova, G.P.

    1979-01-01

    The authors have attempted to assess the toxicity of copper-containing compounds from the point of view of their interrelationship with the structural characteristics of the chelate compound and the structure of the ligand. The copper chelates of the azomethines tested may be provisionally divided into three types: A - complexes with N-alkly-azomethines; B - complexes with N-aryl-azomethines; C - binuclear complexes. Consideration was also given to chelates with aromatic and heterocyclic amino acids and to heteroligand chelates in which the copper atom coordinates azomethine and an amino acid simultaneously. Toxicity was determined by the method previously described and expressed as a critical concentration (C/sub cr/, mg Cu/liter) and in relative toxicity units (T/sub c/). The compounds investigated were obtained from the interaction between a bidentant ligand of an azomethine or anamino acid and copper acetate in a water-alcohol medium at pH 6-8. Since they are not very soluble in water, true solutions were obtained by using dimethyl sulfoxide.

  7. Lanthanide-binding peptides with two pendant aminodiacetate arms: impact of the sequence on chelation.

    Science.gov (United States)

    Niedźwiecka, Agnieszka; Cisnetti, Federico; Lebrun, Colette; Gateau, Christelle; Delangle, Pascale

    2012-03-21

    Lanthanide complexes with a series of hexapeptides-incorporating two unnatural chelating amino acids with aminodiacetate groups, Ada(1) and Ada(2)-have been examined in terms of their speciation, structure, stability and luminescence properties. Whereas Ada(2) acts as a tridentate donor in all cases, Ada(1) may act as a tetradentate donor thanks to the coordination of the amide carbonyl function assisted by the formation of a six-membered chelate ring. The position of the Ada(1) residue in the sequence is demonstrated to be critical for the lanthanide complex speciation and structure. Ada(1) promotes the coordination of the backbone amide function to afford a highly dehydrated Ln complex and an S-shape structure of the peptide backbone, only when found in position 2.

  8. The crystal chemistry of novel thorium and uranium compounds with oxo-anions from group VI of periodic table (S, Se, Te, Cr, Mo and W)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Bin

    2016-01-26

    used as the flux for the high-temperature synthesis method to decrease the crystal growth temperature. This also gives an opportunity to allow Te{sup 4+} anion to interact with anion of Mo{sup 6+} or W{sup 6+}, leading to a more complex mixed oxo-anion system, which is reported in Chapter 7 from page 122. Last, some attractive features of structural chemistry of actinides, such as cation-cation interaction of uranyl groups(Chapter 8.1 from page 136), and the first thorium compounds containing alkaline-earth or rare earth metals (Chapter 8.2 from page 145) are discussed in Chapter 8.

  9. The influence of stereoisomerism on the pharmacokinetics of Tc radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, L.; Taylor, A. [Atlanta, Emory Univ. School of Medicine, GA (United States). Dept. of Chemistry; Marzilli, L.G. [Atlanta, Emory Univ. School of Medicine, GA (United States). Dept. of Radiology

    1998-12-01

    The influence of stereoisomerism on the pharmacokinetics of Tc mono-oxo complexes is reviewed. Tc(V) mono-oxo complexes formed with N/S ligands have four donor groups from the ligands in an equatorial plane; the oxo ligand coordinates in an axial position. Stereoisomerism in Tc(V) mono-oxo complexes can be centered within the ligand (carbon atom in the chelate ring of ligating nitrogen of amine donors) or at the Tc. The metal center becomes chiral when an equatorial ligand has a head and a tail (i.e. the two ends of the ligand differ). All types of stereocenter can produce significantly different pharmacokinetic profiles for individual isomers. Thus, biological evaluation of separated stereoisomers is necessary to identify the optimal stereochemical configuration, particularly for radiopharmaceuticals targeted to receptor molecules with low specificity. Because of inter species variation, there is ultimately no substitute for human testing. Although it is possible that the increase in nonspecific binding of agents incorporating L- vs D-amino acids may more than offset any increased receptor binding, much more information is needed. Stereochemical factors can also lead to unpredictable differences in coordination geometry and thermodynamic preference of a single isomer; thus chemical characterization of stereo-isomers continues to be an important component of radiopharmaceutical development.

  10. Hybrid conducting polymer materials incorporating poly-oxo-metalates for extraction of actinides; Materiaux polymeres conducteurs hybrides incorporant des polyoxometallates pour l'extraction d'actinides

    Energy Technology Data Exchange (ETDEWEB)

    Racimor, D

    2003-09-15

    The preparation and characterization of hybrid conducting polymers incorporating poly-oxo-metalates for extracting actinides is discussed. A study of the coordination of various lanthanide cations (Ce(III), Ce(IV), Nd(III)) by the mono-vacant poly-oxo-metalate {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} showed significant differences according to the cation.. Various {alpha}-A-[PW{sub 9}O{sub 34}(RPO){sub 2}]{sup 5-} hybrids were synthesized and their affinity for actinides or lanthanides was demonstrated through complexation. The first hybrid poly-oxo-metallic lanthanide complexes were then synthesized, as was the first hybrid functionalized with a pyrrole group. The electro-polymerization conditions of this pyrrole remain still to be optimized. Poly-pyrrole materials incorporating {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} or its neodymium or cerium complexes as doping agents proved to be the first conducting polymer incorporating poly-oxo-metalates capable of extracting plutonium from nitric acid. (author)

  11. Thermodynamic stability and relaxation studies of small, triaza-macrocyclic Mn(II) chelates.

    Science.gov (United States)

    de Sá, Arsénio; Bonnet, Célia S; Geraldes, Carlos F G C; Tóth, Éva; Ferreira, Paula M T; André, João P

    2013-04-07

    Due to its favorable relaxometric properties, Mn(2+) is an appealing metal ion for magnetic resonance imaging (MRI) contrast agents. This paper reports the synthesis and characterization of three new triazadicarboxylate-type ligands and their Mn(2+) chelates (NODAHep, 1,4,7-triazacyclononane-1,4-diacetate-7-heptanil; NODABA, 1,4,7-triazacyclononane-1,4-diacetate-7-benzoic acid; and NODAHA, 1,4,7-triazacyclononane-1,4-diacetate-7-hexanoic acid). The protonation constants of the ligands and the stability constants of the chelates formed with Mn(2+) and the endogenous Zn(2+) ion have been determined by potentiometry. In overall, the thermodynamic stability of the chelates is lower than that of the corresponding NOTA analogues (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetate), consistent with the decreased number of coordinating carboxylate groups. Variable temperature (1)H NMRD and (17)O NMR measurements have been performed on the paramagnetic chelates to provide information on the water exchange rates and the rotational dynamics. The values of the (17)O chemical shifts are consistent with the presence of one water molecule in the first coordination sphere of Mn(2+). The three complexes are in the slow to intermediate regime for the water exchange rate, and they all display relatively high rotational correlation times, which explain the relaxivity values between 4.7 and 5.8 mM(-1) s(-1) (20 MHz and 298 K). These relaxivities are higher than expected for Mn(2+) chelates of such size and comparable to those of small monohydrated Gd(3+) complexes. The amphiphilic [Mn(NODAHep)] forms micelles above 22 mM (its critical micellar concentration was determined by relaxometry and fluorescence), and interacts with HSA via its alkylic carbon chain providing a 60% relaxivity increase at 20 MHz due to a longer tumbling time.

  12. 2.2.1. Synthesis, spectroscopic characterization and crystal structure of [ReV(O2(pyz4][ReII(NOBr4(pyz] (pyz = pyrazine

    Directory of Open Access Journals (Sweden)

    Mario Pacheco, Alicia Cuevas, Javier González-Platas, Carlos Kremer*

    2015-03-01

    Full Text Available Abstract: A novel Re(V-Re(II nitrosyl complex, [Re(O2(pyz 4][Re(NOBr4(pyz] (pyz = pyrazine was prepared and characterized by X-ray diffraction, elemental analysis, infrared and ultraviolet-visible absorption spectra. This product is obtained in the initial steps of the reaction of (NBu4[Re(NOBr4(EtOH] with pyrazine. Both, the cation and the anion are mononuclear complexes. The Re(V atom in the cation is six-coordinate with four nitrogen atoms from pyrazine ligands, and two oxo ligands. The Re(II anion is also six-coordinate, with four bromide ligands, a linear nitrosyl group and one nitrogen from pyrazine. The spectroscopic studies are discussed and compared with those already reported separately for the cation and the anion. Supporting information: X-Ray (CIF file

  13. [H2en]2{La2M(SO4)6(H2O)2} (M=Co, Ni): First organically templated 3d-4f mixed metal sulfates

    International Nuclear Information System (INIS)

    Yuan Yanping; Wang Ruiyao; Kong Deyuan; Mao Jianggao; Clearfield, Abraham

    2005-01-01

    The first organically templated 3d-4f mixed metal sulfates, [H 2 en] 2 {La 2 M(SO 4 ) 6 (H 2 O) 2 } (M=Co 1, Ni 2) have been synthesized and structurally determined from non-merohedrally twinned crystals. The two compounds are isostructural and their structures feature a three-dimensional anionic network formed by the lanthanum(III) and nickel(II) ions bridged by sulfate anions. The La(III) ions in both compounds are 10-coordinated by four sulfate anions in bidentate chelating fashion, and two sulfate anions in a unidentate fashion. The transition metal(II) ion is octahedrally coordinated by six oxygens from four sulfate anions and two aqua ligands. The doubly protonated enthylenediamine cations are located at the tunnels formed by 8-membered rings (four La and four sulfate anions)

  14. Terminal Gold-Oxo Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cao, R.; Anderson, T.M.; Piccoli, P.M.B.; Schultz, A.J.; Koetzle, T.F.; Geletii, Y.V.; Slonkina, E.; Hedman, B.; Hodgson, K.O.; Hardcastle, K.I.; Fang, X.; Kirk, M.L.; Knottenbelt, S.; Kogerler, P.; Musaev, D.G.; Morokuma, K.; Takahashi, M.; Hill, C.L.; /Emory U. /Argonne /SLAC, SSRL /New Mexico U. /Iowa State U. /Toho U.

    2007-10-19

    In contradiction to current bonding paradigms, two terminal Au-oxo molecular complexes have been synthesized by reaction of AuCl{sub 3} with metal oxide-cluster ligands that model redox-active metal oxide surfaces. Use of K{sub 10}[{alpha}{sub 2}-P{sub 2}W{sub 17}O{sub 61}] x 20H{sub 2}O and K{sub 2}WO{sub 4} (forming the [A-PW{sub 9}O{sub 34}]{sup 9-} ligand in situ) produces K{sub 15}H{sub 2}[Au(O)(OH{sub 2})P{sub 2}W{sub 18}O{sub 68}] x 25H{sub 2}O (1); use of K{sub 10}[P{sub 2}W{sub 20}O{sub 70}(OH{sub 2}){sub 2}] x 22H{sub 2}O (3) produces K{sub 7}H{sub 2}[Au(O)(OH{sub 2})P{sub 2}W{sub 20}O{sub 70}(OH{sub 2}){sub 2}] x 27H{sub 2}O (2). Complex 1 crystallizes in orthorhombic Fddd, with a = 28.594(4) Angstroms, b = 31.866(4) Angstroms, c = 38.241(5) Angstroms, V = 34844(7) Angstroms{sup 3}, Z = 16 (final R = 0.0540), and complex 2 crystallizes in hexagonal P6(3)/mmc, with a = 16.1730(9) Angstroms, b = 16.1730(9) Angstroms, c = 19.7659(15) Angstroms, V = 4477.4(5) Angstroms{sup 3}, Z = 2 (final R = 0.0634). The polyanion unit in 1 is disorder-free. Very short ({approx}1.76 Angstroms) Au-oxo distances are established by both X-ray and 30 K neutron diffraction studies, and the latter confirms oxo and trans aqua (H2O) ligands on Au. Seven findings clarify that Au and not W is present in the Au-oxo position in 1 and 2. Five lines of evidence are consistent with the presence of d8 Au(III) centers that are stabilized by the flanking polytungstate ligands in both 1 and 2: redox titrations, electrochemical measurements, 17 K optical spectra, Au L2 edge X-ray absorption spectroscopy, and Au-oxo bond distances. Variable-temperature magnetic susceptibility data for crystalline 1 and 2 establish that both solids are diamagnetic, and {sup 31}P and {sup 17}O NMR spectroscopy confirm that both remain diamagnetic in solution. Both complexes have been further characterized by FT-IR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and other techniques.

  15. Oxo-group-14-element bond formation in binuclear uranium(V) pacman complexes

    International Nuclear Information System (INIS)

    Jones, Guy M.; Arnold, Polly L.; Love, Jason B.

    2013-01-01

    Simple and versatile routes to the functionalization of uranyl-derived U"V-oxo groups are presented. The oxo-lithiated, binuclear uranium(V)-oxo complexes [{(py)_3LiOUO}_2(L)] and [{(py)_3LiOUO}(OUOSiMe_3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide ''ate'' complex [Li(py)_2][(OUO)(N'')_3](N''=N(SiMe_3)_2) with the polypyrrolic macrocycle H_4L or the mononuclear uranyl (VI) Pacman complex [UO_2(py)(H_2L)], respectively. These oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo-stannylated complexes [{(R_3Sn)OUO}_2(L)] (R=nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-oxo-group exchange occurred in reactions with [TiCl(OiPr)_3] to form U-O-C bonds [{(py)_3LiOUO}(OUOiPr)(L)] and [(iPrOUO)_2(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo-functionalised by Group 14 elements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. A 3d-4f complex constructed by the assembly of a cationic template, [Cu(en){sub 2}]{sup 2+}, and a 3D anionic coordination polymer, [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-}

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Szu-Yu; Yeh, Chang-Tsung; Wang, Chih-Chieh [Department of Chemistry, Soochow University, Taipei, Taiwan (China); Lee, Gene-Hsiang [Instrumentation Center, National Taiwan University, Taipei, Taiwan (China); Sheu, Hwo-Shuenn [National Synchrotron Radiation Research Center, Hsinchu, Taiwan (China)

    2017-05-18

    A three-dimensional (3D) 3d-4f complex, [Cu(en){sub 2}][Sm{sub 2}(C{sub 5}O{sub 5})(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 2}].8H{sub 2}O (1) (en = ethylenediamine, C{sub 5}O{sub 5}{sup 2-} = dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione), were prepared via the in-situ ring-opening oxidation reaction of croconate in the presence of the template-directed complex, [Cu(en){sub 2}]{sup 2+} cation. The structural characterization determined by X-ray diffraction determination reveals that the 3D anionic coordination polymer of [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-} in 1 can be describe in terms of in-plane 2D honeycomb-like [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}] layered frameworks bridged by oxalate with bis-chelating mode, being mutually interlinked via the bridge of μ{sub 1,2,3,4}-croconate ligands with bis-chelating coordination mode to complete the 3D open framework, which gives rise to 1D channels with pore size of 14.023 x 11.893 Aa (longest atom-atom contact distances) along the b axis. The structure-directing complex, [Cu(en){sub 2}]{sup 2+}, and solvated water molecules are resided into these honeycomb-type hexagonal channels. The thermal stability of 1 was further studied by TGA and in-situ powder X-ray diffraction measurement. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Coordination, non-coordination and semi-coordination of perchlorates in the lanthanide adducts Ln (CLO4)3. 6dmba

    International Nuclear Information System (INIS)

    Tfouni, E.; Giesbrecht, E.

    1983-01-01

    The coordination or not of the perchlorate anions in the previously reported Ln(CLO 4 ) 3 .6 dmba is discussed. The analysis of the infrared spectral data and molar conductance data indicate that they may be formulated as [Ln(dmba) 6 (CLO 4 )n] (CLO 4 ) sub(3-n), n=0,1,2. The individual compounds may be a mixture of species with different n values and/or pure compounds with semi-coordinated and non-coordinated perchlorates. (Author) [pt

  18. Derivatives of Dodecahalo-Closo-Dodecaborate Di-Anion

    OpenAIRE

    Avelar, Amy Cindy

    2009-01-01

    ABSTRACT OF THE DISSERTATIONDerivatives of the Dodecahalo-Closo-Dodecaborate Di-AnionbyAmy AvelarDoctor of Philosophy, Graduate Program in ChemistryUniversity of California, Riverside, December 2009Dr. Christopher A. Reed, ChairpersonThe di-anion, dodecahalo-closo-dodecaborate, B12X122-, where the X = Cl or Br, has been determined to be a useful weakly coordinating anion, WCA. Despite the di- negative charge, several elusive and reactive cationic species were stabilized with B12X122- as the c...

  19. Oxo-group-14-element bond formation in binuclear uranium(V) pacman complexes

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Guy M.; Arnold, Polly L.; Love, Jason B. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom)

    2013-07-29

    Simple and versatile routes to the functionalization of uranyl-derived U{sup V}-oxo groups are presented. The oxo-lithiated, binuclear uranium(V)-oxo complexes [{(py)_3LiOUO}{sub 2}(L)] and [{(py)_3LiOUO}(OUOSiMe{sub 3})(L)] were prepared by the direct combination of the uranyl(VI) silylamide ''ate'' complex [Li(py){sub 2}][(OUO)(N''){sub 3}](N''=N(SiMe{sub 3}){sub 2}) with the polypyrrolic macrocycle H{sub 4}L or the mononuclear uranyl (VI) Pacman complex [UO{sub 2}(py)(H{sub 2}L)], respectively. These oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo-stannylated complexes [{(R_3Sn)OUO}{sub 2}(L)] (R=nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-oxo-group exchange occurred in reactions with [TiCl(OiPr){sub 3}] to form U-O-C bonds [{(py)_3LiOUO}(OUOiPr)(L)] and [(iPrOUO){sub 2}(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo-functionalised by Group 14 elements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Ligand assisted cleavage of uranium oxo-clusters

    Energy Technology Data Exchange (ETDEWEB)

    Nocton, Gregory; Pecaut, Jacques; Mazzanti, Marinella [Laboratoire de Reconnaissance Ionique et Chimie de Coordination, Service de Chimie Inorganique et Biologique, UMR-E 3 CEA-UJF, CEA/DSM/INAC, CEA-Grenoble, 38054 Grenoble, Cedex 09 (France); Filinchuk, Yaroslav [Swiss Norwegian Beam Lines (SNBL) at the European Synchrotron Radiation Facility (ESRF), rue Jules Horowitz, 38043 Grenoble (France)

    2010-07-01

    Dibenzoylmethanate replaces the bridging triflate ligands in uranium triflate poly-oxo-clusters and cleaves the U{sub 12}O{sub 20} core yielding the new [U{sub 6}O{sub 4}(OH){sub 4}({eta}-dbm){sub 12}] dibenzoylmethanate (dbm{sup -}) cluster which slowly dissociates into a monomeric complex. This reactivity demonstrates the importance of bridging ligands in stabilizing uranium poly-oxo-clusters. (authors)

  1. Inter-laboratory validation of procedures for measuring 8-oxo-7,8-dihydrooxoguanine/8-oxo-7,8-dihydro-2`-deoxyguanosine in DNA

    DEFF Research Database (Denmark)

    Collins, A.R.; Gedik, C.M.; Wood, S.

    2002-01-01

    The aim of ESCODD, a European Commission funded Concerted Action, is to improve the precision and accuracy of methods for measuring 8-oxo-7,8-dihydroguanine (8-oxoGua) or the nucleoside (8-oxodG). On two occasions, participating laboratories received samples of different concentrations of 8-oxodG...

  2. Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

    2013-01-01

    Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

  3. Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

    Directory of Open Access Journals (Sweden)

    José Maria Rodrigues da Luz

    Full Text Available Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

  4. Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

    2013-01-01

    Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057

  5. Hexaaquabis[3,5-bis(hydroxyimino-1-methyl-2,4,6-trioxocyclohexanido-κ2N3,O4]barium tetrahydrate

    Directory of Open Access Journals (Sweden)

    Nguyen Dinh Do

    2013-11-01

    Full Text Available In the title compound, [Ba(C7H5N2O52(H2O6]·4H2O, the Ba2+ cation lies on a twofold rotation axis and is ten-coordinated by two 3,5-bis(hydroxyimino-1-methyl-2,4,6-trioxocyclohexanide oxo O atoms [Ba—O = 2.8715 (17 Å], two hydroxyimino N atoms [Ba—N = 3.036 (2 Å], and six water molecules [Ba—O = 2.847 (2, 2.848 (2, and 2.880 (2 Å]. The 3,5-bis(hydroxyimino-1-methyl-2,4,6-trioxocyclohexanide monoanions act in a bidentate chelating manner, coordinating through an N atom of the non-deprotonated hydroxyimino group and an O atom of the neighboring oxo group. Two lattice water molecules are located in the cavities of the framework and are involved in hydrogen bonding to O atoms of one of the coordinating water molecules and the O atom of a keto group of the ligand. As a result, a three-dimensional network is formed.

  6. Various types of metal complexes based on chelating {beta}-diketones and their structural analogues

    Energy Technology Data Exchange (ETDEWEB)

    Skopenko, Viktor V; Amirkhanov, Vladimir M; Sliva, T Yu [Department of Chemistry, Kyiv National Taras Shevchenko University (Ukraine); Vasilchenko, Igor S; Anpilova, E L; Garnovskii, Alexander D [Institute of Physical and Organic Chemistry, Rostov State University, Rostov-on-Don (Russian Federation)

    2004-08-31

    Data on the synthesis and structures of {beta}-diketonates and their N,P-containing structural analogues are generalised and described systematically. The possibility of creating diverse metal complexes with various modes of coordination of typical chelating ligands is discussed.

  7. Various types of metal complexes based on chelating β-diketones and their structural analogues

    International Nuclear Information System (INIS)

    Skopenko, Viktor V; Amirkhanov, Vladimir M; Sliva, T Yu; Vasilchenko, Igor S; Anpilova, E L; Garnovskii, Alexander D

    2004-01-01

    Data on the synthesis and structures of β-diketonates and their N,P-containing structural analogues are generalised and described systematically. The possibility of creating diverse metal complexes with various modes of coordination of typical chelating ligands is discussed.

  8. [Influences of the mobile phase constitution, salt concentration and pH value on retention characters of proteins on the metal chelate column].

    Science.gov (United States)

    Li, R; Di, Z M; Chen, G L

    2001-09-01

    The effects of the nature and concentration of salts, pH value and competitive eluent in the mobile phase on the protein retention have been systematically investigated. A mathematical expression describing the protein retention in metal chelate chromatography has been derived. It is proposed that the eluting power of the salt solution can be expressed by the eluent strength exponent epsilon. According to the retention characters of protein under different chromatographic conditions, the interaction between the various metal chelate ligands and proteins is discussed. The protein retention on the metal chelate column is a cooperative interactions of coordination, electrostatic and hydrophobic interaction. For the strong combined metal column with proteins such as IDA-Cu, the coordination is the most important, and the electrostatic interaction is secondary in chromatographic process. However, for the weak combined metal columns with proteins such as IDA-Ni, IDA-Co and IDA-Zn, the electrostatic interaction between the metal chelate ligands and proteins is the chief one, while the coordination is the next in importance. When the mobile phase contains high concentration of salt which can't form complex with the immobilized metal, the hydrophobic interaction between the protein and stationary phase will be increased. As the interaction between the metal chelate ligand and proteins relates to chromatographic operating conditions closely, different elution processes may be selected for different metal chelate columns. The gradient elution is generally performed by the low concentration of salt or different pH for weakly combined columns with proteins, however the competitive elution procedure is commonly utilized for strongly combined column. The experiment showed that NH3 is an excellent competitive eluent. It isn't only give the efficient separation of proteins, but also has the advantages of cheapness, less bleeding of the immobilized metals and ease of controlling NH3

  9. Chelate forms of biometalls. Theoretical aspects of obtaining and characteristics

    Directory of Open Access Journals (Sweden)

    A. Kapustyan

    2017-04-01

    Full Text Available The problem of microelements bioavailability is highlighted and the correct ways of its solution are substantiated as a result of generalization of theoretical aspects of obtaining of the biometals chelate forms. The characteristics of the main biogenic elements, their physiological significance, electrochemical properties are presented. The main examples of the participation of biometals in various biological processes are given. The properties and the structure peculiarities of biometals coordination complexes are considered in detail. It is shown that in obtaining of biometals chelate forms, there is the mutual selectivity and the affinity of biometals and ligands. The main factors of obtaining a hard metal complex are given. Potential bioligands for obtaining bioavailable forms of microelements are detailed. Among them there are amino acids, peptides, proteins, nucleic acids, carbohydrates. The possible character of complexation depending on the nature of the bioligand is indicated. Practical examples of preparation of biometals mixed ligand complexes are given. The expediency of using metabolic products and processing of lactic acid bacteria as promising components of mixed ligand chelate complexes is substantiated. These substances contain in their composition a mass of potential donor atoms that are capable to form covalent and coordination bonds with biomethalles, and also possess high biological and immunotropic activities. The use of this system in the biocoordination compounds of the "metals of life" can provide a synergistic effect of the components, significantly to expand the range of their physiological activity and to increase the degree of assimilation by the body.

  10. A bis(3-hydroxy-4-pyridinone)-EDTA derivative as a strong chelator for M3+ hard metal ions: complexation ability and selectivity.

    Science.gov (United States)

    Gama, Sofia; Dron, Paul; Chaves, Silvia; Farkas, Etelka; Santos, M Amélia

    2009-08-21

    The study of chelating compounds is very important to solve problems related to human metal overload. 3-Hydroxy-3-pyridinones (HP), namely deferiprone, have been clinically used for chelating therapy of Fe and Al over the last decade. A multi-disciplinary search for alternative molecules led us to develop poly-(3-hydroxy-4-pyridinones) to increase metal chelation efficacy. We present herein a complexation study of a new bis-(3-hydroxy-4-pyridinone)-EDTA derivative with a set of M(3+) hard metal ions (M = Fe, Al, Ga), as well as Zn(2+), a biologically relevant metal ion. Thus a systematic aqueous solution equilibrium study was performed using potentiometric and spectroscopic techniques (UV-Vis, NMR methods). These set of results enables the establishment of specific models as well as the determination of thermodynamic stability constants and coordination modes of the metal complexes. The results indicate that this ligand has a higher affinity for chelating to these hard metal ions than deferiprone, and that the coordination occurs mostly through the HP moieties. Furthermore, it was also found that this ligand has a higher selectivity for chelating to M(3+) hard metal ions (M = Fe, Al, Ga) than Zn(2+).

  11. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. (Abbott Laboratories, Department 90M, Abbott Park, IL (United States))

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

  12. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    International Nuclear Information System (INIS)

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K.

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates

  13. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor; Villalobos Vazquez de la Parra, Luis Francisco; Hilke, Roland

    2015-01-01

    microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  14. Chelation in Metal Intoxication

    Directory of Open Access Journals (Sweden)

    Swaran J.S. Flora

    2010-06-01

    Full Text Available Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.

  15. Six-coordinate oxo-vanadium(V) dimer complex with methoxy bridging: synthesis, crystal structure, biological activity and molecular docking

    Czech Academy of Sciences Publication Activity Database

    Heidari, F.; Fatemi, S.J.A.; Yousef Ebrahimipour, S.; Ebrahimnejad, H.; Castro, J.; Dušek, Michal; Eigner, Václav

    2017-01-01

    Roč. 76, Feb (2017), s. 1-4 ISSN 1387-7003 R&D Projects: GA MŠk(CZ) LO1603; GA ČR(CZ) GA14-03276S EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : oxo-vanadium(V) * Schiff base complex * antimicrobial activity * X-ray crystal structure Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.640, year: 2016

  16. Chelation Therapy for Mercury Poisoning

    Directory of Open Access Journals (Sweden)

    Rong Guan

    2009-01-01

    Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

  17. Sulfur K-edge X-ray absorption spectroscopy and density functional theory calculations on monooxo Mo(IV) and bisoxo Mo(VI) bis-dithiolenes: insights into the mechanism of oxo transfer in sulfite oxidase and its relation to the mechanism of DMSO reductase.

    Science.gov (United States)

    Ha, Yang; Tenderholt, Adam L; Holm, Richard H; Hedman, Britt; Hodgson, Keith O; Solomon, Edward I

    2014-06-25

    Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations have been used to determine the electronic structures of two complexes [Mo(IV)O(bdt)2](2-) and [Mo(VI)O2(bdt)2](2-) (bdt = benzene-1,2-dithiolate(2-)) that relate to the reduced and oxidized forms of sulfite oxidase (SO). These are compared with those of previously studied dimethyl sulfoxide reductase (DMSOr) models. DFT calculations supported by the data are extended to evaluate the reaction coordinate for oxo transfer to a phosphite ester substrate. Three possible transition states are found with the one at lowest energy, stabilized by a P-S interaction, in good agreement with experimental kinetics data. Comparison of both oxo transfer reactions shows that in DMSOr, where the oxo is transferred from the substrate to the metal ion, the oxo transfer induces electron transfer, while in SO, where the oxo transfer is from the metal site to the substrate, the electron transfer initiates oxo transfer. This difference in reactivity is related to the difference in frontier molecular orbitals (FMO) of the metal-oxo and substrate-oxo bonds. Finally, these experimentally related calculations are extended to oxo transfer by sulfite oxidase. The presence of only one dithiolene at the enzyme active site selectively activates the equatorial oxo for transfer, and allows facile structural reorganization during turnover.

  18. Crystal structure of 2-methyl-1H-imidazol-3-ium aquatrichlorido(oxalato-κ2O,O′stannate(IV

    Directory of Open Access Journals (Sweden)

    Mouhamadou Birame Diop

    2015-05-01

    Full Text Available The tin(IV atom in the complex anion of the title salt, (C4H7N2[Sn(C2O4Cl3(H2O], is in a distorted octahedral coordination environment defined by three chlorido ligands, an oxygen atom from a water molecule and two oxygen atoms from a chelating oxalate anion. The organic cation is linked through a bifurcated N—H...O hydrogen bond to the free oxygen atoms of the oxalate ligand of the complex [Sn(H2OCl3(C2O4]− anion. Neighbouring stannate(IV anions are linked through O—H...O hydrogen bonds involving the water molecule and the two non-coordinating oxalate oxygen atoms. In combination with additional N—H...Cl hydrogen bonds between cations and anions, a three-dimensional network is spanned.

  19. Indium extraction by an acidic extractant associated or not with synergetic agents: importance of inorganic anions

    International Nuclear Information System (INIS)

    Goetz-Grandmont, G.; Taheri, M.; Brunette, J.P.; Leroy, M.J.F.

    1985-01-01

    Thermodynamic data are presented for indium extraction from low acidity media (pH value between 1 and 4) and at low concentration by a chelating extractant alone or associated to a solvatant or a lipophylic ammonium salt. Modifications in the nature and/or concentration of inorganic anions can transform the extraction process and allow to change metal distribution between phases [fr

  20. Selective Removal of Toxic Metals like Copper and Arsenic from Drinking Water Using Phenol-Formaldehyde Type Chelating Resins

    Directory of Open Access Journals (Sweden)

    Debasis Mohanty

    2009-01-01

    Full Text Available The concentration of different toxic metals has increased beyond environmentally and ecologically permissible levels due to the increase in industrial activity. More than 100 million people of Bangladesh and West Bengal in India are affected by drinking ground water contaminated with arsenic and some parts of India is also affected by poisoning effect of copper, cadmium and fluoride. Different methods have been evolved to reduce the arsenic concentration in drinking water to a maximum permissible level of 10 μg/L where as various methods are also available to separate copper from drinking water. Of the proven methods available today, removal of arsenic by polymeric ion exchangers has been most effective. While chelating ion exchange resins having specific chelating groups attached to a polymer have found extensive use in sorption and pre concentration of Cu2+ ions. Both the methods are coupled here to separate and preconcentrate toxic metal cation Cu2+ and metal anion arsenate(AsO4– at the same time. We have prepared a series of low-cost polymeric resins, which are very efficient in removing copper ion from drinking water and after coordinating with copper ion they act as polymeric ligand exchanger, which are efficiently removing arsenate from drinking water. For this purpose Schiff bases were prepared by condensing o-phenylenediamine with o-, m-, and p-hydroxybenzaldehydes. Condensing these phenolic Schiff bases with formaldehyde afforded the chelating resins in high yields. These resins are loaded with Cu2+, Ni2+ 2+, and Fe3+ ions. The resins and the polychelates are highly insoluble in water. In powdered form the metal ion-loaded resins are found to very efficiently remove arsenate ion from water at neutral pH. Resins loaded with optimum amount of Cu2+ ion is more effective in removing arsenate ions compared to those with Fe3+ ion, apparently because Cu2+ is a stronger Lewis acid than Fe3+. Various parameters influencing the removal of the

  1. Theoretical analysis of the influence of chelate-ring size and vicinal effects on electronic circular dichroism spectra of cobalt(III) EDDA-type complexes.

    Science.gov (United States)

    Wang, Ai; Wang, Yuekui; Jia, Jie; Feng, Lixia; Zhang, Chunxia; Liu, Linlin

    2013-06-20

    To assess the contributions of configurational and vicinal effects as well as chelate-ring size to rotational strengths, the geometries of a series of cobalt(III) complexes [Co(EDDA-type)(L)](±) with the tetradentate EDDA-type ligands, EDDA (ethylenediamine-N,N'-diacetate), DMEDDA (N,N'-dimethylethylenediamine-N,N'-diacetate), DEEDDA (N,N'-diethylethylenediamine-N,N'-diacetate), and a bidentate ancillary ligand L (L = ethylenediamine, oxalate, carbonate, (S)-alanine, and malonate) in aqueous solution have been optimized at the DFT/B3LYP/6-311++G(2d,p) level of theory. Based on the optimized geometries, the excitation energies and oscillator and rotational strengths have been calculated using the time-dependent density functional theory (TDDFT) method with the same functional and basis set. The calculated circular dichroism (CD) curves are in excellent agreement with the observed ones except for some small red or blue shifts in peak wavelengths. For the influence of chelate-ring size of the bidentate ligands on the CD intensities, a qualitative analysis together with the quantitative TDDFT calculation reveal that it depends on the symmetry of the cobalt-EDDA backbone. For the s-cis-isomers, the influence is negligible due to the perturbation is symmetric. For the uns-cis-isomers, the perturbation is unsymmetric. Since a small ring size means a large perturbation, this leads to the integral CD intensities decreasing with increasing the chelate ring size. The vicinal effects of asymmetric nitrogens incorporate both the substitutent effects and conformational relaxation effects, with the former being dominant. By analyzing the contributions of chiral arrays to rotational strengths, we found that the part of contributions dominated by the S-type chiral nitrogens could be considered as a good measure for the vicinal effects of chiral nitrogens. In addition, we found that the twist form (δ/λ) of the backbone ethylenediamine ring (E-ring) of the coordinated EDDA

  2. The architecture of metal coordination groups in proteins.

    Science.gov (United States)

    Harding, Marjorie M

    2004-05-01

    A set of tables is presented and a survey given of the architecture of metal coordination groups in a representative set of protein structures from the Protein Data Bank [Bernstein et al. (1977), J. Mol. Biol. 112, 535-542; Berman et al. (2000), Nucleic Acids Res. 28, 235-242]. The structures have been determined to a resolution of 2.5 A or better; the metals considered are Ca, Mg, Mn, Fe, Cu, Zn, Na and K, with particular emphasis on Ca and Zn and the exclusion of haem groups and Fe/S clusters; the proteins are a representative set in which none has more than 30% sequence identity with any other. In them the metal is coordinated by several donor groups from different amino-acid residues in the protein chain and often also by water or other small molecules. The tables, for approximately 600 metal coordination groups, include information on the conformations of the protein chain in the region around the metal and reliability indicators. They illustrate the wide variety of coordination numbers, chelate-loop sizes and other properties and the different characteristics of different metals. They show that glycine has a particular significance in the position adjacent to a donor residue, especially in Ca coordination groups. They also show that metal coordination does not appear to lead to significant distortions of the torsion angles phi, psi from their normally allowed values. Very few metal coordination groups occur more than once in the representative set and when they do they are usually related in fold and function; they have similar but not necessarily identical conformations. However, individual chelate loops, for example Zn(-C-X-X'-C-), in which both cysteines are coordinated to Zn through S, and X and X' are any amino acids, are repeated frequently in many different and unrelated proteins. Not all chelate loops with the same composition have the same conformation, but for smaller loops there are usually one or two strongly preferred and well defined

  3. Tetrathiafulvalene-based azine ligands for anion and metal cation coordination

    Directory of Open Access Journals (Sweden)

    Awatef Ayadi

    2015-08-01

    Full Text Available The synthesis and full characterization of two tetrathiafulvalene-appended azine ligands, namely 2-([2,2’-bi(1,3-dithiolylidene]-4-yl-6-((2,4-dinitrophenylhydrazonomethylpyridine (L1 and 5-([2,2’-bi(1,3-dithiolylidene]-4-yl-2-((2,4-dinitrophenylhydrazonomethylpyridine (L2 are described. The crystal structure of ligand L1 indicates that the ligand is completely planar with the presence of a strong intramolecular N3–H3···O1 hydrogen bonding. Titration experiments with inorganic anions showed that both ligands are suitable candidates for the sensing of fluoride anions. Ligand L2 was reacted with a Re(I cation to yield the corresponding rhenium tricarbonyl complex 3. In the crystal structure of the newly prepared electroactive rhenium complex the TTF is neutral and the rhenium cation is hexacoordinated. The electrochemical behavior of the three compounds indicates that they are promising for the construction of crystalline radical cation salts.

  4. Bis(N-ethyl-N-methyldithiocarbamato-κ2S,S′diphenyltin(IV

    Directory of Open Access Journals (Sweden)

    Amirah Faizah Muthalib

    2010-04-01

    Full Text Available The dithiocarbamate anions in the title compound, [Sn(C6H52(C4H8NS22], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The molecule lies across a twofold rotation axis.

  5. Bis(N-isopropyl-N-methyldithiocarbamato-κ2S,S′diphenyltin(IV

    Directory of Open Access Journals (Sweden)

    Amirah Faizah Muthalib

    2010-04-01

    Full Text Available The dithiocarbamate anions in the title compound, [Sn(C6H52(C5H10NS22], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The molecule lies across a twofold rotation axis.

  6. α-Oxo-Ketenimines from Isocyanides and α-Haloketones: Synthesis and Divergent Reactivity.

    Science.gov (United States)

    Mamboury, Mathias; Wang, Qian; Zhu, Jieping

    2017-09-18

    The palladium-catalyzed reaction of α-haloketones with isocyanides afforded α-oxo-ketenimines through β-hydride elimination of the β-oxo-imidoyl palladium intermediates. Reaction of these relatively stable α-oxo-ketenimines with nucleophiles such as hydrazines, hydrazoic acid, amines, and Grignard reagent afforded pyrazoles, tetrazole, β-keto amidines, and enaminone, respectively, with high chemoselectivity. Whereas amines attack exclusively on the ketenimine functions, the formal [3+2] cycloaddition between N-monosubstituted hydrazines and α-oxo-ketenimines was initiated by nucleophilic addition to the carbonyl group. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Silver(i) complexes with 1'-(diphenylphosphino)-1-cyanoferrocene: the art of improvisation in coordination.

    Science.gov (United States)

    Škoch, Karel; Uhlík, Filip; Císařová, Ivana; Štěpnička, Petr

    2016-06-28

    1'-(Diphenylphosphino)-1-cyanoferrocene () reacts with silver(i) halides at a 1 : 1 metal-to-ligand ratio to afford the heterocubane complexes [Ag(μ3-X)(-κP)]4, where X = Cl (), Br (), and I (). In addition, the reaction with AgCl with 2 equiv. of leads to chloride-bridged dimer [(μ-Cl)2{Ag(-κP)2}2] () and, presumably, also to [(μ(P,N)-){AgCl(-κP)}]2 (). While similar reactions with AgCN furnished only the insoluble coordination polymer [(-κP)2Ag(NC)Ag(CN)]n (), those with AgSCN afforded the heterocubane [Ag(-κP)(μ-SCN-S,S,N)]4 () and the thiocyanato-bridged disilver(i) complex [Ag(-κP)2(μ-SCN-S,N)]2 (), thereby resembling reactions in the AgCl- system. Attempted reactions with AgF led to ill-defined products, among which [Ag(-κP)2(μ-HF2)]2 () and [(μ-SiF6){Ag(-κP)2}2] () could be identified. The latter compound was prepared also from Ag2[SiF6] and . Reactions between and AgClO4 or Ag[BF4] afforded disilver complexes [(μ(P,N)-)Ag(ClO4-κO)]2 () and [(μ(P,N)-)Ag(BF4-κF)]2 () featuring pseudolinear Ag(i) centers that are weakly coordinated by the counter anions. A similar reaction with Ag[SbF6] followed by crystallization from ethyl acetate produced an analogous complex, albeit with coordinated solvent, [(μ(P,N)-)Ag(AcOEt-κO)]2[SbF6]2 (). Ultimately, a compound devoid of any additional ligands at the Ag(i) centers, [(μ(P,N)-)Ag]2[B(C6H3(CF3)2-3,5)4]2 (), was obtained from the reaction of with silver(i) tetrakis[3,5-bis(trifluoromethyl)phenyl]borate. The reaction of Ag[BF4] with two equivalents of produced unique coordination polymer [Ag(-κP)(μ(P,N)-)]n[BF4]n (), the structure of which contained one of the phosphinoferrocene ligands coordinated as a P,N-chelate and the other forming a bridge to an adjacent Ag(i) center. All of these compounds were structurally characterized by single-crystal X-ray crystallography, revealing that the lengths of the bonds between silver and its anionic ligand(s) typically exceed the sum of the respective

  8. Coordination Polymer Gels by Electron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Ha; Cho, Young Je; Jung, Jong Hwa [Gyeongsang National Univ., Jinju (Korea, Republic of)

    2011-07-01

    Hydrogenation of a pyridine derivative possessing tetrazole moieties as end groups, without long alkyl chain groups, results in the formation of a Mg(NO{sub 3}){sub 2} coordination polymer gel. The polymer exhibits a strong fluorescence enhancement upon gel formation. 1 can also be gloated with a variety of magnesium anions such as SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Cl{sup -}, Br{sup -} and I{sup -}, indicating that the coordination polymer gel formation of 1 does not strongly depends on anions. The Seam and ABM images of Mg{sup 2+} coordination polymer gel 1 display a flabbier network with several micrometers long, widths in the range 60-70 nm and thicknesses of about 3 nm. In addition, photophysical studies show that the hydrogel exhibits a typical {pi}-{pi} transition and gives rise to high fluorescence behavior. The coordination polymer hydrogel exhibits viscoelastic behavior as evidenced from the rheological studies.

  9. Chemistry of oxovanadium(IV) bound to tetradentate ONNO donors; influence of axial coordination on the V-Osub(1) bond

    International Nuclear Information System (INIS)

    Maity, A.; Ghosh, S.

    1992-01-01

    Chelating behaviour of some tetradentate ONNO donors from q-aminobenzoylhydrazide and some diketones towards oxo-vanadium(IV) ion is reported. The donors react with oxometal cation depending on the pH of the reaction medium. The product containing the neutral keto and the binegative enol form of the donor have the formulae [Vo(H 2 L)(SO 4 )](at pH 3.0)(1) and [VO(L)(H 2 O)] (at pH 6.0) (2) respectively [H 2 L=(2-NH 2 )C 6 H 4 CONH: C(R).(CH 2 ) m C(R) : NNH CO.C 6 H 4 (2-NH 2 ); H 2 L=H 2 DA(R=CH 3 , m=0), H 2 BA(R=C 6 H 5 , m=0), H 2 AA(R=CH 3 , m=2)]. Both (1) and (2) react with a neutral monodentate donor B(B=pyridine, aniline etc.) yielding mixed-ligand complexes [VO(L)(B)]. Influence of the axial coordination on the V-Osub((1)) bond is discussed and a monomeric distorted octahedral donor environment for the oxovanadium(IV) ion has been suggested. (author). 2 refs., 2 tabs., 3 figs

  10. A Mononuclear Non-Heme Manganese(IV)-Oxo Complex Binding Redox-Inactive Metal Ions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Junying; Lee, Yong-Min; Davis, Katherine M.; Wu, Xiujuan; Seo, Mi Sook; Cho, Kyung-Bin; Yoon, Heejung; Park, Young Jun; Fukuzumi, Shunichi; Pushkar, Yulia N.; Nam, Wonwoo [Ewha; (Purdue); (Osaka)

    2013-05-29

    Redox-inactive metal ions play pivotal roles in regulating the reactivities of high-valent metal–oxo species in a variety of enzymatic and chemical reactions. A mononuclear non-heme Mn(IV)–oxo complex bearing a pentadentate N5 ligand has been synthesized and used in the synthesis of a Mn(IV)–oxo complex binding scandium ions. The Mn(IV)–oxo complexes were characterized with various spectroscopic methods. The reactivities of the Mn(IV)–oxo complex are markedly influenced by binding of Sc3+ ions in oxidation reactions, such as a ~2200-fold increase in the rate of oxidation of thioanisole (i.e., oxygen atom transfer) but a ~180-fold decrease in the rate of C–H bond activation of 1,4-cyclohexadiene (i.e., hydrogen atom transfer). The present results provide the first example of a non-heme Mn(IV)–oxo complex binding redox-inactive metal ions that shows a contrasting effect of the redox-inactive metal ions on the reactivities of metal–oxo species in the oxygen atom transfer and hydrogen atom transfer reactions.

  11. Synthesis, structure and properties of oxo- and dioxochloride complexes of molybdenum(VI) and tungsten(VI) with 8-oxyquinoline

    International Nuclear Information System (INIS)

    Abramenko, V.L.; Sergienko, V.S.; Egorova, O.A.

    2005-01-01

    Complexes of oxo- and dioxochlorides of molybdenum(VI) and tungsten(VI) with 8-oxyquinoline of molecular and intracomplex type are synthesized and studied by the method of IR spectroscopy. The complexes have octahedral structure. It is proposed that 8-oxyquinoline in molecular complexes is coordinated by central atom through nitrogen atom of heterocycle, but in intracomplex compounds - through heterocyclic nitrogen atom and oxygen atom of deprotonated OH-group. Thermal stability of the complexes is studied [ru

  12. Er2S[SiO4]: An erbium sulfide ortho-oxosilicate with unusual sulfide anion coordination

    International Nuclear Information System (INIS)

    Hartenbach, Ingo; Lauxmann, Petra; Schleid, Thomas

    2004-01-01

    During the reaction of cadmium sulfide with erbium and sulfur in evacuated silica ampoules pink lath-shaped crystals of Er 2 S[SiO 4 ] occur as by-product which were characterized by X-ray single crystal structure analysis. The title compound crystallizes orthorhombically in the space group Cmce (a = 1070.02(8), b = 1235.48(9), c = 683.64(6) pm) with eight formula units per unit cell. Besides isolated ortho-oxosilicate units [SiO 4 ] 4- , the crystal structure contains two crystallographically independent Er 3+ cations which are both eightfold coordinated by six oxygen and two sulfur atoms. The sulfide anions are surrounded by four erbium cations each in the shape of very distorted tetrahedra. These excentric [SEr 4 ] 10+ tetrahedra build up layers according to 2 ∞ [SEr 4/2 ] 4+ by vertex- and edge-connection. They are piled parallel to (010) and separated by the isolated ortho-oxosilicate tetrahedra. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [de

  13. Bis(N-ethyl-N-methyl?dithio?carbamato-?2 S,S?)diphenyl?tin(IV)

    OpenAIRE

    Muthalib, Amirah Faizah; Baba, Ibrahim; Ng, Seik Weng

    2010-01-01

    The dithio?carbamate anions in the title compound, [Sn(C6H5)2(C4H8NS2)2], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol?ecule lies across a twofold rotation axis.

  14. Bis(N-isopropyl-N-methyl-dithio-carbamato-κS,S')diphenyl-tin(IV).

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Farina, Yang; Ng, Seik Weng

    2010-03-03

    The dithio-carbamate anions in the title compound, [Sn(C(6)H(5))(2)(C(5)H(10)NS(2))(2)], chelate to the Sn(IV) atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol-ecule lies across a twofold rotation axis.

  15. Bis(N-isopropyl-N-methyl?dithio?carbamato-?2 S,S?)diphenyl?tin(IV)

    OpenAIRE

    Muthalib, Amirah Faizah; Baba, Ibrahim; Farina, Yang; Ng, Seik Weng

    2010-01-01

    The dithio?carbamate anions in the title compound, [Sn(C6H5)2(C5H10NS2)2], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol?ecule lies across a twofold rotation axis.

  16. Bis(N-ethyl-N-methyl-dithio-carbamato-κS,S')diphenyl-tin(IV).

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Ng, Seik Weng

    2010-03-03

    The dithio-carbamate anions in the title compound, [Sn(C(6)H(5))(2)(C(4)H(8)NS(2))(2)], chelate to the Sn(IV) atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol-ecule lies across a twofold rotation axis.

  17. Chelation in metal intoxication

    DEFF Research Database (Denmark)

    Aaseth, Jan; Skaug, Marit Aralt; Cao, yang

    2015-01-01

    The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the incon......The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due...... to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new...

  18. Chelating extractants of improved selectivity. Progress report, 1 August 1979-31 July 1980

    International Nuclear Information System (INIS)

    1980-01-01

    During the current contract year, mixed ligand chelate extraction systems for separating lanthanides was extended to elucidating the underlying reasons for the observed enhancement by quaternary ammonium salts. Equilibrium studies reveal the formation of anionic complexes (LnL 4 .HL - ) (where HL is 8-quinolinol) that was extracted when paired with a quaternary ammonium ion. Lathanum, as a lone exception was extracted as R 4 N + , LaL 4 - . Work is underway in the application of similar extractants, 5,7-dibromo-8-quinolinol and Kelex 100 (a 7-alkenyl-8-quinolinol) to the separation of lanthanides

  19. Chelation Therapy for Mercury Poisoning

    OpenAIRE

    Rong Guan; Han Dai

    2009-01-01

    Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role o...

  20. Chelating extractants of improved selectivity. Progress report for period November 1, 1977--July 31 1978

    International Nuclear Information System (INIS)

    Freiser, H.

    1978-08-01

    During the current contract period, the high susceptibility of lanthanide chelate stability to steric hindrance was confirmed. The increase in coordination number of lanthanides from lanthanum to ytterbium as evidenced from extraction equilibria serves to increase their separability. 8-Quinolinol immobilized on silica can separate lanthanide ions

  1. New borohydride anion B6H7-

    International Nuclear Information System (INIS)

    Kuznetsov, I.Yu.; Vinitskij, D.M.; Solntsev, K.A.

    1985-01-01

    The [Ni(Bipy) 3 ] (B 6 H 7 ) 2 , (Ph 4 P)B 6 H 7 , [Ni(Phen) 3 ](B 6 H 7 ) 2 crystals (where Bipy = bipyridine, Phen = phenathroline, Ph = phenyl) are obtained via the exchange reaction with a subsequent recrystallization from aqua-acetonic and acetonic solutions. The structure is studied of a new borohydride anion B 6 H 7 - possessing a four-valence bond unique for polyhedral borohydride anions. A triangular face of boride skeleton coordinating a hydrogen atom is considerably larger than other faces, and the electron density on this hydrogen atom is evidently much higher than at the end hydride hydrogen atoms. The trend of B 6 H 7 - anion to form statistically disordered structurs testifies to a rather slight effect of the seventh hydrogen atom position on the structure pattern of the ionic crystal lattice

  2. Synthesis of Two New Group 13 Benzoato-Chloro Complexes: A Structural Study of Gallium and Indium Chelating Carboxylates

    Science.gov (United States)

    Duraj, Stan A.; Hepp, Aloysius F.; Woloszynek, Robert; Protasiewicz, John D.; Dequeant, Michael; Ren, Tong

    2010-01-01

    Two new heteroleptic chelated-benzoato gallium (III) and indium (III) complexes have been prepared and structurally characterized. The molecular structures of [GaCl2(4-Mepy)2(O2CPh)]4-Mepy (1) and [InCl(4-Mepy)2(O2CPh)2]4-Mepy (2) have been determined by single-crystal x-ray diffraction. The gallium compound (1) is a distorted octahedron with cis-chloride ligands co-planar with the chelating benzoate and the 4-methylpyridines trans to each other. This is the first example of a Ga(III) structure with a chelating benzoate. The indium compound (2) is a distorted pentagonal bipyramid with two chelating benzoates, one 4-methylpyridine in the plane and a chloride trans to the other 4-methylpyridine. The indium bis-benzoate is an unusual example of a seven-coordinate structure with classical ligands. Both complexes, which due to the chelates, could also be described as pseudo-trigonal bipyramidal, include a three-bladed motif with three roughly parallel aromatic rings that along with a solvent of crystallization and electron-withdrawing chloride ligand(s) stabilize the solid-state structures.

  3. Copper and Zinc Chelation as a Treatment of Alzheimer's Disease

    Science.gov (United States)

    Hodak, Miroslav; Bernholc, Jerry

    2014-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. The cause of the disease remains unknown, but amyloid- β (A β), a short peptide, is considered causal its pathogenesis. At cellular level, AD is characterized by deposits mainly composed of A β that also contain elevated levels of transition metals ions. Targeting metals is a promising new strategy for AD treatment, which uses moderately strong metal chelators to sequester them from A β or the environment. PBT2 is a chelating compound that has been the most promising in clinical trials. In our work, we use computer simulations to investigate complexes of a close analog of PBT2 with Cu2+ and Zn2+ ions. The calculations employ KS/FD DFT method, which combines Kohn-Sham DFT with the frozen-density DFT to achieve efficient description of explicit solvent beyond the first solvation shell. Our work is based on recent experiments and examines both 1:1 and 2:1 chelator-metal stochiometries detected experimentally. The results show that copper attaches more strongly than zinc, find that 1:1 complexes involve water in the first coordination shell and determine which one of several possible 2:1 geometries is the most preferable.

  4. Inhibition of filiform corrosion on organic-coated AA2024-T3 by smart-release cation and anion-exchange pigments

    International Nuclear Information System (INIS)

    Williams, G.; McMurray, H.N.

    2012-01-01

    Highlights: ► Filiform corrosion (FFC) inhibition by various smart-release pigments was evaluated by SKP. ► Rare earth cation-containing pigments were ineffective at halting FFC propagation. ► Metal oxo-anions and organic copper-specific agents were exchanged into hydrotalcite. ► Effective inhibition of FFC was demonstrated by anions which stopped copper re-plating. - Abstract: In-coating cation and anion exchange pigments are studied with respect to their ability to inhibit chloride-induced filiform corrosion (FFC) on organic-coated AA2024-T3 aluminium alloy substrates. In-situ scanning Kelvin probe potentiometry is used to quantify both underfilm potentials associated with populations of propagating corrosion filaments and the kinetics of coating disbondment. Smart-release bentonite pigments containing exchangeable cerium (III) and yttrium (III) cations are shown to be largely ineffective in reducing rates of FFC propagation. The reasons for this are discussed in terms of the chemistry of the electrolyte-filled corrosion filament head. In contrast, anion-exchange hydrotalcite (HT) based pigments are highly effective inhibitors of FFC. A comparison of the extent of FFC observed for various inorganic exchangeable anions is made with as-received HT comprising carbonate anions. Of the anions evaluated, exchangeable chromate unsurprisingly provides the highest FFC inhibition efficiency. It is also demonstrated that exchanging the native carbonate ions for certain organic species which act as complexing agents for copper ions, gives rise to an equivalent level of FFC inhibition. The implication of these findings with respect to the mechanism of FFC on copper containing aluminium alloys is considered.

  5. Preparation and properties of a monomeric Mn(IV)-oxo complex.

    Science.gov (United States)

    Parsell, Trenton H; Behan, Rachel K; Green, Michael T; Hendrich, Michael P; Borovik, A S

    2006-07-12

    Manganese-oxo complexes have long been investigated because of their proposed roles in biological and chemical catalysis. However, there are few examples of monomeric complexes with terminal oxo ligands, especially those with oxomanganese(IV) units. A oxomanganese(IV) complex has been prepared from [MnIIIH3buea(O)]2- ([H3buea]3-, tris[(N'-tert-butylureaylato)-N-ethylene]aminato), a monomeric MnIII-O complex in which the oxo ligand arises from cleavage of dioxygen. Treating [MnIIIH3buea(O)]2- with [Cp2Fe]BF4 in either DMF at -45 degrees C or DMSO at room temperature produces [MnIVH3buea(O)]-: lambdamax = 635 nm; nu(Mn-16O) = 737 cm-1; nu(Mn-18O) = 709 cm-1; g = 5.15, 2.44, 1.63, D = 3.0 cm-1, E/D = 0.26, aMn = 66 G (A = 190 MHz). These spectroscopic properties support the assignment of a mononuclear MnIV-oxo complex with an S = 3/2 ground state. Density functional theory supports this assignment and the Jahn-Teller distortion around the high-spin MnIV center that would alter the molecular structure of [MnIVH3buea(O)]- from trigonal symmetry (as indicated by the highly rhombic EPR signal). [MnIVH3buea(O)]- is relatively unstable in DMSO, converting to [MnIIIH3buea(OH)]- via a proposed X-H bond cleavage. [MnIVH3buea(O)]- reacts with 1,2-diphenylhydrazine to from azobenzene (95% yield) and [MnIIIH3buea(OH)]-. The MnIV-oxo does not react with triphenyl- or tricyclohexylphosphine. However, O-atom transfer is observed with methyldiphenylphosphine and dimethylphenylphosphine, producing the corresponding phosphine oxides. These results illustrate the diverse reactivity of the MnIV-oxo unit.

  6. Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

    OpenAIRE

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

    2014-01-01

    In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as su...

  7. Tetraammine(carbonato-κ(2) O,O')cobalt(III) perchlorate.

    Science.gov (United States)

    Mohan, Singaravelu Chandra; Jenniefer, Samson Jegan; Muthiah, Packianathan Thomas; Jothivenkatachalam, Kandasamy

    2013-01-01

    In the title complex, [Co(CO3)(NH3)4]ClO4, both the cation and anion lie on a mirror plane. The Co(III) ion is coordinated by two NH3 ligands and a chelating carbonato ligand in the equatorial sites and by two NH3 groups in the axial sites, forming a distorted octa-hedral geometry. In the crystal, N-H⋯O hydrogen bonds connect the anions and cations, forming a three-dimensional network.

  8. Subtle interactions and electron transfer between UIII, NpIII, or PuIII and uranyl mediated by the oxo group

    International Nuclear Information System (INIS)

    Arnold, Polly L.; Zegke, Markus; Hollis, Emmalina; Pecharman, Anne-Frederique; Love, Jason B.; Dutkiewicz, Michal S.; Walter, Olaf; Apostolidis, Christos; Magnani, Nicola; Griveau, Jean-Christophe; Colineau, Eric; Caciuffo, Roberto; Zhang, Xiaobin; Schreckenbach, Georg

    2016-01-01

    A dramatic difference in the ability of the reducing An III center in AnCp 3 (An=U, Np, Pu; Cp=C 5 H 5 ) to oxo-bind and reduce the uranyl(VI) dication in the complex [(UO 2 )(THF)(H 2 L)] (L=''Pacman'' Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp 3 U forms the U IV -uranyl(V) compound that behaves as a U V -localized single molecule magnet below 4 K. The extent of reduction by the Cp 3 Np group upon oxo-coordination is much less, with a Np III -uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np IV U V but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np III -U VI assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu III -U VI interaction is too weak to be observed in THF solvent, in agreement with calculated predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better.

    Science.gov (United States)

    Avedano, Stefano; Botta, Mauro; Haigh, Julian S; Longo, Dario L; Woods, Mark

    2013-08-05

    The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd(3+) chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of monohydrated Gd(3+) chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd(3+)-water proton distance (rGdH), and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd(3+) chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd(3+) chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the relaxivity of a chelate with "optimal" dissociative water exchange kinetics is actually lower than that of an isomeric chelate with "suboptimal" dissociative water exchange. When the rate of molecular tumbling of these chelates is slowed, an approach that has long been understood to increase relaxivity, the observed difference in relaxivity is increased with the more rapidly exchanging ("optimal") chelate exhibiting lower relaxivity than the "suboptimally" exchanging isomer. The difference between the chelates arises from a non-field-dependent parameter: either the hydration number (q) or rGdH. For solution state Gd(3+) chelates, changes in the values of q and rGdH are indistinguishable. These parametric expressions simply describe the hydration state of the chelate--i.e., the number and position of closely associating water molecules. The hydration state (q/rGdH(6)) of a chelate is intrinsically linked to its dissociative water exchange rate kex, and the interrelation of these parameters must be considered when examining the relaxivity of Gd(3+) chelates. The data presented herein indicate that the changes in the hydration parameter (q/rGdH(6)) associated with changing dissociative

  10. Solvation of the fluorine containing anions and their lithium salts in propylene carbonate and dimethoxyethane.

    Science.gov (United States)

    Chaban, Vitaly

    2015-07-01

    Electrolyte solutions based on the propylene carbonate (PC)-dimethoxyethane (DME) mixtures are of significant importance and urgency due to emergence of lithium-ion batteries. Solvation and coordination of the lithium cation in these systems have been recently attended in detail. However, analogous information concerning anions (tetrafluoroborate, hexafluorophosphate) is still missed. This work reports PM7-MD simulations (electronic-structure level of description) to include finite-temperature effects on the anion solvation regularities in the PC-DME mixture. The reported result evidences that the anions appear weakly solvated. This observation is linked to the absence of suitable coordination sites in the solvent molecules. In the concentrated electrolyte solutions, both BF4(-) and PF6(-) prefer to exist as neutral ion pairs (LiBF4, LiPF6).

  11. Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

    Science.gov (United States)

    Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

    2014-01-01

    Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P = 0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P = 0.0002) and a 43% reduction in total mortality (P = 0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

  12. μ-4,4′-Bipyridine-κ2N:N′-bis[aqua(4,4′-bipyridine-κN(l-valinato-κ2N,Ocopper(II] dinitrate dihydrate

    Directory of Open Access Journals (Sweden)

    Mao-Chun Hong

    2008-02-01

    Full Text Available In the title dinuclear complex, [Cu2(C5H10NO22(C10H8N23(H2O2](NO32·2H2O, each of the two l-valinate anions chelates a CuII center through the amino N and carboxylate O atom, forming a five-membered ring. A 4,4′-bipyridine molecule bridges two water-coordinated Cu atoms, each of which is connected to another 4,4′-bipyridine, giving rise to a square-pyramidal coordination geometry for the CuII centers. The dinuclear dications, nitrate anions and uncoordinated water molecules are linked into a two-dimensional structure.

  13. Crystal structure of bis(cyclohexylammonium diphenyldioxalatostannate(IV

    Directory of Open Access Journals (Sweden)

    Modou Sarr

    2015-02-01

    Full Text Available Reaction of oxalic acid and diphenyltin dichloride in the presence of cyclohexylamine led to the formation of the title salt, (C6H14N2[Sn(C6H52(C2O42]. The dianion is made up from an Sn(C6H52 moiety cis-coordinated by two chelating oxalate anions, leading to an overall distorted octahedral coordination geometry of the SnIV atom. The negative charges are compensated by two surrounding cyclohexylammonium cations adopting chair conformations each. In the crystal, anions and cations are linked via a network of N—H...O hydrogen bonds into a layered arrangement parallel to (101.

  14. Bis(N-ethyl-N-methyl­dithio­carbamato-κ2 S,S′)diphenyl­tin(IV)

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Ng, Seik Weng

    2010-01-01

    The dithio­carbamate anions in the title compound, [Sn(C6H5)2(C4H8NS2)2], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol­ecule lies across a twofold rotation axis. PMID:21580470

  15. Bis(N-isopropyl-N-methyl­dithio­carbamato-κ2 S,S′)diphenyl­tin(IV)

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Farina, Yang; Ng, Seik Weng

    2010-01-01

    The dithio­carbamate anions in the title compound, [Sn(C6H5)2(C5H10NS2)2], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol­ecule lies across a twofold rotation axis. PMID:21580469

  16. Stabilization of very rare tautomers of 1-methylcytosine by an excess electron.

    Science.gov (United States)

    Harańczyk, Maciej; Rak, Janusz; Gutowski, Maciej

    2005-12-22

    We characterized valence anionic states of 1-methylcytosine using various electronic structure methods. We found that the most stable valence anion is related to neither the canonical amino-oxo nor a rare imino-oxo tautomer, in which a proton is transferred from the N4 to N3 atom. Instead, it is related to an imino-oxo tautomer, in which the C5 atom is protonated. This anion is characterized by an electron vertical detachment energy (VDE) of 2.12 eV and it is more stable than the anion based on the canonical tautomer by 1.0 kcal/mol. The latter is characterized by a VDE of 0.31 eV. Another unusual low-lying imino-oxo tautomer with a VDE of 3.60 eV has the C6 atom protonated and is 3.6 kcal/mol less stable than the anion of the canonical tautomer. All these anionic states are adiabatically unbound with respect to the canonical amino-oxo neutral, with the instability of 5.8 kcal/mol for the most stable valence anion. The mechanism of formation of anionic tautomers with carbon atoms protonated may involve intermolecular proton transfer or dissociative electron attachment to the canonical neutral tautomer followed by a barrier-free attachment of a hydrogen atom to the C5 or C6 atom. The six-member ring structure of anionic tautomers with carbon atoms protonated is unstable upon an excess electron detachment. Indeed the neutral systems collapse without a barrier to a linear or a bicyclo structure, which might be viewed as lesions to DNA or RNA. Within the PCM hydration model, the anions become adiabatically bound with respect to the corresponding neutrals, and the two most stable tautomers have a carbon atom protonated.

  17. A general access to organogold(iii) complexes by oxidative addition of diazonium salts.

    Science.gov (United States)

    Huang, Long; Rominger, Frank; Rudolph, Matthias; Hashmi, A Stephen K

    2016-05-11

    At room temperature under mild photochemical conditions, namely irradiation with a simple blue light LED, gold(i) chloro complexes of both phosphane and carbene ligands in combination with aryldiazonium salts afford arylgold(iii) complexes. With chelating P,N-ligands cationic six- or five-membered chelate complexes were isolated in the form of salts with weakly coordinating counter anions that were brought in from the diazonium salt. With monodentate P ligands or N-heterocyclic carbene ligands and diazonium chlorides neutral arylgold(iii) dichloro complexes were obtained. The coordination geometry was determined by X-ray crystal structure analyses of representative compounds, a cis arrangement of the aryl and the phosphane ligand at the square planar gold(iii) center is observed.

  18. Bis(tripyrazol-1-ylmethanenickel(II tetracyanidonickelate(II dihydrate

    Directory of Open Access Journals (Sweden)

    Sean Parkin

    2009-12-01

    Full Text Available The title complex, [Ni(C10H10N62][Ni(CN4]·2H2O, contains an octahedral nickel(II cation and a square-planar nickel(II anion. Both the cation and the anion reside on a crystallographic center of inversion. The NiII center in the cation is coordinated by six pyrazol-1-yl rings of two chelating tripyrazol-1-ylmethane [HC(pz3] ligands, with Ni—N distances that range between 2.0647 (19 and 2.0828 (19 Å. The NiII center in the anion is coordinated by four cyanide ligands, with Ni—C distances in the range 1.869 (2–1.869 (3 Å. The [Ni(CN4]2− anions are linked by inversion-related water molecules into extended chains that run parallel to the a axis.

  19. Tris(2,2′-bipyridine-κ2N,N′cobalt(III bis[bis(pyridine-2,6-dicarboxylato-κ3O2,N,O6cobaltate(III] perchlorate dimethylformamide hemisolvate 1.3-hydrate

    Directory of Open Access Journals (Sweden)

    Irina A. Golenya

    2012-10-01

    Full Text Available In the title compound, [Co(C10H8N23][Co(C7H3NO42]2(ClO4·0.5C3H7NO·1.3H2O, the CoIII atom in the complex cation is pseudooctahedrally coordinated by six N atoms of three chelating bipyridine ligands. The CoIII atom in the complex anion is coordinated by two pyridine N atoms and four carboxylate O atoms of two doubly deprotonated pyridine-2,6-dicarboxylate ligands in a distorted octahedral geometry. One dimethylformamide solvent molecule and two water molecules are half-occupied and one water molecule is 0.3-occupied. O—H...O hydrogen bonds link the water molecules, the perchlorate anions and the complex anions. π–π interactions between the pyridine rings of the complex anions are also observed [centroid–centroid distance = 3.804 (3 Å].

  20. Beliefs about chelation among thalassemia patients

    Directory of Open Access Journals (Sweden)

    Trachtenberg Felicia L

    2012-12-01

    Full Text Available Abstract Background Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy. Methods The Beliefs in Medicine Questionnaire (BMQ was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC of the Thalassemia Clinical Research Network (TCRN. Chelation adherence was based on patient report of doses administered out of those prescribed in the last four weeks. Results Of 371 patients (ages 5-58y, mean 24y, 93% were transfused and 92% receiving chelation (26% deferoxamine (DFO; a slow subcutaneous infusion via portable pump, 63% oral, 11% combination. Patients expressed high “necessity” for transfusion (96%, DFO chelation (92% and oral chelation (89%, with lower “concern” about treatment (48%, 39%, 19% respectively. Concern about oral chelation was significantly lower than that of DFO (p Conclusions Despite their requirement for multimodal therapy, thalassemia patients have positive views about medicine, more so than in other disease populations. Patients may benefit from education about the tolerability of chelation and strategies to effectively cope with side effects, both of which might be beneficial in lowering body iron burden. Clinicaltrials.gov identifier NCT00661804

  1. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  2. Tetraammine(carbonato-κ2 O,O′)cobalt(III) perchlorate

    Science.gov (United States)

    Mohan, Singaravelu Chandra; Jenniefer, Samson Jegan; Muthiah, Packianathan Thomas; Jothivenkatachalam, Kandasamy

    2013-01-01

    In the title complex, [Co(CO3)(NH3)4]ClO4, both the cation and anion lie on a mirror plane. The CoIII ion is coordinated by two NH3 ligands and a chelating carbonato ligand in the equatorial sites and by two NH3 groups in the axial sites, forming a distorted octa­hedral geometry. In the crystal, N—H⋯O hydrogen bonds connect the anions and cations, forming a three-dimensional network. PMID:24109252

  3. Article Commentary: Chelation Therapy for Mercury Poisoning

    Directory of Open Access Journals (Sweden)

    Rong Guan

    2009-01-01

    Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

  4. Use of mass spectrometry for study of coordination compounds

    International Nuclear Information System (INIS)

    Gehrbehlehu, N.V.; Indrichan, K.M.

    1981-01-01

    A review on mass-spectrometry of coordination compounds including the works published up to 1979 inclusive is provided. Mainly the products of metals with bi- and tetradentate ligands are considered using the method. Mo and Be carboxylates for which molecular ions lines are found in mass-spectra are studied. The study of mass-spectra for VO chelates with thiosemicarbazone of salicyl aldehyde is carried out. Application of the mass-spectrometry method permits to establish the mass of coordination compounds, the structure of complexes, dentate structure and the way of ligand coordination, the bond strength [ru

  5. Complexation studies of actinides (U, Pu, Am) with linear polyamino-carboxylate ligands and sidero-chelates

    International Nuclear Information System (INIS)

    Nguyen, L.V.

    2010-01-01

    As part of our research endeavour aimed at developing and improving decontamination processes of wastewater containing alpha emitters, physico-chemical complexation studies of actinides (U, Pu, Am) with organic open-chain ligands such as poly-aminocarboxylic acids (H 4 EDTA) and sidero-chelates (di-hydroxamic acids and desferrioxamine B) have been carried out. Gaining a clear understanding of the coordination properties of the targeted actinides is an essential step towards the selection of the most appropriate chelating agents that will exhibit high uptake efficiencies. EXAFS (Extended X-ray Absorption Fine Structure) measurements at the ESRF synchrotron enabled to elucidate the coordination scheme of uranium and plutonium complexes. Solution thermodynamic investigations were intended to provide valuable information about the nature and the stability of the uranium(VI) and americium(III) complexes prevailing at a given pH in solution. The set of stability constants determined from potentiometric and UV-visible spectrophotometric titrations, allowed to predict the speciation of the selected actinides in presence of the aforementioned ligands and to determine the pH range required for achieving 'ultimate' decontamination. (author) [fr

  6. A concise synthesis of the potent inflammatory mediator 5-oxo-ETE

    DEFF Research Database (Denmark)

    Tyagi, Rahul; Shimpukade, Bharat; Blättermann, Stefanie

    2012-01-01

    A concise and practical method for synthesis of the potent inflammatory mediator 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE, 1) from arachidonic acid in four steps and 70% overall yield is reported. Stability studies indicate that 1 can be safely handled without rigorous precautions...

  7. Measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-guanosine in cerebrospinal fluid by ultra performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Weimann, Allan; Simonsen, Anja Hviid; Poulsen, Henrik E

    2018-01-15

    Increased levels of nucleosides modified by oxidation in human cerebrospinal fluid (CSF) have several times been reported in Alzheimer patients and patients suffering from Parkinson's disease. The focus has especially been on nucleosides containing the 8-hydroxylation of guanine. Only few reports on quantification of the ribonucleoside 8-oxo-7,8-dihydro-guanosine (8oxoGuo) in CSF have been published, whereas more have been published on the quantification of the deoxy-ribonucleoside 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxodGuo). The reports on the quantification of 8oxodGuo concentrations in CSF report absolute concentrations varying by a factor >10 5 in healthy humans. This could indicate that there is a serious specificity problem in some of the methods. In this paper an isotope-dilution UPLC-MS/MS method with high specificity and sensitivity for the quantification of 8oxoGuo and 8oxodGuo in CSF is presented. LLOQ for the two analytes is determined to 4pM and 2pM, respectively. The calibration curves has been tested to be linear in the range from 4 to 3,000pM for 8oxoGuo and between 2 and 3,000pM for 8oxodGuo. Using a weighting factor of 1/x the correlation coefficient "r" for both analytes is >0.999. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Synthesis, characterisation and anion exchange properties of copper, magnesium, zinc and nickel hydroxy nitrates

    Science.gov (United States)

    Biswick, Timothy; Jones, William; Pacuła, Aleksandra; Serwicka, Ewa

    2006-01-01

    Anion exchange reactions of four structurally related hydroxy salts, Cu 2(OH) 3NO 3, Mg 2(OH) 3NO 3, Ni 2(OH) 3NO 3 and Zn 3(OH) 4(NO 3) 2 are compared and trends rationalised in terms of the strength of the covalent bond between the nitrate group and the matrix cation. Powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and elemental analysis are used to characterise the materials. Replacement of the nitrate anions in the zinc and copper salts with benzoate anions is possible although exchange of the zinc salt is accompanied by modification of the layer structure from one where zinc is exclusively six-fold coordinated to a structure where there is both six- and four-fold zinc coordination. Magnesium and nickel hydroxy nitrates, on the other hand, hydrolyse to their respective metal hydroxides.

  9. Crystal structure of tris[4-(dimethylaminopyridinium] tris(oxalato-κ2O,O′chromate(III tetrahydrate

    Directory of Open Access Journals (Sweden)

    Noé Makon ma Houga

    2015-11-01

    Full Text Available In the title hybrid salt, (C7H11N23[Cr(C2O43]·4H2O, the central CrIII ion of the complex anion (point group symmetry 2 is coordinated by six O atoms from three chelating oxalate(2− ligands in a slightly distorted octahedral coordination sphere. The Cr—O bond lengths vary from 1.9577 (11 to 1.9804 (11 Å, while the chelate O—Cr—O angles range from 82.11 (6 to 93.41 (5°. The 4-(dimethylaminopyridinium cations (one situated in a general position and one on a twofold rotation axis are protonated at the pyridine N atoms. In the crystal, N—H...O and O—H...O hydrogen bonds link the cations and anions into a three-dimensional network. π–π interactions between the pyridine rings of adjacent cations provide additional stabilization of the crystal packing, with the closest centroid-to-centroid distances being 3.541 (1 and 3.575 (1 Å.

  10. Adsorption characteristics of 14C-labeled alanine, aspartic acid and adenosine triphosphate by metal-chelating resins

    International Nuclear Information System (INIS)

    Ishiyama, Toshio; Matsunami, Tadao; Shibata, Setsuko; Honda, Yoshihide.

    1987-01-01

    (1) Adsorption properties of 14 C-alanine, 14 C-ATP (adenosine triphosphate) and 14 C-aspartic acid on the metal-chelating resins were determined and found that the Cu(II)-Chelex 100 and Fe(III)-Unicellex UR10, Fe(III)-Chelex 100 chelating resins were highly effective for the adsorption of 14 C-alanine and 14 C-ATP, respectively. (2) Desorption rate of 14 C-ATP from the Fe(III)-Unicellex UR10 and Fe(III)-Chelex 100 resins was somewhat higher than the case of 14 C-alanine, probably because the coordination bonds of Cu-alanine might be stronger than those of Fe-ATP. Thus, 14 C-labeled organic compounds such as 14 C-alanine and 14 C-ATP of a low activity concentration (3.7 mBq/ml) (1 x 10 -7 μCi/ml) in aqueous solution may be measured with liquid scintillation counter after pre-concentration by use of the Fe(III)- and Cu(II)-chelating resin columns. (author)

  11. A non-diazo approach to α-oxo gold carbenes via gold-catalyzed alkyne oxidation.

    Science.gov (United States)

    Zhang, Liming

    2014-03-18

    intermolecular approach offers excellent synthetic flexibility because no tethering of the oxidant is required, and its reduced form is not tangled with the product. We were the first research group to develop this strategy, through the use of pyridine/quinolone N-oxides as the external oxidants. In this manner, we can effectively make a C-C triple bond a surrogate of an α-diazo carbonyl moiety in various gold catalyses. With terminal alkynes, we demonstrated that we can efficiently trap exclusively formed terminal carbene centers by internal nucleophiles en route to the formation of cyclic products, including strained oxetan-3-ones and azetidin-3-ones, and by external nucleophiles when a P,N-bidentate ligand is coordinated to gold. With internal alkynes, we generated synthetically useful regioselectivities in the generation of the α-oxo gold carbene moiety, which enables expedient formation of versatile enone products. Other research groups have also applied this strategy en route to versatile synthetic methods. The α-oxo gold carbenes appear to be more electrophilic than their Rh counterpart, which many chemists have focused on in a large array of excellent work on metal carbene chemistry. The ease of accessing the reactive gold carbenes opens up a vast area for developing new synthetic methods that would be distinctively different from the known Rh chemistry and promises to generate a new round of "gold rush".

  12. A Non-Diazo Approach to α-Oxo Gold Carbenes via Gold-Catalyzed Alkyne Oxidation

    Science.gov (United States)

    2015-01-01

    intermolecular approach offers excellent synthetic flexibility because no tethering of the oxidant is required, and its reduced form is not tangled with the product. We were the first research group to develop this strategy, through the use of pyridine/quinolone N-oxides as the external oxidants. In this manner, we can effectively make a C–C triple bond a surrogate of an α-diazo carbonyl moiety in various gold catalyses. With terminal alkynes, we demonstrated that we can efficiently trap exclusively formed terminal carbene centers by internal nucleophiles en route to the formation of cyclic products, including strained oxetan-3-ones and azetidin-3-ones, and by external nucleophiles when a P,N-bidentate ligand is coordinated to gold. With internal alkynes, we generated synthetically useful regioselectivities in the generation of the α-oxo gold carbene moiety, which enables expedient formation of versatile enone products. Other research groups have also applied this strategy en route to versatile synthetic methods. The α-oxo gold carbenes appear to be more electrophilic than their Rh counterpart, which many chemists have focused on in a large array of excellent work on metal carbene chemistry. The ease of accessing the reactive gold carbenes opens up a vast area for developing new synthetic methods that would be distinctively different from the known Rh chemistry and promises to generate a new round of “gold rush”. PMID:24428596

  13. Synthesis of Substituted Oxo-Azepines by Regio- and Diastereoselective Hydroxylation

    Directory of Open Access Journals (Sweden)

    Harold Spedding

    2017-10-01

    Full Text Available Substituted seven-membered N-heterocycles are prevalent bioactive epitopes and useful synthons for preparing enzyme inhibitors or molecular recognition systems. To fully exploit the chemical properties of this flexible N-heterocycle scaffold, efficient methods for its diverse functionalization are required. Here we utilize the late-stage oxidation of tetrahydroazepines as an approach to access densely functionalized oxo-azepines in a total of 8 steps and ~30% overall yield from commercially available starting materials. Hydroboration of tetrahydroazepines proceeded with diastereoselectivity in a substrate-dependent manner to yield regioisomeric azepanols before their oxidation to the corresponding oxo-azepines. Regioselectivity of the hydroboration step may be improved moderately by a rhodium catalyst, albeit with loss of conversion to a competing hydrogenation pathway. Overall our method allows efficient access to azepanols and oxo-azepines as versatile epitopes and synthons with a high degree of diastereoselectivity and moderate regioselectivity.

  14. Facile Arylation of Four-Coordinate Boron Halides by Borenium Cation Mediated Boro-desilylation and -destannylation.

    Science.gov (United States)

    Crossley, Daniel L; Cid, Jessica; Curless, Liam D; Turner, Michael L; Ingleson, Michael J

    2015-12-28

    The addition of AlCl 3 to four-coordinate boranes of the general formula (C-N-chelate)BCl 2 results in halide abstraction and formation of three-coordinate borenium cations of the general formula [(C-N-chelate)BCl] + . The latter react with both arylstannanes and arylsilanes by boro-destannylation and -desilylation, respectively, to form arylated boranes. Catalytic quantities of AlCl 3 were sufficient to effect high-yielding arylation of (C-N-chelate)BCl 2 . Boro-destannylation is more rapid than boro-desilylation and leads to double arylation at the boron center, whereas in reactions with arylsilanes either single or double arylation occurs dependent on the nucleophilicity of the arylsilane and on the electrophilicity of the borenium cation. The electrophilicity of the borenium cation derived from 2-phenylpyridine was greater than that of the benzothiadiazole analogues, enabling the boro-desilyation of less nucleophilic silanes and the direct electrophilic borylation of 2-methylthiophene.

  15. 8-Oxo-7,8-dihydroadenine and 8-Oxo-7,8-dihydroadenosine-Chemistry, Structure, and Function in RNA and Their Presence in Natural Products and Potential Drug Derivatives.

    Science.gov (United States)

    Choi, Yu Jung; Chang, Stephanie J; Gibala, Krzysztof S; Resendiz, Marino J E

    2017-05-17

    A description and history of the role that 8-oxo-7,8-dihydroadenine (8-oxoAde) and 8-oxo-7,8-dihydroadenosine (8-oxoA) have in various fields has been compiled. This Review focusses on 1) the formation of this oxidatively generated modification in RNA, its interactions with other biopolymers, and its potential role in the development/progression of disease; 2) the independent synthesis and incorporation of this modified nucleoside into oligonucleotides of RNA to display the progress that has been made in establishing its behavior in biologically relevant systems; 3) reported synthetic routes, which date back to 1890, along with the progress that has been made in the total synthesis of the nucleobase, nucleoside, and their corresponding derivatives; and 4) the isolation, total synthesis, and biological activity of natural products containing these moieties as the backbone. The current state of research regarding this oxidatively generated lesion as well as its importance in the context of RNA, natural products, and potential as drug derivatives is illustrated using all available examples reported to date. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Manganese(II) chelate contrast media

    International Nuclear Information System (INIS)

    Rocklage, S.M.; Quay, S.C.

    1994-01-01

    New chelate forming compounds for use as contrast media in NMR imaging are described. Especially mentioned are manganese(II) ion chelates of N,N' dipyridoxaldiamine, N,N' diacetic acid, and salts and esters thereof. 1 fig

  17. Decomposition rates of radiopharmaceutical indium chelates in serum

    International Nuclear Information System (INIS)

    Yeh, S.M.; Meares, C.F.; Goodwin, D.A.

    1979-01-01

    The rates at which six small aminopolycarboxylate chelates of trivalent 111 In and three protein-bound chelates of 111 In deliver indium to the serum protein transferrin have been studied in sterile human serum at pH 7.3, 37 deg C. Sterically hindered chelates containing a substituent on an ethylene carbon of EDTA decompose with rates in the range 0.03 to 0.11% per day - one to two orders of magnitude slower than other chelates. Only small differences are observed between rates of decomposition for low-molecular-weight chelates and for protein-bound chelates having analogous structures. (author)

  18. Fluid extraction using carbon dioxide and organophosphorus chelating agents

    Science.gov (United States)

    Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

    1998-01-01

    Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

  19. Titanium oxo-clusters: precursors for a Lego-like construction of nanostructured hybrid materials.

    Science.gov (United States)

    Rozes, Laurence; Sanchez, Clément

    2011-02-01

    Titanium oxo-clusters, well-defined monodispersed nano-objects, are appropriate nano-building blocks for the preparation of organic-inorganic materials by a bottom up approach. This critical review proposes to present the different structures of titanium oxo-clusters referenced in the literature and the different strategies followed to build up hybrid materials with these versatile building units. In particular, this critical review cites and reports on the most important papers in the literature, concentrating on recent developments in the field of synthesis, characterization, and the use of titanium oxo-clusters for the construction of advanced hybrid materials (137 references).

  20. Hydration energies and specific influence of oxo complexes and high coordination numbers on the predicted chemistry of superheavy elements

    International Nuclear Information System (INIS)

    Jorgensen, C.K.; Penneman, R.A.

    1975-01-01

    On the basis of an analysis of the known ionization energies of gaseous ions and aqua ions of the 3d, 4f, and 6d transition groups and the radius effects, the chemistry of the superheavy elements is predicted. The formation of aqua ion and oxo complexes in the elements with Z below 121 is considered. It is probable that the series from 123 to 140 constitute a close analogy to the lanthanides with Th-like chemistry. Above Z = 140 the elements will probably displace a transition group behavior. A brief comment is made on the analytical aspects to be expected. (U.S.)

  1. Electrochemical Oxidation of [1-X-12-I-CB11Me10–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB11Me10] and Iodonium Ylide Anions [{12-(1-X-CB11Me10–)}2I+

    Czech Academy of Sciences Publication Activity Database

    Wahab, Abdul; Kaleta, Jiří; Wen, Jin; Valášek, Michal; Polášek, Miroslav; Michl, Josef; Ludvík, Jiří

    2016-01-01

    Roč. 55, č. 24 (2016), s. 12815-12821 ISSN 0020-1669 R&D Projects: GA ČR GAP206/11/0727 Institutional support: RVO:61388955 ; RVO:61388963 Keywords : WEAKLY COORDINATING ANIONS * SUBSTITUTION SYMMETRY * CARBORANE ANIONS Subject RIV: CG - Electrochemistry; CA - Inorganic Chemistry (UOCHB-X) Impact factor: 4.857, year: 2016

  2. (Carbonato-κO,O')bis-(1,10-phenan-throline-κN,N')cobalt(III) nitrate monohydrate.

    Science.gov (United States)

    Andaç, Omer; Yolcu, Zuhal; Büyükgüngör, Orhan

    2009-12-12

    The crystal structure of the title compound, [Co(CO(3))(C(12)H(8)N(2))(2)]NO(3)·H(2)O, consists of Co(III) complex cations, nitrate anions and uncoordinated water mol-ecules. The Co(III) cation is chelated by a carbonate anion and two phenanthroline ligands in a distorted octa-hedral coordination geometry. A three-dimensional supra-molecular structure is formed by O-H⋯O and C-H⋯O hydrogen bonding, C-H⋯π and aromatic π-π stacking [centroid-centroid distance = 3.995 (1)Å] inter-actions.

  3. Bis(pyridine-2-carbaldehyde thiosemicarbazonezinc(II dinitrate dihydrate

    Directory of Open Access Journals (Sweden)

    Jian-Quan Wang

    2010-10-01

    Full Text Available The asymmetric unit of the title compound, [Zn(C7H8N4S2](NO32·2H2O, contains two Zn(pht2 cations (pht is pyridine-2-carbaldehyde thiosemicarbazone, four nitrate anions and four water molecules. In the cations, each ZnII ion adopts a distorted octahedral coordination geometry, being chelated by two tridentate pht ligands. In the crystal, the cations, anions and water molecules are connected via O—H...O and N—H...O hydrogen bonds into a three-dimensional network.

  4. Hypervalent Compounds as Ligands: I 3 -Anion Adducts with Transition Metal Pentacarbonyls

    KAUST Repository

    Rogachev, Andrey Yu.

    2013-06-17

    Just a couple of transition metal complexes of the familiar triiodide anion are known. To investigate the bonding in these, as well as isomeric possibilities, we examined theoretically adducts of I3 - with model organometallic fragments, [Cr(CO)5] and [Mn(CO) 5]+. Bonding energy computations were augmented by a Natural Bond Orbital (NBO) perturbation theory analysis and Energy Decomposition Analysis (EDA). The bonding between I3 - and the organometallic fragment is substantial, especially for the electrostatically driven anion-cation case. "End-on" coordination is favored by 5-13 kcal/mol over "side-on" (to the central I of I3 -), with a ∼10 kcal/mol barrier for isomerization. A developing asymmetry in the I-I bonding of "end-on" coordinated I 3 - led us to consider in some detail the obvious fragmentation to a coordinated I- and free I2. While the signs of incipient fragmentation in that direction are there, these is a definite advantage to maintaining some I- to I2 bonding in triiodide complexes. © 2013 American Chemical Society.

  5. Potent PPARα activator derived from tomato juice, 13-oxo-9,11-octadecadienoic acid, decreases plasma and hepatic triglyceride in obese diabetic mice.

    Directory of Open Access Journals (Sweden)

    Young-il Kim

    Full Text Available Dyslipidemia is a major risk factor for development of several obesity-related diseases. The peroxisome proliferator-activated receptor α (PPARα is a ligand-activated transcription factor that regulates energy metabolism. Previously, we reported that 9-oxo-10,12-octadecadienoic acid (9-oxo-ODA is presented in fresh tomato fruits and acts as a PPARα agonist. In addition to 9-oxo-ODA, we developed that 13-oxo-9,11-octadecadienoic acid (13-oxo-ODA, which is an isomer of 9-oxo-ODA, is present only in tomato juice. In this study, we explored the possibility that 13-oxo-ODA acts as a PPARα agonist in vitro and whether its effect ameliorates dyslipidemia and hepatic steatosis in vivo. In vitro luciferase assay experiments revealed that 13-oxo-ODA significantly induced PPARα activation; moreover, the luciferase activity of 13-oxo-ODA was stronger than that of 9-oxo-ODA and conjugated linoleic acid (CLA, which is a precursor of 13-oxo-ODA and is well-known as a potent PPARα activator. In addition to in vitro experiment, treatment with 13-oxo-ODA decreased the levels of plasma and hepatic triglycerides in obese KK-Ay mice fed a high-fat diet. In conclusion, our findings indicate that 13-oxo-ODA act as a potent PPARα agonist, suggesting a possibility to improve obesity-induced dyslipidemia and hepatic steatosis.

  6. Relationship among chelator adherence, change in chelators, and quality of life in thalassemia.

    Science.gov (United States)

    Trachtenberg, Felicia L; Gerstenberger, Eric; Xu, Yan; Mednick, Lauren; Sobota, Amy; Ware, Hannah; Thompson, Alexis A; Neufeld, Ellis J; Yamashita, Robert

    2014-10-01

    Thalassemia, a chronic blood disease, necessitates life-long adherence to blood transfusions and chelation therapy to reduce iron overload. We examine stability of health-related quality of life (HRQOL) in thalassemia and adherence to chelation therapy over time, especially after changes in chelator choice. Thalassemia Longitudinal Cohort participants in the USA, UK, and Canada completed the SF-36v2 (ages 14+) and the PF-28 CHQ (parents of children health status) at baseline who made a single change in chelator, but declined among participants with multiple changes and/or high iron burden (worse health status). Mental health improved among participants with lower iron burden, but iron overload was negatively associated with social functioning. Adherence did not significantly change over follow-up except for an increase after a change from deferoxamine (DFO) infusion to oral deferasirox (p = 0.03). Predictors of lower adherence for adults/adolescents at follow-up included side effects, smoking, younger age, problems preparing DFO, increased number of days per week DFO prescribed, and lower physical quality of life . Strategies to balance medical needs with family, work, and personal life may assist in adherence.

  7. Cation coordination in oxychloride glasses

    International Nuclear Information System (INIS)

    Johnson, J A; Holland, D; Bland, J; Johnson, C E; Thomas, M F

    2003-01-01

    Glasses containing mixtures of cations and anions of nominal compositions [Sb 2 O 3 ] x - [ZnCl 2 ] 1-x where x = 0.25, 0.50, 0.75, and 1.00, have been studied by means of neutron diffraction and Raman and Moessbauer spectroscopy. There is preferential bonding within the system with the absence of Sb-Cl bonds. Antimony is found to be threefold coordinated to oxygen, and zinc fourfold coordinated. The main contributing species are of the form [Sb(OSb) 2 (OZn)] and [Zn(ClZn) 2 (OSb) 2

  8. Repurposing of Copper(II)-chelating Drugs for the Treatment of Neurodegenerative Diseases.

    Science.gov (United States)

    Lanza, Valeria; Milardi, Danilo; Di Natale, Giuseppe; Pappalardo, Giuseppe

    2018-02-12

    There is mounting urgency to find new drugs for the treatment of neurodegenerative disorders. A large number of reviews have exhaustively described either the molecular or clinical aspects of neurodegenerative diseases such as Alzheimer's (AD) and Parkinson's (PD). Conversely, reports outlining how known drugs in use for other diseases can also be effective as therapeutic agents in neurodegenerative diseases are less reported. This review focuses on the current uses of some copper(II) chelating molecules as potential drug candidates in neurodegeneration. Starting from the well-known harmful relationships existing between the dyshomeostasis and mis-management of metals and AD onset, we surveyed the experimental work reported in the literature, which deals with the repositioning of metal-chelating drugs in the field of neurodegenerative diseases. The reviewed papers were retrieved from common literature and their selection was limited to those describing the biomolecular aspects associated with neuroprotection. In particular, we emphasized the copper(II) coordination abilities of the selected drugs. Copper, together with zinc and iron, are known to play a key role in regulating neuronal functions. Changes in copper homeostasis are crucial for several neurodegenerative disorders. The studies included in this review may provide an overview on the current strategies aimed at repurposing copper (II) chelating drugs for the treatment of neurodegenerative disorders. Starting from the exemplary case of clioquinol repurposing, we discuss the challenge and the opportunities that repurposing of other metal-chelating drugs may provide (e.g. PBT-2, metformin and cyclodipeptides) in the treatment of neurodegenerative disease. In order to improve the success rate of drug repositioning, comprehensive studies on the molecular mechanism and therapeutic efficacy are still required. The present review upholds that drug repurposing makes significant advantages over drug discovery since

  9. Comments on chelation therapy

    International Nuclear Information System (INIS)

    Wrenn, M.E.

    1981-01-01

    The primary purpose of actinide chelation is to decrease the risk from radiation-induced cancer. While occupational exposures in the past have mainly involved low specific activity 239 Pu, future exposures will increasingly involve high specific activity plutonium, americium, and curium - all of which clear more rapidly from the lung. This will tend to shift the cancer risk from lung to bone and liver. Although therapy with Ca- or Zn-DTPA rapidly removes 241 Am from the canine, the sub-human primate, and the human liver, improved methods for removal from bone and lung are needed. DTPA can remove 241 Am more easily from the growing skeleton of a child than from the mature skeleton of an adult. Investigators at Karlsruhe are developing chelation agents for oral administration and are investigating the reduction in local dose to bone resulting from chelation therapy

  10. 3,4,5-trihydroxybenzoic acid as chelating agent

    International Nuclear Information System (INIS)

    Agrawal, M.D.; Bhandari, C.S.; Dixit, M.K.; Sogani, N.C.

    1976-01-01

    Stability constants of praseodymium chelates of 3,4,5-trihydroxy sodium benzoate are determined by using Bjerrum-Calvin pH titration techniques at constant ionic strength 0.1M-sodium perchlorate and at 28+-0.1 0 C. Values calculated by different methods are in good agreement. The study reveals that during complexation only one proton of the ligand molecule is replaced by the metal and oxygen of adjacent phenolic group acts as a coordinating atom. IR and NMR spectral studies of the ligand reveal that one of the OH groups (in meta position to carboxylic group) remains free while two other phenolic groups are involved in intramolecular hydrogen bonding. One water molecule is found attached in crystalline gallic acid. (author)

  11. Polynuclear Iron-Oxo/Hydroxy Complexes of Ketoacidoximate Ligands: Synthesis, Structures and Conversion to Ferric Oxide

    KAUST Repository

    Davaasuren, Bambar

    2017-06-13

    The polynuclear iron-oxo/hydroxy complexes containing ketoacidoximate ligands described in this report are [Fe3(μ3-O){O2C-C(C6H5)=NOCH3}6(py)3] (1) (py=pyridine), [Fe2(μ3-O){O2C-C(CH2-C6H5)=NO}2(H2O)(CH3OH)]2 (2) and [{Fe(μ2-OH)(O2C-C(CH3)=NO)}(dmso)]6 (3) (dmso=dimethyl sulfoxide). 1–3 are isolated from the reaction of Fe(NO3)3⋅9H2O and in situ generated anions of ketoacidoximate ligand [(HO2C-C(R1)=NOR2), where R1=CH3, C6H5 and CH2-C6H5; R2=H or CH3] in H2O, followed by crystallization in donor solvents. 1–3 undergo thermal decomposition above 200 °C and form crystalline α-Fe2O3 at 600 °C.

  12. Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

    Directory of Open Access Journals (Sweden)

    José Maria Rodrigues da Luz

    Full Text Available In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2 concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.

  13. Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

    2014-01-01

    In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.

  14. Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

    2014-01-01

    In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process. PMID:25419675

  15. Dowex anion exchanger-loaded-baker's yeast as bi-functionalized biosorbents for selective extraction of anionic and cationic mercury(II) species

    International Nuclear Information System (INIS)

    Mahmoud, Mohamed E.; Yakout, Amr A.; Osman, Maher M.

    2009-01-01

    Dowex anion exchanger-immobilized-baker's yeast [Dae-yeast] were synthesized and potentially applied as environmental friendly biosorbents to evaluate the up-take process of anionic and cationic mercury(II) species as well as other metal ions. Optimization of mass ratio of Dowex anion exchanger versus yeast (1:1-1:10) in presence of various interacting buffer solutions (pH 4.0-9.0) was performed and evaluated. Surface modification of [Dae-yeast] was characterized by scanning electron microscopy (SEM) and infrared spectroscopy. The maximum metal biosorption capacity values of [Dae-yeast] towards mercury(II) were found in the range of 0.800-0.960, 0.840-0.950 and 0.730-0.900 mmol g -1 in presence of buffer solutions pH 2.0, 4.0 and 7.0, respectively. Three possible and different mechanisms are proposed to account for the biosorption of mercury and mercuric species under these three buffering conditions based on ion exchange, ion pair and chelation interaction processes. Factors affecting biosorption of mercury from aqueous medium including the pH effect of aqueous solutions (1.0-7.0), shaking time (1-30 min) and interfering ions were searched. The potential applications of modified biosorbents for selective biosorption and extraction of mercury from different real matrices including dental filling waste materials, industrial waste water samples and mercury lamp waste materials were also explored. The results denote to excellent percentage extraction values, from nitric acid as the dissolution solvent with a pH 2.0, as determined in the range of 90.77-97.91 ± 3.00-5.00%, 90.00-93.40 ± 4.00-5.00% and 92.31-100.00 ± 3.00-4.00% for the three tested samples, respectively.

  16. Photophysical investigation of energy transfer luminescence of lanthanide chelates with aromatic polyaminocarboxylate ligands in aqueous solutions

    International Nuclear Information System (INIS)

    Hoshino, Hitoshi; Saitoh, Takashi; Yotsuyanagi, Takao

    1995-01-01

    Some photophysical data including emission lifetimes (τ), total emission quantum yields (Φ), and ligand phosphorescence data are reported for the energy-transfer luminescence of the Eu(III) chelate of Quin 2 and the Tb(III) chelate of BAPTA: Quin 2 means 2-[(2-amino-5-methylphenoxy)methyl]-6-methoxy-8-aminoquinoline-N,N,N',N'-tetraacetic acid; BAPTA means 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. The energy diagrams for the ligand T 1 and the metal-center f-f levels are proposed. The τ values of Tb(III)-BAPTA chelates are 1.73 ms in H 2 O and 3.44 ms in D 2 O. The Eu(III)-Quin 2 chelate system shows a bi-exponential decay of emission; τ=0.048 and 0.20 ms in H 2 O and 0.066 and 1.44 ms in D 2 O. The Quin 2 chelate is kinetically inert, so that the interchange of these two conformer structures are very slow at room temperature. The number of water molecules in the primary coordination sphere is calculated from the lifetime data to be 1.9-2.4 for Eu-Quin 2 and 0.5 for Tb-BAPTA. The Φ values in aqueous solutions are rather small in these systems; 0.009 for Tb-BAPTA and 0.0023 for Eu-Quin 2, but these are enough counterbalanced by the large molar absorptivities giving the great sensitization factors for the ions; the sensitization factors against each aqua ion are 1380 for Eu-Quin 2 and 1600 for Tb-BAPTA. (author)

  17. Coordination chemistry with phosphine and phosphine oxide-substituted hydroxyferrocenes.

    Science.gov (United States)

    Atkinson, Robert C J; Gibson, Vernon C; Long, Nicholas J; White, Andrew J P

    2010-08-28

    New unsymmetrical hydroxyferrocenes were synthesised from dibromoferrocene. The oxygen heteroatom was introduced via lithiation and quenching with bis-trimethylsilylperoxide followed by hydrolysis to unmask the hydroxyl functionality. The coordination chemistry of 1'-(diphenylphosphino)-1-hydroxyferrocene 2 was explored with palladium and rhodium precursors. A dinuclear palladium methyl complex with bridging ferrocenyloxo groups was obtained from the reaction between 2 and (cyclooctadiene)methylchloropalladium(II). With tetracarbonyldichlorodirhodium(I), two complexes were isolated. The major product was a bis ligand cis phosphine ligated complex with one ligand bound in a chelating mode and one with a pendant hydroxyl group. A minor product was crystallographically characterised as a dinuclear ferrocenyloxo-bridged rhodium carbonyl complex. The coordination chemistry of 2 and the corresponding phosphine oxide 3 was examined with group 4 metals and the resulting complexes examined as ethylene polymerisation catalysts. The ligands were found to bind in either a chelating fashion or with pendant phosphine donors. In all cases, low to moderately active ethylene polymerisation catalysts were found. The catalysts were very unstable and catalyst residues were observed in the isolated polymer indicating a short catalyst lifetime.

  18. Crystal structure of {μ-6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethanylylidene]diphenolato}(methanol(nitratonickel(IIsodium

    Directory of Open Access Journals (Sweden)

    Olesia V. Moroz

    2014-11-01

    Full Text Available In the molecular structure of the title compound, [NaNi(C18H18N2O4(NO3(CH3OH], the Ni2+ ion has a slightly distorted square-planar coordination environment defined by two N and two O atoms which belong to a Schiff base ligand, viz. 6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethanylylidene]diphenolate. Seven O atoms form the coordination environment of the Na+ ion: four from the Schiff base ligand, two from a bidentate chelating nitrate anion and one O atom from a coordinating methanol molecule. In the crystal, the bimetallic complexes are assembled into chains along the b-axis direction via weak C—H...O hydrogen-bond interactions. Neighbouring chains are in turn connected through bifurcated O—H...O hydrogen bonds that involve the coordinating methanol molecules and the nitrate anions, and through π–π stacking interactions between phenyl rings of neighbouring molecules.

  19. o-Iminobenzosemiquinonate and o-imino-p-methylbenzosemiquinonate anion radicals coupled VO2+ stabilization.

    Science.gov (United States)

    Roy, Amit Saha; Saha, Pinaki; Adhikary, Nirmal Das; Ghosh, Prasanta

    2011-03-21

    The diamagnetic VO(2+)-iminobenzosemiquinonate anion radical (L(R)(IS)(•-), R = H, Me) complexes, (L(-))(VO(2+))(L(R)(IS)(•-)): (L(1)(-))(VO(2+))(L(H)(IS)(•-))•3/2MeOH (1•3/2MeOH), (L(2)(-))(VO(2+))(L(H)(IS)(•-)) (2), and (L(2)(-))(VO(2+))(L(Me)(IS)(•-))•1/2 L(Me)(AP) (3•1/2 L(Me)(AP)), incorporating tridentate monoanionic NNO-donor ligands {L = L(1)(-) or L(2)(-), L(1)H = (2-[(phenylpyridin-2-yl-methylene)amino]phenol; L(2)H = 1-(2-pyridylazo)-2-naphthol; L(H)(IS)(•-) = o-iminobenzosemiquinonate anion radical; L(Me)(IS)(•-) = o-imino-p-methylbenzosemiquinonate anion radical; and L(Me)(AP) = o-amino-p-methylphenol} have been isolated and characterized by elemental analyses, IR, mass, NMR, and UV-vis spectra, including the single-crystal X-ray structure determinations of 1•3/2MeOH and 3•1/2 L(Me)(AP). Complexes 1•3/2MeOH, 2, and 3•1/2 L(Me)(AP) absorb strongly in the visible region because of intraligand (IL) and ligand-to-metal charge transfers (LMCT). 1•3/2MeOH is luminescent (λ(ext), 333 nm; λ(em), 522, 553 nm) in frozen dichloromethane-toluene glass at 77 K due to π(diimine→)π(diimine)* transition. The V-O(phenolato) (cis to the V═O) lengths, 1.940(2) and 1.984(2) Å, respectively, in 1•3/2MeOH and 3•1/2 L(Me)(AP) are consistent with the VO(2+) description. The V-O(iminosemiquinonate) (trans to the V═O) lengths, 2.1324(19) in 1•3/2MeOH and 2.083(2) Å in 3•1/2 L(Me)(AP), are expectedly ∼0.20 Å longer due to the trans influence of the V═O bond. Because of the stronger affinity of the paramagnetic VO(2+) ion to the L(H)(IS)(•-) or L(Me)(IS)(•-), the V-N(iminosemiquinonate) lengths, 1.908(2) and 1.921(2) Å, respectively, in 1•3/2MeOH and 3•1/2 L(Me)(AP), are unexpectedly shorter. Density functional theory (DFT) calculations using B3LYP, B3PW91, and PBE1PBE functionals on 1 and 2 have established that the closed shell singlet (CSS) solutions (VO(3+)-amidophenolato (L(R)(AP)(2-)) coordination) of these

  20. Developmental changes in rat liver branched-chain 2-oxo acid dehydrogenase.

    OpenAIRE

    May, E E; May, M E; Aftring, R P; Buse, M G

    1982-01-01

    Branched-chain 2-oxo acid dehydrogenase catalyses the first irreversible step in the degradation of the branched-chain amino acids leucine, isoleucine and valine. With specifically labelled 4-methyl-2-oxo[1-14C]pentanoate as substrate, the enzyme's activity was measured in rat liver homogenates. Activity (per g wet wL of liver or per mg of protein) increased most rapidly during the perinatal period (2 days before to 1 day after birth), reaching approximately adult values by the time of weanin...

  1. Distinct energetics and closing pathways for DNA polymerase β with 8-oxoG template and different incoming nucleotides

    Directory of Open Access Journals (Sweden)

    Wang Yanli

    2007-02-01

    Full Text Available Abstract Background 8-Oxoguanine (8-oxoG is a common oxidative lesion frequently encountered by DNA polymerases such as the repair enzyme DNA polymerase β (pol β. To interpret in atomic and energetic detail how pol β processes 8-oxoG, we apply transition path sampling to delineate closing pathways of pol β 8-oxoG complexes with dCTP and dATP incoming nucleotides and compare the results to those of the nonlesioned G:dCTP and G:dATPanalogues. Results Our analyses show that the closing pathways of the 8-oxoG complexes are different from one another and from the nonlesioned analogues in terms of the individual transition states along each pathway, associated energies, and the stability of each pathway's closed state relative to the corresponding open state. In particular, the closed-to-open state stability difference in each system establishes a hierarchy of stability (from high to low as G:C > 8-oxoG:C > 8-oxoG:A > G:A, corresponding to -3, -2, 2, 9 kBT, respectively. This hierarchy of closed state stability parallels the experimentally observed processing efficiencies for the four pairs. Network models based on the calculated rate constants in each pathway indicate that the closed species are more populated than the open species for 8-oxoG:dCTP, whereas the opposite is true for 8-oxoG:dATP. Conclusion These results suggest that the lower insertion efficiency (larger Km for dATP compared to dCTP opposite 8-oxoG is caused by a less stable closed-form of pol β, destabilized by unfavorable interactions between Tyr271 and the mispair. This stability of the closed vs. open form can also explain the higher insertion efficiency for 8-oxoG:dATP compared to the nonlesioned G:dATP pair, which also has a higher overall conformational barrier. Our study offers atomic details of the complexes at different states, in addition to helping interpret the different insertion efficiencies of dATP and dCTP opposite 8-oxoG and G.

  2. Overview of current chelation practices

    Directory of Open Access Journals (Sweden)

    Y. Aydinok

    2011-12-01

    Full Text Available Deferoxamine (DFO is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO is inadequate, intolerable or unacceptable. There are still limited data available on the use of DFP in children between 6 and 10 years of age, and no data on DFP use in children under 6 years of age. Subsequently the oral chelator Deferasirox (DFX was approved by FDA and EMA for the treatment of patients with transfusional iron overload -older than 2 years of age- as first line therapy, in 2005 and 2006 respectively. The primary objective of iron chelation is to maintain body iron at safe levels at all times but once iron is accumulated, the objective of iron chelation is to reduce tissue iron to safe levels which is a slow process. The chelation regimen, dose and frequency of administration, of the chelator(s are mainly determined based on body iron burden, presence of myocardial iron and the transfusional iron loading rate. A proper monitoring of chelation is of importance for measuring the response rate to a particular regimen and providing dose adjustments to enhance chelation efficacy and to avoid toxicity. Efficacy of a chelation regimen may exhibit individual variability resulting from factors such as absorbtion and metabolism of the chelator. Tolerability and compliance are also individual variables effecting the response to chelation. Understanding of advantages and limitations of chelators, accurately determining chelation needs of patients with iron overload and designing individualized chelation regimens with less toxicity but optimum efficacy

  3. Influence of structural and surface properties of whey-derived peptides on zinc-chelating capacity, and in vitro gastric stability and bioaccessibility of the zinc-peptide complexes.

    Science.gov (United States)

    Udechukwu, M Chinonye; Downey, Brianna; Udenigwe, Chibuike C

    2018-02-01

    Gastrointestinal stability of zinc-peptide complexes is essential for zinc delivery. As peptide surface charge can influence their metal complex stability, we evaluated the zinc-chelating capacity and stability of zinc complexes of whey protein hydrolysates (WPH), produced with Everlase (WPH-Ever; ζ-potential, -39mV) and papain (WPH-Pap; ζ-potential, -7mV), during simulated digestion. WPH-Ever had lower amount of zinc-binding amino acids but showed higher zinc-chelating capacity than WPH-Pap. This is attributable to the highly anionic surface charge of WPH-Ever for electrostatic interaction with zinc. Release of zinc during peptic digestion was lower for WPH-Ever-zinc, and over 50% of zinc remained bound in both peptide complexes after peptic-pancreatic digestion. Fourier transform infrared spectroscopy suggests the involvement of carboxylate ion, and sidechain carbon-oxygen of aspartate/glutamate and serine/threonine in zinc-peptide complexation. The findings indicate that strong zinc chelation can promote gastric stability and impede intestinal release, for peptides intended for use as dietary zinc carriers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. NMR structural studies of the ionizing radiation adduct 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) opposite deoxyadenosine in a DNA duplex. 8-oxo-7H-dG(syn)·dA(anti) alignment at lesion site

    International Nuclear Information System (INIS)

    Kouchakdjian, M.; Patel, D.J.; Bodepudi, V.; Shibutani, S.; Eisenberg, M.; Johnson, F.; Grollman, A.P.

    1991-01-01

    Proton NMR studies are reported on the complementary d(C1-C2-A3-C4-T5-A6-oxo-G7-T8-C9-A10-C11-C12)·d(G13-G14-T15-G16-A17-A18-T19-A20-G21-T22-G23-G24) dodecanucleotide duplex (designated 8-oxo-7H-dG·dA 12-mer), which contains a centrally located 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) residue, a group commonly found in DNA that has been exposed to ionizing radiation or oxidizing free radicals. From the NMR spectra it can be deduced that this moiety exists as two tautomers, or gives rise to two DNA conformations, that are in equilibrium and that exchange slowly. The present study focuses on the major component of the equilibrium that originates in the 6,8-dioxo tautomer of 8-oxo-7H-dG. The authors have assigned the exchangeable NH1, NH7, and NH 2 -2 base protons located on the Watson-Crick and Hoogsteen edges of 8-oxo-7H-dG7 in the 8-oxo-7H-dG·dA 12-mer duplex, using an analysis of one- and two-dimensional nuclear Overhauser enhancement (NOE) data in H 2 O solution. They were able to detect a set of intra- and interstrand NOEs between protons (exchangeable and nonexchangeable) on adjacent residues in the d(A6-oxo-G7-T8)·d(A17-A18-T19) trinucleotide segment centered about the lesion site that establishes stacking of the oxo-dG7(syn)·dA(anti) pair between stable Watson-Crick dA6·dT19 and dT8·A17 base pairs with minimal perturbation of the helix. The structural studies demonstrate that 8-oxo-7H-dG(syn)·dA(anti) forms a stable pair in the interior of the helix, providing a basis for the observed incorporation of dA opposite 8-oxo-7H-dG when readthrough occurs past this oxidized nucleoside base

  5. Chelation in root canal therapy reconsidered.

    Science.gov (United States)

    Zehnder, Matthias; Schmidlin, Patrick; Sener, Beatrice; Waltimo, Tuomas

    2005-11-01

    The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.

  6. Synthesis, characterization and ion- exchange study of poly[(2,4-dihydroxy benzophenone)butylene] resin and its poly chelates with transition metals

    International Nuclear Information System (INIS)

    Joshi, J. D.; Patel, N.B.; Patel, S. D.

    2006-01-01

    The polymeric ligand poly[(2,4-dihydroxy benzophenone)butylene] H(DHBP-BD) forms 1 :2 metal-ligand complexes with Ni(ll), Co(ll), Cu(ll) and Zn(ll). The polymeric ligand and its poly chelates were characterized on the basis of elemental analyses, magnetic susceptibilities, IR-spectroscopy, UV-visible spectra, NMR, thermogravimetric analyses. The molecular weight of resin was determined using number average molecular weight (M n ) by vapour pressure osmometry method. The stereochemistry in case of the Cu(ll) poly chelate is square-planar, tetrahedral for Zn(ll) and octahedral for Ni(ll) and Co(ll). The stereochemistry in each chelate is proposed on the basis of magnetic susceptibilities and electronic spectra. The IR spectra show that the bidentate ligand coordinates through the oxygen atom of the carbonyl and phenolic group with replacement of hydrogen by metal ions, respectively. All the chelates are paramagnetic in nature except the Zn(ll) chelate which is diamagnetic. The ion-exchange study of the prepared resin was checked by batch equilibration method with selected metal ions [Cu(ll), Ni(ll), Fe(lll) and UO 2 2+( VI)] at varying electrolyte concentration, pH and time. It is found that, resin can be used as an ion-exchanger

  7. Effect of Structure on Charge Distribution in the Isatin Anions in Aprotic Environment: Spectral Study

    Directory of Open Access Journals (Sweden)

    Pavol Tisovský

    2017-11-01

    Full Text Available Five isatin anions were prepared by deprotonation of initial isatins in aprotic solvents using basic fluoride and acetate anions (F− and CH3COO−. The F− basicity is sufficient to deprotonate isatin NH hydrogen from all the studied compounds. This process is reversible. In the presence of proton donor solvents, the anions form the corresponding isatins. The isatin hydrogen acidity depends on the overall structure of the isatin derivatives. The anions were characterized by ultraviolet–visible (UV–Vis, Fourier transform infrared (FTIR and nuclear magnetic resonance (NMR spectroscopy. Interestingly, the anions form aggregates at concentrations above 10−3 mol·dm−3. Further, the effect of cations on the UV–Vis spectra of the studied anions was studied. Charge transfer and its distribution in the anion depends on the radius and the cation electron configuration. The alkali metal cations, tetrabutylammonium (TBA+, Mg2+ and Ag+, interact with the C-2 carbonyl oxygen of the isatin anion. The interaction has a coulombic character. On the other hand, Cd2+, Zn2+, Hg2+, Co2+, and Cu+ cations form a coordinate bond with the isatin nitrogen.

  8. Isolation and identification of calcium-chelating peptides from Pacific cod skin gelatin and their binding properties with calcium.

    Science.gov (United States)

    Wu, Wenfei; Li, Bafang; Hou, Hu; Zhang, Hongwei; Zhao, Xue

    2017-12-13

    A calcium-chelating peptide is considered to have the ability to improve calcium absorption. In this study, Pacific cod skin gelatin hydrolysates treated with trypsin for 120 min exhibited higher calcium-chelating activity. Sequential chromatography, involving hydroxyapatite affinity chromatography and reversed phase high performance liquid chromatography, was used for the purification of calcium-chelating peptides. Two novel peptides with the typical characteristics of collagen were sequenced as GDKGESGEAGER and GEKGEGGHR based on LC-HRMS/MS, which showed a high affinity to calcium. Calcium-peptide complexation was further characterized by ESI-MS (MS and MS/MS) and FTIR spectroscopy. The results showed that the complexation of the two peptides with calcium was conducted mainly at the ratio of 1 : 1. The amino terminal group and the peptide bond of the peptide backbone as well as the amino group of the lysine side chain and the carboxylate of the glutamate side chain were the possible calcium binding sites for the two peptides. Meanwhile, several amino acid side chain groups, including the hydroxyl (Ser) and carboxylate (Asp) of GDKGESGEAGER and the imine (His) of GEKGEGGHR, were crucial in the complexation. The arginine residue in GEKGEGGHR also participated in the calcium coordination. Additionally, several active fragments with calcium-chelating activity were obtained using MS/MS spectra, including GDKGESGEAGE, GEAGER, GEK, EKG and KGE. This study suggests that gelatin-derived peptides have the potential to be used as a calcium-chelating ingredient to combat calcium deficiency.

  9. Evaluation of extractants and chelating resins in polishing actinide-contaminated waste streams

    International Nuclear Information System (INIS)

    Schreiber, S.B.; Dunn, S.L.; Yarbro, S.L.

    1991-06-01

    At the Los Alamos National Laboratory Plutonium Facility, anion exchange is used for recovering plutonium from nitric acid solutions. Although this approach recovers >99%, the trace amounts of plutonium and other actinides remaining in the effluent require additional processing. We are doing research to develop a secondary unit operation that can directly polish the effluent so that actinide levels are reduced to below the maximum allowed for facility discharge. We selected solvent extraction, the only unit operation that can meet the stringent process requirements imposed; several carbonyl and phosphoryl extractants were evaluated and their performance characterized. We also investigated various engineering approaches for solvent extraction; the most promising was a chelating resin loaded with extractant. Our research now focuses on the synthesis of malonamides, and our goal is to bond these extractants to a resin matrix. 7 refs., 12 figs., 1 tab

  10. Tris(2,2′-bipyridine-κ2 N,N′)cobalt(III) bis­[bis­(pyridine-2,6-dicarboxyl­ato-κ3 O 2,N,O 6)cobaltate(III)] perchlorate dimethyl­formamide hemisolvate 1.3-hydrate

    Science.gov (United States)

    Golenya, Irina A.; Boyko, Alexander N.; Kotova, Natalia V.; Haukka, Matti; Iskenderov, Turganbay S.

    2012-01-01

    In the title compound, [Co(C10H8N2)3][Co(C7H3NO4)2]2(ClO4)·0.5C3H7NO·1.3H2O, the CoIII atom in the complex cation is pseudoocta­hedrally coordinated by six N atoms of three chelating bipyridine ligands. The CoIII atom in the complex anion is coordinated by two pyridine N atoms and four carboxyl­ate O atoms of two doubly deprotonated pyridine-2,6-dicarboxyl­ate ligands in a distorted octa­hedral geometry. One dimethyl­formamide solvent mol­ecule and two water mol­ecules are half-occupied and one water mol­ecule is 0.3-occupied. O—H⋯O hydrogen bonds link the water mol­ecules, the perchlorate anions and the complex anions. π–π inter­actions between the pyridine rings of the complex anions are also observed [centroid–centroid distance = 3.804 (3) Å]. PMID:23125573

  11. Exceptional Structural Compliance of the B12F122- Superweak Anion.

    Science.gov (United States)

    Peryshkov, Dmitry V; Strauss, Steven H

    2017-04-03

    The single-crystal X-ray structures, thermogravimetric analyses, and/or FTIR spectra of a series of salts of the B 12 F 12 2- anion and homoleptic Ag(L) n + cations are reported (L = CH 2 Cl 2 , n = 2; L = PhCH 3 , n = 3; L = CH 3 CN; n = 2-4; L = CO, n = 1, 2). The superweak-anion nature of B 12 F 12 2- (Y 2- ) was demonstrated by the rapid reaction of microcrystalline Ag 2 (Y) with 1 atm of CO to form a nonclassical silver(I) carbonyl compound with an FTIR ν(CO) band at 2198 cm -1 (and with the proposed formula [Ag(CO) n ] 2 [Y]). In contrast, microcrystalline Ag 2 (B 12 Cl 12 ) did not exhibit ν(CO) bands and therefore did not form Ag(CO) + species, even after 32 h under 24 atm of CO. When Ag 2 (Y) was treated with carbon monoxide pressures higher than 1 atm, a new ν(CO) band at 2190 cm -1 appeared, which is characteristic of a Ag(CO) 2 + dicarbonyl cation. Both Ag 2 (CH 3 CN) 8 (Y) and Ag 2 (CH 3 CN) 5 (Y) rapidly lost coordinated CH 3 CN at 25 °C to form Ag 2 (CH 3 CN) 4 (Y), which formed solvent-free Ag 2 (Y) only after heating above 100 °C. Similarly, Ag 2 (PhCH 3 ) 6 (Y) rapidly lost coordinated PhCH 3 at 25 °C to form Ag 2 (PhCH 3 ) 2 (Y), which formed Ag 2 (Y) after heating above 150 °C, and Ag 2 (CH 2 Cl 2 ) 4 (Y) rapidly lost three of the four coordinated CH 2 Cl 2 ligands between 25 and 100 °C and formed Ag 2 (Y) when it was heated above 200 °C. Solvent-free Ag 2 (Y) was stable until it was heated above 380 °C. The rapid evaporative loss of coordinated ligands at 25 °C from nonporous crystalline solids requires equally rapid structural reorganization of the lattice and is one of three manifestations of the structural compliance of the Y 2- anion reported in this work. The second, more quantitative, manifestation is that Ag + bond-valence sums for Ag 2 (CH 3 CN) n (Y) are virtually constant, 1.20 ± 0.03, for n = 8, 5, 4, because the Y 2- anion precisely compensated for the lost CH 3 CN ligands by readily forming the necessary number of weak

  12. Enhanced phosphate selectivity from wastewater using copper-loaded chelating resin functionalized with polyethylenimine.

    Science.gov (United States)

    An, Byungryul; Nam, Juhee; Choi, Jae-Woo; Hong, Seok-Won; Lee, Sang-Hyup

    2013-11-01

    In water and wastewater, phosphate is considered a critical contaminant due to cause algae blooms and eutrophication. To meet the stringent regulation of phosphate in water, a new commercial chelating resin functionalized with polyethylenimine was tested for phosphate removal by loading Cu(2+) and Fe(2+)/Fe(3+) to enhance selectivity for phosphate. Batch and column experiments showed that CR20-Cu exhibited high selectivity for phosphate over other strong anions such as sulfate. The average binary phosphate/nitrate and phosphate/sulfate factors for CR20-Cu were calculated to be 7.3 and 4.8, respectively, which were more than 0.97 and 0.22 for a commercial anion exchanger (AMP16). The optimal pH for the phosphate removal efficiency was determined to be 7. According to the fixed-bed column test, the breakthrough sequence for multiple ions was HPO4(2-)>SO4(2-)>NO3(-)>Cl(-). Saturated CR20-Cu can be regenerated using 4% NaCl at pH 7. More than 95% of the phosphate from CR20-Cu was recovered, and the phosphate uptake capacity for CR20-Cu was not reduced after 7 regeneration cycles. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Subtle interactions and electron transfer between U{sup III}, Np{sup III}, or Pu{sup III} and uranyl mediated by the oxo group

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Polly L.; Zegke, Markus; Hollis, Emmalina; Pecharman, Anne-Frederique; Love, Jason B. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom); Dutkiewicz, Michal S. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom); European Commission, Directorate for Nuclear Safety and Security, Joint Research Centre, Karlsruhe (Germany); Walter, Olaf; Apostolidis, Christos; Magnani, Nicola; Griveau, Jean-Christophe; Colineau, Eric; Caciuffo, Roberto [European Commission, Directorate for Nuclear Safety and Security, Joint Research Centre, Karlsruhe (Germany); Zhang, Xiaobin; Schreckenbach, Georg [Department of Chemistry, University of Manitoba, Winnipeg, MB (Canada)

    2016-10-04

    A dramatic difference in the ability of the reducing An{sup III} center in AnCp{sub 3} (An=U, Np, Pu; Cp=C{sub 5}H{sub 5}) to oxo-bind and reduce the uranyl(VI) dication in the complex [(UO{sub 2})(THF)(H{sub 2}L)] (L=''Pacman'' Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp{sub 3}U forms the U{sup IV}-uranyl(V) compound that behaves as a U{sup V}-localized single molecule magnet below 4 K. The extent of reduction by the Cp{sub 3}Np group upon oxo-coordination is much less, with a Np{sup III}-uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np{sup IV}U{sup V} but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np{sup III}-U{sup VI} assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu{sup III}-U{sup VI} interaction is too weak to be observed in THF solvent, in agreement with calculated predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Biological behaviour of some 67Ga and 64Cu chelates

    International Nuclear Information System (INIS)

    Leonovicova, T.; Angelis, B.; Cifka, J.; Cifkova, I.

    1984-01-01

    Chelates of 67 Ga and 64 Cu with iminodiacetic acid (IDA) and its two phenyl derivatives as well as with nitrilotriacetic acid (NTA) and benzylnitrilotriacetic acid (BNTA) were prepared. All the chelates were found to be negatively charged. A study of the biological distribution of these chelates in rats during time intervals of 3 to 180 min showed that the chelate of 67 Ga with IDA substituted at a phenyl by a hydrophobic substituent is excreted by the kidneys into the urine at a much higher rate than the IDA chelate of 67 Ga. The excretion of NTA and BNTA chelates of 67 Ga is the opposite. Blood clearance of 64 Cu chelates is more rapid than that of 67 Ga chelates. Chelates of 64 Cu accumulate in the liver and with the bile are slowly excreted into the intestines, urinary excretion is negligible. (author)

  15. Infrared multiple photon dissociation spectroscopy of sodium and potassium chlorate anions.

    Science.gov (United States)

    Dain, Ryan P; Leavitt, Christopher M; Oomens, Jos; Steill, Jeffrey D; Groenewold, Gary S; Van Stipdonk, Michael J

    2010-01-01

    The structures of gas-phase, metal chlorate anions with the formula [M(ClO(3))(2)](-), M = Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental vibrational spectra for the two species with those predicted by density functional theory (DFT) and involve conformations that feature either bidentate or tridentate coordination of the cation by chlorate. Our results strongly suggest that a structure in which both chlorate anions are bidentate ligands is preferred for [Na(ClO(3))(2)](-). However, for [K(ClO(3))(2)](-) the best agreement between experimental and theoretical spectra is obtained from a composite of predicted spectra for which the chlorate anions are either both bidentate or both tridentate ligands. In general, we find that the overall accuracy of DFT calculations for prediction of IR spectra is dependent on both functional and basis set, with best agreement achieved using frequencies generated at the B3LYP/6-311+g(3df) level of theory. Copyright 2009 John Wiley & Sons, Ltd.

  16. Cation coordination in oxychloride glasses

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J A [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Holland, D [Physics Department, Warwick University, Coventry (United Kingdom); Bland, J [Physics Department, University of Liverpool, PO Box 147, Liverpool (United Kingdom); Johnson, C E [Physics Department, Northern Illinois University, DeKalb, IL (United States); Thomas, M F [Physics Department, University of Liverpool, PO Box 147, Liverpool (United Kingdom)

    2003-02-19

    Glasses containing mixtures of cations and anions of nominal compositions [Sb{sub 2}O{sub 3}]{sub x} - [ZnCl{sub 2}]{sub 1-x} where x = 0.25, 0.50, 0.75, and 1.00, have been studied by means of neutron diffraction and Raman and Moessbauer spectroscopy. There is preferential bonding within the system with the absence of Sb-Cl bonds. Antimony is found to be threefold coordinated to oxygen, and zinc fourfold coordinated. The main contributing species are of the form [Sb(OSb){sub 2}(OZn)] and [Zn(ClZn){sub 2}(OSb){sub 2}].

  17. (Carbonato-κ2 O,O′)bis­(1,10-phenan­throline-κ2 N,N′)cobalt(III) nitrate monohydrate

    Science.gov (United States)

    Andaç, Ömer; Yolcu, Zuhal; Büyükgüngör, Orhan

    2010-01-01

    The crystal structure of the title compound, [Co(CO3)(C12H8N2)2]NO3·H2O, consists of CoIII complex cations, nitrate anions and uncoordinated water mol­ecules. The CoIII cation is chelated by a carbonate anion and two phenanthroline ligands in a distorted octa­hedral coordination geometry. A three-dimensional supra­molecular structure is formed by O—H⋯O and C—H⋯O hydrogen bonding, C—H⋯π and aromatic π–π stacking [centroid–centroid distance = 3.995 (1)Å] inter­actions. PMID:21579944

  18. μ-Oxalato-bis[(2,2′-bipyridylcopper(II] bis(perchlorate dimethylformamide disolvate monohydrate

    Directory of Open Access Journals (Sweden)

    Alexander N. Boyko

    2010-09-01

    Full Text Available The title compound, [Cu2(C2O4(C10H8N24](ClO42·2C3H7NO·H2O, contains doubly charged centrosymmetric dinuclear oxalato-bridged copper(II complex cations, perchlorate anions, and DMF and water solvate molecules. In the complex cation, the oxalate ligand is coordinated in a bis-bidentate bridging mode to the Cu atoms. Each Cu atom has a distorted tetragonal-bipyramidal environment, being coordinated by two N atoms of the two chelating bipy ligands and two O atoms of the doubly deprotonated oxalate anion. Pairs of perchlorate anions and water molecules are linked into rectangles by O—H...O bonds in which the perchlorate O atoms act as acceptors and the water molecules as donors. Methyl groups of the DMF solvent molecule are disordered over two sites with occupancies of 0.453 (7:0.547 (7, and the water molecule is half-occupied.

  19. Titanium coordination compounds: from discrete metal complexes to metal–organic frameworks

    KAUST Repository

    Assi, Hala

    2017-05-24

    Owing to their promise in photocatalysis and optoelectronics, titanium based metal–organic frameworks (MOFs) are one of the most appealing classes of MOFs reported to date. Nevertheless, Ti-MOFs are still very scarce because of their challenging synthesis associated with a poor degree of control of their chemistry and crystallization. This review aims at giving an overview of the recent progress in this field focusing on the most relevant existing titanium coordination compounds as well as their promising photoredox properties. Not only Ti-MOFs but also Ti-oxo-clusters will be discussed and particular interest will be dedicated to highlight the different successful synthetic strategies allowing to overcome the still “unpredictable” reactivity of titanium ions, particularly to afford crystalline porous coordination polymers.

  20. Poly[tetraaqua(μ6-9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylatodimanganese(II

    Directory of Open Access Journals (Sweden)

    Rui Xu

    2012-07-01

    Full Text Available The title complex, [Mn2(C18H4O10(H2O4]n, was synthesized from manganese(II chloride tetrahydrate and 9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylic acid (H4AQTC in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one MnII atom, two water ligands and one half AQTC4− anion. The MnII atom is coordinated in a distorted octahedral geometry by four O atoms from three AQTC4− ligands and two water O atoms. Two of the carboxylate groups coordinate one MnII atom in a chelating mode, whereas the others each coordinate two MnII atoms. Each AQTC4− tetra-anion therefore coordinates six different MnII ions and, as a result, a three-dimensional coordination polymer is formed. O—H...O hydrogen bonds, some of them bifurcated, between water ligands and neighboring water or anthraquinone ligands are observed in the crystal structure.

  1. Tripodal polyphosphine ligands as inductors of chelate ring-opening processes in mononuclear palladium(II) and platinum(II) compounds. The X-ray crystal structure of two derivatives containing dangling phosphorus.

    Science.gov (United States)

    Fernández-Anca, Damián; García-Seijo, M Inés; García-Fernández, M Esther

    2010-03-07

    The reaction of NP(3) (tris[2-(diphenylphosphino)ethyl]amine and PP(3) (tris[2-(diphenylphosphino)ethyl]phosphine) with the five-coordinate complexes [PdCl(NP(3))]Cl (1) and [MX(PP(3))]X [M = Pd: X = Cl(2), Br(3), I(4); M = Pt: X = Cl(5), Br(6), I(7)], respectively, followed by (31)P{(1)H}NMR when X = Cl, led to the formation of unprecedented four-coordinate halides in a 1 : 2 metal to ligand ratio, [M(AP(3))(2)]X(2) [A = N, M = Pd: X = Cl(8); A = P, M = Pd: X = Cl(9), Br(10), I(11); A = P, M = Pt: X = Cl(12), Br(13), I (14)], containing reactive dangling phosphorus. Given the non characterised precursors [M(ONO(2))(PP(3))](NO(3))], the interaction between the heteronuclear species [MAg(NO(3))(3)(PP(3))] [M = Pd(15), Pt(16)] and PP(3) was explored. It was found that the addition of 1 equivalent of phosphine afforded [MAg(NO(3))(PP(3))(2)](NO(3))(2) [M = Pd(15*), Pt(16*)] containing Ag(I) bound to two dangling phosphorus while the reaction with 2 equivalents led to the complexes [M(PP(3))(2)](NO(3))(2) [M = Pd (17), Pt (18)] in coexistence with [Ag(2)(mu-PP(3))(2)](NO(3))(2). The fate of Ag(I) on the reaction of the mixed metal compounds with excess PP(3) consisted of preventing dissociation, observed in solution for halides, and acting as an assistant for crystallization. Colourless single crystals of 18 and 10, studied by X-ray diffraction, were afforded by reaction of 16 with 4 equivalents of PP(3) and from solutions of 10 in chloroform coexisting with red crystals of 3, respectively. The structures revealed the presence of dications [M(PP(3))(2)](2+) that show two five-membered chelate rings to M(II) in a square-planar arrangement and four uncoordinated phosphine arms with the counter anions being symmetrically placed at 4.431 (Br(-)) and 13.823 (NO(3)(-)) A from M(II) above and below its coordination, MP(4), plane. Complexes 9 and 12 were shown to undergo an interesting reactivity in solution versus group 11 monocations. The reactions consisted of conversions

  2. Chelate-assisted phytoextraction of lead from contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, E.M.; Sims, J.T.; Cunningham, S.D.; Huang, J.W.; Berti, W.R.

    1999-12-01

    Phytoextraction, a remediation strategy for lead (Pb)-contaminated soils that removes soil Pb through plant uptake and harvest, may be enhanced by use of synthetic chelates. The authors evaluated Pb desorption from four contaminated soils by seven chelates (CDTA, DTPA, EDDHA, EFTA, HEDTA, HEIDA, and NTA) at three rates. The three most effective chelates (CDTA, DTPA, and HEDTA) were used in greenhouse studies with an uncontaminated soil and a Pb-contaminated soil to determine the effect of chelate type and rate on growth, Pb uptake, and plant elemental composition. Lead desorption varied with chelate and soil and increased with chelate rate, averaging 948 mg Pb kg{sup {minus}1} at the 20 mmol kg{sup {minus}1} rate vs. 28 mg Pb kg{sup {minus}1} by the control. The general ranking of chelate effectiveness, based on total Pb desorbed, was HEDTA > CDTA > DTPA > EGTA > HEIDA > EDDHA {approximately} NTA. Plant uptake of Pb from the contaminated soil was enhanced by CDTA, DTPA, and HEDTA, but with even the most effective treatment (corn, high CDTA rate), the amount of Pb extracted by plants was rather low. Lead extractable by the Toxicity Characteristic Leaching Procedure (TCLP) was increased from 9 mg L{sup {minus}1} in the control to from 47 to 174 mg L{sup {minus}1} in soils treated with 20 mmol kg{sup {minus}1} CDTA or DTPA and chelates generally caused a shift in Pb from resistant to more soluble chemical fractions.

  3. Bis[2-(2-aminoethyl-1H-benzimidazole-κ2N2,N3](nitrato-κ2O,O′cobalt(II chloride trihydrate

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2012-06-01

    Full Text Available In the title compound, [Co(NO3(C9H11N32]Cl·3H2O, the CoII atom is coordinated by four N atoms from two chelating 2-(2-aminoethyl-1H-benzimidazole ligands and two O atoms from one nitrate anion in a distorted octahedral coordination environment. In the crystal, N—H...Cl, N—H...O, O—H...Cl and O—H...O hydrogen bonds link the complex cations, chloride anions and solvent water molecules into a three-dimensional network. π–π interactions between the imidazole and benzene rings and between the benzene rings are observed [centroid–centroid distances = 3.903 (3, 3.720 (3, 3.774 (3 and 3.926 (3 Å].

  4. Water molecule-enhanced CO2 insertion in lanthanide coordination polymers

    International Nuclear Information System (INIS)

    Luo Liushan; Huang Xiaoyuan; Wang Ning; Wu Hongyan; Chen Wenbin; Feng Zihao; Zhu Huiping; Peng Xiaoling; Li Yongxian; Huang Ling; Yue Shantang; Liu Yingliang

    2009-01-01

    Two new lanthanide coordination polymers H 2 N(CH 3 ) 2 .[Eu III 2 (L 1 ) 3 (L 2 )] (1, L 1 =isophthalic acid dianion, L 2 =formic acid anion) and [La III (2,5-PDC)(L 2 )](2, 2,5-PDC=2,5-pyridinedicarboxylate dianion) were synthesized under solvothermal conditions. It is of interest that the formic ligand (L 2 ) is not contained in the stating materials, but arises from the water molecule-enhanced CO 2 insertion during the solvothermal process. Both of the two compounds exhibit complicated three dimensional sandwich-like frameworks. - Graphical abstract: Two new lanthanide coordination polymers involving water molecule-enhanced CO 2 insertion resulting in the formation of formic anion and dimethylammonium cation were synthesized under solvothermal conditions.

  5. Urinary excretion of 8-oxo-7,8-dihydroguanine as biomarker of oxidative damage to DNA

    DEFF Research Database (Denmark)

    Loft, Steffen; Danielsen, Pernille Høgh; Løhr, Mille

    2012-01-01

    to air pollution, toxic metals, tobacco smoke and low plasma antioxidant levels, whereas fruit and vegetable intake or dietary interventions showed no association. In rodent studies some types of feed may be source of 8-oxoGua in collected urine. Of cancer therapies, cisplatin increased 8-oxo...

  6. One step synthesis of 6-oxo-cholestan-3β,5α-diol

    International Nuclear Information System (INIS)

    Voisin, Maud; Silvente-Poirot, Sandrine; Poirot, Marc

    2014-01-01

    Highlights: • Cholesterol-5,6-epoxides are metabolized into cholestane-3β,5α,6β-triol (CT) in cancer cells. • 6-Oxo-cholestan-3β,5α-diol (OCDO) is a putative metabolite of CT. • The one step syntheses of CT and OCDO from cholesterol are reported. • The one step syntheses of labelled CT and OCDO are reported. - Abstract: Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [ 14 C]-cholestane-3β,5α,6β-triol and [ 14 C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [ 14 C]-cholestane-3β,5α,6β-triol and [ 14 C]-6-oxo-cholestan-3β,5α-diol by oxidation of [ 14 C]-cholesterol with iodide metaperiodate (HIO 4 )

  7. The complex compounds of manganese (II) with poly dental ligands and polyhedron borane anions

    International Nuclear Information System (INIS)

    Buranova, S.A.

    1996-01-01

    The purpose of the present work is synthesis of complex compounds of manganese with organic ligands. Their studying by spectroscopic methods purposely to determinate the influence of borane anions on composition and structure of coordinating sphere of manganese

  8. (Carbonato-κO,O')bis-(di-2-pyridyl-amine-κN,N')cobalt(III) bromide.

    Science.gov (United States)

    Czapik, Agnieszka; Papadopoulos, Christos; Lalia-Kantouri, Maria; Gdaniec, Maria

    2011-04-01

    In the title compound, [Co(CO(3))(C(10)H(9)N(3))(2)]Br, a distorted octa-hedral coordination of the Co(III) atom is completed by four N atoms of the two chelating di-2-pyridyl-amine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridyl-amine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C(2) symmetry, is connected to the bromide ion via an N-H⋯Br(-) hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N-H⋯O inter-actions about an inversion centre. A set of weaker C-H⋯O and C-H⋯Br(-) inter-actions connect the dimers into a three-dimensional network.

  9. [Susceptibility of enterococci to natural and synthetic iron chelators].

    Science.gov (United States)

    Lisiecki, Paweł; Mikucki, Jerzy

    2002-01-01

    A total of 79 strains of enterococci belonging to 10 species were tested for susceptibility to natural and synthetic iron chelators. All strains produced siderophores. These enterococci were susceptible to three synthetic iron chelators only: 8-hydroxyquinoline, disodium versenate (EDTA) and o-phenanthroline. They were resistant to all other synthetic chelators: ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), nitrilotriacetate, 2,2'-bipiridyl, salicylic acid, 8-hydroxy-5-sulphonic acid and to all natural chelators: ovotransferrine, human apotransferrine, horse apoferritine, desferrioxamine B, ferrichrome and rhodotorulic acid. The relations between susceptibility/resistance, iron assimilation and structure and stability constants of iron chelators were discussed.

  10. Complexation studies of actinides (U, Pu, Am) with linear polyamino-carboxylate ligands and sidero-chelates; Etudes de la chelation d'actinides (U, Pu, Am) par des ligands polyaminocarboxylate lineaires et des siderochelates d'interet environnemental

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, L.V.

    2010-11-25

    As part of our research endeavour aimed at developing and improving decontamination processes of wastewater containing alpha emitters, physico-chemical complexation studies of actinides (U, Pu, Am) with organic open-chain ligands such as poly-aminocarboxylic acids (H{sub 4}EDTA) and sidero-chelates (di-hydroxamic acids and desferrioxamine B) have been carried out. Gaining a clear understanding of the coordination properties of the targeted actinides is an essential step towards the selection of the most appropriate chelating agents that will exhibit high uptake efficiencies. EXAFS (Extended X-ray Absorption Fine Structure) measurements at the ESRF synchrotron enabled to elucidate the coordination scheme of uranium and plutonium complexes. Solution thermodynamic investigations were intended to provide valuable information about the nature and the stability of the uranium(VI) and americium(III) complexes prevailing at a given pH in solution. The set of stability constants determined from potentiometric and UV-visible spectrophotometric titrations, allowed to predict the speciation of the selected actinides in presence of the aforementioned ligands and to determine the pH range required for achieving 'ultimate' decontamination. (author) [French] Dans le cadre du developpement et de l'amelioration des procedes de decontamination d'effluents aqueux contamines par des radioelements emetteurs alpha, des etudes physico-chimiques sur la complexation des actinides (U, Pu, Am) avec des ligands organiques tels que des acides polyaminocarboxyliques lineaires (H{sub 4}EDTA) et des siderochelates (acides dihydroxamiques et desferrioxamine B) ont ete effectuees. La comprehension des proprietes de coordination est une etape essentielle pour selectionner les meilleurs agents chelatants qui se montreront efficaces dans le traitement des effluents. Les schemas de coordination des complexes d'uranium et de plutonium avec ces ligands ont ete determines a l

  11. Studies on treatment of low level radioactive liquid waste for removal of anionic species of 125Sb, 99Tc and 106Ru. Contributed Paper RD-14

    International Nuclear Information System (INIS)

    Shivakamy, K.; Chitra, S.; Rao, S.V.S.; Paul, Biplob

    2014-01-01

    The treatment of intermediate level waste at Waste Immobilization Plant generates low level radioactive waste which would require further management before discharge to sea. This waste is expected to contain polymeric oxo anions of 125 Sb, 99 Tc, 106 Ru in addition to cationic species like 137 Cs, 90 Sr etc. Chemical treatment takes care of the major contributors to radioactivity viz 137 Cs, 90 Sr etc but traces of activity due to anionic species remain in the treated waste effluent. Novel composite anionic exchanger namely Polyurethane foam coated with Hydrous Zirconium Oxide was developed for removal of these anionic species. This material was successfully employed for removal of anionic 1 25S b from radioactive waste effluent at Waste Management Division, Trombay. Based on our experience with Sb removal using the above material it was decided to assess the ability of the exchanger in removal of other anionic species bearing Ru and Tc. It was observed that in addition to complete removal of Sb, 50% Ru removal and 40% Tc could also be removed using this material from radioactive waste effluents. In lab experiments, similar results were obtained with simulated low level waste bearing inactive Ru. Among several hydrous oxides tried in a batch study, Hydrous Zirconium Oxide showed a maximum removal of 40% for Tc in actual waste generated from reprocessing plant. Based on the above it has been planned to set up an anion exchange column with Hydrous Zirconium Oxide coated Polyurethane foam for final treatment of chemically treated waste effluent prior to discharge as a prime step towards achieving our goal of minimum discharge to Sea. (author)

  12. Thermodynamic properties and cloud droplet activation of a series of oxo-acids

    Directory of Open Access Journals (Sweden)

    M. Frosch

    2010-07-01

    Full Text Available We have investigated the thermodynamic properties of four aliphatic oxo-dicarboyxlic acids identified or thought to be present in atmospheric particulate matter: oxosuccinic acid, 2-oxoglutaric acid, 3-oxoglutaric acid, and 4-oxopimelic acid. The compounds were characterized in terms of their cloud condensation nuclei (CCN activity, vapor pressure, density, and tendency to decarboxylate in aqueous solution. We deployed a variety of experimental techniques and instruments: a CCN counter, a Tandem Differential Mobililty Analyzer (TDMA coupled with a laminar flow-tube, and liquid chromatography/mass spectrometry (LC/MS. The presence of the oxo functional group in the α-position causes the vapor pressure of the compounds to diminish by an order of magnitude with respect to the parent dicarboxylic acid, while the CCN activity is similar or increased. Dicarboxylic acids with an oxo-group in the β-position decarboxylate in aqueous solution. We studied the effects of this process on our measurements and findings.

  13. Chelating agents in pharmacology, toxicology and therapeutics

    International Nuclear Information System (INIS)

    1988-01-01

    The proceedings contain 71 abstracts of papers. Fourteen abstracts were inputted in INIS. The topics covered include: the effects of chelating agents on the retention of 63 Ni, 109 Cd, 203 Hg, 144 Ce, 95 Nb and the excretion of 210 Po, 63 Ni, 48 V, 239 Pu, 241 Am, 54 Mn; the applications of tracer techniques for studies of the efficacy of chelation therapy in patients with heart and brain disorders; and the treatment of metal poisoning with chelating agents. (J.P.)

  14. Di-tert-butyl-bis(N-isopropyl-N-methyl-dithio-carbamato-κS,S')tin(IV).

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Samsudin, Mohd Wahid; Ng, Seik Weng

    2010-03-03

    The dithio-carbamate anions in the title compound, [Sn(C(4)H(9))(2)(C(5)H(10)NS(2))(2)], chelate to the Sn(IV) atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol-ecule lies across a twofold rotation axis. The crystal studied was a non-merohedral twin, the ratio of the twin components being 0.82 (1):0.18 (1).

  15. Di-tert-butylbis(N-isopropyl-N-methyldithiocarbamato-κ2S,S′tin(IV

    Directory of Open Access Journals (Sweden)

    Amirah Faizah Muthalib

    2010-04-01

    Full Text Available The dithiocarbamate anions in the title compound, [Sn(C4H92(C5H10NS22], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The molecule lies across a twofold rotation axis. The crystal studied was a non-merohedral twin, the ratio of the twin components being 0.82 (1:0.18 (1.

  16. Synthesis and chemical characterization of the novel agronomically relevant pentadentate chelate 2-(2-((2-hydroxybenzyl)amino)ethylamino)-2-(2-hydroxyphenyl)acetic acid (DCHA).

    Science.gov (United States)

    López-Rayo, Sandra; Hernández, Diana; Lucena, Juan J; Escudero, Rosa; Gómez-Gallego, Mar; Sierra, Miguel A

    2010-07-14

    Iron chelates analogous to o,o-EDDHA/Fe(3+) are the fertilizers chosen to treat iron chlorosis in plants growing on calcareous soil. The isomer o,p-EDDHA/Fe(3+) presents less stability but faster assimilation by the plant than o,o-EDDHA/Fe(3+), because only five coordinating groups are able to complex Fe(3+). The new chelating agent 2-(2-((2-hydroxybenzyl)amino)ethylamino)-2-(2-hydroxyphenyl)acetic acid (DCHA) has been synthesized to obtain an iron fertilizer with intermediate stability between o,o-EDDHA/Fe(3+) and o,p-EDDHA/Fe(3+) and with fast assimilation. Its synthesis has been done starting from phenol, N-acetylethylendiamine, glyoxylic acid, and NaOH in a three-step sequence. The purity of the DCHA chelating agent, its protonation, and Ca(2+), Mg(2+), Fe(3+), and Cu(2+) stability constants, together with its ability to maintain iron in solution in different agronomic conditions, have been determined. The results indicate that the chelate DCHA/Fe(3+) has intermediate stability between those of o,o-EDDHA/Fe(3+) and o,p-EDDHA/Fe(3+) complexes and that it is capable of maintaining the Fe(3+) in agronomic conditions. This new chelating agent may be effective in correcting iron chlorosis in plants.

  17. Bis(di-2-pyridylamine-κ2N2,N2'platinum(II dibromide monohydrate

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2012-04-01

    Full Text Available The asymmetric unit of the title compound, [Pt(C10H9N32]Br2·H2O, contains two crystallographically independent half-molecules of the cationic PtII complex, two Br− anions and a lattice water molecule; an inversion centre is located at the centroid of each complex. Each PtII ion is four-coordinated in an essentially square-planar environment by four pyridine N atoms derived from the two chelating di-2-pyridylamine (dpa ligands, and the PtN4 unit is exactly planar. The chelate ring formed by the dpa ligand displays a boat conformation, with dihedral angles between the pyridine rings of 35.9 (2 and 41.0 (2°. The complex cations, Br− anions and solvent water molecules are linked by O—H...Br, N—H...Br, C—H...O and C—H...Br hydrogen bonds, forming a three-dimensional network.

  18. The influence of iron coordination compounds on producing capacity of some crops

    International Nuclear Information System (INIS)

    Rakhimova, M.M.; Yusupov, Z.N.; Nurmatov, T.M.; Dzhafarov, M.I.

    1993-01-01

    Present article is devoted to influence of iron coordination compounds on producing capacity of some crops. The influence of aqueous solutions of iron coordination compounds with anions of acetic and ethylen diamin disuccinic acids on germinative energy and germination of cotton crops and grapes was studied in laboratory conditions. The conducted researches shown that application of iron coordination compounds improves the growth, fruiting and the quality of studied crops.

  19. A new multifunctional 1, 10-phenanthroline based fluorophore for anion and cation sensing

    Energy Technology Data Exchange (ETDEWEB)

    Alreja, Priya; Kaur, Navneet, E-mail: neet_chem@yahoo.co.in

    2015-12-15

    We report a new multi-ion responsive fluorophore 1 possessing an amide functionality featuring with 1, 10-phenanthroline unit with appropriately placed coordination sites for sensing Cu{sup 2+} and Zn{sup 2+} ions in 1:2 stoichiometry. Also, various functionalities of 1 organize to create an appropriate cavity to accommodate weakly basic and larger iodide ion generating 1:1 complex. The fluorescence intensity was greatly quenched on coordination of Cu{sup 2+}, Zn{sup 2+} and I{sup −} ions with appropriately placed multiple donor sites of 1 which was further supported by Density Functional Theory (DFT) computational studies. - Highlights: • A novel multifunctional 1, 10- Phenanthroline based fluorophore for sensing anion and cations. • First report on applicability of amides as multiple users for anion and cations. • Fluorescence quenching observed with Cu{sup 2+}, Zn{sup 2+} and I{sup -}. • Fluorescence titration experiments are well supported by DFT calculations.

  20. One step synthesis of 6-oxo-cholestan-3β,5α-diol

    Energy Technology Data Exchange (ETDEWEB)

    Voisin, Maud; Silvente-Poirot, Sandrine; Poirot, Marc, E-mail: marc.poirot@inserm.fr

    2014-04-11

    Highlights: • Cholesterol-5,6-epoxides are metabolized into cholestane-3β,5α,6β-triol (CT) in cancer cells. • 6-Oxo-cholestan-3β,5α-diol (OCDO) is a putative metabolite of CT. • The one step syntheses of CT and OCDO from cholesterol are reported. • The one step syntheses of labelled CT and OCDO are reported. - Abstract: Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [{sup 14}C]-cholestane-3β,5α,6β-triol and [{sup 14}C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [{sup 14}C]-cholestane-3β,5α,6β-triol and [{sup 14}C]-6-oxo-cholestan-3β,5α-diol by oxidation of [{sup 14}C]-cholesterol with iodide metaperiodate (HIO{sub 4})

  1. IR, UV-Vis, magnetic and thermal characterization of chelates of some catecholamines and 4-aminoantipyrine with Fe(III) and Cu(II)

    Science.gov (United States)

    Mohamed, Gehad G.; Zayed, M. A.; El-Dien, F. A. Nour; El-Nahas, Reham G.

    2004-07-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. α-Methyldopa (α-MD) in tablets is used in medication of hypertension. The Fe(III) and Cu(II) chelates with coupled products of adrenaline hydrogen tartarate (AHT), levodopa (LD), α-MD and carbidopa (CD) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical methods like IR, magnetic and UV-Vis spectra are used to investigate the structure of these chelates. Fe(III) form 1:2 (M:catecholamines) chelates while Cu(II) form 1:1 chelates. Catecholamines behave as a bidentate mono- or dibasic ligands in binding to the metal ions. IR spectra show that the catecholamines are coordinated to the metal ions in a bidentate manner with O,O donor sites of the phenolic - OH. Magnetic moment measurements reveal the presence of Fe(III) chelates in octahedral geometry while the Cu(II) chelates are square planar. The thermal decomposition of Fe(III) and Cu(II) complexes is studied using thermogravimetric (TGA) and differential thermal analysis (DTA) techniques. The water molecules are removed in the first step followed immediately by decomposition of the ligand molecules. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  2. Role of chelates in magnetic resonance imaging studies

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2009-01-01

    Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

  3. Cation-Dependent Gold Recovery with α-Cyclodextrin Facilitated by Second-Sphere Coordination.

    Science.gov (United States)

    Liu, Zhichang; Samanta, Avik; Lei, Juying; Sun, Junling; Wang, Yuping; Stoddart, J Fraser

    2016-09-14

    Herein, we report an alkali metal cation-dependent approach to gold recovery, facilitated by second-sphere coordination with eco-friendly α-cyclodextrin (α-CD). Upon mixing eight salts composed of Na(+), K(+), Rb(+), or Cs(+) cations and [AuX4](-) (X = Cl/Br) anions with α-, β-, or γ-CD in water, co-precipitates form selectively from the three (out of 24) aqueous solutions containing α-CD with KAuBr4, RbAuBr4, and CsAuBr4, from which the combination of α-CD and KAuBr4 affords the highest yield. Single-crystal X-ray analyses reveal that in 20 of the 24 adducts CD and [AuX4](-) anions form 2:1 sandwich-type second-sphere adducts driven partially by [C-H···X-Au] interactions between [AuX4](-) anions and the primary faces of two neighboring CDs. In the adduct formed between α-CD and KAuBr4, a [K(OH2)6](+) cation is encapsulated inside the cavity between the secondary faces of two α-CDs, leading to highly efficient precipitation owing to the formation of a cation/anion alternating ion wire residing inside a continuous α-CD nanotube. By contrast, in the other 19 adducts, the cations are coordinated by OH groups and glucopyranosyl ring O atoms in CDs. The strong coordination of Rb(+) and Cs(+) cations by these ligands, in conjunction with the stereoelectronically favorable binding of [AuBr4](-) anions with two α-CDs, facilitates the co-precipitation of the two adducts formed between α-CD with RbAuBr4 and CsAuBr4. In order to develop an efficient process for green gold recovery, the co-precipitation yield of α-CD and KAuBr4 has been optimized regarding both the temperature and the molar ratio of α-CD to KAuBr4.

  4. Polyaminoquinoline iron chelators for vectorization of antiproliferative agents: design, synthesis, and validation.

    Science.gov (United States)

    Corcé, Vincent; Morin, Emmanuelle; Guihéneuf, Solène; Renault, Eric; Renaud, Stéphanie; Cannie, Isabelle; Tripier, Raphaël; Lima, Luís M P; Julienne, Karine; Gouin, Sébastien G; Loréal, Olivier; Deniaud, David; Gaboriau, François

    2012-09-19

    Iron chelation in tumoral cells has been reported as potentially useful during antitumoral treatment. Our aim was to develop new polyaminoquinoline iron chelators targeting tumoral cells. For this purpose, we designed, synthesized, and evaluated the biological activity of a new generation of iron chelators, which we named Quilamines, based on an 8-hydroxyquinoline (8-HQ) scaffold linked to linear polyamine vectors. These were designed to target tumor cells expressing an overactive polyamine transport system (PTS). A set of Quilamines bearing variable polyamine chains was designed and assessed for their ability to interact with iron. Quilamines were also screened for their cytostatic/cytotoxic effects and their selective uptake by the PTS in the CHO cell line. Our results show that both the 8-HQ moiety and the polyamine part participate in the iron coordination. HQ1-44, the most promising Quilamine identified, presents a homospermidine moiety and was shown to be highly taken up by the PTS and to display an efficient antiproliferative activity that occurred in the micromolar range. In addition, cytotoxicity was only observed at concentrations higher than 100 μM. We also demonstrated the high complexation capacity of HQ1-44 with iron while much weaker complexes were formed with other cations, indicative of a high selectivity. We applied the density functional theory to study the binding energy and the electronic structure of prototypical iron(III)-Quilamine complexes. On the basis of these calculations, Quilamine HQ1-44 is a strong tridentate ligand for iron(III) especially in the form of a 1:2 complex.

  5. Obligatory reduction of ferric chelates in iron uptake by soybeans.

    Science.gov (United States)

    Chaney, R L; Brown, J C; Tiffin, L O

    1972-08-01

    The contrasting Fe(2+) and Fe(3+) chelating properties of the synthetic chelators ethylenediaminedi (o-hydroxyphenylacetate) (EDDHA) and 4,7-di(4-phenylsulfonate)-1, 10-phenanthroline (bathophenanthrolinedisulfonate) (BPDS) were used to determine the valence form of Fe absorbed by soybean roots supplied with Fe(3+)-chelates. EDDHA binds Fe(3+) strongly, but Fe(2+) weakly; BPDS binds Fe(2+) strongly but Fe(3+) weakly. Addition of an excess of BPDS to nutrient solutions containing Fe(3+)-chelates inhibited soybean Fe uptake-translocation by 99+%; [Fe(II) (BPDS)(3)](4-) accumulated in the nutrient solution. The addition of EDDHA caused little or no inhibition. These results were observed with topped and intact soybeans. Thus, separation and absorption of Fe from Fe(3+)-chelates appear to require reduction of Fe(3+)-chelate to Fe(2+)-chelate at the root, with Fe(2+) being the principal form of Fe absorbed by soybean.

  6. Anion exchange membrane

    Science.gov (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  7. Multiple anion...π interactions in tris(1,10-phenanthroline-κ(2)N,N')iron(II) bis[1,1,3,3-tetracyano-2-(2-hydroxyethyl)propenide] monohydrate.

    Science.gov (United States)

    Setifi, Zouaoui; Domasevitch, Konstantin V; Setifi, Fatima; Mach, Pavel; Ng, Seik Weng; Petříček, Vaclav; Dušek, Michal

    2013-11-01

    In the ionic structure of the title compound, [Fe(C12H8N2)3](C9H5N4O2)2·H2O, the octahedral tris-chelate [Fe(phen)3](2+) dications [Fe-N = 1.9647 (14)-1.9769 (14) Å; phen is 1,10-phenathroline] afford one-dimensional chains by a series of slipped π-π stacking interactions [centroid-to-centroid distances = 3.792 (3) and 3.939 (3) Å]. The 1,1,3,3-tetracyano-2-(2-hydroxyethyl)propenide anions, denoted tcnoetOH(-), reveal an appreciable delocalization of π-electron density, involving the central propenide [C-C = 1.383 (3)-1.401 (2) Å] fragment and four nitrile groups, and this is also supported by density functional theory (DFT) calculations at the B97D/6-311+G(2d,2p) level. Primary noncovalent inter-moiety interactions comprise conventional O-H...O(N) and weak C-H...O(N) hydrogen bonding [O...O(N) = 2.833 (2)-3.289 (5) Å and C...O(N) = 3.132 (2)-3.439 (2) Å]. The double anion...π interaction involving a nitrile group of tcnoetOH(-) and two cis-positioned pyridine rings (`π-pocket') of [Fe(phen)3](2+) [N...centroid = 3.212 (2) and 3.418 (2) Å] suggest the relevance of anion...π stackings for charge-diffuse polycyanoanions and common M-chelate species.

  8. Luminescent lanthanide coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

    1999-12-13

    One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

  9. Moessbauer and EPR studies on iron-dihydroxybenzoic acid and iron-itoic acid chelate complexes

    International Nuclear Information System (INIS)

    Bagyinka, Cs.; Horvath, L.I.; Keszthelyi, L.

    1984-01-01

    Low molecular weight iron-dihydroxybenzoic acid and iron-itoic acid complexes were investigated by Moessbauer and EPR spectroscopy. In strong acidic medium the iron is chelated in high spin ferrous form. By varying the pH of the medium a (S=2)Fesup(2+)→(S=5/2)Fesup(3+) transition was found with a midpoint pH value of 4. From the g'-tensor anisotropy it is concluded that the metal atom is coordinated by six oxygen atoms in rhombically distorted octahedral configuration. The biological significance of these structural data is briefly discussed. (author)

  10. Structures of plutonium coordination compounds: A review of past work, recent single crystal x-ray diffraction results, and what we're learning about plutonium coordination chemistry

    Science.gov (United States)

    Neu, M. P.; Matonic, J. H.; Smith, D. M.; Scott, B. L.

    2000-07-01

    The compounds we have isolated and characterized include plutonium(III) and plutonium(IV) bound by ligands with a range of donor types and denticity (halide, phosphine oxide, hydroxamate, amine, sulfide) in a variety of coordination geometries. For example, we have obtained the first X-ray structure of Pu(III) complexed by a soft donor ligand. Using a "one pot" synthesis beginning with Pu metal strips and iodine in acetonitrile and adding trithiacyclononane we isolated the complex, PuI3(9S3)(MeCN)2 (Figure 1). On the other end of the coordination chemistry spectrum, we have obtained the first single crystal structure of the Pu(IV) hexachloro anion (Figure 2). Although this species has been used in plutonium purification via anion exchange chromatography for decades, the bond distances and exact structure were not known. We have also characterized the first plutonium-biomolecule complex, Pu(IV) bound by the siderophore desferrioxamine E.In this presentation we will review the preparation, structures, and importance of previously known coordination compounds and of those we have recently isolated. We will show the coordination chemistry of plutonium is rich and varied, well worth additional exploration.

  11. Development of iron chelators for Cooley's anemia. Final report

    International Nuclear Information System (INIS)

    Crosby, W.H.; Green, R.

    1982-01-01

    Iron chelators were screened in an iron-loaded rat model using selective radioiron probes. In all experiments, chelators D and F, in that order, induced significant loss of radioiron compared with controls. However, use of chelator D was associated with side effects, and resulted in the death of some animals. There was some evidence that chelator A also caused iron loss significantly greater than controls. Chelators B, C and E were without apparent enhancing effect on radioiron excretion. This was a blind study and the compounds used were A - 2,3-Dihydroxybenzoic acid; B - N,N1-Dimethyladipohydroxamic acid; C - DL-Phenylalanine hydroxamic acid; D - Ethylenediamine-N,N1-bis(2-hydroxphenylacetic acid); E - Propionohydroxamic acid; and F - Deferrioxamine B

  12. Emission properties of Sm(III) complex having ten-coordination structure

    International Nuclear Information System (INIS)

    Hasegawa, Yasuchika; Tsuruoka, Shin-ichi; Yoshida, Takahiko; Kawai, Hideki; Kawai, Tsuyoshi

    2008-01-01

    Sammarium(III) complex having ten-coordination structure, bis-(1,10-phenanthroline)tris-(hexafluoroacetylacetonato)samarium(III) (Sm(hfa) 3 (phen) 2 ) was prepared by chelation of tris-(hexafluoroacetylacetonato) samarium(III) (Sm(hfa) 3 (H 2 O) 2 ) with 1,10-phenantroline (phen). The characteristic ten-coordination structure of Sm(hfa) 3 (phen) 2 was determined by 1 H NMR and elemental analyses. Strong deep-red emission (λ max =643 nm) and narrow emission band (FWHM=5 nm) of Sm(hfa) 3 (phen) 2 originated from electronic allowed transition from characteristics ten coordinate structure. The emission quantum yields Sm(hfa) 3 (phen) 2 excited at absorption bands of ligands and Sm(III) ion were found to be 0.36 and 1.4%, respectively

  13. Anion effect controlling the selectivity in the zinc-catalysed copolymerisation of CO2 and cyclohexene oxide

    Directory of Open Access Journals (Sweden)

    Sait Elmas

    2015-01-01

    Full Text Available The choice of the anion has a surprisingly strong effect on the incorporation of CO2 into the polymer obtained during the zinc-catalysed copolymerisation of CO2 and cyclohexene oxide. The product span ranges from polyethercarbonates, where short polyether sequences alternate with carbonate linkages, to polycarbonates with a strictly alternating sequence of the repeating units. Herein, we report on the influence of the coordination ability of the anion on the selectivity and kinetics of the copolymerisation reaction.

  14. The synthesis and complex anion-vacancy ordered structure of La0.33Sr0.67MnO2.42

    International Nuclear Information System (INIS)

    Dixon, Edward; Hadermann, Joke; Hayward, Michael A.

    2011-01-01

    The low-temperature topotactic reduction of La 0.33 Sr 0.67 MnO 3 with NaH results in the formation of La 0.33 Sr 0.67 MnO 2.42 . A combination of neutron powder and electron diffraction data show that La 0.33 Sr 0.67 MnO 2.42 adopts a novel anion-vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the 'octahedral' and tetrahedral layers (Pcmb, a=5.5804(1) A, b=23.4104(7) A, c=11.2441(3) A). A significant concentration of anion vacancies at the anion site, which links neighbouring 'octahedral' layers means that only 25% of the 'octahedral' manganese coordination sites actually have 6-fold MnO 6 coordination, the remainder being MnO 5 square-based pyramidal sites. The chains of cooperatively twisted apex-linked MnO 4 tetrahedra adopt an ordered -L-R-L-R- arrangement within each tetrahedral layer. This is the first published example of a fully refined structure of this type which exhibits such intralayer ordering of the twisted tetrahedral chains. The rationale behind the contrasting structures of La 0.33 Sr 0.67 MnO 2.42 and other previously reported reduced La 1-x Sr x MnO 3-y phases is discussed. - Graphical Abstract: The topotactic reduction of the perovskite phase La 0.33 Sr 0.67 MnO 3 with NaH yields La 0.33 Sr 0.67 MnO 2.42(3) , which adopts a novel anion vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the 'octahedral' and tetrahedral layers. The anion site that links the neighbouring octahedral layers is partially occupied so only 25% of the 'octahedral' manganese sites actually have 6-fold MnO 6 coordination. Highlights: → Topotactic reduction with NaH to form a mixed valent Mn 2+ /Mn 3+ phase. → Novel layered anion-vacancy ordered structure. → Comparison to related brownmillerite structure types.

  15. Bis(μ-bis{[4-(2-pyridylpyrimidin-2-yl]sulfanyl}methanedisilver(I bis(perchlorate

    Directory of Open Access Journals (Sweden)

    Hai-Bin Zhu

    2010-12-01

    Full Text Available In the macrocyclic centrosymmetric dinuclear complex, [Ag2(C19H14N6S22](ClO42, the AgI atom, bis{[4-(2-pyridylpyrimidin-2-yl]sulfanyl}methane (2-bppt ligand and perchlorate anion each lie on a twofold rotation axis. The 2-bppt ligand chelates two four-coordinated AgI atoms through its two bipyridine-like arms. The O atoms of the perchlorate anion are disordered each over two positions of equal occupancy. Adjacent complex molecules are linked by π–π interactions between the pyridine and pyrimidine rings [centroid–centroid distance = 3.663 (8 Å].

  16. Bis(tetraphenylphosphonium bis[N-(trifluoromethylsulfonyldithiocarbimato(2−-κ2S,S′]zincate(II

    Directory of Open Access Journals (Sweden)

    Paula S. Pinto

    2012-01-01

    Full Text Available The title salt, (C24H20P2[Zn(C2F3NO2S32], consists of a complex dianion and two tetraphenylphosphonium cations. The ZnII ion displays a distorted tetrahedral coordination environment with four S atoms from two S,S′-chelated N-(trifluoromethylsulfonyldithiocarbimate anions. In the crystal, besides the ionic interaction of the oppositely charged ions, intermolecular C—H...O interactions between cations and anions are observed. One of the cations interacts with an inversion-related equivalent by π–π stacking between phenyl rings, with a centroid–centroid distance of 3.932 (4 Å.

  17. (Carbonato-κ2 O,O′)bis­(di-2-pyridyl­amine-κ2 N,N′)cobalt(III) bromide

    Science.gov (United States)

    Czapik, Agnieszka; Papadopoulos, Christos; Lalia-Kantouri, Maria; Gdaniec, Maria

    2011-01-01

    In the title compound, [Co(CO3)(C10H9N3)2]Br, a distorted octa­hedral coordination of the CoIII atom is completed by four N atoms of the two chelating di-2-pyridyl­amine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridyl­amine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C 2 symmetry, is connected to the bromide ion via an N—H⋯Br− hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N—H⋯O inter­actions about an inversion centre. A set of weaker C—H⋯O and C—H⋯Br− inter­actions connect the dimers into a three-dimensional network. PMID:21753946

  18. New Anion-Exchange Resins for Improved Separations of Nuclear Materials

    International Nuclear Information System (INIS)

    Bartsch, Richard A.; Barr, Mary E.

    2001-01-01

    Improved separations of nuclear materials will have a significant impact upon a broad range of DOE activities. DOE-EM Focus Areas and Crosscutting Programs have identified improved methods for the extraction and recovery of radioactive metal ions from process, waste, and environmental waters as critical needs for the coming years. We propose to develop multifunctional anion-exchange resins that facilitate anion uptake by carefully controlling the structure of the anion receptor site. Our new ion-exchange resins interface the field of ion-specific chelating ligands with robust, commercial ion-exchange technology to provide materials which exhibit superior selectivity and kinetics of sorption and desorption. The following Focus Areas and Crosscutting Programs have described needs that would be favorably impacted by the new material: Efficient Separations and Processing - radionuclide removal from aqueous phases; Plutonium - Pu, Am or total alpha removal to meet regulatory requirement s before discharge to the environment; Plumes - U and Tc in groundwater, U, Pu, Am, and Tc in soils; Mixed Waste - radionuclide partitioning; High-Level Tank Waste - actinide and Tc removal from supernatants and/or sludges. The basic scientific issues which need to be addressed are actinide complex speciation along with modeling of metal complex/functional site interactions in order to determine optimal binding-site characteristics. Synthesis of multifunctionalized extractants and ion-exchange materials that implement key features of the optimized binding site, and testing of these materials, will provide feedback to the modeling and design activities. Resin materials which actively facilitate the uptake of actinide complexes from solution should display both improved selectivity and kinetic properties. The long-range implications of this research, however, go far beyond the nuclear complex. This new methodology of ''facilitated uptake'' could revolutionize ion-exchange technology

  19. New anion-exchange resins for improved separations of nuclear materials

    International Nuclear Information System (INIS)

    Barr, M.E.; Bartsch, R.A.

    1998-01-01

    'The overall objective of this research is to develop a predictive capability which allows the facile design and implementation of multi-functionalized anion-exchange materials which selectively sorb metal complexes of interest from targeted process, waste, and environmental streams. The basic scientific issues addressed are actinide complex speciation along with modeling of the metal complex/functional-site interactions in order to determine optimal binding-site characteristics. The new ion-exchange resins interface the rapidly developing field of ion-specific chelating ligands with robust, commercial ion-exchange technology. Various Focus Areas and Crosscutting Programs have described needs that would be favorably impacted by the new materials: Efficient Separations and Processing; Plutonium; Plumes; Mixed Waste; High-Level Tank Waste. Sites within the DOE complex which would benefit from the improved anion-exchange technology include Hanford, INEL, Los Alamos, Oak Ridge, and Savannah River. As of April 1998, this report summarizes work after 1.6 years of a 3-year project. The authors technical approach combines empirical testing with theoretical modeling (applied in an iterative mode) in order to determine optimal binding-site characteristics. They determine actinide-complex speciation in specific media, then develop models for the metal complex/functional-site interactions Synthesis and evaluation of multi-functionalized extractants and ion-exchange materials that implement key features of the optimized binding site provide feedback to the modeling and design activities. Resin materials which actively facilitate the uptake of actinide complexes from solution should display both improved selectivity and kinetic properties. The implementation of the bifunctionality concept involves N-derivatization of pyridinium units from a base poly(4-vinylpyridine) resin with a second cationic site such that the two anion-exchange sites are linked by spacer arms of varying

  20. Coordination Networks Based on Boronate and Benzoxaborolate Ligands

    Directory of Open Access Journals (Sweden)

    Saad Sene

    2016-05-01

    Full Text Available Despite the extensive range of investigations on boronic acids (R-B(OH2, some aspects of their reactivity still need to be explored. This is the case for the coordination chemistry of boronate anions (R-B(OH3−, which has only recently been started to be studied. The purpose of this review is to summarize some of the key features of boronate ligands (and of their cyclic derivatives, benzoxaborolates in materials: (i coordination properties; (ii spectroscopic signatures; and (iii emerging applications.

  1. Bis[(diphenylphosphanylmethyldiphenylphosphane sulfide-κ2P,S]copper(I hexafluoridophosphate

    Directory of Open Access Journals (Sweden)

    Jing-Jing Zhang

    2012-06-01

    Full Text Available In the title compound, [Cu(C25H22P2S2]PF6, the CuI atom, lying on a twofold rotation axis, adopts a distorted tetrahedral geometry. The (diphenylphosphanylmethyldiphenylphosphane sulfide ligand coordinates to the CuI atom through one S and one P atom, forming a stable five-membered chelate ring. The P atom of the PF6− anion also lies on a twofold rotation axis.

  2. Di-tert-butyl­bis(N-isopropyl-N-methyl­dithio­carbamato-κ2 S,S′)tin(IV)

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Samsudin, Mohd Wahid; Ng, Seik Weng

    2010-01-01

    The dithio­carbamate anions in the title compound, [Sn(C4H9)2(C5H10NS2)2], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol­ecule lies across a twofold rotation axis. The crystal studied was a non-merohedral twin, the ratio of the twin components being 0.82 (1):0.18 (1). PMID:21580471

  3. Understanding the nitrate coordination to Eu3+ ions in solution by potential of mean force calculations

    International Nuclear Information System (INIS)

    Duvail, M.; Guilbaud, Ph.

    2011-01-01

    Coordination of nitrate anions with lanthanoid cations (Ln 3+ ) in water, methanol and octanol-1 has been studied by means of molecular dynamics simulations with explicit polarization. Potential of mean force (PMF) profiles have been calculated for a mono-complex of lanthanoid nitrate (Ln(NO 3 ) 2+ ) in these solvents using umbrella-sampling molecular dynamics. In pure water, no difference in the nitrato coordination to lanthanoids (Nd 3+ , Eu 3+ and Dy 3+ ) is observed, i.e. the nitrate anion prefers the monodentate coordination, which promotes the salt dissociation. Then, the influence of the nature of the solvating molecules on the nitrato coordination to Eu 3+ has been investigated. PMF profiles point out that both monodentate and bidentate coordinations are stable in neat methanol, while in neat octanol, only the bidentate one is. MD simulations of Eu(NO 3 ) 3 in water-octanol mixtures with different concentrations of water have been then performed and confirm the importance of the water molecules' presence on the nitrate ion's coordination mode. (authors)

  4. Binding of anions in triply interlocked coordination catenanes and dynamic allostery for dehalogenation reactions† †Electronic supplementary information (ESI) available: Characterization data and additional tables and figures. CCDC 1515722 and 1515723. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc04070a

    Science.gov (United States)

    Yang, Linlin; Jing, Xu; An, Bowen; Yang, Yang

    2017-01-01

    By synergistic combination of multicomponent self-assembly and template-directed approaches, triply interlocked metal organic catenanes that consist of two isolated chirally identical tetrahedrons were constructed and stabilized as thermodynamic minima. In the presence of suitable template anions, the structural conversion from the isolated tetrahedral conformers into locked catenanes occurred via the cleavage of an intrinsically reversible coordination bond in each of the tetrahedrons, followed by the reengineering and interlocking of two fragments with the regeneration of the broken coordination bonds. The presence of several kinds of individual pocket that were attributed to the triply interlocked patterns enabled the possibility of encapsulating different anions, allowing the dynamic allostery between the unlocked/locked conformers to promote the dehalogenation reaction of 3-bromo-cyclohexene efficiently, as with the use of dehalogenase enzymes. The interlocked structures could be unlocked into two individual tetrahedrons through removal of the well-matched anion templates. The stability and reversibility of the locked/unlocked structures were further confirmed by the catching/releasing process that accompanied emission switching, providing opportunities for the system to be a dynamic molecular logic system. PMID:29675152

  5. F-Element ion chelation in highly basic media. Annual progress report, October 1, 1996 - July 1, 1997

    International Nuclear Information System (INIS)

    Paine, R.T.

    1997-01-01

    'The specific fundamental chemical objectives of this project are to: (1) study the chemical speciation of Sr and Ln ions in basic media formed in aqueous solutions with and without classical chelation agents (e.g., EDTA, polyphosphates, and organic carboxylates); (2) prepare pyridine N-oxide phosphonate and phosphonoacetate chelators of the types 1--3 and characterize their ionization properties by titrimetric techniques; (3) study the interactions of 5--7 with soluble oxide-hydroxide metallate species and higher molecular weight sols, gels and precipitates containing Sr and Ln ions, as time permits, interactions with oxide-hydroxide metallates of U, Th, Ba, Al and Fe will also be studied; (4) study the interactions of newly designed phosphonate ligands with oxide-hydroxide metallate species; (5) transfer the fundamental coordination chemistry revealed here to research groups at LANL and PNNL that will utilize the results to improve tank waste treatment protocols.'

  6. Metal regeneration of iron chelates in nitric oxide scrubbing

    Science.gov (United States)

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  7. Gold nanoparticles modified with coordination compounds of metals: synthesis and application

    International Nuclear Information System (INIS)

    Beloglazkina, Elena K; Majouga, Alexander G; Romashkina, Renata B; Zyk, Nikolai V; Zefirov, Nikolai S

    2012-01-01

    The data on the preparation methods and applications of gold nanoparticles with coordinated metal ions on the surfaces are generalized. The currently available data on the interaction of metal ions with gold nanoparticles modified with organic (particularly, sulfur-containing) ligands comprising terminal chelating groups are considered in detail as well as the applications of such modified nanoparticles. The bibliography includes 141 references.

  8. Network Formation via Anion Coordination: Crystal Structures Based on the Interplay of Non-Covalent Interactions

    Directory of Open Access Journals (Sweden)

    Matteo Savastano

    2018-03-01

    Full Text Available We describe the synthesis and the structural characterization of new H2L(CF3CO22 (1 and H2L(Ph2PO42 (2 compounds containing the diprotonated form (H2L2+ of the tetrazine-based molecule 3,6-di(pyridin-4-yl-1,2,4,5-tetrazine. X-ray diffraction (XRD analysis of single crystals of these compounds showed that H2L2+ displays similar binding properties toward both anions when salt bridge interactions are taken into account. Nevertheless, the different shapes, sizes and functionalities of trifluoroacetate and diphenyl phosphate anions define quite different organization patterns leading to the peculiar crystal lattices of 1 and 2. These three-dimensional (3D architectures are self-assembled by a variety of non-covalent forces, among which prominent roles are played by fluorine–π (in 1 and anion–π (in 2 interactions.

  9. Aloe vera extract reduces 8-oxo-2'-deoxyguanosine levels and improves total antioxidants in streptozotocin-induced diabetic rats

    Directory of Open Access Journals (Sweden)

    Wulan Christijanti

    2017-04-01

    Full Text Available Background Diabetes mellitus is a chronic disease caused by lack of insulin production in the pancreas or by insulin resistance, the disease being characterized by elevated blood glucose levels. Hyperglycemia in diabetes could lead to oxidative stress due to the rise in 8-oxo-2'-deoxyguanosine (8-oxo-dG levels and the decrease in levels of total antioxidant status (TAS. The purpose of this study was to assess the effect Aloe vera extract on 8-oxo-dG level and total antioxidant status in diabetic rat testis.   Methods This was an experimental laboratory study with 20 rat samples which were divided into 4 groups (1 control group and 3 treatment groups. Diabetes was induced in the rats by streptozotocin (STZ at 65 mg/kgBW. The diabetic rats were then treated for 28 days with Aloe vera extract at 0 mg (P0, 200 mg rind (P1, 200 mg pulp (P2, respectively. The level of 8 -oxo-dG was measured by ELISA and total antioxidant status with 2,2' -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS. Data were analyzed with ANOVA and Least Significant Difference Advanced Test at P<0.05.   Results 8-Oxo-dG levels were significantly different between the control group and both P0 and P2, but not between the control group and P1. Among the treatment groups the 8-oxo-dG levels were significantly different. Mean total antioxidant status was significantly different between control and treatment groups, and also between treatment groups (p<0.05.   Conclusions Aloe vera extract reduced free radicals (level of 8-oxo-dG and increased the total antioxidant status in diabetic rat testis.

  10. Cd(II) and Zn(II) thiocyanate coordination compounds with 3-ethylpyridine. Synthesis, crystal structures and properties

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Tristan; Jess, Inke; Dos Santos Cunha, Cesar; Terraschke, Huayna; Naether, Christian [Kiel Univ. (Germany). Inst. fuer Anorganische Chemie

    2018-04-01

    Reaction of Cd(NCS){sub 2} and Zn(NCS){sub 2} with 3-ethylpyridine leads to the formation of compounds of compositions M(NCS){sub 2}(3-ethylpyridine){sub 4} (M=Cd, 1-Cd; Zn, 1-Zn) and M(NCS){sub 2}(3-ethylpyridine){sub 2} (M=Cd, 2-Cd; Zn, 2-Zn). 1-Cd and 1-Zn are isotypic and form discrete complexes in which the metal cations are octahedrally coordinated by two trans-coordinating N-bonded thiocyanate anions and four 3-ethylpyridine co-ligands. In 2-Cd the cations are also octahedrally coordinated but linked into chains by pairs of μ-1,3-bridging anionic ligands. 2-Zn is built up of discrete complexes, in which the Zn cation is tetrahedrally coordinated by two N-bonded thiocyanate anions and two 3-ethylpyridine co-ligands. Compounds 1-Cd, 2-Cd and 2-Zn can be prepared in a pure state, whereas 1-Zn is unstable and transforms on storage into 2-Zn. If 1-Cd and 1-Zn are heated, a transformation into 2-Cd, respectively 2-Zn is observed. Luminescence measurements reveal that 1-Cd, 2-Cd and 2-Zn emit light in the blue spectral range with maxima at, respectively, 21724, 21654 and 22055 cm{sup -1}, assigned to ligand-based luminescence.

  11. The influence of channel anion identity on the high-pressure crystal structure, compressibility, and stability of apatite

    Science.gov (United States)

    Skelton, Richard; Walker, Andrew M.

    2018-03-01

    The material properties of the common phosphate mineral apatite are influenced by the identity of the channel anion, which is usually F-, Cl-, or (OH)-. Density functional theory calculations have been used to determine the effect of channel anion identity on the compressibility and structure of apatite. Hydroxyapatite and fluorapatite are found to have similar zero pressure bulk moduli, of 79.2 and 82.1 GPa, respectively, while chlorapatite is considerably more compressible, with K 0 = 55.0 GPa. While the space groups of hydroxyapatite and fluorapatite do not change between 0 and 25 GPa, symmetrization of the Cl- site in chlorapatite at 7.5 GPa causes the space group to change from P2 1 /b to P6 3 /m. Examination of the valence electron density distribution in chlorapatite reveals that this symmetry change is associated with a change in the coordination of the Cl- anion from threefold to sixfold coordinated by Ca. We also calculate the pressure at which apatite decomposes to form tuite, a calcium orthophosphate mineral, and find that the transition pressure is sensitive to the identity of the channel anion, being lowest for fluorapatite (13.8 GPa) and highest for chlorapatite (26.9 GPa). Calculations are also performed within the DFT-D2 framework to investigate the influence of dispersion forces on the compressibility of apatite minerals.

  12. Ligand influences on properties of uranium coordination complexes. Structure, reactivity, and spectroscopy

    International Nuclear Information System (INIS)

    Kosog, Boris

    2012-01-01

    In this thesis several different aspects of uranium chemistry are presented. It was shown that terminal uranium(V) oxo and imido complexes [(( R ArO) 3 tacn)U V (O)] and [(( R ArO) 3 tacn)U V (NSiMe 3 )] (R = t Bu, Ad) can be oxidized by silver(I) hexafluoro-antimonate to the uranium(VI) oxo and imido complexes [(( R ArO) 3 tacn)U VI (O)]SbF 6 and [(( R ArO) 3 tacn)U VI (NSiMe 3 )]SbF 6 . While for the t Bu-derivative of the oxo complex an equatorial coordination is observed due to stabilization by the inverse trans-influence, normal axial coordination is observed for the Ad-derivative and both imido complexes. The inverse trans-influence was thus proven to be a key factor for the coordination mode of a terminal ligand on high valent uranium complexes. L III XANES was shown to be a great tool for the determination of oxidation states of uranium complexes. Therefore, a series of uranium complexes in all stable oxidation states for uranium, +III to +VI was prepared, and their spectra analyzed. All compounds bear only O-donor ligands in addition to the chlating trisaryloxide-tacn-ligand. A separation of 1.5 to 3 eV in the white line energy is observed between the different oxidation states. This series can be used as reference for compounds, where oxidation state assignment is not obvious, such as a ketyl radical complex [(( t-Bu Ar)O 3 tacn)U(O-C( t-Bu Ph) 2 .- )]. For this complex, the oxidation state of +IV could be assigned. Moreover, a series of isostructural uranium(IV) complexes was prepared. The influence of different ligands according to the spectrochemical series on the electronic and magnetic properties could be shown using UV/vis/NIR spectroscopy and variable temperature SQUID measurements. Calculations of uranium L III XANES spectra show a variation in the shape of the spectra and thus high resolution PFY-XANES would be a great tool to determine the electronic influence of these different axial ligands. Using the single N-anchored ligand system, the first

  13. 3-hydroxy-2(1H)-pyridinone chelating agents

    Science.gov (United States)

    Raymond, K.; Xu, J.

    1999-04-06

    Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. 2 figs.

  14. Crystal structure of diaquabis(7-diethylamino-3-formyl-2-oxo-2H-chromen-4-olato-κ2O3,O4zinc(II dimethyl sulfoxide disolvate

    Directory of Open Access Journals (Sweden)

    Aaron B. Davis

    2016-07-01

    Full Text Available The structure of the title coordination complex, [Zn(C14H14NO42(H2O2]·2C2H6OS, shows that the ZnII cation adopts an octahedral geometry and lies on an inversion center. Two organic ligands occupy the equatorial positions of the coordination sphere, forming a chelate ring motif via the O atom on the formyl group and another O atom of the carbonyl group (a pseudo-β-diketone motif. Two water molecules occupy the remaining coordination sites of the ZnII cation in the axial positions. The water molecules are each hydrogen bonded to a single dimethyl sulfoxide molecule that has been entrapped in the crystal lattice.

  15. Red-excitation resonance Raman analysis of the nu(Fe=O) mode of ferryl-oxo hemoproteins.

    Science.gov (United States)

    Ikemura, Kenichiro; Mukai, Masahiro; Shimada, Hideo; Tsukihara, Tomitake; Yamaguchi, Satoru; Shinzawa-Itoh, Kyoko; Yoshikawa, Shinya; Ogura, Takashi

    2008-11-05

    The Raman excitation profile of the nuFe O mode of horseradish peroxidase compound II exhibits a maximum at 580 nm. This maximum is located within an absorption band with a shoulder assignable to an oxygen-to-iron charge transfer band on the longer wavelength side of the alpha-band. Resonance Raman bands of the nuFe O mode of various ferryl-oxo type hemoproteins measured at 590 nm excitation indicate that many hemoproteins in the ferryl-oxo state have an oxygen-to-iron charge transfer band in the visible region. Since this red-excited resonance Raman technique causes much less photochemical damage in the proteins relative to blue-excited resonance Raman spectroscopy, it produces a higher signal-to-noise ratio and thus represents a powerful tool for investigations of ferryl-oxo intermediates of hemoproteins.

  16. Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

    Science.gov (United States)

    Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

    2013-01-14

    A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

  17. Metabolism of leukotriene B4 to dihydro and dihydro-oxo products by porcine leukocytes

    International Nuclear Information System (INIS)

    Powell, W.S.; Gravelle, F.

    1989-01-01

    Porcine leukocytes contain a novel pathway for the metabolism of leukotriene B4 (LTB4) which results in reduction of the conjugated triene chromophore to a conjugated diene. These cells converted LTB4 to two major metabolites, both of which exhibited maximal absorbance at 230 nm in their UV spectra. These products were purified by high pressure liquid chromatography and identified as 10, 11-dihydro-LTB4 and 10,11-dihydro-12-oxo-LTB4 on the basis of the mass spectra of various derivatives. The position of the double bond of LTB4 which had been reduced was established by cleaving the remaining double bonds of 10, 11-dihydro-LTB4 with ozone followed by oxidation or reduction of the resulting ozonide and analysis of the products by mass spectrometry. Experiments with deuterium-labeled substrate indicated that LTB4 could be directly converted to 10, 11-dihydro-LTB4 without the prior oxidation of either of its hydroxyl groups, as is required for the formation of dihydro metabolites of prostaglandins. Incubation of porcine leukocytes with 10, 11-dihydro-LTB4 and 10, 11-dihydro-12-oxo-LTB4 indicated that these two products can be interconverted and are in equilibrium with one another. The dihydro-oxo metabolite can therefore be formed from 10, 11-dihydro-LTB4, although we have not ruled out the possibility that it is also produced via 12-oxo-LTB4, which could be a transitory intermediate. These results indicate that porcine leukocytes contain a novel reductase/dehydrogenase pathway distinct from the pathway responsible for the metabolism of prostaglandins. This pathway is also different from the pathway in human polymorphonuclear leukocytes which converts 6-trans-isomers of LTB4 to dihydro products, since the latter pathway involves 5-oxo intermediates and results in a shift in the positions of the remaining double bonds

  18. Hydrothermal syntheses and anion-induced structural transformation of three Cadmium phosphonates

    Science.gov (United States)

    Hu, Han; Zhai, Fupeng; Liu, Xiaofeng; Ling, Yun; Chen, Zhenxia; Zhou, Yaming

    2018-05-01

    Three cadmium phosphonate coordinated polymers, namely as [Cd5(ptz)3(SO4)2(5H2O)]·6H2O (Cdptz-1), [Cd3(ptz)2(Cl)2(4H2O)]·2H2O (Cdptz-2) and [Cd4(ptz)2(SO4)(Cl)(OH)H2O]·H2O (Cdptz-3) have been hydrothermally synthesized using 4-(1,2,4-triazol-4-yl)phenylphosphonic acid (H2ptz) as ligand. Single crystal X-ray analyses revealed Cdptz-2 as layered structure and Cdptz-1,3 as pillar-layered structures with Cl- or SO42- as bridging anions. Due to the weak bonding between metal and anions, Cdptz-1 and 2 can reversibly convert into each other by simple immersing in the corresponding solution at room temperature. While the transformations between Cdptz-1,2 and Cdptz-3 can only happen under hydrothermal condition. The causes for the transformation involve the metal-ligand bond breaking/formation, replacement of anions and enhancement/decrement of the network dimensionality.

  19. Use of chelating agents as immovable phase in extraction chromatography

    International Nuclear Information System (INIS)

    Sebesta, F.

    1978-01-01

    Extraction chromatography using chelating agents is reviewed. The theory of element extraction by chelating agents and factors influencing this process (pH, extracting agent concentration in organic phase, masking agent concentration in aqueous phase) are briefly considered. The effect of kinetic factors on the extraction chromatography process is discussed. Ways of preparing columns are emphasized. Examples of using chelating reagents in various extraction chromatography systems are given. β-Diketones, oximes, hydroxamic acids, dithizon, diethyl dithiocarbamic acid are chosen as chelating agents

  20. Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

    International Nuclear Information System (INIS)

    Manwar, S.; Iram, S.

    2014-01-01

    Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

  1. Glyphosate, a chelating agent-relevant for ecological risk assessment?

    Science.gov (United States)

    Mertens, Martha; Höss, Sebastian; Neumann, Günter; Afzal, Joshua; Reichenbecher, Wolfram

    2018-02-01

    Glyphosate-based herbicides (GBHs), consisting of glyphosate and formulants, are the most frequently applied herbicides worldwide. The declared active ingredient glyphosate does not only inhibit the EPSPS but is also a chelating agent that binds macro- and micronutrients, essential for many plant processes and pathogen resistance. GBH treatment may thus impede uptake and availability of macro- and micronutrients in plants. The present study investigated whether this characteristic of glyphosate could contribute to adverse effects of GBH application in the environment and to human health. According to the results, it has not been fully elucidated whether the chelating activity of glyphosate contributes to the toxic effects on plants and potentially on plant-microorganism interactions, e.g., nitrogen fixation of leguminous plants. It is also still open whether the chelating property of glyphosate is involved in the toxic effects on organisms other than plants, described in many papers. By changing the availability of essential as well as toxic metals that are bound to soil particles, the herbicide might also impact soil life, although the occurrence of natural chelators with considerably higher chelating potentials makes an additional impact of glyphosate for most metals less likely. Further research should elucidate the role of glyphosate (and GBH) as a chelator, in particular, as this is a non-specific property potentially affecting many organisms and processes. In the process of reevaluation of glyphosate its chelating activity has hardly been discussed.

  2. Chelation therapy to prevent diabetes-associated cardiovascular events.

    Science.gov (United States)

    Diaz, Denisse; Fonseca, Vivian; Aude, Yamil W; Lamas, Gervasio A

    2018-05-24

    For over 60 years, chelation therapy with disodium ethylene diamine tetraacetic acid (EDTA, edetate) had been used for the treatment of cardiovascular disease (CVD) despite lack of scientific evidence for efficacy and safety. The Trial to Assess Chelation Therapy (TACT) was developed and received funding from the National Institutes of Health (NIH) to ascertain the safety and efficacy of chelation therapy in patients with CVD. This pivotal trial demonstrated an improvement in outcomes in postmyocardial infarction (MI) patients. Interestingly, it also showed a particularly large reduction in CVD events and all-cause mortality in the prespecified subgroup of patients with diabetes. The TACT results may support the concept of metal chelation to reduce metal-catalyzed oxidation reactions that promote the formation of advanced glycation end products, a precursor of diabetic atherosclerosis. In this review, we summarize the epidemiological and basic evidence linking toxic metal accumulation and diabetes-related CVD, supported by the salutary effects of chelation in TACT. If the ongoing NIH-funded TACT2, in diabetic post-MI patients, proves positive, this unique therapy will enter the armamentarium of endocrinologists and cardiologists seeking to reduce the atherosclerotic risk of their diabetic patients.

  3. Calcium and strontium salts of (glycinato-κ(2)N,O)oxidobis(peroxido-κ(2)O,O')vanadate(V) tetrahydrate.

    Science.gov (United States)

    Higuchi, Takeshi; Uchida, Ayana; Hashimoto, Masato

    2013-12-15

    The title salts calcium (glycinato-κ(2)N,O)oxidobis(peroxido-κ(2)O,O')vanadate(V) tetrahydrate, Ca[VO(O2)2(NH2CH2COO)]·4H2O, and strontium (glycinato-κ(2)N,O)oxidobis(peroxido-κ(2)O,O')vanadate(V) tetrahydrate, Sr[VO(O2)2(NH2CH2COO)]·4H2O, crystallized at pH ca 7.4 with similar lattice parameters. The glycinate anion acts as a bidentate N,O-chelating ligand, and the V atom has a pentagonal bipyramidal geometry, with two η(2)-peroxo groups and the glycinate N atom in the equatorial plane, and one terminal oxo and a glycinate O atom at the axial positions. The H atoms of three of the four water molecules in the strontium salt exhibited disorder over three positions for each molecule.

  4. Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

    International Nuclear Information System (INIS)

    Dodi, Alain; Bouscarel, Maelle

    2008-01-01

    This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

  5. Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Dodi, Alain; Bouscarel, Maelle [Commissariat a l' energie atomique - C.E.A, Centre d' Etude de Cadarache, Laboratoire d' Analyses Radiochimiques et Chimiques, St Paul lez Durance (France)

    2008-07-01

    This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

  6. Preparation, Spectroscopic Investigation and Biological Activity of New Mixed Ligand Chelates

    International Nuclear Information System (INIS)

    Alassbaly, F.S.; Ajaily, M.M.E.

    2014-01-01

    Preparation and investigation of new Co(II), Ni(II), Zn(II) and Cr(III) chelates with mixed ligands including Schiff base (L1) formed from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol and anthranilic acid (L2) were studied. The obtained Schiff base and mixed ligand chelates were subjected to several physiochemical techniques, in terms of CHN elemental analyses, molar conductivity, magnetic moment measurements, infrared, proton nuclear magnetic resonance, electronic and mass spectra. The analytical data showed the formation of the Schiff base compound and the ratio of metal to ligands of the chelates are 1:1:1(M:L1:L2). The infrared spectral data exhibited that the used ligands behaving as bidentate ligands towards the metal ions. The proton nuclear magnetic resonance spectral data showed the signals of the active groups in the ligands which entered in chelation with Zn(II) metal ion. The electronic spectral results showed the existence of pie (phenyl ring) and n = pie (C=N) of the ligands and suggested the geometrical structures of the chelates. Meanwhile, the mass spectral data revealed the fragmentations of the Schiff base, anthranilic acid and their Ni(II) mixed ligand chelate has been preformed the only chelate conducted for justification. All the prepared mixed chelates were non-electrolyte in nature. The antibacterial activity of the Schiff base, anthranilic acid, metal salts and mixed ligand chelates were studied and found to be that mixed ligand chelates have the most biological activity in comparison to the free ligands and salts. (author)

  7. New functionalized β-diketiminate ligands and f elements

    International Nuclear Information System (INIS)

    Dulong, Florian

    2013-01-01

    β-diketiminate ligands have received increased interest in coordination chemistry, especially for homogeneous catalysis. Their successful applications arise from an easy and fine tuning of the ligand electronic and geometric properties. However, these modifications are limited to the introduction of neutral donors (ethers or amines), on the nitrogen substituents of the β-diketiminate skeleton. The main focus of this research project is to overcome this limitation by synthesizing new β-diketiminate ligands functionalized by one or two anionic aryl-oxide groups, and to study their coordination chemistry with lanthanide and actinide ions. Access to these species relies on a fine understanding of the mechanism underlying their formation, and the sensitivity of the β-di-iminium skeleton towards nucleophiles (phenols) has been identified as the limiting side reaction in the synthetic route. Addition of reactants in well defined order allowed the formation of two new N-aryl-oxy-β-diketiminate dianions on a multi-gram scale. The two ligands differ by their steric bulk and exhibit different coordination behaviors towards lanthanides and actinide ions, which were rationalized on geometric considerations. The reactivity of three of these new complexes has been investigated. A Ce(III) N-aryl-oxy-β-diketiminate complex exhibits interesting reduction properties, due to the shift of its oxidation potential to negative values by its coordination environment. A Th(IV) complex presents a vacant coordination site, which has been probed with different Lewis bases, emphasizing two spatial arrangements ruled by inter-ligand repulsion. It has been compared to its U(IV) analogue, which can be oxidized to a rare terminal mono-oxo uranium(VI) species. The latter was reversibly reduced to its U(V) and U(IV) derivatives, creating the first series of terminal mono-oxo uranium complexes with three successive oxidation states. These compounds represent an opportunity to better understand

  8. Study of cyclization of chelating compounds using electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Shi Ying; Campbell, J.A.

    2000-01-01

    Electrospray ionization mass spectrometry (ESI-MS) was used for the study of cyclization of organic chelating compounds (chelators). Four chelating compounds were studied: Symmetrical ethylenediaminediacetic acid (s-EDDA), Unsymmetrical ethylenediaminediacetic acid (u-EDDA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA). The chelators were cyclized with treatments of acids and heating. The open and cyclized form of the chelators were semi-quantified by both positive and negative ion modes ESI-MS. The kinetics of chelator cyclization was studied as a function of reaction temperature and the pH of the matrix. The cyclization of s-EDDA was found to be a pseudo-first order reaction in s-EDDA and overall second order. The cyclizations of HEIDA and HEDTA are reversible reactions. Higher temperature and lower pH favors cyclization. (author)

  9. Butylbis(diphenylglyoximato(pyridine-κNcobalt(IIIThis article is dedicated to late Professor B. D. Gupta.

    Directory of Open Access Journals (Sweden)

    Sarvendra Kumar

    2012-02-01

    Full Text Available In the title compound, [Co(C4H9(C14H11N2O22(C5H5N], the CoIII atom is coordinated by a butyl group, a nitrogen-bonded pyridine and two N,N′-bidentate diphenylglyoximate ligands in a distorted octahedral geometry. The crystal structure features two short O—H...O bridges between the two chelating anions, with O...O distances less than 2.5 Å.

  10. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, S.G.T.

    1994-12-06

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

  11. 3-oxo-rhazinilam: a new indole alkaloid from Rauvolfia serpentina x Rhazya stricta hybrid plant cell cultures.

    Science.gov (United States)

    Gerasimenko, I; Sheludko, Y; Stöckigt, J

    2001-01-01

    A new monoterpenoid indole alkaloid, 3-oxo-rhazinilam (1), was isolated from intergeneric somatic hybrid cell cultures of Rauvolfia serpentina and Rhazya stricta, and the structure was determined by detailed 1D and 2D NMR analysis. It was also proved that 3-oxo-rhazinilam (1) is a natural constituent of the hybrid cells.

  12. Reactions of 1-methyl-derivatives of 2-oxo-1,2,3,4-tetrahydropyrimidine with phosphorus pentachloride and phosphorus oxychloride

    International Nuclear Information System (INIS)

    Khanina, E.L.; Liepin'sh, E.E.; Mutsenietse, D.Kh.; Dubur, G.Ya.

    1987-01-01

    In the reaction of 4-phenyl-and 4,6-diphenyl-1-methyl-2-oxo-5-ethoxycarbonyl-1,2,3,4-tetrahydropyrimidines with phosphorus pentachloride, oxidation and dealkylation takes place in addition to chlorination and as a result one obtained 4-phenyl- and 4,6-diphenyl-1-methyl-5-ethoxycarbonyl-2-pyrimidones and also 4-phenyl-, (4,6-diphenyl)-5-ethoxycarbonyl-2-chloropyrimidines. 1,6-Dimethyl-2-oxo-4-phenyl-5-ethoxycarbonyl-1,2,3,4-tetrahydropyrimidine in the same reaction gives 1-methyl-2-oxo-4-phenyl-5-ethoxycarbonyl 6-dichloromethyl-1,2,3,4-tetrahydropyrimidine, together with 6-chloromethylene- and 6-dichloromethylene-1-methyl-2-oxo-4-phenyl-5-chloro-5-ethoxycarbonylhexahydropyrimidines. The structure was established on the basis of elemental analysis, proton NMR spectra, and carbon-13 NMR spectra, taking into account the long-range 2 H- 13 C coupling constants

  13. Polymer complexes.. XXXX. Supramolecular assembly on coordination models of mixed-valence-ligand poly[1-acrylamido-2-(2-pyridyl)ethane] complexes

    Science.gov (United States)

    El-Sonbati, A. Z.; El-Bindary, A. A.; Diab, M. A.

    2003-02-01

    The build-up of polymer metallic supramolecules based on homopolymer (1-acrylamido-2-(2-pyridyl)ethane (AEPH)) and ruthenium, rhodium, palladium as well as platinum complexes has been pursued with great interest. The homopolymer shows three types of coordination behaviour. In the mixed valence paramagnetic trinuclear polymer complexes [( 11)+( 12)] in the paper and in mononuclear polymer complexes ( 1)-( 5) it acts as a neutral bidentate ligand coordinating through the N-pyridine and NH-imino atoms, while in the mixed ligand diamagnetic poly-chelates, which are obtained from the reaction of AEPH with PdX 2 and KPtCl 4 in the presence of N-heterocyclic base consisting of polymer complexes ( 9)+( 10), and in monouclear compounds ( 6)-( 8), it behaves as a monobasic bidentate ligand coordinating through the same donor atoms. In mononuclear compounds ( 13)+( 14) it acts as a monobasic and neutral bidentate ligand coordinating only through the same donor atoms. Monomeric distorted octahedral or trimeric chlorine-bridged, approximately octahedral structures are proposed for these polymer complexes. The poly-chelates are of 1:1, 1:2 and 3:2 (metal-homopolymer) stoichiometry and exhibit six coordination. The values of ligand field parameters were calculated. The homopolymer and their polymer complexes have been characterized physicochemically.

  14. Bifunctional chelates of Rh-105 and Au-199 as potential radiotherapeutic agents

    International Nuclear Information System (INIS)

    Troutner, D.E.; Schlemper, E.O.

    1990-01-01

    Since last year we have: continued the synthesis of pentadentate bifunctional chelating agents based on diethylene triamine; studied the chelation Rh-105, Au-198 (as model for Au-199) and Tc-99m with these agents as well as chelation of Pd-109, Cu-67, In-111, and Co-57 with some of them; synthesized a new class of potential bifunctional chelating agents based on phenylene diamine; investigated the behavior of Au-198 as a model for Au-199; begun synthesis of bifunctional chelating agents based on terpyridly and similar ligands; and continued attempts to produce tetradentate bifunctional chelates based on diaminopropane. Each of these will be addressed in this report

  15. Nucleation-growth of salicylic acid-oxoTiO{sub 2} colloids synthesized by sol-gel processing

    Energy Technology Data Exchange (ETDEWEB)

    Tieng, S.; Jia, Z. [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse (France); Subra-Paternault, P. [Laboratoire de Chimie et Biologie des Membranes et Nanoobjets, CBMN – UMR 5248, Bâtiment, 14B, Allée Geoffroy Saint Hilaire, 33600 Pessac (France); Kanaev, A. [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse (France); Chhor, K., E-mail: khay.chhor@lspm.cnrs.fr [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse (France)

    2014-12-15

    In this work, the preparation of hybrid oxo-TiO{sub 2} nanoparticles modified by salicylic acid (SA) is reported. The size-selected TiO{sub 2} nanoparticles were synthesized in a sol-gel reactor with rapid micromixing of reagents and binding of SA molecules occurs at the nucleation stage. UV-visible absorption, Raman spectroscopy and Light scattering measurements evidence the formation of a SA–oxo-TiO{sub 2} charge-transfer complex. In particularly, the C=O vibration mode of SA shifts to lower frequencies upon complexation while the C-O vibration modes of both carboxylate and phenolic groups retain their position. The absence of C-O shift comes from two effects that cancel each other, i.e. the hardening of this mode related to the C=O mode changes and its softening due to the replacement of hydrogen in COH group by Ti atoms. Kinetic studies of the oxo-TiO{sub 2} nanoparticles nucleation and growth in presence of SA show that the acidic ligand at the nanoparticle surface acts as an attractor for another oxo-TiO{sub 2} nanoparticle leading to polycondensation. This mechanism is responsible for the acceleration of the nanoparticle aggregation kinetics and shortening of the induction time. The hybrid nanoparticles are stable at pH ≤ 7.7 and release SA molecules at pH ≥ 8.5. - Highlights: • Hybrid oxo-TiO{sub 2} nanoparticles modified by salicylic acid (SA) are prepared. • The synthesis is achieved during the nucleation stage of sol-gel process. • The formation of SA–oxo-TiO{sub 2} charge-transfer complex is evidenced. • Mechanism responsible for the acceleration of the nanoparticle aggregation kinetics is proposed. • SA-TiO{sub 2} nanoparticles are stable at pH ≤ 7.7 and release SA molecules at pH ≥ 8.5.

  16. Anions in Cometary Comae

    Science.gov (United States)

    Charnley, Steven B.

    2011-01-01

    The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of IP/Halley. The anions 0-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not yet been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydro dynamical model of Rodgers & Charnley (2002), we investigate the role of large carbon-chain anions in cometary coma chemistry. We calculate the effects of these anions on coma thermodynamics, charge balance and examine their impact on molecule formation.

  17. Carbon dioxide transport in molten calcium carbonate occurs through an oxo-Grotthuss mechanism via a pyrocarbonate anion.

    Science.gov (United States)

    Corradini, Dario; Coudert, François-Xavier; Vuilleumier, Rodolphe

    2016-05-01

    The reactivity, speciation and solvation structure of CO2 in carbonate melts are relevant for both the fate of carbon in deep geological formations and for its electroreduction to CO (to be used as fuel) when solvated in a molten carbonate electrolyte. In particular, the high solubility of CO2 in carbonate melts has been tentatively attributed to the formation of the pyrocarbonate anion, C2O5(2-). Here we study, by first-principles molecular dynamics simulations, the behaviour of CO2 in molten calcium carbonate. We find that pyrocarbonate forms spontaneously and the identity of the CO2 molecule is quickly lost through O(2-) exchange. The transport of CO2 in this molten carbonate thus occurs in a fashion similar to the Grotthuss mechanism in water, and is three times faster than molecular diffusion. This shows that Grotthuss-like transport is more general than previously thought.

  18. C_6_0"3"- versus C_6_0"4"- /C_6_0"2"- - synthesis and characterization of five salts containing discrete fullerene anions

    International Nuclear Information System (INIS)

    Boeddinghaus, M. Bele; Klein, Wilhelm; Wahl, Bernhard; Faessler, Thomas F.; Jakes, Peter; Eichel, Ruediger A.

    2014-01-01

    Five new compounds, [Rb(18crown-6)]_3[C_6_0] (1), [Rb(18crown-6)]_6[C_6_0]_2(C_3H_7NO)_2(C_4H_8O)_2 (2), [Rb(benzo18crown-6)]_6[C_6_0]_2(C_2H_8N_2)_5 (3), [Cs(benzo18crown-6)]_3C_6_0(C_2H_8N_2)_2 (4), and [Cs_3(benzo18crown-6)_5]C_6_0(C_2H_8N_2)_(_4_._5_+_x_) (5) were synthesized and characterized by single-crystal X-ray structure determination. All compounds contain discrete C_6_0 anions, which are ordered in 1, 2, and 4, where direct cation-anion contacts occur. The unit cells of 1 and 2 contain two independent fullerides, which coordinate to the rubidium atoms either of two or of four [Rb(18crown-6)] units. Owing to the presence of differently coordinated fullerene units in compounds 1 and 2, a possible disproportionation of C_6_0"3"- into C_6_0"2"- and C_6_0"4"- anions is discussed. In 3 and 4 the C_6_0 anions are coordinated by three Rb and Cs atoms, respectively. In all compounds the average charge of the anion is -3. Magnetic data reveal a doublet spin state for 3. The EPR spectra are discussed for compounds 3 and 5. The role of a dynamic Jahn-Teller distortion is discussed, and we report the first IR spectroscopic data of fullerene trianions, which have been obtained in solution. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Cobalt(III) complexes of [3(5)]adamanzane, 1,5,9,13-tetraazabicyclo[7.7.3]nonadecane. Report of an inert, chelate hydrogen carbonate ion

    DEFF Research Database (Denmark)

    Broge, Louise; Søtofte, Inger; Olsen, Carl Erik

    2001-01-01

    .H2O (3a). The coordination geometry around the cobalt(III) ion is a distorted octahedron with the inorganic ligands at cis-positions. Complex 2 is the second example of a cobalt(III) complex for which the X-ray structure,sfiows a chelate binding mode of the hydrogen carbonate entity. The pK(a) value...

  20. A density functional study of carbon monoxide adsorption on small cationic, neutral, and anionic gold clusters

    Science.gov (United States)

    Wu, X.; Senapati, L.; Nayak, S. K.; Selloni, A.; Hajaligol, M.

    2002-08-01

    CO adsorption on small cationic, neutral, and anionic Aun (n=1-6) clusters has been investigated using density functional theory in the generalized gradient approximation. Among various possible CO adsorption sites, the on-top (one-fold coordinated) is found to be the most favorable one, irrespective of the charge state of the cluster. In addition, planar structures are preferred by both the bare and the CO-adsorbed clusters. The adsorption energies of CO on the cationic clusters are generally greater than those on the neutral and anionic complexes, and decrease with size. The adsorption energies on the anions, instead, increase with cluster size and reach a local maximum at Au5CO-, in agreement with recent experiment. The differences in adsorption energies for the different charge states decrease with increasing cluster size.

  1. Chelation and stabilization of berkelium in oxidation state +IV

    Science.gov (United States)

    Deblonde, Gauthier J.-P.; Sturzbecher-Hoehne, Manuel; Rupert, Peter B.; An, Dahlia D.; Illy, Marie-Claire; Ralston, Corie Y.; Brabec, Jiri; de Jong, Wibe A.; Strong, Roland K.; Abergel, Rebecca J.

    2017-09-01

    Berkelium (Bk) has been predicted to be the only transplutonium element able to exhibit both +III and +IV oxidation states in solution, but evidence of a stable oxidized Bk chelate has so far remained elusive. Here we describe the stabilization of the heaviest 4+ ion of the periodic table, under mild aqueous conditions, using a siderophore derivative. The resulting Bk(IV) complex exhibits luminescence via sensitization through an intramolecular antenna effect. This neutral Bk(IV) coordination compound is not sequestered by the protein siderocalin—a mammalian metal transporter—in contrast to the negatively charged species obtained with neighbouring trivalent actinides americium, curium and californium (Cf). The corresponding Cf(III)-ligand-protein ternary adduct was characterized by X-ray diffraction analysis. Combined with theoretical predictions, these data add significant insight to the field of transplutonium chemistry, and may lead to innovative Bk separation and purification processes.

  2. Solution structures of lipoyl domains of the 2-oxo acid dehydrogenase complexes from Azotobacter vinelandii : implications for molecular recognition

    NARCIS (Netherlands)

    Berg, A.

    1997-01-01

    The 2-oxo acid dehydrogenase complexes are large multienzyme complexes that catalyse the irreversible oxidative decarboxylation of a specific 2-oxo acid to the corresponding acyl-CoA derivative. The pyruvate dehydrogenase complex (PDHC) converts the product of the glycolysis, pyruvate, to

  3. Chelating agents as stationary phase in extraction chromatography, ch. 11

    International Nuclear Information System (INIS)

    Sebesta, F.

    1975-01-01

    Chelating agents have been used largely in extraction chromatography for separations related to activation analysis, for concentration of metals from dilute solutions, and for preparation of radiochemically pure or carrier-free radionuclides. This review deals with the theory of extraction by chelating agents, the experimental technique, and the chelating agents and systems used (β-diketones, oximes, hydroxamic acid, dithizone and diethyldithiocarbamic acid)

  4. Inorganic, coordination and organometallic compounds

    International Nuclear Information System (INIS)

    Jursik, F.

    1978-01-01

    Separation of cations and anions of inorganic, coordination and metalloorganic compounds by the method of liquid column chromatography is considered. Common scheme of multicomponent cation mixture is suggesteed. Separation conditions, adsrbents, eluents, pH value solution concenstration, elution rate are also suggested. Separation of rare earth elements Cs, Be, Cd, Te, Th, U, Mo, Re, V, Ru, Zr, In compounds is considered as an example of liquid column chromatography application. Data on column chromatography application are summarized in a table

  5. Formation process of the poly-oxo cluster U{sub 38}

    Energy Technology Data Exchange (ETDEWEB)

    Henning, Christoph [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Molecular Structures; Falaise, C.; Volkringer, Christoph; Loiseau, T. [Lille Univ., Villeneuve d' Ascq (France). Unite de Catalyse et Chimie du Solide

    2016-07-01

    Recently, a new poly-oxo cluster with 38 uranium atoms, U{sub 38}O{sub 56}Cl{sub 18}(THF){sub 8}(bz){sub 24}.8THF, (U{sub 38}), has been synthesized [1]. We studied ex situ the reaction kinetics of this complex [2].

  6. Mechanistic insights into dioxygen activation, oxygen atom exchange and substrate epoxidation by AsqJ dioxygenase from quantum mechanical/molecular mechanical calculations.

    Science.gov (United States)

    Song, Xudan; Lu, Jiarui; Lai, Wenzhen

    2017-08-02

    Herein, we use in-protein quantum mechanical/molecular mechanical (QM/MM) calculations to elucidate the mechanism of dioxygen activation, oxygen atom exchange and substrate epoxidation processes by AsqJ, an Fe II /α-ketoglutarate-dependent dioxygenase (α-KGD) using a 2-His-1-Asp facial triad. Our results demonstrated that the whole reaction proceeds through a quintet surface. The dioxygen activation by AsqJ leads to a quintet penta-coordinated Fe IV -oxo species, which has a square pyramidal geometry with the oxo group trans to His134. This penta-coordinated Fe IV -oxo species is not the reactive one in the substrate epoxidation reaction since its oxo group is pointing away from the target C[double bond, length as m-dash]C bond. Instead, it can undergo the oxo group isomerization followed by water binding or the water binding followed by oxygen atom exchange to form the reactive hexa-coordinated Fe IV -oxo species with the oxo group trans to His211. The calculated parameters of Mössbauer spectra for this hexa-coordinated Fe IV -oxo intermediate are in excellent agreement with the experimental values, suggesting that it is most likely the experimentally trapped species. The calculated energetics indicated that the rate-limiting step is the substrate C[double bond, length as m-dash]C bond activation. This work improves our understanding of the dioxygen activation by α-KGD and provides important structural information about the reactive Fe IV -oxo species.

  7. Enhanced removal of 241Am by DTPA chelation therapy in an adult and teenage subject

    International Nuclear Information System (INIS)

    Sasso, T.L.; Cohen, N.

    1975-01-01

    A series of Na 3 (Ca-DTPA) chelation treatments were carried out on two human subjects, an adult man and a teenage boy, who have long-term body burdens of 241 Am. The in vivo whole-body counting, bioassay of urine and feces, and various blood chemistry measurements were coordinated to coincide with this therapy schedule. Decreases in total body burdens for this treatment period were measured as 5 percent in the adult and 30 percent in the youth. High concentrations of zinc in urine and a corresponding decrease of activity of the zinc-dependent erythropoietic enzyme, ALAD, were also observed. (U.S.)

  8. The Role of Coulomb Interactions for Spin Crossover Behaviors and Crystal Structural Transformation in Novel Anionic Fe(III Complexes from a π-Extended ONO Ligand

    Directory of Open Access Journals (Sweden)

    Suguru Murata

    2016-05-01

    Full Text Available To investigate the π-extension effect on an unusual negative-charged spin crossover (SCO FeIII complex with a weak N2O4 first coordination sphere, we designed and synthesized a series of anionic FeIII complexes from a π-extended naphthalene derivative ligand. Acetonitrile-solvate tetramethylammonium (TMA salt 1 exhibited an SCO conversion, while acetone-solvate TMA salt 2 was in a high-spin state. The crystal structural analysis for 2 revealed that two-leg ladder-like cation-anion arrays derived from π-stacking interactions between π-ligands of the FeIII complex anion and Coulomb interactions were found and the solvated acetone molecules were in one-dimensional channels between the cation-anion arrays. A desolvation-induced single-crystal-to-single-crystal transformation to desolvate compound 2’ may be driven by Coulomb energy gain. Furthermore, the structural comparison between quasi-polymorphic compounds 1 and 2 revealed that the synergy between Coulomb and π-stacking interactions induces a significant distortion of coordination structure of 2.

  9. A two-dimensional bilayered Cd(II) coordination polymer with a three-dimensional supramolecular architecture incorporating 1,2-bis(pyridin-4-yl)ethene and 2,2'-(diazenediyl)dibenzoic acid.

    Science.gov (United States)

    Liu, Lei-Lei; Zhou, Yan; Li, Ping; Tian, Jiang-Ya

    2014-02-01

    In poly[[μ2-1,2-bis(pyridin-4-yl)ethene-κ(2)N:N'][μ2-2,2'-(diazenediyl)dibenzoato-κ(3)O,O':O'']cadmium(II)], [Cd(C14H8N2O4)(C12H10N2)]n, the asymmetric unit contains one Cd(II) cation, one 2,2'-(diazenediyl)dibenzoate anion (denoted L(2-)) and one 1,2-bis(pyridin-4-yl)ethene ligand (denoted bpe). Each Cd(II) centre is six-coordinated by four O atoms of bridging/chelating carboxylate groups from three L(2-) ligands and by two N atoms from two bpe ligands, forming a distorted octahedron. The Cd(II) cations are bridged by L(2-) and bpe ligands to give a two-dimensional (4,4) layer. The layers are interlinked through bridging carboxylate O atoms from L(2-) ligands, generating a two-dimensional bilayered structure with a 3(6)4(13)6(2) topology. The bilayered structures are further extended to form a three-dimensional supramolecular architecture via a combination of hydrogen-bonding and aromatic stacking interactions.

  10. Cobalt(III)-oxo cubane clusters as catalysts for oxidation of organic ...

    Indian Academy of Sciences (India)

    been prepared by a general method and these have been characterized by analytical, spectroscopic, electro- chemical and ... alkylaromatics, alkenes and alcohols.1 Several indus- .... us to obtain the cobalt(III)-oxo clusters in good to very.

  11. Oxo-exchange of gas-phase uranyl, neptunyl, and plutonyl with water and methanol.

    Science.gov (United States)

    Lucena, Ana F; Odoh, Samuel O; Zhao, Jing; Marçalo, Joaquim; Schreckenbach, Georg; Gibson, John K

    2014-02-17

    A challenge in actinide chemistry is activation of the strong bonds in the actinyl ions, AnO2(+) and AnO2(2+), where An = U, Np, or Pu. Actinyl activation in oxo-exchange with water in solution is well established, but the exchange mechanisms are unknown. Gas-phase actinyl oxo-exchange is a means to probe these processes in detail for simple systems, which are amenable to computational modeling. Gas-phase exchange reactions of UO2(+), NpO2(+), PuO2(+), and UO2(2+) with water and methanol were studied by experiment and density functional theory (DFT); reported for the first time are experimental results for UO2(2+) and for methanol exchange, as well as exchange rate constants. Key findings are faster exchange of UO2(2+) versus UO2(+) and faster exchange with methanol versus water; faster exchange of UO2(+) versus PuO2(+) was quantified. Computed potential energy profiles (PEPs) are in accord with the observed kinetics, validating the utility of DFT to model these exchange processes. The seemingly enigmatic result of faster exchange for uranyl, which has the strongest oxo-bonds, may reflect reduced covalency in uranyl as compared with plutonyl.

  12. Oxo Crater on (1) Ceres: Geological History and the Role of Water-ice

    Energy Technology Data Exchange (ETDEWEB)

    Nathues, A.; Platz, T.; Hoffmann, M.; Thangjam, G.; Le Corre, L.; Reddy, V. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Goettingen (Germany); Cloutis, E. A.; Applin, D. M. [University of Winnipeg, Winnipeg, MB R3B 2E9 (Canada); Mengel, K. [IELF, TU Clausthal, Adolph-Roemer-Straße 2A, D-38678 Clausthal-Zellerfeld (Germany); Protopapa, S. [University of Maryland, Department of Astronomy, College Park, MD 20742 (United States); Takir, D. [SETI Institute, Mountain View, CA 94043 (United States); Preusker, F. [German Aerospace Center (DLR), Institute of Planetary Research, D-12489 Berlin (Germany); Schmidt, B. E. [Georgia Institute of Technology, Atlanta, GA (United States); Russell, C. T., E-mail: nathues@mps.mpg.de [Institute of Geophysics and Planetary Physics, Dept. of Earth, Planetary and Space Sciences, University of California Los Angeles, Los Angeles, CA (United States)

    2017-09-01

    Dwarf planet Ceres (∅ ∼ 940 km) is the largest object in the main asteroid belt. Investigations suggest that Ceres is a thermally evolved, volatile-rich body with potential geological activity, a body that was never completely molten, but one that possibly partially differentiated into a rocky core and an ice-rich mantle, and may contain remnant internal liquid water. Thermal alteration and the infall of exogenic material contribute to producing a (dark) carbonaceous chondritic-like surface containing ammoniated phyllosilicates. Here we report imaging and spectroscopic analyses of data on the bright Oxo crater derived from the Framing Camera and the Visible and Infrared Spectrometer on board the Dawn spacecraft. We confirm that the transitional complex crater Oxo (∅ ∼ 9 km) exhibits exposed surface water-ice. We show that this water-ice-rich material is associated exclusively with two lobate deposits at pole-facing scarps, deposits that also contain carbonates and admixed phyllosilicates. Due to Oxo’s location at −4802 m below the cerean reference ellipsoid and its very young age of only 190 ka (1 σ : +100 ka, −70 ka), Oxo is predestined for ongoing water-ice sublimation.

  13. Physical and chemical transformations of μ-oxo dimers and alkoxy complexes of Fe-octaethylporphyrins in solids and in solutions

    Science.gov (United States)

    Ivashin, N. V.; Shulga, A. M.; Terekhov, S. N.; Dzilinski, K.

    1996-11-01

    It has been found that relatively small changes in conditions of crystallization in the synthesis process of μ-oxo dimers can lead to quite different products with dimeric or monomeric structures. Molecular structures of these products, discussed on the basis of Fe-octaethylporphyrin (FeOEP) complexes, have been studied using IR, NMR, EPR, resonance Raman (RR), mass and Mössbauer spectroscopies. The use of chloroform with admixture of alcohols (methanol, deuteromethanol and ethanol) in place of pure chloroform for crystallization of the eluate obtained during synthesis of μ-oxo dimers leads to the formation of alkoxy complexes instead of the μ-oxo dimers. It has been also established that dissolution of the μ-oxo dimers in chloroform-ethanol or chloroform-methanol mixtures leads to conversion of the μ-oxo dimers into the alkoxy complexes after evaporation of the solvents. Methoxy and ethoxy ligands in Fe(OEP)OCH 3 and Fe(OEP)OC 2H 5 complexes can exchange the positions during addition of ethanol to the former and methanol to the latter complex in solution. The possibility of generation of doubly bridged structures of the type: OEP Fe< RRFe OEP where R is OCH 3 or OC 2H 5 is discussed.

  14. Aquabis(3,5-dimethyl-1H-pyrazole-κN(oxalato-κ2O,O′copper(II

    Directory of Open Access Journals (Sweden)

    Andrii I. Buvailo

    2008-01-01

    Full Text Available In the title compound, [Cu(C2O4(C5H8N22(H2O], the CuII atom is coordinated in a slightly distorted square-pyramidal geometry by two N atoms belonging to the two 3,5-dimethyl-1H-pyrazole ligands, two O atoms of the oxalate anion providing an O,O′-chelating coordination mode, and an O atom of the water molecule occupying the apical position. The crystal packing shows a well defined layer structure. Intra-layer connections are realised through a system of hydrogen bonds while the nature of the inter-layer interactions is completely hydrophobic, including no hydrogen-bonding interactions.

  15. The activity state of the branched-chain 2-oxo acid dehydrogenase complex in rat tissues.

    OpenAIRE

    Wagenmakers, A J; Schepens, J T; Veldhuizen, J A; Veerkamp, J H

    1984-01-01

    An assay is described to define the proportion of the branched-chain 2-oxo acid dehydrogenase complex that is present in the active state in rat tissues. Activities are measured in homogenates in two ways: actual activities, present in tissues, by blocking both the kinase and phosphatase of the enzyme complex during homogenization, preincubation, and incubation with 1-14C-labelled branched-chain 2-oxo acid, and total activities by blocking only the kinase during the 5 min preincubation (neces...

  16. Crystal structure of a samarium(III nitrate chain cross-linked by a bis-carbamoylmethylphosphine oxide ligand

    Directory of Open Access Journals (Sweden)

    Julie A. Stoscup

    2014-10-01

    Full Text Available In the title compound poly[aquabis(μ-nitrato-κ4O,O′:O,O′′tetrakis(nitrato-κ2O,O′{μ4-tetraethyl [(ethane-1,2-diylbis(azanediylbis(2-oxoethane-2,1-diyl]diphosphonate-κ2O,O′}disamarium(III], [Sm2(NO36(C14H30N2O8P2(H2O]n, a 12-coordinate SmIII and a nine-coordinate SmIII cation are alternately linked via shared bis-bidentate nitrate anions into a corrugated chain extending parallel to the a axis. The nine-coordinate SmIII atom of this chain is also chelated by a bidentate, yet flexible, carbamoylmethylphoshine oxide (CMPO ligand and bears one water molecule. This water molecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate SmIII cation. The CMPO ligand, which lies about an inversion center, links neighboring chains along the c axis, forming sheets parallel to the ac plane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along the b axis through only van der Waals interactions.

  17. The adsorption of chelating reagents on oxide minerals

    International Nuclear Information System (INIS)

    Bryson, M.A.W.

    1984-06-01

    This work constitutes a fundamental study of the interaction between chelating reagents and oxide minerals. The adsorption mechanisms have been elucidated for most of the systems generated by the oxides of copper(II) or iron(III) and chelating reagents octyl hydroxamate, N-phenylbenzohydroxamate, salicylaldoxime, 5-nitro-salicylaldoxime or 8-hydroxyquinoline. In order to better understand the adsorption process associated with copper(II) oxide, the oxide was recrystallized to produce a coarser material with a more uniform surface. This allowed the oxide surface to be viewed under the scanning electron microscope. A detailed investigation of the effect of the system variables; pH, conditioning period, concentration, temperature, surface area and dispersing reagent on the rate of precipitation of the copper chelate species of general form, Cu(chel) 2 , was made. In addition the chemical nature of the adsorbed species and the structural form of the precipitates were determined with the aid of infra-red spectroscopy and the scanning electron microscope. On the basis of these results a model has been formulated for the adsorption processes. The precipitation process was examined in more detail by the study of the adsorption of chelate on copper metal. Contact angle measurements of air bubbles on copper metal conditioned with chelate were related to the adsorption results in an attempt to isolate the optimum conditions for flotation of oxide minerals

  18. Antimicrobial activity study of a μ3-oxo bridged [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2] cluster

    Science.gov (United States)

    Pathak, Sayantan; Jana, Barun; Mandal, Manab; Mandal, Vivekananda; Ghorai, Tanmay K.

    2017-11-01

    Synthesis, characterization and antimicrobial activity of a tri-nuclear μ3-Oxobridged Fe(III) cluster [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2(1) is reported. Cluster 1 is synthesized in a single pot reaction among Fe(NO3)3·9H2O, C6H5COOH, NaN3 (1:4:1) in MeOH. Single crystal X-ray diffraction studies of the isolated crystals show that it is μ3-Oxo bridged trimeric assembly of three Fe atoms via bridging benzoate anions. Furthermore, BVS calculations show that all three Fe atoms in complex 1 are in +3 oxidation state and are surrounded by benzoate anions and methanol in octahedral environment. The oxidation state of iron is also confirmed from the cyclic voltamogram. FT-IR spectroscopy and CHN analysis of the isolated crystals further supports the functional group attached to the periphery of the complex. The nanomolecular size of complex 1 is 1.29 nm. The antimicrobial efficiency studies of the complex 1 show significant inhibition of the growth of the organisms, viz. B. cereus MTCC 1272, S. epidermidis MTCC 3086 and S. typhimurium MTCC 98 and produced 23 ± 1.93 mm, 16 ± 1.77 mm and 12 ± 2.42 mm inhibition zones respectively. However, it shows zero inhibition to the strain of E. coli MTCC 723.

  19. Labelling of bacteria with indium chelates

    International Nuclear Information System (INIS)

    Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

    1985-01-01

    The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

  20. Study of the Chemistry of Coordination of Oxide-anions of Nitrogen with Species of Iron and Copper as Models of Enzymes of the Cycle of the Nitrogen

    International Nuclear Information System (INIS)

    Quesada Espinoza, F

    2001-01-01

    In the present work, a study is carried out about the reactivity of some nitrogen oxide-anions, like nitrite (NO 2 - ) and trioxide-dinitrate (N 2 O 3 2- ), besides nitric oxide (NO), with copper species, iron, and cobalt in their states of oxidation II, in presence of the binding spectator bispicen. The synthesis and characterization of the [Cu(bispicen)NO 2 ]BF 4 was obtained, which can help to consolidate some mechanisms, proposed for the action of the nitrite reductase. The Fe(bispicen)(NO 2 ) 2 was also characterized; this is the fourth compound that presents two nitrites coordinated to an iron (II) through nitrogen. It has the characteristic of possessing short connection distances, which gives it a special attractiveness, and it opens the possibility of studying a spin exchange [es

  1. Theoretical investigation on the mechanism and dynamics of oxo exchange of neptunyl(VI) hydroxide in aqueous solution.

    Science.gov (United States)

    Yang, Xia; Chai, Zhifang; Wang, Dongqi

    2015-03-21

    Four types of reaction mechanisms for the oxo ligand exchange of monomeric and dimeric neptunyl(VI) hydroxide in aqueous solution were explored computationally using density functional theory (DFT) and ab initio classical molecular dynamics. The obtained results were compared with previous studies on the oxo exchange of uranyl hydroxide, as well as with experiments. It is found that the stable T-shaped [NpO3(OH)3](3-) intermediate is a key species for oxo exchange in the proton transfer in mononuclear Path I and binuclear Path IV, similar to the case of uranyl(VI) hydroxide. Path I is thought to be the preferred oxo exchange mechanism for neptunyl(VI) hydroxide in our calculations, due to the lower activation energy (22.7 and 13.1 kcal mol(-1) for ΔG(‡) and ΔH(‡), respectively) of the overall reaction. Path II via a cis-neptunyl structure assisted by a water molecule might be a competitive channel against Path I with a mononuclear mechanism, owing to a rapid dynamical process occurring in Path II. In Path IV with the binuclear mechanism, oxo exchange is accomplished via the interaction between [NpO2(OH)4](2-) and T-shaped [NpO3(OH)3](3-) with a low activation energy for the rate-determining step, however, the overall energy required to fulfill the reaction is slightly higher than that in mononuclear Path I, suggesting a possible binuclear process in the higher energy region. The chemical bonding evolution along the reaction pathways was discussed by using topological methodologies of the electron localization function (ELF).

  2. Review of actinide decorporation with chelating agents

    Energy Technology Data Exchange (ETDEWEB)

    Ansoborlo, E. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/CETAMA), 30 - Marcoule (France); Amekraz, B.; Moulin, Ch. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Moulin, V. [CEA Saclay, Dir. du Developpement et de l' Innovation Nucleares (DEN/DDIN/MR), 91 - Gif Sur Yvette (France); Taran, F. [CEA Saclay (DSV/DBJC/SMMCB), 91 - Gif-sur-Yvette (France); Bailly, Th.; Burgada, R. [Centre National de la Recherche Scientifique (CNRS/LCSB/UMR 7033), 93 - Bobigny (France); Henge-Napoli, M.H. [CEA Valrho, Site de Marcoule (INSTN), 30 (France); Jeanson, A.; Den Auwer, Ch.; Bonin, L.; Moisy, Ph. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS), 30 - Marcoule (France)

    2007-10-15

    In case of accidental release of radionuclides in a nuclear facility or in the environment, internal contamination (inhalation, ingestion or wound) with actinides represents a severe health risk to human beings. It is therefore important to provide effective chelation therapy or decorporation to reduce acute radiation damage, chemical toxicity, and late radiation effects. Speciation governs bioavailability and toxicity of elements and it is a prerequisite tool for the design and success of new ligands or chelating agents. The purpose of this review is to present the state-of-the-art of actinide decorporation within biological media, to recall briefly actinide metabolism, to list the basic constraints of actinide-ligand for development, to describe main tools developed and used for decorporation studies, to review mainly the chelating agents tested for actinides, and finally to conclude on the future trends in this field. (authors)

  3. Density functional study of carbon monoxide adsorption on small cationic, neutral, and anionic aluminum nitride clusters

    Science.gov (United States)

    Guo, Ling

    CO adsorption on small cationic, neutral, and anionic (AlN)n (n = 1-6) clusters has been investigated using density functional theory in the generalized gradient approximation. Among various possible CO adsorption sites, an N on-top (onefold coordinated) site is found to be the most favorable one, irrespective of the charge state of the clusters. The adsorption energies of CO on the anionic (AlN)nCO (n = 2-4) clusters are greater than those on the neutral and cationic complexes. The adsorption energies on the cationic and neutral complexes reflect the odd-even oscillations, and the adsorption energies of CO on the cationic (AlN)nCO (n = 5, 6) clusters are greater than those on the neutral and anionic complexes. The adsorption energies for the different charge states decrease with increasing cluster size.

  4. Radiopharmaceutical chelates and method of external imaging

    International Nuclear Information System (INIS)

    1976-01-01

    The preparation of the following chemicals is described: chelates of technetium-99m, cobalt-57, gallium-67, gallium-68, indium-111 or indium-113m and a substituted iminodiacetic acid or an 8-hydroxyquinoline useful as a radiopharmaceutical external imaging agent. The compounds described are suitable for intravenous injection, have an excellent in vivo stability and are good organ seekers. Tin(II) choride or other tin(II) compounds are used as chelating agents

  5. Cytotoxic mechanisms of hydrosulfide anion and cyanide anion in primary rat hepatocyte cultures

    International Nuclear Information System (INIS)

    Thompson, Rodney W.; Valentine, Holly L.; Valentine, William M.

    2003-01-01

    Hydrogen sulfide and hydrogen cyanide are known to compromise mitochondrial respiration through inhibition of cytochrome c oxidase and this is generally considered to be their primary mechanism of toxicity. Experimental studies and the efficiency of current treatment protocols suggest that H 2 S may exert adverse physiological effects through additional mechanisms. To evaluate the role of alternative mechanisms in H 2 S toxicity, the relative contributions of electron transport inhibition, uncoupling of mitochondrial respiration, and opening of the mitochondrial permeability transition pore (MPTP) to hydrosulfide and cyanide anion cytotoxicity in primary hepatocyte cultures were examined. Supplementation of hepatocytes with the glycolytic substrate, fructose, rescued hepatocytes from cyanide anion induced toxicity, whereas fructose supplementation increased hydrosulfide anion toxicity suggesting that hydrosulfide anion may compromise glycolysis in hepatocytes. Although inhibitors of the MPTP opening were protective for hydrosulfide anion, they had no effect on cyanide anion toxicity, consistent with an involvement of the permeability transition pore in hydrosulfide anion toxicity but not cyanide anion toxicity. Exposure of isolated rat liver mitochondria to hydrosulfide did not result in large amplitude swelling suggesting that if H 2 S induces the permeability transition it does so indirectly through a mechanism requiring other cellular components. Hydrosulfide anion did not appear to be an uncoupler of mitochondrial respiration in hepatocytes based upon the inability of oligomycin and fructose to protect hepatocytes from hydrosulfide anion toxicity. These findings support mechanisms additional to inhibition of cytochrome c oxidase in hydrogen sulfide toxicity. Further investigations are required to assess the role of the permeability transition in H 2 S toxicity, determine whether similar affects occur in other cell types or in vivo and evaluate whether this may

  6. Reaction of uranyl nitrate with carboxylic di-acids under hydrothermal conditions. Crystal structure of complexes with L(+)-tartaric and oxalic acids

    International Nuclear Information System (INIS)

    Thuery, P.

    2007-01-01

    L(+)-tartaric acid reacts with uranyl nitrate in the presence of KOH, under mild hydrothermal conditions, to give the complex [UO 2 (C 4 H 4 O 6 )(H 2 O)] (1), the first uranyl tartrate to be crystallographically characterized. Each tartrate ligand bridges three uranyl ions, one of them in chelating fashion through proximal carboxylate and hydroxyl groups. The resulting assemblage is two-dimensional, with the uranyl pentagonal bipyramidal coordination polyhedra separated from one another. Prolonged heating of an uranyl tartrate solution resulted in oxidative cleavage of the acid and formation of the oxalate complex [(UO 2 ) 2 (C 2 O 4 ) 2 (OH)Na(H 2 O) 2 ] (2). The bis-bidentate oxalate and bridging hydroxide groups ensure the formation of sheets with corner-sharing uranyl pentagonal bipyramidal coordination polyhedra, in which six-membered metallacycles encompass the sodium ions. These sheets are assembled into a three-dimensional framework through further oxo-bonding of the sodium ions. (authors)

  7. Crystal structure of 2-amino-1,3-dibromo-6-oxo-5,6-dihydropyrido[1,2-a]quinoxalin-11-ium bromide monohydrate

    Directory of Open Access Journals (Sweden)

    Md. Serajul Haque Faizi

    2015-11-01

    Full Text Available In the title hydrated salt, C12H8Br2N3O+·Br−·H2O, which was synthesized by the reaction of the pyridine derivative Schiff base N1,N4-bis(pyridine-2-ylmethylenebenzene-1,4-diamine with bromine, the asymmetric unit contains a 2-amino-1,3-dibromo-6-oxo-5,6-dihydropyrido[1,2-a]quinoxalin-11-ium cation, with a protonated pyridine moiety, a bromide anion and a water molecule of solvation. The cation is non-planar with the dibromo-substituted benzene ring, forming dihedral angles of 24.3 (4 and 11.5 (4° with the fused pyridine and pyrazine ring moieties, respectively. In the crystal, the cations are linked through a centrosymmetric hydrogen-bonded cyclic R42(8 Br2(H2O2 unit by N—H...Br, N—H...O and O—H...Br hydrogen bonds, forming one-dimensional ribbons extending along b, with the planes of the cations lying parallel to (100.

  8. The Effect of the Equatorial Environment on Oxo-Group Silylation of the Uranyl Dication: A Computational Study

    International Nuclear Information System (INIS)

    Yahia, A.; Maron, L.; Yahia, A.; Arnold, P.L.; Love, J.B.

    2010-01-01

    A theoretical investigation of the reductive oxo-group silylation reaction of the uranyl dication held in a Pacman macrocyclic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single oxo group identified as a key component in promoting the reaction between the Si-X and uranium-oxo bonds. This reductive silylation reaction is also proposed to occur in an aqueous environment but was found not to operate on bare ions; in this latter case, substitution of a ligand in the equatorial plane was the most likely reaction. These results demonstrate the importance of the presence but not the identity of the equatorial ligands upon the silylation of the uranyl U-O bond. (authors)

  9. Reversible formation of high-valent-iron-oxo-porphyrin intermediate in heme-based catalysis: revisiting the kinetic model for horseradish peroxidase.

    NARCIS (Netherlands)

    Haandel, van M.J.H.; Primus, J.L.; Teunis, C.; Boersma, M.G.; Osman, A.M.; Veeger, C.; Rietjens, I.M.C.M.

    1998-01-01

    Many heme-containing biocatalysts exert their catalytic action through the initial formation of so-called high-valent-iron-oxo porphyrin intermediates. For horseradish peroxidase the initial intermediate formed has been identified as a high-valent-iron-oxo porphyrin π-radical cation, called compound

  10. Modelling the transport of carbonic acid anions through anion-exchange membranes

    International Nuclear Information System (INIS)

    Nikonenko, V.; Lebedev, K.; Manzanares, J.A.; Pourcelly, G.

    2003-01-01

    Electrodiffusion of carbonate and bicarbonate anions through anion-exchange membranes (AEM) is described on the basis of the Nernst-Planck equations taking into account coupled hydrolysis reactions in the external diffusion boundary layers (DBLs) and internal pore solution. The model supposes local electroneutrality as well as chemical and thermodynamic equilibrium. The transport is considered in three layers being an anion exchange membrane and two adjoining diffusion layers. A mechanism of competitive transport of HCO 3 - and CO 3 2- anions through the membrane which takes into account Donnan exclusion of H + ions is proposed. It is predicted that the pH of the depleting solution decreases and that of the concentrating solution increases during electrodialysis (ED). Eventual deviations from local electroneutrality and local chemical equilibrium are discussed

  11. Bromido(1,4,7,10,13-pentaazacyclohexadecanecobalt(III dibromide dihydrate

    Directory of Open Access Journals (Sweden)

    Tsutomu Kurisaki

    2013-04-01

    Full Text Available The title salt, [CoBr(C11H27N5]Br2·2H2O, contains a complex cation with mirror symmetry and two Br− counter-anions that are likewise located on the mirror plane. The central CoIII atom of the complex cation has one Br− ion in an axial position, one N atom of the pentadentate macrocyclic ligand in the other axial position and four N atoms of the ligand in equatorial positions, defining a distorted octahedral coordination geometry. The macrocyclic ligand is coordinated to the CoIII atom within a 5, 6, 5 arrangement of chelate rings in the equatorial plane of the four N atoms. Due to symmetry, the configuration of the chiral N atoms is 1RS, 4SR, 10RS, 13SR. In the crystal, N—H...Br, O—H...Br and N—H...O hydrogen bonds between the complex cation, anions and lattice water molecules generate a three-dimensional network.

  12. CARDIAC FUNCTION AND IRON CHELATION IN THALASSEMIA MAJOR AND INTERMEDIA: A REVIEW OF THE UNDERLYING PATHOPHYSIOLOGY AND APPROACH TO CHELATION MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Athanasios Aessopos

    2009-07-01

    Full Text Available Heart disease is the leading cause of mortality and one of the main causes of morbidity in beta-thalassemia. Patients with homozygous thalassemia may have either a severe phenotype which is usually transfusion dependent or a milder form that is thalassemia intermedia.  The two main factors that determine cardiac disease in homozygous β thalassemia are the high output state that results from chronic tissue hypoxia, hypoxia-induced compensatory reactions and iron overload.  The high output state playing a major role in thalassaemia intermedia and the iron load being more significant in the major form. Arrhythmias, vascular involvement that leads to an increased pulmonary vascular resistance and an increased systemic vascular stiffness and valvular abnormalities also contribute to the cardiac dysfunction in varying degrees according to the severity of the phenotype.  Endocrine abnormalities, infections, renal function and medications can also play a role in the overall cardiac function.  For thalassaemia major, regular and adequate blood transfusions and iron chelation therapy are the mainstays of management. The approach to thalassaemia intermedia, today, is aimed at monitoring for complications and initiating, timely, regular transfusions and/or iron chelation therapy.  Once the patients are on transfusions, then they should be managed in the same way as the thalassaemia major patients.  If cardiac manifestations of dysfunction are present in either form of thalassaemia, high pre transfusion Hb levels need to be maintained in order to reduce cardiac output and appropriate intensive chelation therapy needs to be instituted.  In general recommendations on chelation, today, are usually made according to the Cardiac Magnetic Resonance findings, if available.  With the advances in the latter technology and the ability to tailor chelation therapy according to the MRI findings as well as the availability of three iron chelators, together with

  13. Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, F.C.; Maddalena, D.J. (Australian Atomic Energy Commission Research Establishment, Lucas Heights)

    The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo.

  14. Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

    International Nuclear Information System (INIS)

    Pachauri, Vidhu; Saxena, Geetu; Mehta, Ashish; Mishra, Deepshikha; Flora, Swaran J.S.

    2009-01-01

    Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

  15. Rates of cuticular penetration of chelated Fe(III): role of humidity, concentration, adjuvants, temperature, and type of chelate.

    Science.gov (United States)

    Schönherr, Jörg; Fernández, Victoria; Schreiber, Lukas

    2005-06-01

    Time courses of cuticular penetration of FeCl3 and Fe(III) complexes of citric acid, EDTA, EDDHA (Sequestrene 138Fe), imidodisuccinic acid (IDHA), and ligninsulfonic acid (Natrel) were studied using astomatous cuticular membranes (CMs) isolated from Populus x canescens leaves. At 100% relative humidity, the Fe(III) chelates disappeared exponentially with time from the surface of the CMs; that is, penetration was a first-order process that can be described using rate constants or half-times of penetration (t(1/2)). Half-times ranged from 20 to 30 h. At 90% humidity, penetration rates were insignificant with the exception of Natrel, for which t(1/2) amounted to 58 h. Rate constants were independent of temperature (15, 25, and 35 degrees C). Permeability decreased with increasing Fe chelate concentration (IDHA and EDTA). At 100% humidity, half-times measured with FeIDHA were 11 h (2 mmol L(-1)), 17 h (10 mmol L(-1)) and 36 h (20 mmol L(-1)), respectively. In the presence of FeEDTA, penetration of CaCl2 was slowed greatly. Half-times for penetration of CaCl2, which were 1.9 h in the absence of FeEDTA, rose to 3.12 h in the presence of an equimolar concentration of EDTA and 13.3 h when the FeEDTA concentration was doubled. Hence, Fe chelates reduced permeability of CMs to CaCl2 and to the Fe chelates themselves. It is suggested that Fe chelates reduced the size of aqueous pores. This view is supported by the fact that rate constants for calcium salts were about 5 times higher than for Fe chelates with the same molecular weights. Adding Tween 20 (5 g L(-1)) as a humectant did not increase permeability to FeIDHA at 90% humidity and below, while addition of glycine betaine did. Penetration of FeCl3 applied at 5 g L(-1) (pH 1.5) was not a first order process as rate constants decreased rapidly with time. Only 2% of the dose penetrated during the first 2 h and less than that in the subsequent 8 h. Recovery was only 70%. This was attributed to the formation of insoluble Fe

  16. Potentials and drawbacks of chelate-enhanced phytoremediation of soils

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Bouwman, L.A.; Japenga, J.; Draaisma, C.

    2002-01-01

    Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and

  17. Mixed and chelated waste test programs with bitumen solidification

    International Nuclear Information System (INIS)

    Simpson, S.I.; Morris, M.; Vidal, H.

    1988-01-01

    This paper presents the results of bitumen solidification tests on mixed wastes and chelated wastes. The French Atomic Energy Commission (CEA) performed demonstration tests on radioactive wastes contaminated with chelating agents for Associated Technologies, Inc. (ATI). The chelated wastes were produced and concentrated by Commonwealth Edison Co. as a result of reactor decontamination at Dresden Nuclear Station, Unit 1. Law Engineering in Charlotte, N. C. produced samples and performed tests on simulated heavy metal laden radioactive waste (mixed) to demonstrate the quality of the bituminous product. The simulation is intended to represent waste produced at Oak Ridge National Labs operated by Martin-Marietta

  18. Radiolabeling Silica-Based Nanoparticles via Coordination Chemistry: Basic Principles, Strategies, and Applications.

    Science.gov (United States)

    Ni, Dalong; Jiang, Dawei; Ehlerding, Emily B; Huang, Peng; Cai, Weibo

    2018-03-20

    As one of the most biocompatible and well-tolerated inorganic nanomaterials, silica-based nanoparticles (SiNPs) have received extensive attention over the last several decades. Recently, positron emission tomography (PET) imaging of radiolabeled SiNPs has provided a highly sensitive, noninvasive, and quantitative readout of the organ/tissue distribution, pharmacokinetics, and tumor targeting efficiency in vivo, which can greatly expedite the clinical translation of these promising NPs. Encouraged by the successful PET imaging of patients with metastatic melanoma using 124 I-labeled ultrasmall SiNPs (known as Cornell dots or C dots) and their approval as an Investigational New Drug (IND) by the United States Food and Drug Administration, different radioisotopes ( 64 Cu, 89 Zr, 18 F, 68 Ga, 124 I, etc.) have been reported to radiolabel a wide variety of SiNPs-based nanostructures, including dense silica (dSiO 2 ), mesoporous silica (MSN), biodegradable mesoporous silica (bMSN), and hollow mesoporous silica nanoparticles (HMSN). With in-depth knowledge of coordination chemistry, abundant silanol groups (-Si-O-) on the silica surface or inside mesoporous channels not only can be directly used for chelator-free radiolabeling but also can be readily modified with the right chelators for chelator-based labeling. However, integrating these labeling strategies for constructing stably radiolabeled SiNPs with high efficiency has proven difficult because of the complexity of the involved key parameters, such as the choice of radioisotopes and chelators, nanostructures, and radiolabeling strategy. In this Account, we present an overview of recent progress in the development of radiolabeled SiNPs for cancer theranostics in the hope of speeding up their biomedical applications and potential translation into the clinic. We first introduce the basic principles and mechanisms for radiolabeling SiNPs via coordination chemistry, including general rules of selecting proper

  19. Influence of substituents in meso-aryl groups of iron l-oxo porphyrins\

    Czech Academy of Sciences Publication Activity Database

    Tabor, Edyta; Poltowicz, J.; Pamin, K.; Basag, S.; Kubiak, W.

    2016-01-01

    Roč. 119, NOV 2016 (2016), s. 342-349 ISSN 0277-5387 Institutional support: RVO:61388955 Keywords : iron porphyrins * μ-Oxo porphyrins * oxidation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.926, year: 2016

  20. Synthesis and crystal structures of 2-methyl-4-aryl-5-oxo-5H-indeno [1,2-b] pyridine carboxylate derivatives

    DEFF Research Database (Denmark)

    Pandian, Ramesh; Naushad, Edayadulla; Vijayakumar, Vinodhkumar

    2014-01-01

    pyridine derivatives through oxidation. Consequently, the interest in this aromatization reaction, investigation of a wide range of 1, 4-DHPs continues to attract the attention of researchers. Herein, we report the preparation of pyridine derivatives and the crystal structures determined by X......-ray crystallographic methods.Results: The crystal structures and conformational studies of two organic compounds, namely ethyl 2-methyl-4-phenyl-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate (I) and ethyl 2-methyl-4-(4 chlorophenyl)-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate (II) are reported. The terminal ethyl......) dimer running along 011 direction.Conclusion: The crystal structures ethyl 2-methyl-4-phenyl-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate and ethyl 2-methyl-4-(4 chlorophenyl)-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate have been investigated in detail. The terminal ethyl group of compound I...

  1. Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

    International Nuclear Information System (INIS)

    Hunt, F.C.; Maddalena, D.J.

    1982-01-01

    The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo. (U.K.)

  2. Antioxidant, Iron-chelating and Anti-glucosidase Activities of Typha ...

    African Journals Online (AJOL)

    Iron chelating activity was assessed using a ferrozine-based assay. Anti- glucosidase activity was determined using 4-nitrophenyl ... flavonoid (TF) content was determined based an aluminum chloride colorimetric assay [6]. TF content was ..... Dietary iron restriction or iron chelation protects from diabetes and loss of β-cell.

  3. Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Division of Inorganic and Physical Chemistry, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, 40132 (Indonesia)

    2015-09-30

    Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

  4. Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

    Science.gov (United States)

    Asriza, Ristika O.; Arcana, I. Made

    2015-09-01

    Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

  5. Urinary albumin and 8-oxo-7,8-dihydroguanosine as markers of mortality and cardiovascular disease during 19 years after diagnosis of type 2 diabetes

    DEFF Research Database (Denmark)

    Broedbaek, Kasper; Køster-Rasmussen, Rasmus; Siersma, Volkert

    2017-01-01

    ,8-dihydroguanosine (8-oxoGuo) that represents intracellular oxidative stress. We investigated the ability of microalbuminuria (MA) and urinary 8-oxoGuo, alone and in combination, to predict mortality and cardiovascular disease (CVD) in patients with type 2 diabetes. We used data from 1381 newly diagnosed diabetes...... patients, and urinary albumin and 8-oxoGuo were assessed in morning urine collected at the time of diabetes diagnosis and at a follow-up visit 6 years later. Associations between the urinary markers and mortality and CVD were assessed in Cox proportional hazards regression models. Test performance......-up. At diagnosis only urinary albumin was associated with CVD. In contrast, only 8-oxoGuo was associated with CVD at 6-year follow-up. When investigating test performance, we found that by combining information from MA and 8-oxoGuo the ability to correctly identify patients at risk could be improved. The findings...

  6. Olivine-type cathode for rechargeable batteries: Role of chelating agents

    International Nuclear Information System (INIS)

    Kandhasamy, Sathiyaraj; Singh, Pritam; Thurgate, Stephen; Ionescu, Mihail; Appadoo, Dominique; Minakshi, Manickam

    2012-01-01

    Highlights: ► Olivine powder was synthesized by sol–gel method using a range of chelating agents. ► Role of chelating agents in olivine cathode was investigated for battery application. ► Battery was fabricated with olivine cathode, Zn anode and aqueous electrolyte. ► Synergetic effect of additives (CA + TEA + PVP) led to improved storage capacity. - Abstract: Olivine (LiCo 1/3 Mn 1/3 Ni 1/3 PO 4 ) powders were synthesized at 550–600 °C for 6 h in air by a sol–gel method using multiple chelating agents and used as a cathode material for rechargeable batteries. Range of chelating agents like a weak organic acid (citric acid – CA), emulsifier (triethanolamine – TEA) and non-ionic surfactant (polyvinylpyrrolidone – PVP) in sol–gel wet chemical synthesis were used. The dependence of the physicochemical properties of the olivine powders such as particle size, morphology, structural bonding and crystallinity on the chelating agent was extensively investigated. Among the chelating agents used, unique cycling behavior (75 mAh/g after 25 cycles) is observed for the PVP assisted olivine. This is due to volumetric change in trapped organic layer for first few cycles. The trapped organic species in the electrode–electrolyte interface enhances the rate of lithium ion diffusion with better capacity retention. In contrast, CA and TEA showed a gradual capacity fade of 30 and 38 mAh/g respectively after multiple cycles. The combination of all the three mixed chelating agents showed an excellent electrochemical behavior of 100 mAh/g after multiple cycles and the synergistic effect of these agents are discussed.

  7. A new Pb{sup II}(ethylenediaminetetraacetate) coordination polymer with a two-dimensional layer structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, D., E-mail: iamzd@hpu.edu.cn; Zhang, R. H.; Li, F. F. [Henan Polytechnic University, Department of Physics and Chemistry (China)

    2016-12-15

    A new Pb{sup II}−edta{sup 4–} coordination polymer, Pb{sub 2}(edta)(H{sub 2}O){sub 0.76} (edta{sup 4–} = ethylenediaminetetraacetate) was synthesized under hydrothermal condition. Single crystal X-ray analysis reveals that it represents a novel two-dimensional (2D) Pb{sup 2+}–edta{sup 4–} layer structure with a (4,8{sup 2})-topology. Each edta{sup 4–} ligand employs its four carboxylate O and two N atoms to chelate one Pb{sup II} atom (hexa-coordinated) and connects five Pb{sup II} atoms (ennea-coordinated) via its four carboxylate groups to form 2D layer framework. Adjacent layers are packed into the overall structure through vander Waals interactions.

  8. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    International Nuclear Information System (INIS)

    Sessler, Jonathan L.

    2007-01-01

    The major thrust of this project, led by the University of Kansas (Prof. Kristin Bowman-James), entails an exploration of the basic determinants of anion recognition and their application to the design, synthesis, and testing of novel sulfate extractants. A key scientific inspiration for the work comes from the need, codified in simple-to-appreciate terms by the Oak Ridge National Laboratory component of the team (viz. Dr. Bruce Moyer), for chemical entities that can help in the extractive removal of species that have low solubilities in borosilicate glass. Among such species, sulfate anion, has been identified as particularly insidious. Its presence interferes with the vitrification process, thus rendering the remediation of tank waste from, e.g., the Hanford site far more difficult and expensive. The availability of effective extractants, that would allow for the separation of separating sulfate from the major competing anions in the waste, especially nitrate, could allow for pre-vitrification removal of sulfate via liquid-liquid extraction. The efforts at The University of Texas, the subject of this report, have thus concentrated on the development of new sulfate receptors. These systems are designed to increase our basic understanding of anion recognition events and set the stage for the development of viable sulfate anion extractants. In conjunction with the Oak Ridge National Laboratory (ORNL) members of the research team, several of these new receptors were studied as putative extractants, with two of the systems being shown to act as promising synergists for anion exchange.

  9. Ab initio investigation of isomerism, structure and stability of complex molecules of salts of oxo- and thiohalide and dihydride borates and aluminates Li[X2MY] (M=B, Al; X=F, Cl, H; Y=O, S)

    International Nuclear Information System (INIS)

    Charkin, D.O.; MakKi, M.L.; Charkin, O.P.

    2000-01-01

    To obtain full summary molecular constants of mixed salts Li[X 2 MY] and to analyze tendencies of their changes during substitution of B for Al, F - for C and H, and O - for S and to trace the character of polarization and deformation of X 2 MY - anions in the field of Li + cation in the cases of their different coordination in the framework of correlated approximation method MP4/6-31(+)G**//MP2/6-31G* + ZPE(MP2/6-31G*) ab initio calculation of surfaces of potential energy of plane trigonal anions X 2 MY - (M=B, Al; X=F, Cl, H; Y=O, S) and their lithium salts are done. Equilibrium geometrical parameters of isomers, frequencies and relative IR intensities of normal vibrations, their relative energies and decomposition energies are determined. Structure where Li + cation is coordinated bidentately to chalcogen and one of the X atom is the most profitable one. Polarization and deformation of X 2 MY - anion in the field of Li + cation in the cases of different ways of their coordination, tendencies in changes of the calculated parameters during B substitution are analyzed [ru

  10. Is DTPA a good competing chelating agent for Th(IV) in human serum and suitable in targeted alpha therapy?

    Science.gov (United States)

    Le Du, Alicia; Sabatié-Gogova, Andrea; Morgenstern, Alfred; Montavon, Gilles

    2012-04-01

    The interaction between thorium and human serum components was studied using difference ultraviolet spectroscopy (DUS), ultrafiltration and high-pressure-anion exchange chromatography (HPAEC) with external inductively conducted plasma mass spectrometry (ICP-MS) analysis. Experimental data are compared with modelling results based on the law of mass action. Human serum transferrin (HSTF) interacts strongly with Th(IV), forming a ternary complex including two synergistic carbonate anions. This complex governs Th(IV) speciation under blood serum conditions. Considering the generally used Langmuir-type model, values of 10(33.5) and 10(32.5) were obtained for strong and weak sites, respectively. We showed that trace amounts of diethylene triamine pentaacetic acid (DTPA) cannot complex Th(IV) in the blood serum at equilibrium. Unexpectedly this effect is not related to the competition with HSTF but is due to the strong competition with major divalent metal ions for DTPA. However, Th-DTPA complex was shown to be stable for a few hours when it is formed before addition in the biological medium; this is related to the high kinetic stability of the complex. This makes DTPA a potential chelating agent for synthesis of (226)Th-labelled biomolecules for application in targeted alpha therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Bis(morpholine) hydrogen bond pincer - a novel series of heteroleptic Cu(II) coordination compounds as receptors for electron rich guests

    NARCIS (Netherlands)

    Stilinovic, Vladimir; Uzarevic, Krunoslav; Cvrtila, Ivica; Kaitner, Branko

    2012-01-01

    Crystallisation from morpholine (morph) solutions of copper(II) salts with monovalent anions (A) and 1,3-diketones (Hdkt) yielded nine heteroleptic coordination compounds [Cu(dkt)(morph)(2)A]. The coordination polyhedron of the copper ion in these compounds is a square pyramid with a monovalent

  12. Metal-chelating active packaging film enhances lysozyme inhibition of Listeria monocytogenes.

    Science.gov (United States)

    Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2014-07-01

    Several studies have demonstrated that metal chelators enhance the antimicrobial activity of lysozyme. This study examined the effect of metal-chelating active packaging film on the antimicrobial activity of lysozyme against Listeria monocytogenes. Polypropylene films were surface modified by photoinitiated graft polymerization of acrylic acid (PP-g-PAA) from the food contact surface of the films to impart chelating activity based on electrostatic interactions. PP-g-PAA exhibited a carboxylic acid density of 113 ± 5.4 nmol cm(-2) and an iron chelating activity of 53.7 ± 9.8 nmol cm(-2). The antimicrobial interaction of lysozyme and PP-g-PAA depended on growth media composition. PP-g-PAA hindered lysozyme activity at low ionic strength (2.48-log increase at 64.4 mM total ionic strength) and enhanced lysozyme activity at moderate ionic strength (5.22-log reduction at 120 mM total ionic strength). These data support the hypothesis that at neutral pH, synergy between carboxylate metal-chelating films (pKa(bulk) 6.45) and lysozyme (pI 11.35) is optimal in solutions of moderate to high ionic strength to minimize undesirable charge interactions, such as lysozyme absorption onto film. These findings suggest that active packaging, which chelates metal ions based on ligand-specific interactions, in contrast to electrostatic interactions, may improve antimicrobial synergy. This work demonstrates the potential application of metal-chelating active packaging films to enhance the antimicrobial activity of membrane-disrupting antimicrobials, such as lysozyme.

  13. Effect of degrading yellow oxo-biodegradable low-density polyethylene films to water quality

    Science.gov (United States)

    Requejo, B. A.; Pajarito, B. B.

    2017-05-01

    Polyethylene (PE) contributes largely to plastic wastes that are disposed in aquatic environment as a consequence of its widespread use. In this study, yellow oxo-biodegradable low-density PE films were immersed in deionized water at 50°C for 49 days. Indicators of water quality: pH, oxidation-reduction potential, turbidity, and total dissolved solids (TDS), were monitored at regular intervals. It was observed that pH initially rises and then slowly decreases with time, oxidation-reduction potential decreases then slowly increases with time, turbidity rises above the control at varied rates, and TDS increases abruptly and rises at a hindered rate. Moreover, the films potentially leach out lead chromate. The results imply that degrading oxo-biodegradable LDPE films results to significant reduction of water quality.

  14. The influence of functional groups on the permeation and distribution of antimycobacterial rhodamine chelators.

    Science.gov (United States)

    Moniz, T; Leite, A; Silva, T; Gameiro, P; Gomes, M S; de Castro, B; Rangel, M

    2017-10-01

    We formerly hypothesized a mechanism whereby the antimycobacterial efficiency of a set of rhodamine labelled iron chelators is improved via the rhodamine fluorophore which enhances the chelators' permeation properties through membranes. To validate our hypothesis in a cellular context and to understand the influence of the structure of the fluorophore on the chelator's uptake and distribution within macrophages we now report comparative confocal microscopy studies performed with a set of rhodamine labelled chelators. We identify the functional groups of the chelator's framework that favor uptake by macrophages and conclude that the antimycobacterial effect is strongly related with the capacity of the chelator to distribute within the host cell and its compartments, a property that is closely related with the chelators' ability to interact with membranes. The quantification of the chelators' interaction with membranes was assessed through measurement of the corresponding partition constants in liposomes. The overall results support that the compounds which are preferentially taken up are the most efficient antimycobacterial chelators and for that reason we infer that the biological activity is modulated by the structural features of the fluorophore. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Iron chelators ICL670 and 311 inhibit HIV-1 transcription

    International Nuclear Information System (INIS)

    Debebe, Zufan; Ammosova, Tatyana; Jerebtsova, Marina; Kurantsin-Mills, Joseph; Niu, Xiaomei; Charles, Sharroya; Richardson, Des R.; Ray, Patricio E.; Gordeuk, Victor R.; Nekhai, Sergei

    2007-01-01

    HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics

  16. Interaction of chelating agents with cadmium in mice and rats

    International Nuclear Information System (INIS)

    Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

    1984-01-01

    The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl 2 and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl 2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl 2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes

  17. Bone marrow and chelatable iron in patients with protein energy ...

    African Journals Online (AJOL)

    chelatable iron is present and is excreted in the urine of children with kwashiorkor ... venous blood sample was drawn for routine biochemical and haematological .... storage.l.1:m In response to chelation, the kwashiorkor children excrete large ...

  18. Spectral, biological screening of metal chelates of chalcone based Schiff bases of N-(3-aminopropyl) imidazole.

    Science.gov (United States)

    Kalanithi, M; Rajarajan, M; Tharmaraj, P; Sheela, C D

    2012-02-15

    Tridentate chelate complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the chalcone based ligands 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol(HL(1)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-p-tolylallyl]phenol(HL(2)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol(HL(3)). Microanalytical data, UV-vis spectrophotometric method, magnetic susceptibility measurements, IR, 1H NMR, Mass, and EPR techniques were used to characterize the structure of chelates. The electronic absorption spectra and magnetic susceptibility measurements suggest a distorted square planar geometry for the copper(II) ion. The other metal complexes show distorted tetrahedral geometry. The coordination of the ligands with metal(II) ions was further confirmed by solution fluorescence spectrum. The antimicrobial activity of the ligands and metal(II) complexes against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger has been carried out and compared. The electrochemical behavior of copper(II) complex is studied by cyclic voltammetry. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. In vitro and in vivo evaluation of potential aluminum chelators.

    Science.gov (United States)

    Graff, L; Muller, G; Burnel, D

    1995-10-01

    The potential for aluminium (Al) chelation by different compounds was determined using 2 in vitro techniques. The formation of stable complexes with Al in an aqueous solution was evaluated using pulse polarography. This technique allowed the influence of temperature and calcium (Ca) to be studied for each compound. Certain compounds (EDDHA, HAES, citric acid and HBED) showed great chelation in the absence of Ca2+ at a temperature of 37 +/- 1 C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy allowed the efficiency of different substances to complex Al that were previously bound to serum proteins to be estimated. The kinetics of chelation and minimum efficient concentration have been determined for all products studied. EDDHA had chelation potential similar to DFO. The real efficacies of the compounds were studied in vivo to compare the effectiveness of repeated administrations of the best chelating agents (EDDHA, DFO, HAES and tartaric acid) on the distribution and excretion of Al after repeated i.p. administrations to rats. Intraperitoneal EDDHA significantly increased urinary metal (Al, Ca, Cu, Fe and Zn) excretion. These excretions may be correlated to a renal toxic potential property.

  20. Selectivity in extraction of copper and indium with chelate extractants

    International Nuclear Information System (INIS)

    Zivkovic, D.

    2003-01-01

    Simultaneous extraction of copper and indium with chelate extractants (LIX84 and D2E11PA) was described. Stechiometry of metal-organic complexes examined using the method of equimolar ratios resulted in CuR 2 and InR 3 forms of hydrophobic extracting species. A linear correlation was obtained between logarithm of distribution coefficients and chelate agents and pH, respectively. Selectivity is generally higher with higher concentrations of chelate agents in the organic phase, and is decreased with increase of concentration of hydrogen ions in feeding phase. (Original)

  1. Bis[2,6-bis(trimethylsilylaminopyridine-κN1]{[6-bis(trimethylsilylaminopyridin-2-yl-κN1](trimethylsilylazanido-κN}lithium

    Directory of Open Access Journals (Sweden)

    Justin A. Rave

    2016-03-01

    Full Text Available The title complex, [Li(C11H22N3Si2(C11H23N3Si22], contains a single lithium cation coordinated to three ligands. This is the first reported example of the ligand 2,6-bis(trimethylsilylaminopyridine supporting a monometallic complex. One ligand is mono-anionic and forms a four-membered chelate ring with the lithium cation via the pyridine and silylamido N atoms. The other two ligands are neutral and bind via the pyridine nitrogen. The lithium cation is coordinated in a tetrahedral environment. No intra- or intermolecular hydrogen bonding is observed in the crystal structure, likely indicating that weak electrostatic interactions are the dominant feature of the crystal packing.

  2. Polarographic investigation of complexing kinetics of polyacrylate anions with cadmium ions

    International Nuclear Information System (INIS)

    Avlyanov, Zh.K.; Kabanov, N.M.; Zezin, A.B.; Askarov, M.A.

    1990-01-01

    The processes which occur during the reduction of cadmium ions from polymer-metallic complexes (PMC) are studied for the purposes of polarographic investigation of complexing kinetics of polyacrylate anions (PAA) of different molecular masses with cadmium ions in KCl aqueous solutions. An expression is derived for establishing semiwave potential. PMC formation and dissociation reduction rate constants are calculated. It is shown that intramolecular reorderings required for the formation of a two-coordinate complex proceed much slower as compared to the diffusion of free ions

  3. ELECTED PROBLEMS RELATED TO ENVIRONMENTAL HEAVY METALS EXPOSURE AND CHELATION THERAPY

    Directory of Open Access Journals (Sweden)

    Anna Skoczyńska

    2010-09-01

    Full Text Available Background: Exposure to heavy metals leads to functional and metabolic disturbances and many of them are included in pathogenesis of common diseases (arterial hypertension, atherosclerosis, neurodegenerative processes. In this context new therapeutic and prophylactic strategies are necessary. Patients diagnosed with chronic heavy metals intoxication usually require chelation to increase mobilisation of metals from tissues and elimination of them via urine. Acute poisoning with toxic metal may be difficult to diagnosis, especially in case of accidental intoxication or suicidal intention. Patients also require chelation after causative factor is identified. Objectives: To describe some problems connected with toxicity of metals poisoning and to review pharmacologic therapies that could have a role in poisoning with metals. Methods: A review of the literature was carried out and expert opinion expressed. Results/conclusion: Chelation is a common therapy in case of poisoning with toxic metals but it is satisfied only partially. A combined therapy with structurally different chelators or long-term acting chelators could become viable alternatives in the future. A combined therapy with an antioxidant plus chelator may be a good choice in patients chronically poisoned with metals. Exposure to lead should be taken into account during estimation of global cardiovascular risk.

  4. N-acetylcysteine protects rats with chronic renal failure from gadolinium-chelate nephrotoxicity.

    Directory of Open Access Journals (Sweden)

    Leonardo Victor Barbosa Pereira

    Full Text Available The aim of this study was to evaluate the effect of Gd-chelate on renal function, iron parameters and oxidative stress in rats with CRF and a possible protective effect of the antioxidant N-Acetylcysteine (NAC. Male Wistar rats were submitted to 5/6 nephrectomy (Nx to induced CRF. An ionic-cyclic Gd (Gadoterate Meglumine was administrated (1.5 mM/KgBW, intravenously 21 days after Nx. Clearance studies were performed in 4 groups of anesthetized animals 48 hours following Gd- chelate administration: 1--Nx (n = 7; 2--Nx+NAC (n = 6; 3--Nx+Gd (n = 7; 4--Nx+NAC+Gd (4.8 g/L in drinking water, initiated 2 days before Gd-chelate administration and maintained during 4 days (n = 6. This group was compared with a control. We measured glomerular filtration rate, GFR (inulin clearance, ml/min/kg BW, proteinuria (mg/24 hs, serum iron (µg/dL; serum ferritin (ng/mL; transferrin saturation (%, TIBC (µg/dL and TBARS (nmles/ml. Normal rats treated with the same dose of Gd-chelate presented similar GFR and proteinuria when compared with normal controls, indicating that at this dose Gd-chelate is not nephrotoxic to normal rats. Gd-chelate administration to Nx-rats results in a decrease of GFR and increased proteinuria associated with a decrease in TIBC, elevation of ferritin serum levels, transferrin oversaturation and plasmatic TBARS compared with Nx-rats. The prophylactic treatment with NAC reversed the decrease in GFR and the increase in proteinuria and all alterations in iron parameters and TBARS induced by Gd-chelate. NAC administration to Nx rat did not modify the inulin clearance and iron kinetics, indicating that the ameliorating effect of NAC was specific to Gd-chelate. These results suggest that NAC can prevent Gd-chelate nephrotoxicity in patients with chronic renal failure.

  5. EDTA chelation therapy for cardiovascular disease: a systematic review

    Directory of Open Access Journals (Sweden)

    Wu Ping

    2005-11-01

    Full Text Available Abstract Background Numerous practitioners of both conventional and complementary and alternative medicine throughout North America and Europe claim that chelation therapy with EDTA is an effective means to both control and treat cardiovascular disease. These claims are controversial, and several randomized controlled trials have been completed dealing with this topic. To address this issue we conducted a systematic review to evaluate the best available evidence for the use of EDTA chelation therapy in the treatment of cardiovascular disease. Methods We conducted a systematic review of 7 databases from inception to May 2005. Hand searches were conducted in review articles and in any of the trials found. Experts in the field were contacted and registries of clinical trials were searched for unpublished data. To be included in the final systematic review, the studies had to be randomized controlled clinical trials. Results A total of seven articles were found assessing EDTA chelation for the treatment of cardiovascular disease. Two of these articles were subgroup analyses of one RCT that looked at different clinical outcomes. Of the remaining five studies, two smaller studies found a beneficial effect whereas the other three exhibited no benefit for cardiovascular disease from the use of EDTA chelation therapy. Adverse effects were rare but those of note included a few cases of hypocalcemia and a single case of increased creatinine in a patient on the EDTA intervention. Conclusion The best available evidence does not support the therapeutic use of EDTA chelation therapy in the treatment of cardiovascular disease. Although not considered to be a highly invasive or harmful therapy, it is possible that the use of EDTA chelation therapy in lieu of proven therapy may result in causing indirect harm to the patient.

  6. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    Science.gov (United States)

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

  7. Copper chelators: chemical properties and bio-medical applications.

    Science.gov (United States)

    Tegoni, M; Valensin, D; Toso, L; Remelli, M

    2014-01-01

    Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined.

  8. Defects in doped LaGaO3 anionic conductors: linking NMR spectral features, local environments, and defect thermodynamics.

    Science.gov (United States)

    Blanc, Frédéric; Middlemiss, Derek S; Gan, Zhehong; Grey, Clare P

    2011-11-09

    Doped lanthanum gallate perovskites (LaGaO(3)) constitute some of the most promising electrolyte materials for solid oxide fuel cells operating in the intermediate temperature regime. Here, an approach combining experimental multinuclear NMR spectroscopy with density functional theory total energy and GIPAW NMR calculations yields a comprehensive understanding of the structural and defect chemistries of Sr- and Mg-doped LaGaO(3) anionic conductors. The DFT energetics demonstrate that Ga-V(O)-Ga (V(O) = oxygen vacancy) environments are favored (vs Ga-V(O)-Mg, Mg-V(O)-Mg and Mg-O-Mg-V(O)-Ga) across a range y = 0.0625, 0.125, and 0.25 of fractional Mg contents in LaGa(1-y)Mg(y)O(3-y/2). The results are interpreted in terms of doping and mean phase formation energies (relative to binary oxides) and are compared with previous calculations and experimental calorimetry data. Experimental multinuclear NMR data reveal that while Mg sites remain six-fold coordinated across the range of phase stoichiometries, albeit with significant structural disorder, a stoichiometry-dependent minority of the Ga sites resonate at a shift consistent with Ga(V) coordination, demonstrating that O vacancies preferentially locate in the first anion coordination shell of Ga. The strong Mg-V(O) binding inferred by previous studies is not observed here. The (17)O NMR spectra reveal distinct resonances that can be assigned by using the GIPAW NMR calculations to anions occupying equatorial and axial positions with respect to the Ga(V)-V(O) axis. The disparate shifts displayed by these sites are due to the nature and extent of the structural distortions caused by the O vacancies.

  9. Single-molecule magnetism in a single-ion triamidoamine uranium(V) terminal mono-oxo complex

    Energy Technology Data Exchange (ETDEWEB)

    King, David M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [Nottingham Univ. (United Kingdom). School of Chemistry; Tuna, Floriana; McInnes, Eric J.L. [Manchester Univ. (United Kingdom). School of Chemistry

    2013-04-26

    Straightforward oxidation of a triamidoamine uranium(III) complex with trimethyl-N-oxide affords a uranium(V) terminal mono-oxo complex which is the first clear-cut example of a uranium(V) single-molecule magnet (SMM). This monometallic complex unambiguously shows that a strongly axially ligated and thus anisotropic ligand field can be used to overcome the limited magnetic anisotropy of uranium(V). [German] Die direkte Oxidation eines Triamidoamin-Uran(III)-Komplexes mit Trimethyl-N-oxid liefert einen terminalen Uran(V)-Mono(oxo)komplex, der das erste gesicherte Beispiel eines Uran(V)-Einzelmolekuelmagnets ist. Dieser monometallische Komplex zeigt eindeutig, dass ein starkes axiales und somit anisotropes Ligandenfeld die begrenzte magnetische Anisotropie von Uran(V) beseitigen kann.

  10. A review of pitfalls and progress in chelation treatment of metal poisonings.

    Science.gov (United States)

    Andersen, Ole; Aaseth, Jan

    2016-12-01

    Most acute and chronic human metal poisonings are due to oral or inhalation exposure. Almost 80% of published animal experiments on chelation in metal poisoning used single or repeated intraperitoneal, intramuscular or intravenous administration of metal and chelator, impeding extrapolation to clinical settings. Intramuscular administration of dimercaptopropanol (BAL) has until now been used in acute arsenic, lead, and mercury poisonings, but repeated BAL administration increased the brain uptake of As, Pb and Hg in experimental animals. Also, diethyl dithiocarbamate (DDC) has been used as antidote in acute experimental animal parenteral Cd poisoning, and both DDC and tetraethylthiuram disulfide (TTD, disulfiram, Antabuse) have been used in nickel allergic patients. However, even one dose of DDC given immediately after oral Cd or Ni increased their brain uptake considerably. The calcium salt of ethylenediamminetetraacetic acid (CaEDTA) but not dimercaptosuccinic acid (DMSA) increased the brain uptake of Pb. In oral Cd or Hg poisoning, early oral administration of DMSA or dimercaptopropane sulfonate (DMPS) increased survival and reduced intestinal metal uptake. Oral administration of Prussian Blue or resins with fixed chelating groups that are not absorbed offer chelation approaches for decorporation after oral exposure to various metals. Diethylenetriaminepentaacetic acid (DTPA) nebulizers for pulmonary chelation after inhalation exposure need further development. Also, combined chelation with more than one compound may offer extensive advances. Solid knowledge on the chemistry of metal chelates together with relevant animal experiments should guide development of chelation procedures to alleviate and not aggravate the clinical status of poisoned patients. Copyright © 2016 Elsevier GmbH. All rights reserved.

  11. Selective separation of uranium using alizarin red S (ARS)-modified anion-exchange resin or by flotation of U-ARS chelate

    International Nuclear Information System (INIS)

    Khalifa, M.E.

    1998-01-01

    An alizarin red S (ARS)-modified anion exchange resin was prepared by a simple reaction of ARS with the anion exchange Doulite A101 and used for the efficient sorption of uranium from aqueous media. The effect of various parameters on the sorption of U(VI) (pH effect, sorption kinetics, resin capacity and breakthrough curves) was investigated. The modified resin sorbs U(VI) over a wide range of pH (2.8--5) with a maximum sorption capacity of 0.68 mmol/g at pH 3.2 to 4.0. Iron(III), Zr(IV), Ti(IV), Cu(II), and Th(IV) ions are also sorbed to different extents, but Be(II), Bi(III), Ca(II), Mg(II), Pb(II), Hg(II), Zn(II), Cd(II), Al(III), Mn(II), Co(II) and Ni(II) are not sorbed; thus, conditions for separating U(VI) from these metal ions have been identified. For eluting U(VI) from the resin, 0.2 mol/L HCl was used and the recovery recorded was as high as 99.9%. The use of ARS is extended to float uranium quantitatively and selectively from aqueous media at pH ∼ 4 by using oleic acid as a surfactant. The different parameters affecting the flotation process have also been investigated. Uranium(VI) has been effectively separated from natural water samples and certified uranium ores using both procedures

  12. Transition metal coordination chemistry ofN,N-bis(2-{pyrid-2-ylethyl})hydroxylamine.

    Science.gov (United States)

    Belock, Christopher W; Cetin, Anil; Barone, Natalie V; Ziegler, Christopher J

    2008-08-18

    Although directly relevant to metal mediated biological nitrification as well as the coordination chemistry of peroxide, the metal complexes of hydroxylamines and their functionalized variants remain largely unexplored. The chelating hydroxylamine ligand N,N-bis(2-{pyrid-2-ylethyl})hydroxylamine can be readily generated via a solvent free reaction in high purity; however, the ligand is prone to decomposition which can hamper metal reaction. N,N-bis(2-{pyrid-2-ylethyl})hydroxylamine forms stable complexes with chromium(III), manganese(II), nickel(II), and cadmium(II) ions, coordinating in a side-on mode in the case of chromium and via the nitrogen in the case of the latter three metal ions. The hydroxylamine ligand can also be reduced to form N,N-bis(2-{pyrid-2-ylethyl})amine upon exposure to a stoichiometric amount of the metal salts cobalt(II) nitrate, vanadium(III) chloride, and iron(II) chloride. In the reaction with cobalt nitrate, the reduced ligand then chelates to the metal to form [N,N-bis(2-{pyrid-2-ylethyl})amine]dinitrocobalt(II). Upon reaction with vanadium(III) chloride and iron(III) chloride, the reduced ligand is isolated as the protonated free base, resulting from a metal-mediated decomposition reaction.

  13. Ruthenium(II) 2,2'-bibenzimidazole complex as a second-sphere receptor for anions interaction and colorimeter.

    Science.gov (United States)

    Cui, Ying; Niu, Yan-Li; Cao, Man-Li; Wang, Ke; Mo, Hao-Jun; Zhong, Yong-Rui; Ye, Bao-Hui

    2008-07-07

    A ruthenium(II) complex [Ru(bpy) 2(H 2bbim)](PF 6) 2 ( 1) as anions receptor has been exploited, where Ru(II)-bpy moiety acts as a chromophore and the H 2bbim ligand as an anion binding site. A systematic study suggests that 1 interacts with the Cl (-), Br (-), I (-), NO 3 (-), HSO 4 (-), and H 2PO 4 (-) anions via the formation of hydrogen bonds. Whereas 1 undergoes a stepwise process with the addition of F (-) and OAc (-) anions: formation of the monodeprotonated complex [Ru(bpy) 2(Hbbim)] with a low anion concentration, followed by the double-deprotonated complex [Ru(bpy) 2(bbim)], in the presence of a high anion concentration. These stepwise processes concomitant with the changes of vivid colors from yellow to orange brown and then to violet can be used for probing the F (-) and OAc (-) anions by naked eye. The deprotonation processes are not only determined by the basicity of the anion but also related to the strength of hydrogen bonding, as well as the stability of the formed compounds. Moreover, a double-deprotonated complex [Ru(bpy) 2(bbim)].CH 3OH.H 2O ( 3) has been synthesized, and the structural changes induced by the deprotonation has also been investigated. In addition, complexes [Ru(bpy) 2(Hbbim)] 2(HOAc) 3Cl 2.12H 2O ( 2), [Ru(bpy) 2(Hbbim)](HCCl 3CO 2)(CCl 3CO 2).2H 2O ( 4), and [Ru(bpy) 2(H 2bbim)](CF 3CO 2) 2.4H 2O ( 5) have been synthesized to observe the second sphere coordination between the Ru(II)-H 2bbim moiety and carboxylate groups via hydrogen bonds in the solid state.

  14. Determination of the pKa value of the hydroxyl group in the alpha-hydroxycarboxylates citrate, malate and lactate by 13C NMR: implications for metal coordination in biological systems.

    Science.gov (United States)

    Silva, Andre M N; Kong, XiaoLe; Hider, Robert C

    2009-10-01

    Citric acid is an important metal chelator of biological relevance. Citric acid helps solubilizing metals, increasing their bioavailability for plants and microbes and it is also thought to be a constituent of both the extracellular and cytoplasmic low molecular iron pools occurring in plants and vertebrates. Metal coordination by citric acid involves coordination both by the carboxylate and hydroxyl groups, of particular interest is its alpha-hydroxycarboxylate function. This structural feature is highly conserved in siderophores produced by evolutionarily distant species and seems to confer specificity toward Fe(III) binding. In order to understand the mechanism of metal coordination by alpha-hydroxycarboxylates and correctly evaluate the respective complex stability constants, it is essential to improve the knowledge about the ionisation of the alcohol group in these compounds. We have evaluated the hydroxyl pKa value of citric, malic and lactic acids with the objective of understanding the influence of alpha-carbon substitution. Studies at high pH values, utilizing (13)C NMR, permitted estimation of the pKa values for the three acids. The pKa (alcohol) values (14.4 for citric acid, 14.5 for malic acid, and 15.1 for lactic acid) are considerably higher than the previously reported value for citric acid (11.6) but still lower than the value of 15.5 for methanol. A comparative analysis of the three compounds indicates that different substitutions on the alpha-carbon introduce changes to the inductive effect experienced by the hydroxyl group thereby modulating its ionisation behaviour. Comparison with the siderophore rhizoferrin, which pKa (alcohol) values were confirmed to be 10 and 11.3, suggests that intra-molecular hydrogen bonding may also aid in the hydroxyl ionisation by stabilizing the resulting anion. Studies of metal coordination by alpha-hydroxycarboxylates should take these factors into account.

  15. Metabolic characteristics of 13-cis-retinoic acid (isotretinoin) and anti-tumour activity of the 13-cis-retinoic acid metabolite 4-oxo-13-cis-retinoic acid in neuroblastoma.

    Science.gov (United States)

    Sonawane, Poonam; Cho, Hwang Eui; Tagde, Ashujit; Verlekar, Dattesh; Yu, Alice L; Reynolds, C Patrick; Kang, Min H

    2014-12-01

    Isotretinoin (13-cis-retinoic acid; 13-cRA) is a differentiation inducer used to treat minimal residual disease after myeloablative therapy for high-risk neuroblastoma. However, more than 40% of children develop recurrent disease during or after 13-cRA treatment. The plasma concentrations of 13-cRA in earlier studies were considered subtherapeutic while 4-oxo-13-cis-RA (4-oxo-13-cRA), a metabolite of 13-cRA considered by some investigators as inactive, were greater than threefold higher than 13-cRA. We sought to define the metabolic pathways of 13-cRA and investigated the anti-tumour activity of its major metabolite, 4-oxo-13-cRA. Effects of 13-cRA and 4-oxo-13-cRA on human neuroblastoma cell lines were assessed by DIMSCAN and flow cytometry for cell proliferation, MYCN down-regulation by reverse transcription PCR and immunoblotting, and neurite outgrowth by confocal microscopy. 13-cRA metabolism was determined using tandem MS in human liver microsomes and in patient samples. Six major metabolites of 13-cRA were identified in patient samples. Of these, 4-oxo-13-cRA was the most abundant, and 4-oxo-13-cRA glucuronide was also detected at a higher level in patients. CYP3A4 was shown to play a major role in catalysing 13-cRA to 4-oxo-13-cRA. In human neuroblastoma cell lines, 4-oxo-13-cRA and 13-cRA were equi-effective at inducing neurite outgrowth, inhibiting proliferation, decreasing MYCN mRNA and protein, and increasing the expression of retinoic acid receptor-β mRNA and protein levels. We showed that 4-oxo-13-cRA is as active as 13-cRA against neuroblastoma cell lines. Plasma levels of both 13-cRA and 4-oxo-13-cRA should be evaluated in pharmacokinetic studies of isotretinoin in neuroblastoma. © 2014 The British Pharmacological Society.

  16. C{sub 60}{sup 3-} versus C{sub 60}{sup 4-} /C{sub 60}{sup 2-} - synthesis and characterization of five salts containing discrete fullerene anions

    Energy Technology Data Exchange (ETDEWEB)

    Boeddinghaus, M. Bele; Klein, Wilhelm; Wahl, Bernhard; Faessler, Thomas F. [Department of Chemistry, Technische Universitaet Muenchen, Garching (Germany); Jakes, Peter; Eichel, Ruediger A. [Institut fuer Energie- und Klimaforschung (IEK-9), Forschungszentrum Juelich (Germany)

    2014-04-15

    Five new compounds, [Rb(18crown-6)]{sub 3}[C{sub 60}] (1), [Rb(18crown-6)]{sub 6}[C{sub 60}]{sub 2}(C{sub 3}H{sub 7}NO){sub 2}(C{sub 4}H{sub 8}O){sub 2} (2), [Rb(benzo18crown-6)]{sub 6}[C{sub 60}]{sub 2}(C{sub 2}H{sub 8}N{sub 2}){sub 5} (3), [Cs(benzo18crown-6)]{sub 3}C{sub 60}(C{sub 2}H{sub 8}N{sub 2}){sub 2} (4), and [Cs{sub 3}(benzo18crown-6){sub 5}]C{sub 60}(C{sub 2}H{sub 8}N{sub 2}){sub (4.5+x)} (5) were synthesized and characterized by single-crystal X-ray structure determination. All compounds contain discrete C{sub 60} anions, which are ordered in 1, 2, and 4, where direct cation-anion contacts occur. The unit cells of 1 and 2 contain two independent fullerides, which coordinate to the rubidium atoms either of two or of four [Rb(18crown-6)] units. Owing to the presence of differently coordinated fullerene units in compounds 1 and 2, a possible disproportionation of C{sub 60}{sup 3-} into C{sub 60}{sup 2-} and C{sub 60}{sup 4-} anions is discussed. In 3 and 4 the C{sub 60} anions are coordinated by three Rb and Cs atoms, respectively. In all compounds the average charge of the anion is -3. Magnetic data reveal a doublet spin state for 3. The EPR spectra are discussed for compounds 3 and 5. The role of a dynamic Jahn-Teller distortion is discussed, and we report the first IR spectroscopic data of fullerene trianions, which have been obtained in solution. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Interaction of chelating agents with cadmium in mice and rats.

    Science.gov (United States)

    Eybl, V; Sýkora, J; Koutenský, J; Caisová, D; Schwartz, A; Mertl, F

    1984-01-01

    The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl2 and on the whole body retention and tissue distribution of cadmium after the IV application of 115mCdCl2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatment of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination of the retention and distribution of Cd in mice, it was demonstrated that the combined application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of 115mCd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes. PMID:6734561

  18. Crystal structure and thermochemical properties of a novel coordination compound sodium pyruvate C3H3O3Na(s)

    International Nuclear Information System (INIS)

    Gao, Zhen-Fei; Di, You-Ying; Liu, Su-Zhou; Lu, Dong-Fei; Dou, Jian-Min

    2014-01-01

    Graphical abstract: A novel coordination compound sodium pyruvate C 3 H 3 O 3 Na(s) is synthesised. Elemental analysis and X-ray crystallography are used to characterise the composition and crystal structure of the compound. The lattice potential energy and ionic volume of the anion are obtained from crystallographic data. The standard molar enthalpy of formation of the compound is calculated by an isoperibol solution-reaction calorimeter. Molar enthalpies of dissolution of the compound at various molalities are measured at T = 298.15 K. According to Pitzer’s theory, molar enthalpy of dissolution of the title compound at infinite dilution is calculated. The values of relative apparent molar enthalpies and relative partial molar enthalpies of the solvent and the compound at different concentrations m/(mol · kg −1 ) are derived. - Highlights: • The sodium pyruvate was synthesised and crystal structure was determined. • The enthalpy change of the synthesis reaction was obtained. • Standard molar enthalpy of formation was obtained. • Molar enthalpy of dissolution at infinite dilution was calculated. - Abstract: A novel coordination compound sodium pyruvate C 3 H 3 O 3 Na(s) is synthesised by a liquid phase reaction. The compound has an obvious bioactivity and can be used as the biological carbon source and the chemical identification of primary and secondary alcohols. It can be also used to determinate transaminase. Elemental analysis and X-ray crystallography are used to characterise the composition and crystal structure of the compound. Single crystal X-ray analysis reveals that the compound is formed by one CH 3 COCOO − anion and one Na + cation. An obvious feature of the crystal structure is the formation of the five-membered chelate ring by the coordination of O1 of carboxylate and O3 of keto form with Na + cation, and it is good for the stability of the compound in structure. The lattice potential energy and ionic volume of the anion are obtained

  19. The Recently Identified Isoleucine Conjugate of cis-12-Oxo-Phytodienoic Acid Is Partially Active in cis-12-Oxo-Phytodienoic Acid-Specific Gene Expression of Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Arnold, M.D.; Gruber, C.; Floková, Kristýna; Miersch, Otto; Strnad, Miroslav; Novák, Ondřej; Wasternack, Claus; Hause, B.

    2016-01-01

    Roč. 11, č. 9 (2016), e0162829 E-ISSN 1932-6203 R&D Projects: GA ČR GA14-34792S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : ALLENE-OXIDE-CYCLASE * 12-OXO-PHYTODIENOIC ACID * JASMONIC ACID Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.806, year: 2016

  20. Methylene-bis[(aminomethyl)phosphinic acids]: synthesis, acid-base and coordination properties.

    Science.gov (United States)

    David, Tomáš; Procházková, Soňa; Havlíčková, Jana; Kotek, Jan; Kubíček, Vojtěch; Hermann, Petr; Lukeš, Ivan

    2013-02-21

    Three symmetrical methylene-bis[(aminomethyl)phosphinic acids] bearing different substituents on the central carbon atom, (NH(2)CH(2))PO(2)H-C(R(1))(R(2))-PO(2)H(CH(2)NH(2)) where R(1) = OH, R(2) = Me (H(2)L(1)), R(1) = OH, R(2) = Ph (H(2)L(2)) and R(1),R(2) = H (H(2)L(3)), were synthesized. Acid-base and complexing properties of the ligands were studied in solution as well as in the solid state. The ligands show unusually high basicity of the nitrogen atoms (log K(1) = 9.5-10, log K(2) = 8.5-9) if compared with simple (aminomethyl)phosphinic acids and, consequently, high stability constants of the complexes with studied divalent metal ions. The study showed the important role of the hydroxo group attached to the central carbon atom of the geminal bis(phosphinate) moiety. Deprotonation of the hydroxo group yields the alcoholate anion which tends to play the role of a bridging ligand and induces formation of polynuclear complexes. Solid-state structures of complexes [H(2)N=C(NH(2))(2)][Cu(2)(H(-1)L(2))(2)]CO(3)·10H(2)O and Li(2)[Co(4)(H(-1)L(1))(3)(OH)]·17.5H(2)O were determined by X-ray diffraction. The complexes show unexpected geometries forming dinuclear and cubane-like structures, respectively. The dinuclear copper(II) complex contains a bridging μ(2)-alcoholate group with the (-)O-P(=O)-CH(2)-NH(2) fragments of each ligand molecule chelated to the different central ion. In the cubane cobalt(II) complex, one μ(3)-hydroxide and three μ(3)-alcoholate anions are located in the cube vertices and both phosphinate groups of one ligand molecule are chelating the same cobalt(II) ion while each of its amino groups are bound to different neighbouring metal ions. All such three metal ions are bridged by the alcoholate group of a given ligand.

  1. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    OpenAIRE

    Liren Fan; Jiqing Song; Wenbo Bai; Shengping Wang; Ming Zeng; Xiaoming Li; Yang Zhou; Haifeng Li; Haiwei Lu

    2016-01-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shel...

  2. Femtomolar Ln(III) affinity in peptide-based ligands containing unnatural chelating amino acids.

    Science.gov (United States)

    Niedźwiecka, Agnieszka; Cisnetti, Federico; Lebrun, Colette; Delangle, Pascale

    2012-05-07

    The incorporation of unnatural chelating amino acids in short peptide sequences leads to lanthanide-binding peptides with a higher stability than sequences built exclusively from natural residues. In particular, the hexadentate peptide P(22), which incorporates two unnatural amino acids Ada(2) with aminodiacetate chelating arms, showed picomolar affinity for Tb(3+). To design peptides with higher denticity, expected to show higher affinity for Ln(3+), we synthesized the novel unnatural amino acid Ed3a(2) which carries an ethylenediamine triacetate side-chain and affords a pentadentate coordination site. The synthesis of the derivative Fmoc-Ed3a(2)(tBu)(3)-OH, with appropriate protecting groups for direct use in the solid phase peptide synthesis (Fmoc strategy), is described. The two high denticity peptides P(HD2) (Ac-Trp-Ed3a(2)-Pro-Gly-Ada(2)-Gly-NH(2)) and P(HD5) (Ac-Trp-Ada(2)-Pro-Gly-Ed3a(2)-Gly-NH(2)) led to octadentate Tb(3+) complexes with femtomolar stability in water. The position of the high denticity amino acid Ed3a(2) in the hexapeptide sequence appears to be critical for the control of the metal complex speciation. Whereas P(HD5) promotes the formation of polymetallic species in excess of Ln(3+), P(HD2) forms exclusively the mononuclear complex. The octadentate coordination of Tb(3+) by both P(HD) leads to total dehydration of the metal ion in the mononuclear complexes with long luminescence lifetimes (>2 ms). Hence, we demonstrated that unnatural amino acids carrying polyaminocarboxylate side-chains are interesting building blocks to design high affinity Ln-binding peptides. In particular the novel peptide P(HD2) forms a unique octadentate Tb(3+) complex with femtomolar stability in water and an improvement of the luminescence properties with respect to the trisaquo TbP(22) complex by a factor of 4.

  3. Single-Crystal-to-Single-Crystal Anion Exchange in a Gadolinium MOF: Incorporation of POMs and [AuCl4]−

    Directory of Open Access Journals (Sweden)

    Javier López-Cabrelles

    2016-04-01

    Full Text Available The encapsulation of functional molecules inside porous coordination polymers (also known as metal-organic frameworks, MOFs has become of great interest in recent years at the field of multifunctional materials. In this article, we present a study of the effects of size and charge in the anion exchange process of a Gd based MOF, involving molecular species like polyoxometalates (POMs, and [AuCl4]−. This post-synthetic modification has been characterized by IR, EDAX, and single crystal diffraction, which have provided unequivocal evidence of the location of the anion molecules in the framework.

  4. Plutonium(IV) complexation by diglycolamide ligands - coordination chemistry insight into TODGA-based actinide separations

    NARCIS (Netherlands)

    Reilly, S.D.; Gaunt, A.J.; Scott, B.L.; Modolo, G.; Iqbal, M.; Verboom, Willem; Sarsfield, M.J.

    2012-01-01

    Complexation of Pu(IV) with TMDGA, TEDGA, and TODGA diglycolamide ligands was followed by vis-NIR spectroscopy. A crystal structure determination reveals that TMDGA forms a 1:3 homoleptic Pu(IV) complex with the nitrate anions forced into the outer coordination sphere

  5. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Together with hydrotalcite-like layered double hydroxides, bivalent and trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange ...

  6. Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants.

    Science.gov (United States)

    Grimes, Travis S; Heathman, Colt R; Jansone-Popova, Santa; Ivanov, Alexander S; Roy, Santanu; Bryantsev, Vyacheslav S; Zalupski, Peter R

    2018-02-05

    The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am 3+ , Cm 3+ , and Ln 3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL (aq) complexes at the same aqueous acidity. The denticity change observed for Eu 3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL (aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am 3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am 3+ , Cm 3+ ) and trivalent lanthanide chelates (La 3+ -Lu 3+ ) are observed in liquid-liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by

  7. Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

    Science.gov (United States)

    Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

    2016-10-01

    Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  8. Bis(μ-2-methylquinolin-8-olato-κ3N,O:O;κ3O:N,O-bis[(methanol-κO(nitrato-κ2O,O′lead(II

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available The molecule of the title compound, [Pb2(C10H8NO2(NO32(CH3OH2], lies about a centre of inversion. The Pb atom is chelated by nitrate and substituted quinolin-8-olate anions. The O atom of the quinolin-8-olate also bridges, to confer a six-coordinate status on the metal centre. When a longer Pb...O interaction is considered, the geometry approximates a Ψ-cube in which one of the sites is occupied by a stereochemically active lone pair.

  9. Click-to-Chelate: Development of Technetium and Rhenium-Tricarbonyl Labeled Radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Thomas L. Mindt

    2013-03-01

    Full Text Available The Click-to-Chelate approach is a highly efficient strategy for the radiolabeling of molecules of medicinal interest with technetium and rhenium-tricarbonyl cores. Reaction of azide-functionalized molecules with alkyne prochelators by the Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC; click reaction enables the simultaneous synthesis and conjugation of tridentate chelating systems for the stable complexation of the radiometals. In many cases, the functionalization of (biomolecules with the ligand system and radiolabeling can be achieved by convenient one-pot procedures. Since its first report in 2006, Click-to-Chelate has been applied to the development of numerous novel radiotracers with promising potential for translation into the clinic. This review summarizes the use of the Click-to-Chelate approach in radiopharmaceutical sciences and provides a perspective for future applications.

  10. Measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-guanosine in cerebrospinal fluid by ultra performance liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Weimann, Allan; Simonsen, Anja Hviid; Poulsen, Henrik E

    2018-01-01

    absolute concentrations varying by a factor >105 in healthy humans. This could indicate that there is a serious specificity problem in some of the methods. In this paper an isotope-dilution UPLC-MS/MS method with high specificity and sensitivity for the quantification of 8oxoGuo and 8oxodGuo in CSF...

  11. Expanding the Therapeutic Potential of the Iron Chelator Deferasirox in the Development of Aqueous Stable Ti(IV) Anticancer Complexes.

    Science.gov (United States)

    Loza-Rosas, Sergio A; Vázquez-Salgado, Alexandra M; Rivero, Kennett I; Negrón, Lenny J; Delgado, Yamixa; Benjamín-Rivera, Josué A; Vázquez-Maldonado, Angel L; Parks, Timothy B; Munet-Colón, Charlene; Tinoco, Arthur D

    2017-07-17

    The recent X-ray structure of titanium(IV)-bound human serum transferrin (STf) exhibiting citrate as a synergistic anion reveals a difference in Ti(IV) coordination versus iron(III), the metal endogenously delivered by the protein to cells. This finding enriches our bioinspired drug design strategy for Ti(IV)-based anticancer therapeutics, which applies a family of Fe(III) chelators termed chemical transferrin mimetic (cTfm) ligands to inhibit Fe bioavailability in cancer cells. Deferasirox, a drug used for iron overload disease, is a cTfm ligand that models STf coordination to Fe(III), favoring Fe(III) binding versus Ti(IV). This metal affinity preference drives deferasirox to facilitate the release of cytotoxic Ti(IV) intracellularly in exchange for Fe(III). An aqueous speciation study performed by potentiometric titration from pH 4 to 8 with micromolar levels of Ti(IV) deferasirox at a 1:2 ratio reveals exclusively Ti(deferasirox) 2 in solution. The predominant complex at pH 7.4, [Ti(deferasirox) 2 ] 2- , exhibits the one of the highest aqueous stabilities observed for a potent cytotoxic Ti(IV) species, demonstrating little dissociation even after 1 month in cell culture media. UV-vis and 1 H NMR studies show that the stability is unaffected by the presence of biomolecular Ti(IV) binders such as citrate, STf, and albumin, which have been shown to induce dissociation or regulate cellular uptake and can alter the activity of other antiproliferative Ti(IV) complexes. Kinetic studies on [Ti(deferasirox) 2 ] 2- transmetalation with Fe(III) show that a labile Fe(III) source is required to induce this process. The initial step of this process occurs on the time scale of minutes, and equilibrium for the complete transmetalation is reached on a time scale of hours to a day. This work reveals a mechanism to deliver Ti(IV) compounds into cells and trigger Ti(IV) release by a labile Fe(III) species. Cellular studies including other cTfm ligands confirm the Fe(III) depletion

  12. Supramolecular Chemistry of Environmentally Relevant Anions

    International Nuclear Information System (INIS)

    Bowman-James, Kristin; Moyer, B.A.; Sessler, Jonathan L.

    2003-01-01

    The goal of this project is the development of highly selective extractants for anions targeting important and timely problems of critical interest to the EMSP mission. In particular, sulfate poses a special problem in cleaning up the Hanford waste tanks in that it interferes with vitrification, but available technologies for sulfate removal are limited. The basic chemical aspects of anion receptor design of functional pH independent systems as well as design of separations strategies for selective and efficient removal of targeted anions have been probed. Key findings include: (1) some of the first synthetic sulfate-selective anion-binding agents; (2) simple, structure-based methods for modifying the intrinsic anion selectivity of a given class of anion receptors; and (3) the first system capable of extracting sulfate from acidic, nitrate-containing aqueous media. Receptor design, structural influences on anion binding affinities, and findings from liquid-liquid extraction studies will be discussed

  13. Protracted chelate therapy after incorporation of plutonium 239 in rats

    International Nuclear Information System (INIS)

    Gemenetzis, E.

    1976-01-01

    The author has tested in how far 239 Pu can be mobilized by Ca and Zn, Desfenioxamin B(DFDA) and by combined doses of Ca-DTPA and DFDA. The pre-experiment covered the 239 Pu-metabolism in untreated male and female rats and the distribution in dependence of the way of application. If treatment is started immediately by multiple chelate doses, the first two injections play the main part in the decorporation of 239 Pu. The combination Ca-DTPA30 + DFDA30 μMol x kg -1 is proved to be the best means of decorporation for the whole body. The efficiency of another therapy depends essentially on the treatment used, a daily treatment showing the best effects. If treatment is started later with multiple chelate doses, the total decorporation efficiency is of less value, especially in the skeleton. Aequimolar doses of Ca-DTPA and Zn-DTPA have the same degree of efficiency. This indicates that during protracted chelate treatment starting later, Ca-DTPA could be substituted by the less toxic Zn-DTPA after incorporation of 239 Pu. These results show that intermittant administration of the week's dose is more efficient than a single chelate administration of the whole week's dose at once. Permanent chelate infusion does not seem necessary in any case since it has the same effect as 3 to 5 injections per week and is difficult to carry out in medical practice. Thus, it seems advisable to divide up the weekly dose into 3-5 injections. In case of a wound contamination, the efficiency of immediate intensive treatment depends on the 239 Pu compound used, on the chelate used, and on its dosage. (orig.) [de

  14. Hydration of a Large Anionic Charge Distribution - Naphthalene-Water Cluster Anions

    Science.gov (United States)

    Weber, J. Mathias; Adams, Christopher L.

    2010-06-01

    We report the infrared spectra of anionic clusters of naphthalene with up to three water molecules. Comparison of the experimental infrared spectra with theoretically predicted spectra from quantum chemistry calculations allow conclusions regarding the structures of the clusters under study. The first water molecule forms two hydrogen bonds with the π electron system of the naphthalene moiety. Subsequent water ligands interact with both the naphthalene and the other water ligands to form hydrogen bonded networks, similar to other hydrated anion clusters. Naphthalene-water anion clusters illustrate how water interacts with negative charge delocalized over a large π electron system. The clusters are interesting model systems that are discussed in the context of wetting of graphene surfaces and polyaromatic hydrocarbons.

  15. Archetypes for actinide-specific chelating agents

    International Nuclear Information System (INIS)

    Smith, W.L.

    1980-01-01

    The complexes of uranium and thorium with monomeric hydroxamic acids can serve as archetypes for an optimized macrochelate designed for tetravalent actinides. The eight-coordinate complexes, Th(i-PrN(O)C(O)R) 4 , where R = tert-butyl or R = neopentyl, have been synthesized and their structures have been determined by x-ray diffraction. The bulky alkyl substituents impart remarkable volatility and hydrocarbon solubility to these complexes, and the steric interactions of these substituents largely determine the structures. When R = tert-butyl, the substituents occupy the corners of a tetrahedron and force the complex into a distorted cubic geometry with crystallographic S 4 symmetry. Insertion of a methylene group between the carbonyl carbon and the tert-butyl group relaxes the steric requirements, and the coordination polyhedron of the neopentyl derivative is close to the mmmm isomer of the trigonal-faced dodecahedron. Uranium tetrachloride was quantitatively oxidized via an oxygen transfer reaction with two equivalents of N-phenylbenzohydroxamic acid anion (PBHA) in tetrahydrofuran (THF) to form UO 2 Cl(PBHA)(THF) 2 and benzanilide. The structure of the uranyl complex has been determined from x-ray diffraction data; the linear uranyl ion is surrounded by a planar pentagonal array composed of two hydroxamate oxygen atoms, a chloride ion and two THF oxygens, such that the chloride ion is opposite the hydroxamate group. That the THF and phenyl rings are twisted from this equatorial plane limits the molecular geometry to that of the C 1 point group. Some aspects of the chemistry of hydroxamic acids and of their incorporation into molecules that may serve as precursors of tetravalent actinide specific sequestering agents have also been investigated

  16. Unusual saccharin-N,O (carbonyl) coordination in mixed-ligand copper(II) complexes: Synthesis, X-ray crystallography and biological activity

    Science.gov (United States)

    Mokhtaruddin, Nur Shuhada Mohd; Yusof, Enis Nadia Md; Ravoof, Thahira B. S. A.; Tiekink, Edward R. T.; Veerakumarasivam, Abhi; Tahir, Mohamed Ibrahim Mohamed

    2017-07-01

    Three tridentate Schiff bases containing N and S donor atoms were synthesized via the condensation reaction between S-2-methylbenzyldithiocarbazate with 2-acetyl-4-methylpyridine (S2APH); 4-methyl-3-thiosemicarbazide with 2-acetylpyridine (MT2APH) and 4-ethyl-3-thiosemicarbazide with 2-acetylpyridine (ET2APH). Three new, binuclear and mixed-ligand copper(II) complexes with the general formula, [Cu(sac)(L)]2 (sac = saccharinate anion; L = anion of the Schiff base) were then synthesized, and subsequently characterized by IR and UV/Vis spectroscopy as well as by molar conductivity and magnetic susceptibility measurements. The Schiff bases were also spectroscopically characterized using NMR and MS to further confirm their structures. The spectroscopic data indicated that the Schiff bases behaved as a tridentate NNS donor ligands coordinating via the pyridyl-nitrogen, azomethine-nitrogen and thiolate-sulphur atoms. Magnetic data indicated a square pyramidal environment for the complexes and the conductivity values showed that the complexes were essentially non-electrolytes in DMSO. The X-ray crystallographic analysis of one complex, [Cu(sac)(S2AP)]2 showed that the Cu(II) atom was coordinated to the thiolate-S, azomethine-N and pyridyl-N donors of the S2AP Schiff base and to the saccharinate-N from one anion, as well as to the carbonyl-O atom from a symmetry related saccharinate anion yielding a centrosymmetric binuclear complex with a penta-coordinate, square pyramidal geometry. All the copper(II) saccharinate complexes were found to display strong cytotoxic activity against the MCF-7 and MDA-MB-231 human breast cancer cell lines.

  17. Multinary lithium (oxo)nitridosilicates. Syntheses, structures and their materials properties

    International Nuclear Information System (INIS)

    Horky, Katrin

    2017-01-01

    The objective of this thesis was the synthesis, identification and characterization of novel lithium(oxo)nitridosilicates in order to investigate as well as to expand the materials properties of this compound class. Therefore, different synthesis strategies were carried out. Crystal structure elucidation with single-crystal X-ray diffraction was carried out on new compounds. Moreover, investigations of physical properties like luminescence and lithium ion conductivity were performed.

  18. Multinary lithium (oxo)nitridosilicates. Syntheses, structures and their materials properties

    Energy Technology Data Exchange (ETDEWEB)

    Horky, Katrin

    2017-11-06

    The objective of this thesis was the synthesis, identification and characterization of novel lithium(oxo)nitridosilicates in order to investigate as well as to expand the materials properties of this compound class. Therefore, different synthesis strategies were carried out. Crystal structure elucidation with single-crystal X-ray diffraction was carried out on new compounds. Moreover, investigations of physical properties like luminescence and lithium ion conductivity were performed.

  19. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    International Nuclear Information System (INIS)

    Bowman-James, K.; Wilson, G.; Moyer, B. A.

    2004-01-01

    This project involves the design and synthesis of receptors for oxoanions of environmental importance, including emphasis on high level and low activity waste. Target anions have included primarily oxoanions and a study of the basic concepts behind selective binding of target anions. A primary target has been sulfate because of its deleterious influence on the vitrification of tank wastes

  20. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    Science.gov (United States)

    Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

    2016-02-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed.

  1. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    Science.gov (United States)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  2. Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil.

    Science.gov (United States)

    Cantera, Rodrigo G; Zamarreño, Angel M; García-Mina, José M

    2002-12-18

    Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.

  3. Synthesis, screening and QSAR studies of 3-benzoyl-2-oxo/thioxo-1 ...

    African Journals Online (AJOL)

    5-Acyl-6-methyl-4-substituted-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidines (A) were synthesized by cyclocondensation reaction between appropriate aldehyde, acetoacetate and urea/thiourea in presence of aluminium chloride and hydrochloric acid which upon treatment with benzoyl chloride in presence of pyridine in ...

  4. Chelation therapy and cardiovascular disease: connecting scientific silos to benefit cardiac patients.

    Science.gov (United States)

    Peguero, Julio G; Arenas, Ivan; Lamas, Gervasio A

    2014-08-01

    Medical practitioners have treated atherosclerotic disease with chelation therapy for over 50 years. Lack of strong of evidence led conventional practitioners to abandon its use in the 1960s and 1970s. This relegated chelation therapy to complementary and alternative medicine practitioners, who reported good anecdotal results. Concurrently, the epidemiologic evidence linking xenobiotic metals with cardiovascular disease and mortality gradually accumulated, suggesting a plausible role for chelation therapy. On the basis of the continued use of chelation therapy without an evidence base, the National Institutes of Health released a Request for Applications for a definitive trial of chelation therapy. The Trial to Assess Chelation Therapy (TACT) was formulated as a 2 × 2 factorial randomized controlled trial of intravenous EDTA-based chelation vs. placebo and high-dose oral multivitamins and multiminerals vs. oral placebo. The composite primary endpoint was death, reinfarction, stroke, coronary revascularization, or hospitalization for angina. A total of 1708 post-MI patients who were 50 years or older with a creatinine of 2.0 or less were enrolled and received 55,222 infusions of disodium EDTA or placebo with a median follow-up of 55 months. Patients were on evidence-based post-MI medications including statins. EDTA proved to be safe. EDTA chelation therapy reduced cardiovascular events by 18%, with a 5-year number needed to treat (NNT) of 18. Prespecified subgroup analysis revealed a robust benefit in patients with diabetes mellitus with a 41% reduction in the primary endpoint (5-year NNT = 6.5), and a 43% 5-year relative risk reduction in all-cause mortality (5-year NNT = 12). The magnitude of benefit is such that it suggests urgency in replication and implementation, which could, due to the excellent safety record, occur simultaneously. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. The preparation and characterization of novel human-like collagen metal chelates

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chenhui; Sun, Yan [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China); Wang, Yaoyu [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Xi' an 710069 (China); Luo, Yane, E-mail: luoyane@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China)

    2013-07-01

    In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet–visible absorption (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ∆H, ∆G and ∆S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay. - Highlights: ► HLC-Ca, HLC-Cu and HLC-Mn were new chemical compounds and different to free HLC. ► Possible sites for Ca{sup 2+}, Cu{sup 2+} and Mn{sup 2+} to bind with HLC were presented. ► The chelation process between HLC and metal ions was performed spontaneously. ► The thermodynamic stability of the new chelates was higher than that of free HLC.

  6. Chelate chase of radiopharmaceuticals reversibly bound to monoclonal antibodies improves dosimetry

    International Nuclear Information System (INIS)

    Goodwin, D.A.; Smith, S.I.; Meares, C.F.; David, G.S.; McTigue, M.; Finston, R.A.

    1986-01-01

    One hundred micrograms of monoclonal antibody (MoAb) CHA 255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labeled BLEDTA II, GLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-hour tumor and organ distribution in BALB/c mice bearing KHJJ tumors was studied for each compound alone, the antibody complex, and 3 hours following a chelate chase of the antibody complex. Whole-body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-hour whole-body counts dropped 20-60% within 3 hours of administering the chelate chase. Blood concentration fell over 89% within 3 hours of administering the chase and there was a decrease in concentration in all organs, except the kidneys, of 10 to 85%. Theoretical equivalent human doses were calculated from the 24-hour organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads per millicurie. The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labeled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies, greatly improves the radiation dosimetry of tumor imaging agents. 28 references, 5 figures, 5 tables

  7. Controlling lipid oxidation via a biomimetic iron chelating active packaging material.

    Science.gov (United States)

    Tian, Fang; Decker, Eric A; Goddard, Julie M

    2013-12-18

    Previously, a siderophore-mimetic metal chelating active packaging film was developed by grafting poly(hydroxamic acid) (PHA) from the surface of polypropylene (PP) films. The objective of the current work was to demonstrate the potential applicability of this PP-g-PHA film to control iron-promoted lipid oxidation in food emulsions. The iron chelating activity of this film was investigated, and the surface chemistry and color intensity of films were also analyzed after iron chelation. In comparison to the iron chelating activity in the free Fe(3+) solution, the PP-g-PHA film retained approximately 50 and 30% of its activity in nitrilotriacetic acid (NTA)/Fe(3+) and citric acid/Fe(3+) solutions, respectively (pH 5.0), indicating a strong chelating strength for iron. The ability of PP-g-PHA films to control lipid oxidation was demonstrated in a model emulsion system (pH 3.0). PP-g-PHA films performed even better than ethylenediaminetetraacetic acid (EDTA) in preventing the formation of volatile oxidation products. The particle size and ζ potential results of emulsions indicated that PP-g-PHA films had no adverse effects on the stability of the emulsion system. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis suggested a non-migratory nature of the PP-g-PHA film surface. These results suggest that such biomimetic, non-migratory metal chelating active packaging films have commercial potential in protecting foods against iron-promoted lipid oxidation.

  8. IRON CHELATION THERAPY IN THALASSEMIA SYNDROMES

    Directory of Open Access Journals (Sweden)

    Paolo Cianciulli

    2009-06-01

    Full Text Available Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as  thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce  complications, and improve survival and quality of life of transfused patients

  9. Chelation therapy to treat atherosclerosis, particularly in diabetes: is it time to reconsider?

    Science.gov (United States)

    Lamas, Gervasio A; Ergui, Ian

    2016-08-01

    Case reports and case series have suggested a possible beneficial effect of chelation therapy in patients with atherosclerotic disease. Small randomized trials conducted in patients with angina or peripheral artery disease, however, were not sufficiently powered to provide conclusive evidence on clinical outcomes. The Trial to Assess Chelation Therapy (TACT) was the first randomized trial adequately powered to detect the effects of chelation therapy on clinical endpoints. We discuss results and future research. Expert commentary: Chelation reduced adverse cardiovascular events in a post myocardial infarction (MI) population. Patients with diabetes demonstrated even greater benefit, with a number needed to treat of 6.5 patients to prevent a cardiac event over 5 years, with a 41% relative reduction in risk of a cardiac event (p = 0.0002). These results led to the revision of the ACC/AHA guideline recommendations for chelation therapy, changing its classification from class III to class IIb. TACT2, a replicative trial, will assess the effects of chelation therapy on cardiovascular outcomes in diabetic patients with a prior myocardial infarction. We are seeking participating sites for TACT2.

  10. Decorporation of metal ions by chelating agents

    International Nuclear Information System (INIS)

    Koenig, T.

    1978-01-01

    Simple model designs to simulate the effect of therapeutical chelating agents on the behaviour of metals in mammal organisms with and without excretion have been derived and analytical solutions given for the corresponding differential equations. The possibilities of these models in the short-term description of plasma kinetics of various metals, the competition of the therapeutical ligands with proteins for the metal and of the metabolism of chelating agents were tested and the properties applying extreme conceivable parameters were analyzed. The simple models were successsively expanded in logical sequence, so that it was possible to qualitatively well describe over a long period of time, the metallic kinetics in plasma, organs and urine, the retention of the ligands and their effect on the metal excretion. Two suggestions were given to describe the so-called after-effect, an increased excretion of the metal at times when the ligand is almost completely excreted and their different behaviour after injecting the metal chelate is given. Calculations on the therapy with several ligand data as well as on dose fractionation are described resting on the ratios in the plutonium-239 chosen model parameters and the determining mechanisms analyzed. (orig./MG) [de

  11. Bis(1,10-phenanthroline-κ2N,N′(sulfato-Ocopper(II ethane-1,2-diol monosolvate

    Directory of Open Access Journals (Sweden)

    Kai-Long Zhong

    2011-09-01

    Full Text Available In the title compound, [Cu(SO4(C12H8N22]·C2H6O2, the CuII ion is five-coordinated in a distorted square-pyramidal manner by four N atoms from two chelating 1,10-phenanthroline (phen ligands and one O atom from a monodentate sulfate anion. The four N atoms comprise a square and the one O atom the apex of a square pyramid. The two chelating N2C2 groups are oriented at 71.1 (2°. In the crystal, the components are connected by intermolecular O—H...O hydrogen bonding. The presence of pseudosymmetry in the structure suggests the higher symmetry space group C2/c, but attempts to refine the structure in this space group resulted in an unsatisfactory model.

  12. Measured and Calculated Oxidation Potentials of 1-X-12-Y-CB11Me10- Anions

    Czech Academy of Sciences Publication Activity Database

    Wahab, Abdul; Stepp, Brian R.; Douvris, C.; Valášek, Michal; Štursa, Jan; Klíma, Jiří; Piqueras, M. C.; Crespo, R.; Ludvík, Jiří; Michl, Josef

    2012-01-01

    Roč. 51, č. 9 (2012), s. 5128-5137 ISSN 0020-1669 R&D Projects: GA MŠk LC510; GA MŠk ME09002; GA AV ČR IAA400550708; GA ČR GC203/09/J058 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : weakly coordinating anions * density-functional theory * redox potentials Subject RIV: CG - Electrochemistry Impact factor: 4.593, year: 2012

  13. Detection of the electronic structure of iron-(iii)-oxo oligomers forming in aqueous solutions.

    Science.gov (United States)

    Seidel, Robert; Kraffert, Katrin; Kabelitz, Anke; Pohl, Marvin N; Kraehnert, Ralph; Emmerling, Franziska; Winter, Bernd

    2017-12-13

    The nature of the small iron-oxo oligomers in iron-(iii) aqueous solutions has a determining effect on the chemical processes that govern the formation of nanoparticles in aqueous phase. Here we report on a liquid-jet photoelectron-spectroscopy experiment for the investigation of the electronic structure of the occurring iron-oxo oligomers in FeCl 3 aqueous solutions. The only iron species in the as-prepared 0.75 M solution are Fe 3+ monomers. Addition of NaOH initiates Fe 3+ hydrolysis which is followed by the formation of iron-oxo oligomers. At small enough NaOH concentrations, corresponding to approximately [OH]/[Fe] = 0.2-0.25 ratio, the iron oligomers can be stabilized for several hours without engaging in further aggregation. Here, we apply a combination of non-resonant as well as iron 2p and oxygen 1s resonant photoelectron spectroscopy from a liquid microjet to detect the electronic structure of the occurring species. Specifically, the oxygen 1s partial electron yield X-ray absorption (PEY-XA) spectra are found to exhibit a peak well below the onset of liquid water and OH - (aq) absorption. The iron 2p absorption gives rise to signal centered between the main absorption bands typical for aqueous Fe 3+ . Absorption bands in both PEY-XA spectra are found to correlate with an enhanced photoelectron peak near 20 eV binding energy, which demonstrates the sensitivity of resonant photoelectron (RPE) spectroscopy to mixing between iron and ligand orbitals. These various signals from the iron-oxo oligomers exhibit maximum intensity at [OH]/[Fe] = 0.25 ratio. For the same ratio, we observe changes in the pH as well as in complementary Raman spectra, which can be assigned to the transition from monomeric to oligomeric species. At approximately [OH]/[Fe] = 0.3 we begin to observe particles larger than 1 nm in radius, detected by small-angle X-ray scattering.

  14. Studies of the competition for thorium ion between chelating agents and bovine serum albumin

    International Nuclear Information System (INIS)

    Luo Meichu; Zhang Meizhen; Sun Meizhen; Chen Shijie

    1995-01-01

    Fourteen chelation agents (polyaminopolcarboxylate type--TTHA, DTPA, EDTA; phenolicpolycarboxylate type--811, 8102, 7601, 7602, 7603, 7616, 7711, 7724, 7803, 7804, 8307) were studied their competitive ability to mobilize the thorium with bovine serum albumin (BSA). The experimental results showed that the competitive ability of TTHA, 8102, 811 to chelate Thorium with BSA were the strongest, and EDTA was the worst in all chelating agents. The measured order of the competitive ability of chelators is basically consistent with animal experimental results in vivo. The parameter F is defined as the competitive ability of chelators. F is taken as a screening criterion for de-corporate thorium which is simple, quick and effective method in vitro

  15. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Poly-imido analogues of various phosphorus oxo anions have gained recent attention in inorganic chemistry. Current methods to obtain these anions require strong organometallic deprotonating agents in reaction with phosphonium salt like [(NHPh)4P]Cl or phosphoramides such as [(RNH)3P=E] (E = NSiMe3, O, S or Se) ...

  16. Investigation of complexing equilibrium of polyacrylate-anion with cadmium ions by polarographic method

    Energy Technology Data Exchange (ETDEWEB)

    Avlyanov, Zh K; Kabanov, N M; Zezin, A B

    1985-01-01

    Polarographic investigation of cadmium complex with polyacrylate-anion in aqueous KCl solution is carried out. It is shown that the polarographic method allows one to define equilibrium constants of polymer metallic complex (PMC) formation even in the case when current magnitudes are defined by PMC dissociation reaction kinetic characteristics. The obtained equilibrium constants of stepped complexing provide the values of mean coordination PAAxCd complex number of approximately 1.5, that coincides with the value obtained by the potentiometric method.

  17. Investigation of complexing equilibrium of polyacrylate-anion with cadmium ions by polarographic method

    International Nuclear Information System (INIS)

    Avlyanov, Zh.K.; Kabanov, N.M.; Zezin, A.B.

    1985-01-01

    Polarographic investigation of cadmium complex with polyacrylate-anion in aqueous KCl solution is carried out. It is shown that the polarographic method allows one to define equilibrium constants of polymer metallic complex (PMC) formation even in the case, when current magnitudes are defined by PMC dissociation reaction kinetic characteristics. The obtained equilibrium constants of stepped complexing provide the values of mean coordination PAAxCd complex number of approximately 1.5, that coinsides with the value obtained by the potentiometric method

  18. Evaluation of macrocyclic hydroxyisophthalamide ligands as chelators for zirconium-89.

    Science.gov (United States)

    Bhatt, Nikunj B; Pandya, Darpan N; Xu, Jide; Tatum, David; Magda, Darren; Wadas, Thaddeus J

    2017-01-01

    The development of bifunctional chelators (BFCs) for zirconium-89 immuno-PET applications is an area of active research. Herein we report the synthesis and evaluation of octadentate hydroxyisophthalamide ligands (1 and 2) as zirconium-89 chelators. While both radiometal complexes could be prepared quantitatively and with excellent specific activity, preparation of 89Zr-1 required elevated temperature and an increased reaction time. 89Zr-1 was more stable than 89Zr-2 when challenged in vitro by excess DTPA or serum proteins and in vivo during acute biodistribution studies. Differences in radiometal complex stability arise from structural changes between the two ligand systems, and suggest further ligand optimization is necessary to enhance 89Zr chelation.

  19. Evaluation of macrocyclic hydroxyisophthalamide ligands as chelators for zirconium-89.

    Directory of Open Access Journals (Sweden)

    Nikunj B Bhatt

    Full Text Available The development of bifunctional chelators (BFCs for zirconium-89 immuno-PET applications is an area of active research. Herein we report the synthesis and evaluation of octadentate hydroxyisophthalamide ligands (1 and 2 as zirconium-89 chelators. While both radiometal complexes could be prepared quantitatively and with excellent specific activity, preparation of 89Zr-1 required elevated temperature and an increased reaction time. 89Zr-1 was more stable than 89Zr-2 when challenged in vitro by excess DTPA or serum proteins and in vivo during acute biodistribution studies. Differences in radiometal complex stability arise from structural changes between the two ligand systems, and suggest further ligand optimization is necessary to enhance 89Zr chelation.

  20. Coordination compound of vanadyl with meta-nitrobenzoilgydrozine and polyedric closo-borate anions B11H11CH

    International Nuclear Information System (INIS)

    Safarov, Sh.S; Kayumov, A.; Mirsaidov, U.M.

    2005-01-01

    The new complex compound [V O(m-NBzH) 4 (H 2 O)](B 1 1H 1 1CH) 2 C 2 H 5 OH have been synthesised and their properties have investigated. The compound of medetomidine of meta-nitronbenzoilgydrazinum with the nitroge nium of amine group and external sphere of clozo-borate anions was defined by analysis of IR-spectra

  1. Synthesis, crystal structure, and magnetic properties of two-dimensional divalent metal glutarate/dipyridylamine coordination polymers, with a single crystal-to-single crystal transformation in the copper derivative

    International Nuclear Information System (INIS)

    Montney, Matthew R.; Supkowski, Ronald M.; Staples, Richard J.; LaDuca, Robert L.

    2009-01-01

    Hydrothermal reaction of divalent metal chlorides with glutaric acid and 4,4'-dipyridylamine (dpa) has afforded an isostructural family of coordination polymers with formulation [M(glu)(dpa)] n (M=Co (1), Ni (2), Cu (3); glu=glutarate). Square pyramidal coordination is seen in 1-3, with semi-ligation of a sixth donor to produce a '5+1' extended coordination sphere. Neighboring metal atoms are linked into 1D [M(glu)] n neutral chains through chelating/monodentate bridging glutarate moieties with a syn-anti binding mode, and semi-chelation of the pendant carboxylate oxygen. These chains further connect into 2D layers through dipodal dpa ligands. Neighboring layers stack into the pseudo 3D crystal structure of 1-3 through supramolecular hydrogen bonding between dpa amine units and the semi-chelated glutarate oxygen atoms. The variable temperature magnetic behavior of 1-3 was explored and modeled as infinite 1D Heisenberg chains. Notably, complex 3 undergoes a thermally induced single crystal-to-single crystal transformation between centric and acentric space groups, with a conformationally disordered unilayer structure at 293 K and an ordered bilayer structure at 173 K. All materials were further characterized via infrared spectroscopy and elemental and thermogravimetric analyses. - Graphical abstract: The coordination polymers [M(glu)(dpa)] n (M=Co (1), Ni (2), Cu (3); glu=glutarate, dpa=4,4'-dipyridylamine) exhibit 2D layer structures based on 1D [M(glu)] n chains linked through dpa tethers. Antiferromagnetic coupling is observed for 2 and 3, while ferromagnetism is predominant in 1. Compound 3 undergoes a thermally induced single crystal-to-single crystal transformation from an acentric to a centrosymmetric space group

  2. Molecular, crystal, and electronic structure of the cobalt(II) complex with 10-(2-benzothiazolylazo)-9-phenanthrol

    Energy Technology Data Exchange (ETDEWEB)

    Linko, R. V., E-mail: rlinko@mail.ru [Peoples' Friendship University of Russia (Russian Federation); Sokol, V. I. [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation); Polyanskaya, N. A.; Ryabov, M. A.; Strashnov, P. V.; Davydov, V. V. [Peoples' Friendship University of Russia (Russian Federation); Sergienko, V. S. [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation)

    2013-05-15

    The reaction of 10-(2-benzothiazolylazo)-9-phenanthrol (HL) with cobalt(II) acetate gives the coordination compound [CoL{sub 2}] {center_dot} CHCl{sub 3} (I). The molecular and crystal structure of I is determined by X-ray diffraction. The coordination polyhedron of the Co atom in complex I is an octahedron. The anion L acts as a tridentate chelating ligand and is coordinated to the Co atom through the phenanthrenequinone O1 atom and the benzothiazole N1 atom of the moieties L and the N3 atom of the azo group to form two five-membered metallocycles. The molecular and electronic structures of the compounds HL, L, and CoL{sub 2} are studied at the density functional theory level. The results of the quantum-chemical calculations are in good agreement with the values determined by X-ray diffraction.

  3. Molecular, crystal, and electronic structure of the cobalt(II) complex with 10-(2-benzothiazolylazo)-9-phenanthrol

    International Nuclear Information System (INIS)

    Linko, R. V.; Sokol, V. I.; Polyanskaya, N. A.; Ryabov, M. A.; Strashnov, P. V.; Davydov, V. V.; Sergienko, V. S.

    2013-01-01

    The reaction of 10-(2-benzothiazolylazo)-9-phenanthrol (HL) with cobalt(II) acetate gives the coordination compound [CoL 2 ] · CHCl 3 (I). The molecular and crystal structure of I is determined by X-ray diffraction. The coordination polyhedron of the Co atom in complex I is an octahedron. The anion L acts as a tridentate chelating ligand and is coordinated to the Co atom through the phenanthrenequinone O1 atom and the benzothiazole N1 atom of the moieties L and the N3 atom of the azo group to form two five-membered metallocycles. The molecular and electronic structures of the compounds HL, L, and CoL 2 are studied at the density functional theory level. The results of the quantum-chemical calculations are in good agreement with the values determined by X-ray diffraction.

  4. Methods and systems for measuring anions

    KAUST Repository

    Masih, Dilshad; Mohammed, Omar F.; Aly, Shawkat M.; Alarousu, Erkki

    2016-01-01

    Embodiments of the present disclosure provide for methods for detecting the presence and/or concentration of anions in a solution, systems for detecting the presence and/or concentration of anions in a solution, anion sensor systems, and the like.

  5. Methods and systems for measuring anions

    KAUST Repository

    Masih, Dilshad

    2016-08-18

    Embodiments of the present disclosure provide for methods for detecting the presence and/or concentration of anions in a solution, systems for detecting the presence and/or concentration of anions in a solution, anion sensor systems, and the like.

  6. Acid-base equilibria in the reaction of tantalum pentafluoride with O,O-diphenyl-H-benzoylamidophosphate (PhO)2P(0)NHC(O)Ph

    International Nuclear Information System (INIS)

    Il'in, E.G.; Kharrmann, Eh.; Shcherbakova, M.N.; Buslaev, Yu.A.

    1987-01-01

    Method of 19 F NMR was used to study TaF 5 interaction with imidodiphosphoric acid ester (PhO) 2 P(O)NHC(O)Ph(LH) in methylene chloride. Dimeric molecular LH(TaF 5 ) 2 complex was the main form in the solution with towfold TaF 5 excess; phosphoryl and carbonyl groups partisipate in complexing at that. Increase of ligand content in the solution up to equimolar one results to preliminary ligand coordination via P=O-group. Introduction of the base excess to the solution results to formation of L - anion which is coordinated to TaF 5 in a monodentate way via phosphoryl group or in a chelate way with fluorine ion substitution and formation of LTaF 4 + cationw

  7. catena-Poly[[[trans-diaquabis(pyridine-κNcobalt(II]-μ-(4-{N′-[1-(3-acetyl-4-methyl-1H-pyrazol-5-ylethylidene]hydrazino}benzoato-κ3O:N,N′-[bis(pyridine-κNcobalt(III]-μ-(4-{N′-[1-(3-acetyl-4-methyl-1H-pyrazol-5-ylethylidene]hydrazino}benzoato-κ3N,N′:O]perchlorate 3.66-hydrate

    Directory of Open Access Journals (Sweden)

    Igor O. Fritsky

    2008-02-01

    Full Text Available The title compound, {[Co2(C15H14N4O32(C5H5N4(H2O2]ClO4·3.66H2O}n, is a one-dimensional coordination polymer, with both CoII and CoIII centres in its structure. The ligand environment surrounding CoIII is formed by two N,N-chelating pyrazole-containing ligands and two pyridine molecules in axial positions. The high-spin CoII ions, situated at crystallographic centres of inversion, exhibit a distorted octahedral coordination mode. The ClO4− anion is linked to the polymer chain via hydrogen bonds. The chains are connected by hydrogen bonds to produce a three-dimensional structure.

  8. Phosphazene-promoted anionic polymerization

    KAUST Repository

    Zhao, Junpeng

    2014-01-01

    In the recent surge of metal-free polymerization techniques, phosphazene bases have shown their remarkable potential as organic promoters/catalysts for the anionic polymerization of various types of monomers. By complexation with the counterion (e.g. proton or lithium cation), phosphazene base significantly improve the nucleophilicity of the initiator/chain-end resulting in rapid and usually controlled anionic/quasi-anionic polymerization. In this review, we will introduce the general mechanism, i.e. in situ activation (of initiating sites) and polymerization, and summarize the applications of such a mechanism on macromolecular engineering toward functionalized polymers, block copolymers and complex macromolecular architectures.

  9. F-Element ion chelation in highly basic media. 1998 annual progress report

    International Nuclear Information System (INIS)

    Paine, R.T.

    1998-01-01

    'A large percentage of high-level radioactive waste (HLW) produced in the DOE complex over the last thirty years temporarily resides in storage tanks maintained at highly basic pH. The final permanent waste remediation plan will probably require that liquid and solid fractions be chemically treated in order to partition and concentrate the dominate hazardous emitters from the bulk of the waste. This is no small task. Indeed, there does not exist a well developed molecular chemistry knowledge base to guide the development of suitable separations for actinide and fission products present in the strongly basic media. The goal of this project is to undertake fundamental studies of the coordination chemistry of f-element ions and their species formed in basic aqueous solutions containing common waste treatment ions (e.g., NO 3 - , CO 3 2- , organic carboxylates, and EDTA), as well as new waste scrubbing chelators produced in this study.'

  10. Chelates for Micronutrient Nutrition among Crops

    Indian Academy of Sciences (India)

    years, it has been recognised that compounds containing che- lated metals could .... when using small amounts and no build up of harmful levels. ... degradation of iron chelates. .... down by soil microorganisms into much smaller units for ab-.

  11. Metal chelate conjugated monoclonal antibodies, wherein the metal is an α emitter

    International Nuclear Information System (INIS)

    Gansow, O.A.; Strand, M.

    1984-01-01

    Methods of manufacturing and purifying metal chelate conjugated monoclonal antibodies are described, wherein the chelated metal emits alpha radiation. The conjugates are suited for therapeutic uses being substantially free of nonchelated radiometal. (author)

  12. Study of Anti-Fatigue Effect in Rats of Ferrous Chelates Including Hairtail Protein Hydrolysates

    Directory of Open Access Journals (Sweden)

    Saibo Huang

    2015-12-01

    Full Text Available The ability of ferrous chelates including hairtail protein hydrolysates to prevent and reduce fatigue was studied in rats. After hydrolysis of hairtail surimi with papain, the hairtail protein hydrolysates (HPH were separated into three groups by range of relative molecular weight using ultrafiltration membrane separation. Hairtail proteins were then chelated with ferrous ions, and the antioxidant activity, the amino acid composition and chelation rate of the three kinds of ferrous chelates including hairtail protein hydrolysates (Fe-HPH were determined. Among the three groups, the Fe-HPH chelate showing the best conditions was selected for the anti-fatigue animal experiment. For it, experimental rats were randomly divided into seven groups. Group A was designated as the negative control group given distilled water. Group B, the positive control group, was given glutathione. Groups C, D and E were designated as the Fe-HPH chelate treatment groups and given low, medium, and high doses, respectively. Group F was designated as HPH hydrolysate treatment group, and Group G was designated as FeCl2 treatment group. The different diets were orally administered to rats for 20 days. After that time, rats were subjected to forced swimming training after 1 h of gavage. Rats given Fe-FPH chelate had higher haemoglobin regeneration efficiency (HRE, longer exhaustive swimming time and higher SOD activity. Additionally, Fe-FPH chelate was found to significantly decrease the malondialdehyde content, visibly enhance the GSH-Px activity in liver and reduce blood lactic acid of rats. Fe-HPH chelate revealed an anti-fatigue effect, similar to or better than the positive control substance and superior to HPH or Fe when provided alone.

  13. Neutron activation analysis for chemical characterization of Brazilian oxo-biodegradable plastics

    International Nuclear Information System (INIS)

    Mateus Eugenio Boscaro; De Nadai Fernandes, E.A.; Marcio Arruda Bacchi; Luis Gustavo Cofani dos Santos; Cofani dos Santos, S.N.S.; Sandra Mara Martins-Franchetti

    2015-01-01

    The chemical characterization of oxo-biodegradable plastic bags was performed by neutron activation analysis. The presence of several chemical elements (As, Br, Ca, Co, Cr, Fe, Hf, K, La, Na, Sb, Sc, Ta and Zn) with large variability of mass fractions amongst samples indicates that these plastics receive additives and may have been contaminated during manufacturing process thereby becoming potential environmental pollutants. (author)

  14. Enhanced in vitro activity of tigecycline in the presence of chelating agents.

    Science.gov (United States)

    Deitchman, Amelia N; Singh, Ravi Shankar Prasad; Rand, Kenneth H; Derendorf, Hartmut

    2018-05-01

    The lack of availability of novel antibiotic agents and the rise of resistance to existing therapies has led clinicians to utilise combination therapy to adequately treat bacterial infections. Here we examined how chelators may impact the in vitro activity of tigecycline (TIG) against Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Minimum inhibitory concentrations (MICs) were determined by broth dilution with and without various combinations of chelators (EDTA and other tetracyclines) and metal ions (i.e. calcium, magnesium). Trimethoprim (TMP) was used as a non-chelating control. Addition of metal ions led to increases in MICs, whilst addition of EDTA led to decreases in MICs. The chelating effects of EDTA were reversed by addition of magnesium and most profoundly calcium. Similar effects of EDTA and calcium were observed for tetracycline (TET) and TMP. When other tetracyclines (TET, oxytetracycline (OXY) and chlortetracycline (CHL)) were used as chelators at concentrations below their MICs, TIG MICs decreased for P. aeruginosa but not for E. coli. Some decreases in TIG MICs were observed for K. pneumoniae when TET and CHL were added. A dose-dependent decrease in TIG MIC was observed for TET and was reversed by the addition of calcium. The presence of effects of EDTA and calcium on TMP MICs indicates that mechanisms outside of TIG chelation likely play a role in enhanced activity. Full characterisation of an unexpected interaction such as TIG-TET with different microorganisms could provide valuable insights into the underlying mechanisms and design of physiologically viable chelators as candidates for future combinations regimens. Copyright © 2018 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  15. Enabling the high capacity of lithium-rich anti-fluorite lithium iron oxide by simultaneous anionic and cationic redox

    Science.gov (United States)

    Zhan, Chun; Yao, Zhenpeng; Lu, Jun; Ma, Lu; Maroni, Victor A.; Li, Liang; Lee, Eungje; Alp, Esen E.; Wu, Tianpin; Wen, Jianguo; Ren, Yang; Johnson, Christopher; Thackeray, Michael M.; Chan, Maria K. Y.; Wolverton, Chris; Amine, Khalil

    2017-12-01

    Anionic redox reactions in cathodes of lithium-ion batteries are allowing opportunities to double or even triple the energy density. However, it is still challenging to develop a cathode, especially with Earth-abundant elements, that enables anionic redox activity for real-world applications, primarily due to limited strategies to intercept the oxygenates from further irreversible oxidation to O2 gas. Here we report simultaneous iron and oxygen redox activity in a Li-rich anti-fluorite Li5FeO4 electrode. During the removal of the first two Li ions, the oxidation potential of O2- is lowered to approximately 3.5 V versus Li+/Li0, at which potential the cationic oxidation occurs concurrently. These anionic and cationic redox reactions show high reversibility without any obvious O2 gas release. Moreover, this study provides an insightful guide to designing high-capacity cathodes with reversible oxygen redox activity by simply introducing oxygen ions that are exclusively coordinated by Li+.

  16. 16-Cyclopentadienyl tricarbonyl 99mTc 16-oxo-hexadecanoic acid: synthesis and evaluation of fatty acid metabolism in mouse myocardium.

    Science.gov (United States)

    Lee, Byung Chul; Kim, Dong Hyun; Lee, Iljung; Choe, Yearn Seong; Chi, Dae Yoon; Lee, Kyung-Han; Choi, Yong; Kim, Byung-Tae

    2008-06-26

    We synthesized 16-cyclopentadienyl tricarbonyl 99mTc 16-oxo-hexadecanoic acid (99mTc-CpTT-16-oxo-HDA, 1) and investigated its potential as a radiotracer for evaluating fatty acid metabolism in myocardium. Radiotracer 1 was synthesized in 22.6 +/- 6.3% decay-corrected yield by a double ligand transfer reaction between the ferrocene adduct of methyl hexadecanoate ( 2) and Na99mTcO 4 in the presence of Cr(CO)6 and CrCl3, followed by hydrolysis of the methyl ester group. Radiotracer 1 was found to be chemically stable (99% at 6 h) when incubated in human serum. A tissue distribution study in mice showed that high radioactivity accumulated in heart (9.03%ID/g at 1 min and 5.41%ID/g at 5 min postinjection) with rapid clearance and that heart to blood uptake ratios increased with time (2.13 at 5 min and 3.76 at 30 min postinjection). Metabolite analysis of the heart tissues using a simple extraction method showed that 99mTc-CpTT-4-oxo-butyric acid was detected as the major radioactive metabolite by HPLC, suggesting that 1 is metabolized to 99mTc-CpTT-4-oxo-butyric acid via beta-oxidation in myocardium.

  17. Anion-π Catalysts with Axial Chirality.

    Science.gov (United States)

    Wang, Chao; Matile, Stefan

    2017-09-04

    The idea of anion-π catalysis is to stabilize anionic transition states by anion-π interactions on aromatic surfaces. For asymmetric anion-π catalysis, π-acidic surfaces have been surrounded with stereogenic centers. This manuscript introduces the first anion-π catalysts that operate with axial chirality. Bifunctional catalysts with tertiary amine bases next to π-acidic naphthalenediimide planes are equipped with a bulky aromatic substituent in the imide position to produce separable atropisomers. The addition of malonic acid half thioesters to enolate acceptors is used for evaluation. In the presence of a chiral axis, the selective acceleration of the disfavored but relevant enolate addition was much better than with point chirality, and enantioselectivity could be observed for the first time for this reaction with small-molecule anion-π catalysts. Enantioselectivity increased with the π acidity of the π surface, whereas the addition of stereogenic centers around the aromatic plane did not cause further improvements. These results identify axial chirality of the active aromatic plane generated by atropisomerism as an attractive strategy for asymmetric anion-π catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

    International Nuclear Information System (INIS)

    Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K.

    1996-03-01

    The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates

  19. Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-03-01

    The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

  20. Inositol hexa-phosphate: a potential chelating agent for uranium

    International Nuclear Information System (INIS)

    Cebrian, D.; Tapia, A.; Real, A.; Morcillo, M.A.

    2007-01-01

    Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

  1. On-load chelating agent treatments for conventional and nuclear power stations

    International Nuclear Information System (INIS)

    Turner, D.J.

    1978-01-01

    The paper is concerned with the application of on-load chelating agent treatments to those types of water circuit for which they are not currently available: high pressure drum boilers, sub-critical once-through boilers and water reactors. An attempt was made to see whether the most thermally stable types of chelating agent are likely to be sufficiently strong chelating agents either to dissolve established Fe 3 O 4 deposits or to prevent their precipitation from solution. It seems likely that they are strong enough to prevent Fe 3 O 4 depositing in a once-through boiler, through some may require that mildly reducing conditions are maintained. They would not be effective in a high pressure drum boiler (at 350 0 C) unless much more strongly reducing conditions could be maintained. For such boilers it would probably be better to seek multidentate ligands of less than maximum thermal stability. There are some indications that chelating agents based on carbon chains are more stable than NTA or EDTA so that citric acid or some of the unidentified chelating agents recently found to be produced radiolytically may have potential in the treatment of high pressure drum boilers. The prospects for periodic full-load cleaning seem less good for both types of boiler. There may also be a role for radiolytically produced chelating agents in alleviating some of the problems caused by the deposition of radioactive corrosion products in water reactor circuits. The chances for successful development fall from quite good to very low down the series SGHWR moderator circuit, PWR primary circuit, ammonia dosed BWR, neutral chemistry BWR (including SGHWR). (author)

  2. Alkali metal – yttrium borohydrides: The link between coordination of small and large rare-earth

    International Nuclear Information System (INIS)

    Sadikin, Yolanda; Stare, Katarina; Schouwink, Pascal; Brix Ley, Morten; Jensen, Torben R.; Meden, Anton; Černý, Radovan

    2015-01-01

    The system Li–A–Y–BH 4 (A=K, Rb, Cs) is found to contain five new compounds and four further ones known from previous work on the homoleptic borohydrides. Crystal structures have been solved and refined from synchrotron X-ray powder diffraction, thermal stability of new compounds have been investigated and ionic conductivity measured for selected samples. Significant coordination flexibility for Y 3+ is revealed, which allows the formation of both octahedral frameworks and tetrahedral complex anions with the tetrahydroborate anion BH 4 both as a linker and terminal ligand. Bi- and trimetallic cubic double-perovskites c-A 3 Y(BH 4 ) 6 or c-A 2 LiY(BH 4 ) 6 (A=Rb, Cs) form in all the investigated systems, with the exception of the Li–K–Y system. The compounds with the stoichiometry AY(BH 4 ) 4 crystallize in all investigated systems with a great variety of structure types which find their analog amongst metal oxides. In-situ formation of a new borohydride – closo-borane is observed during decomposition of all double perovskites. - Graphical abstract: The system Li–A–Y–BH 4 (A=K, Rb, Cs) is found to contain five novel compounds and four further ones previously reported. Significant coordination flexibility of Y 3+ is revealed, which can be employed to form both octahedral frameworks and tetrahedral complex anions, very different structural topologies. Versatility is also manifested in three different simultaneously occurring coordination modes of borohydrides for one metal cation, as proposed by DFT optimization of the monoclinic KY(BH 4 ) 4 structural model observed by powder diffraction. - Highlights: • The system Li-A-Y-BH 4 (A=K, Rb, Cs) contains nine compounds in total. • Y 3+ forms octahedral frameworks and tetrahedral complex anions. • Bi- and trimetallic double-perovskites crystallize in most systems. • Various AY(BH 4 ) 4 crystallize with structure types analogous to metal oxides. • Double-perovskites decompose and form a novel

  3. Study of the simultaneous complexation of a cation and of an anion using functionalized calixarenes; Etude de la complexation simultanee d'un cation et d'un anion par des calixarenes fonctionnalises

    Energy Technology Data Exchange (ETDEWEB)

    Moli, Ch [CEA Cadarache, Dept. d' Etudes des Dechets, DED, 13 - Saint Paul lez Durance (France); [Universite Louis Pasteur, 67 - Strasbourg (France)

    2002-03-01

    The chemical reprocessing of irradiated nuclear fuels leads to the production of high-level radioactive liquid wastes which contain long-lived toxic radioelements. In the framework of the long-term management of these wastes, important research work is carried out for the separation of these radioelements for their further transmutation or immobilization inside specific matrices. These radioelements are present in acid solutions of fission products in the form of cations (cesium), anions (technetium, selenium) and molecules (iodine). Crown calixarenes have been successfully used for the extraction of cesium thanks to their exceptional selectivities. This work is mainly based on the use of the chelating properties of calixarenes for the extraction of anionic radioelements. Calixarenes functionalized by amino-carbon chains have been selected. The synthesis of amine calix[4]arenes and calix[6]arenes is described and their extractive and ionophoretic properties with respect to radioelements are shown using aqueous selective separation techniques like the liquid-liquid extraction and the supported liquid membrane transport. Technetium and selenium are extracted by amine calixarenes from a 10{sup -2} M aqueous solution of nitric acid. At this acidity, no selenium transport is observed, while technetium transport is efficient: the solution is quasi-totally decontaminated in 6 hours. Molecular iodine is efficiently extracted with a simple organic diluent, the 1,2-nitro-phenyl-hexyl-ether, from a strongly concentrated aqueous solution of nitric acid (HNO{sub 3} = 3 M). The transport of iodine becomes faster and more efficient when its concentration in the solution is higher. (J.S.)

  4. Creating molecular macrocycles for anion recognition

    Directory of Open Access Journals (Sweden)

    Amar H. Flood

    2016-03-01

    Full Text Available The creation and functionality of new classes of macrocycles that are shape persistent and can bind anions is described. The genesis of triazolophane macrocycles emerges out of activity surrounding 1,2,3-triazoles made using click chemistry; and the same triazoles are responsible for anion capture. Mistakes made and lessons learnt in anion recognition provide deeper understanding that, together with theory, now provides for computer-aided receptor design. The lessons are acted upon in the creation of two new macrocycles. First, cyanostars are larger and like to capture large anions. Second is tricarb, which also favors large anions but shows a propensity to self-assemble in an orderly and stable manner, laying a foundation for future designs of hierarchical nanostructures.

  5. Improved paramagnetic chelate for molecular imaging with MRI

    International Nuclear Information System (INIS)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-01-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent

  6. Improved paramagnetic chelate for molecular imaging with MRI

    Science.gov (United States)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-05-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

  7. Chelator induced phytoextraction and in situ soil washing of Cu

    International Nuclear Information System (INIS)

    Kos, Bostjan; Lestan, Domen

    2004-01-01

    In a soil column experiment, we investigated the effect of 5 mmol kg -1 soil addition of citric acid, ethylenediamine tetraacetate (EDTA), diethylenetriamine-pentaacetate (DTPA) and [S,S]-stereoisomer of ethylenediamine-disuccinate (EDDS) on phytoextraction of Cu from a vineyard soil with 162.6 mg kg -1 Cu, into the test plant Brassica rapa var. pekinensis. We also examined the use of a horizontal permeable barrier, composed of layers of nutrient enriched sawdust and apatite, for reduction of chelator induced Cu leaching. The addition of all chelators, except citric acid, enhanced Cu mobility and caused leaching of 19.5-23% of initial total Cu from the soil column. However, Cu plant uptake did not increase accordingly; the most effective was the EDDS treatment, in which plant Cu concentration reached 37.8±1.3 mg kg -1 Cu and increased by 3.3-times over the control treatment. The addition of none of the chelators in the concentration range from 5 to 15 mmol kg -1 exerted any toxic effect on respiratory soil microorganisms. When EDDS was applied into the columns with horizontal permeable barriers, only 0.53±0.32% of the initial total Cu was leached. Cu (36.7%) was washed from the 18 cm soil layer above the barrier and accumulated in the barrier. Our results indicate that rather than for a reduction of Cu leaching during rather ineffective chelate induced Cu phytoextraction, horizontal permeable barriers could be more effective in a new remediation technique of controlled in situ soil washing of Cu with biodegradable chelates

  8. The activity state of the branched-chain 2-oxo acid dehydrogenase complex in rat tissues.

    Science.gov (United States)

    Wagenmakers, A J; Schepens, J T; Veldhuizen, J A; Veerkamp, J H

    1984-05-15

    An assay is described to define the proportion of the branched-chain 2-oxo acid dehydrogenase complex that is present in the active state in rat tissues. Activities are measured in homogenates in two ways: actual activities, present in tissues, by blocking both the kinase and phosphatase of the enzyme complex during homogenization, preincubation, and incubation with 1-14C-labelled branched-chain 2-oxo acid, and total activities by blocking only the kinase during the 5 min preincubation (necessary for activation). The kinase is blocked by 5 mM-ADP and absence of Mg2+ and the phosphatase by the simultaneous presence of 50 mM-NaF. About 6% of the enzyme is active in skeletal muscle of fed rats, 7% in heart, 20% in diaphragm, 47% in kidney, 60% in brain and 98% in liver. An entirely different assay, which measures activities in crude tissue extracts before and after treatment with a broad-specificity protein phosphatase, gave similar results for heart, liver and kidney. Advantages of our assay with homogenates are the presence of intact mitochondria, the simplicity, the short duration and the high sensitivity. The actual activities measured indicate that the degradation of branched-chain 2-oxo acids predominantly occurs in liver and kidney and is limited in skeletal muscle in the fed state.

  9. From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2016-12-01

    Full Text Available The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenylborane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenolimidazol-2-ylidene reacts with (triphenylphosphinegold(I chloride to give the cationic NHC complex [Au(NHC2][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolateimidazol-2-ylidene gives the complexes [K][Au(NHC−2], [Rh(NHC−3] and [Ni(NHC−2], respectively. Results of four single crystal analyses are presented.

  10. Photo-Curable Metal-Chelating Coatings Offer a Scalable Approach to Production of Antioxidant Active Packaging.

    Science.gov (United States)

    Lin, Zhuangsheng; Goddard, Julie

    2018-02-01

    Synthetic metal chelators (for example, ethylenediaminetetraacetic acid, EDTA) are widely used as additives to control trace transition metal induced oxidation in consumer products. To enable removal of synthetic chelators in response to increasing consumer demand for clean label products, metal-chelating active food packaging technologies have been developed with demonstrated antioxidant efficacy in simulated food systems. However, prior work in fabrication of metal-chelating materials leveraged batch chemical reactions to tether metal-chelating ligands, a process with limited industrial translatability for large-scale fabrication. To improve the industrial translatability, we have designed a 2-step laminated photo-grafting process to introduce metal chelating functionality onto common polymeric packaging materials. Iminodiacetic acid (IDA) functionalized materials were fabricated by photo-grafting poly(acrylic acid) onto polypropylene (PP) films, followed by a second photo-grafting process to graft-polymerize an IDA functionalized vinyl monomer (GMA-IDA). The photo-grafting was conducted under atmospheric conditions and was completed in 2 min. The resulting IDA functionalized metal-chelating material was able to chelate iron and copper, and showed antioxidant efficacy against ascorbic acid degradation, supporting its potential to be used synergistically with natural antioxidants for preservation of food and beverage products. The 2-step photo-grafting process improves the throughput of active packaging coatings, enabling potential roll-to-roll fabrication of metal-chelating active packaging materials for antioxidant food packaging applications. To address consumer and retail demands for "clean label" foods and beverages without a corresponding loss in product quality and shelf life, producers are seeking next generation technologies such as active packaging. In this work, we will report the synthesis of metal-chelating active packaging films, which enable removal

  11. SBA-15-functionalized 3-oxo-ABNO as recyclable catalyst for aerobic oxidation of alcohols under metal-free conditions.

    Science.gov (United States)

    Karimi, Babak; Farhangi, Elham; Vali, Hojatollah; Vahdati, Saleh

    2014-09-01

    The nitroxyl radical 3-oxo-9-azabicyclo [3.3.1]nonane-N-oxyl (3-oxo-ABNO) has been prepared using a simple protocol. This organocatalyst is found to be an efficient catalyst for the aerobic oxidation of a wide variety of alcohols under metal-free conditions. In addition, the preparation and characterization of a supported version of 3-oxo-ABNO on ordered mesoporous silica SBA-15 (SABNO) is described for the first time. The catalyst has been characterized using several techniques including simultaneous thermal analysis (STA), transmission electron microscopy (TEM), and nitrogen sorption analysis. This catalyst exhibits catalytic performance comparable to its homogeneous analogue and much superior catalytic activity in comparison with (2,2,6,6-tetramethylpiperidin-1-yl)oxy (TEMPO) for the aerobic oxidation of almost the same range of alcohols under identical reaction conditions. It is also found that SABNO can be conveniently recovered and reused at least 12 times without significant effect on its catalytic efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Derivatives of 16alpha-hydroxy-dehydroepiandrosterone with an additional 7-oxo or 7-hydroxy substituent: synthesis and gas chromatography/mass spectrometry analysis.

    Science.gov (United States)

    Pouzar, Vladimír; Cerný, Ivan; Hill, Martin; Bicíková, Marie; Hampl, Richard

    2005-10-01

    Derivatives of 16alpha-hydroxy-dehydroepiandrosterone, which have an additional oxygen substituent at position 7 (oxo or hydroxy group), were synthesized. Firstly, 17,17-dimethoxyandrost-5-ene-3beta,16alpha-diyl diacetate was prepared and then oxidized with a complex of chromium(VI) oxide and 2,5-dimethylpyrazole to the respective 7-oxo derivative. This key intermediate was both deprotected or reduced by l-Selectride or sodium borohydride in the presence of cerium(III) chloride and then deprotected to give 7-oxo, 7alpha-hydroxy and 7beta-hydroxy derivatives of 16alpha-hydroxy-dehydroepiandrosterone. The target compounds were characterized by (1)H and (13)C NMR spectra and in the form of O-methyloxime-trimethylsilyl derivatives, by gas chromatography/mass spectrometry methods.

  13. Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, Travis S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heathman, Colt R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jansone-Popova, Santa [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Alexander S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roy, Santanu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryantsev, Vyacheslav S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zalupski, Peter R. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2018-01-05

    Here, the novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N",N"-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N",N"-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA

  14. Causes and consequences of plant radio-resistance. Formation of DNA basis lesions and self-repairing activity of one of them, the 8-oxo-7,8-dihydro-guanine in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Dany, A.L.

    2001-01-01

    In this research thesis, the author first explains how and why DNA is injured when it is submitted to an oxidizing stress, and describes precisely the formation and the biological consequences of lesions of DNA bases, the 8-oxo-7,8-dihydro-guanine (8-oxoGua). She describes the repairing activities of the oxidized DNA, and more particularly the repairing of 8-oxoGua, in prokaryotes as well as in yeast, mammals and plants. Methodologies used are described, together with the repair activities of the 8-oxo-7,8-dihydro-guanine following a biochemical type approach and a molecular biology approach

  15. Albumin microspheres labeled with Ga-67 by chelation: concise communication

    International Nuclear Information System (INIS)

    Hnatowich, D.J.; Schlegel, P.

    1981-01-01

    Albumin microspheres have been synthesized with EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after 24 hr in 50% plasma at 37 0 C, whereas with DTPA microspheres the label shows no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +- 16)% of the activity localizes in the lungs at 5 min, with (60 +- 7)% remaining after 2 h. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  16. Fructose and tagatose protect against oxidative cell injury by iron chelation.

    Science.gov (United States)

    Valeri, F; Boess, F; Wolf, A; Göldlin, C; Boelsterli, U A

    1997-01-01

    To further investigate the mechanism by which fructose affords protection against oxidative cell injury, cultured rat hepatocytes were exposed to cocaine (300 microM) or nitrofurantoin (400 microM). Both drugs elicited massively increased lactate dehydrogenase release. The addition of the ketohexoses D-fructose (metabolized via glycolysis) or D-tagatose (poor glycolytic substrate) significantly attenuated cocaine- and nitrofurantoin-induced cell injury, although both fructose and tagatose caused a rapid depletion of ATP and compromised the cellular energy charge. Furthermore, fructose, tagatose, and sorbose all inhibited in a concentration-dependent manner (0-16 mM) luminolenhanced chemiluminescence (CL) in cell homogenates, indicating that these compounds inhibit the iron-dependent reactive oxygen species (ROS)-mediated peroxidation of luminol. Indeed, both Fe2+ and Fe3+ further increased cocaine-stimulated CL, which was markedly quenched following addition of the ketohexoses. The iron-independent formation of superoxide anion radicals (acetylated cytochrome c reduction) induced by the prooxidant drugs remained unaffected by fructose or tagatose. The iron-chelator deferoxamine similarly protected against prooxidant-induced cell injury. In contrast, the nonchelating aldohexoses D-glucose and D-galactose did not inhibit luminol CL nor did they protect against oxidative cell injury. These data indicate that ketohexoses can effectively protect against prooxidant-induced cell injury, independent of their glycolytic metabolism, by suppressing the iron-catalyzed formation of ROS.

  17. Synthesis and Microbiological Activity of Some Newly Synthesized Derivatives of 2-Oxo-2H-chromen-2-one

    OpenAIRE

    Daci-Ajvazi, Majlinda; Govori, Sevdije; Omeragiq, Shuhreta

    2011-01-01

    By the action of 2-amino-5-methylthio-1,3,4-thiadiazole, 3-amino-5-methylisoxazole, 2-amino-6-fluorobenzothiazole, 2-amino-5-chloropyridine, respectively, on 4-chloro-2-oxo-2H-chromene-3-sulfonyl chloride, the corresponding 9-methylthio-7,7-dioxo-7,7a-dihydro-5-oxo-7λ6,10-dithia-8,11-diaza-cyclopenta[b] phenantren-6-one, 9-methyl-7,7-dioxo-7H-5,8-dioxa-7λ6-thia-7a,11-diaza-cyclopenta[b] phenantren-6-one, 9-fluoro-7,7-dioxo-7H-5-oxa-7λ6,12-dithia-7a,13-diaza-indeno[1,2-b] phenantren-6-one and ...

  18. A Cadmium Anionic 1-D Coordination Polymer {[Cd(H2O6][Cd2(atr2(μ2-btc2(H2O4] 2H2O}n within a 3-D Supramolecular Charge-Assisted Hydrogen-Bonded and π-Stacking Network

    Directory of Open Access Journals (Sweden)

    Anas Tahli

    2016-03-01

    Full Text Available The hydrothermal reaction of 4,4′-bis(1,2,4-triazol-4-yl (btr and benzene-1,3,5-tricarboxylic acid (H3btc with Cd(OAc2·2H2O at 125 °C in situ forms 4-amino-1,2,4-triazole (atr from btr, which crystallizes to a mixed-ligand, poly-anionic chain of [Cd2(atr2(µ2-btc2(H2O4]2–. Together with a hexaaquacadmium(II cation and water molecules the anionic coordination-polymeric forms a 3-D supramolecular network of hexaaquacadmium(II-catena-[bis(4-amino-1,2,4-triazoletetraaquabis(benzene-1,3,5-tricarboxylatodicadmate(II] dihydrate, 1-D-{[Cd(H2O6][Cd2(atr2(µ2-btc2(H2O4] 2H2O}n which is based on hydrogen bonds (in part charge-assisted and π–π interactions.

  19. Structure investigation, spectral, thermal, X-ray and mass characterization of piroxicam and its metal complexes

    Science.gov (United States)

    Zayed, M. A.; Nour El-Dien, F. A.; Mohamed, Gehad G.; El-Gamel, Nadia E. A.

    2004-10-01

    [M(H 2L) 2](A) 2. yH 2O (where H 2L: neutral piroxicam (Pir), A: Cl - in case of Ni(II) or acetate anion in case of Cu(II) and Zn(II) ions and y=0-2.5) and [M(H 2L) 3](A) z. yH 2O (A: SO 42- in case of Fe(II) ion ( z=1) or Cl - in case of Fe(III) ( z=3) and Co(II) ions ( z=2) and y=1-4) chelates are prepared and characterized using elemental analyses, IR, magnetic and electronic reflectance measurements, mass spectra and thermal analyses. IR spectra reveal that Pir behaves a neutral bidentate ligand coordinated to the metal ions through the pyridyl-N and carbonyl-O of the amide moiety. The reflectance and magnetic moment measurements reveal that these chelates have tetrahedral, square planar and octahedral geometrical structures. Mass spectra and thermal analyses are also used to confirm the proposed formulae and the possible fragments resulted from fragmentation of Pir and its chelates. The thermal behaviour of the chelates (TGA and DTA) are discussed in detail and the thermal stability of the anhydrous chelates follow the order Ni(II)≅Cu(II)chelates. The water molecules are removed in the first step while the Pir molecule is removed in the second and subsequent steps. X-ray powder diffraction was also used as a confirmatory tool to elucidate the crystallinity of the chelates.

  20. Anion concurrence and anion selectivity in the sorption of radionuclides by organotones

    International Nuclear Information System (INIS)

    Behnsen, Julia G.

    2007-01-01

    Some long-lived and radiologically important nuclear fission products, such as I-129 (half-life t 1/2 = 1,6 . 10 7 a), Tc-99 (t 1/2 = 2,1 . 10 5 a), and Se-79 (t 1/2 = 6,5 . 10 4 a) are anionic in aqueous environments. This study focuses on the adsorption of such anions to organoclays and the understanding of the selectivity of the process. The organoclays used in this study were prepared from a bentonite (MX-80) and a vermiculite clay, and the cationic surfactants hexadcylpyridium, hexadecyltrimethylammonium, and benzethonium. Surfactant adsorption to the bentonite exceeds the cation exchange capacity of the clay, with the surplus positive charge being balanced by the co-adsorption of chloride. The interlayer distance of the bentonites is increased sufficiently to contain bi- and pseudotrimolecular structures of the surfactants. Adsorption experiments were carried out using the batch technique. Anion adsorption of iodide, perrhenate, selenite, nitrate, and sulphate is mainly due to ion exchange with chloride. As an additional adsorption mechanism, the incorporation of inorganic ion pairs into the interlayer space of the clay is proposed as a result of experiments showing differences in the adsorption levels of sodium and potassium iodide. Anion adsorption results show a clear selectivity of the organoclays, with the affinity sequence being: ReO - 4 > I - > NO - 3 > Cl - > SO 2- 4 > SeO 2- 3 . This sequence corresponds to the sequence of increasing hydration energies of the anions, thus selectivity could be due to the process of minimization of free energy of the system. (orig.)

  1. catena-Poly[manganese(II-(μ2-3,5-di-2-pyridyl-1,2,4-triazolato-μ2-formato

    Directory of Open Access Journals (Sweden)

    Ya-Wen Zhang

    2008-08-01

    Full Text Available Owing to the presence of crystallographic twofold rotation axes (site symmetry 2, Wyckoff letters e and f, the asymmetric unit of the title compound, [Mn(C12H8N5(CHO2]n, contains one-half of an MnII cation, one-half of a bpt anion (Hbpt is 3,5-di-2-pyridyl-4H-1,2,4-triazole and one-half of a formate anion. The bpt and formate ligands occupy the same C2 symmetry, while the MnII ion resides on another crystallographic twofold rotation axis. Each bpt ligand acts as a cis-bis-chelate to ligate two MnII ions into a one-dimensional chain running along the crystallographic 41 screw axis. Adjacent MnII ions are further bridged by a μ2-formate ligand, completing the distorted octahedral coordination geometry of the cation.

  2. Reaction of the phosphorus, niobium and tantalum pentafluorides with dioxides of diphosphjines cis-isomers

    International Nuclear Information System (INIS)

    Il'in, E.G.; Nesterova, N.P.; Kovalev, V.V.; Simonov, M.V.; Medved', T.Ya.; Kabachnik, M.I.; Buslaev, Yu.A.

    1991-01-01

    NbF 5 and TaF 5 complex formation reactions with cis-isomers of diphosphine dioxides in methylene chloride are studied by NMR 19 F and 31 P method. Interaction of TaF 5 with Ph 2 P(0)CH=CHP(0)Ph 2 (L) results information of three basic foprms in the solution: TaF 5 molecular complex, TaF 6 - anion and TaF 4 L + octahedral cation. At NbF 5 interaction with L besides NbF 6 anion trifluorocomplex, the NMP 19 F spectrum of which testifies to the presence of short-linked ligand in the first coordination sphere is observed. It is shown that cis-vinylenediphosphine dioxides in octahedral complexes of transition and nontransition elements may play the role of mono-and bidentant ligands, forming a bridge group or closing 7 member chelating cycle

  3. Selective chelation-supercritical fluid extraction of metal ions from waste materials

    International Nuclear Information System (INIS)

    Wai, C.N.; Laintz, K.E.; Yonker, C.R.

    1993-01-01

    The removal of toxic organics, metals, and radioisotopes from solids or liquids is a major concern in the treatment of industrial and nuclear wastes. For this reason, developing methods for selective separation of toxic metals and radioactive materials from solutions of complex matrix is an important problem in environmental research. Recent developments indicate supercritical fluids are good solvents for organic compounds. Many gases become supercritical fluids under moderate temperatures and pressures. For example, the critical temperature and pressure of carbon dioxide are 31 degrees C and 73 atm, respectively. The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties of supercritical fluid extraction (SFE). Since CO 2 offers the additional benefits of stability and non-toxicity, the SFE technique avoids generation of organic liquid waste and exposure of personnel to toxic solvents. While direct extraction of metal ions by supercritical fluids is highly inefficient, these ions when complexed with organic ligands become quite soluble in supercritical fluids. Specific ligands can be used to achieve selective extraction of metal ions in this process. After SFE, the fluid phase can be depressurized for precipitation of the metal chelates and recycled. The ligand can also be regenerated for repeated use. The success of this selective chelation-supercritical fluid extraction (SC-SFE) process depends on a number of factors including the efficiencies of the selective chelating agents, solubilities of metal chelates in supercritical fluids, rate of extraction, ease of regeneration of the ligands, etc. In this report, the authors present recent results on the studies of the solubilities of metal chelates in supercritical CO 2 , experimental ions from aqueous solution, and the development of selective chelating agents (ionizable crown ethers) for the extraction of lanthanides and actinides

  4. Diaquabis[2-(2-hydroxyethylpyridine-κ2N,O]cobalt(II dichloride

    Directory of Open Access Journals (Sweden)

    Hocine Merazig

    2013-08-01

    Full Text Available In the title salt, [Co(C7H9NO2(H2O2]Cl2, the CoII cation, located on an inversion center, is N,O-chelated by two hydroxyethylpyridine ligands and coordinated by two water molecules in a distorted O4N2 octahedral geometry. In the crystal, the Cl− anions link with the complex cations via O—H...Cl hydrogen bonds, forming a three-dimensional supramolecular architecture. π–π stacking is observed between the pyridine rings of adjacent molecules [centroid–centroid distance = 3.5810 (11 Å].

  5. Synthesis, characterization and vibrational spectra analysis of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate

    Science.gov (United States)

    Kıbrız, İbrahim Evren; Sert, Yusuf; Saçmacı, Mustafa; Şahin, Ertan; Yıldırım, İsmail; Ucun, Fatih

    2013-10-01

    In the present study, the experimental and theoretical vibrational spectra of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate (AOX) were investigated. The experimental FT-IR (400-4000 cm-1) and Laser-Raman spectra (100-4000 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles and torsion angles) were calculated using ab initio Hartree Fock (HF), Density Functional Theory (B3LYP and B3PW91) methods with 6-311++G(d,p) basis set by Gaussian 03 program, for the first time. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. The hydrogen bonding geometry of the molecule was also simulated to evaluate the effect of intermolecular hydrogen bonding on the vibrational frequencies. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were found.

  6. Substitutional disorder in the ionic diorganoantimony halide adduct [bromido/chlorido(0.33/0.67][2-(dimethylaminomethylphenyl][2-(dimethylammoniomethylphenyl]antimony(III 0.75-bromide 0.25-chloride

    Directory of Open Access Journals (Sweden)

    Albert P. Soran

    2010-04-01

    Full Text Available The title complex, [SbBr0.33Cl0.67(C9H13N(C9H12N]Br0.75Cl0.25, exhibits substitutional disorder of both halogen atoms in the asymmetric unit, however, with different occupancies. Thus, the halogen atom bonded to Sb has 0.67 (4 occupancy for Cl and 0.33 (4 for Br, while the anionic halogen atom shows 0.75 (4 occupancy for Br and 0.25 (4 for Cl. An N—H...Cl/Br hydrogen bond is established between the cation and the halide anion. The coordination geometry of the Sb center in the cation is distorted pseudo-trigonal-bipyramidal as a result of the strong intramolecular N→Sb coordination trans to the Sb—Cl/Br bond. The pendant arm on the second ligand is twisted away from the metal center. The compound crystallizes as a racemate, i.e. a mixture of (RN2,CSb1 and (SN2,ASb1 isomers with respect to planar chirality induced by the coordinating N atom and chelate-induced Sb chirality. These isomers are associated through Cphenyl—H...Cl/Br hydrogen bonds, forming a three-dimensional architecture.

  7. catena-Poly[[[aquapyridinezinc(II]-μ2-3,3′-(p-phenylenediacrylato] pyridine solvate

    Directory of Open Access Journals (Sweden)

    Dongpo Su

    2010-09-01

    Full Text Available The title compound, {[Zn(C12H8O4(C5H5N(H2O]·C5H5N}n, has been prepared by hydrothermal reaction. The ZnII atom is six-coordinated by four carboxylate O atoms of two p-phenylenediacrylate (ppda2− ligands, one N atom of a pyridine molecule and one O atom of a water molecule in a distorted octahedral environment. The carboxylate groups of the ppda2− anions are in a bridging–chelating mode, in which two O atoms chelate one Zn2+ ion. These connections result in an extended chain structure. Parallel packing of the chains forms a two-dimensional network with intermolecular edge-to-face interactions. Further linkages between the layers through O—H...O hydrogen-bonding interactions result in a three-dimensional supramolecular architecture with one-dimensional rectanglar channels.

  8. Which psychosocial factors are related to chelation adherence in thalassemia? A systematic review.

    Science.gov (United States)

    Evangeli, Michael; Mughal, Kulsoom; Porter, John B

    2010-06-01

    Good adherence to iron chelation therapy in thalassemia is crucial. Although there is evidence that adherence is related to regimen factors, there has been less emphasis on the relationship between psychosocial (psychological, demographic and social) factors and adherence. We present a systematic review of psychosocial correlates of chelation adherence in thalassemia. Nine studies met the inclusion criteria. Information was extracted regarding the study characteristics and the relationship between psychosocial factors and chelation adherence. Methodological quality was rated. The studies took place in a range of countries, were mostly cross sectional in design, and examined adherence to deferoxamine (DFO) only. Sample sizes ranged from 15 to 1573. A variety of psychosocial variables were examined. Definitions of adherence varied between studies and non adherence rates were also variable (9 to 66%). Older age was consistently associated with lower levels of chelation adherence. There were few other consistent findings. The methodological quality of studies was variable. There is a need for more methodologically sophisticated and theoretically informed studies on psychosocial correlates of chelation adherence. We offer specific suggestions.

  9. Simultaneous anion and cation mobility in polypyrrole

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; Vidanapathirana, K.

    2003-01-01

    and the expulsion of anions; a broad anodic peak centered at ca. - 0.5 V representing the expulsion of cations; and a second broad peak at +0.2 to +0.5 V corresponding to anions being inserted. Although the motion of cations is the most important, as expected, there is a significant anion contribution, thereby...... complicating reproducibility when employing PPy(DBS) polymers as actuators. When the cation is doubly charged, it enters the film less readily, and anions dominate the mobility. Using a large and bulky cation switches the mechanism to apparently total anion motion. The changes in area of the three peaks...

  10. Graphene-coated polymeric anion exchangers for ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Cao, Minyi; Lou, Chaoyan [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Wu, Shuchao, E-mail: wushch2002@163.com [Zhejiang Institute of Geology and Mineral Resources, Hangzhou 310007 (China); Zhang, Peimin [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Zhi, Mingyu [Hangzhou Vocational & Technical College, Hangzhou, 310018 (China); Zhu, Yan, E-mail: zhuyan@zju.edu.cn [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China)

    2017-06-01

    Carbonaceous stationary phases have gained much attention for their peculiar selectivity and robustness. Herein we report the fabrication and application of a graphene-coated polymeric stationary phase for anion exchange chromatography. The graphene-coated particles were fabricated by a facile evaporation-reduction method. These hydrophilic particles were proven appropriate substrates for grafting of hyperbranched condensation polymers (HBCPs) to make pellicular anion exchangers. The new phase was characterized by zeta potentials, Fourier transform infrared spectroscopy, thermogravimetry and scanning electron microscope. Frontal displacement chromatography showed that the capacities of the anion exchangers were tuned by both graphene amount and HBCPs layer count. The chromatographic performance of graphene-coated anion exchangers was demonstrated with separation of inorganic anions, organic acids, carbohydrates and amino acids. Good reproducibility was obtained by consecutive injections, indicating high chemical stability of the coating. - Highlights: • Graphene-coated polymeric particles were fabricated by a facile method. • Hyperbranched condensation polymers (HBCPs) were grafted from graphene-coated particles to make anion exchangers. • Graphene amount and HBCPs layer count had significant effects on the anion exchange capacities. • Separation of diverse anionic analytes on the anion exchangers was demonstrated. • The prepared anion exchangers exhibited high stability.

  11. Controlling Second Coordination Sphere Effects in Luminescent Ruthenium Complexes by Means of External Pressure.

    Science.gov (United States)

    Pannwitz, Andrea; Poirier, Stéphanie; Bélanger-Desmarais, Nicolas; Prescimone, Alessandro; Wenger, Oliver S; Reber, Christian

    2018-06-04

    Two luminescent heteroleptic Ru II complexes with a 2,2'-biimidazole (biimH 2 ) ligand form doubly hydrogen-bonded salt bridges to 4-sulfobenzoate anions in single crystals. The structure of one of these cation-anion adducts shows that the biimH 2 ligand is deprotonated. Its 3 MLCT luminescence band does not shift significantly under the influence of an external hydrostatic pressure, a behavior typical for these electronic transitions. In contrast, hydrostatic pressure on the other crystalline cation-anion adduct induces a shift of proton density from the peripheral N-H groups of biimH 2 towards benzoate, leading to a pronounced redshift of the 3 MLCT luminescence band. Such a significant and pressure-tunable influence from an interaction in the second coordination sphere is unprecedented in artificial small-molecule-based systems. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Deaths associated with hypocalcemia from chelation therapy--Texas, Pennsylvania, and Oregon, 2003-2005.

    Science.gov (United States)

    2006-03-03

    Chelating agents bind lead in soft tissues and are used in the treatment of lead poisoning to enhance urinary and biliary excretion of lead, thus decreasing total lead levels in the body. During the past 30 years, environmental and dietary exposures to lead have decreased substantially, resulting in a considerable decrease in population blood lead levels (BLLs) and a corresponding decrease in the number of patients requiring chelation therapy. Chelating agents also increase excretion of other heavy metals and minerals, such as zinc and, in certain cases, calcium. This report describes three deaths associated with chelation-therapy--related hypocalcemia that resulted in cardiac arrest. Several drugs are used in the treatment of lead poisoning, including edetate disodium calcium (CaEDTA), dimercaperol (British anti-Lewisite), D-penicillamine, and meso-2,3-dimercaptosuccinic acid (succimer). Health-care providers who are unfamiliar with chelating agents and are considering this treatment for lead poisoning should consult an expert in the chemotherapy of lead poisoning. Hospital pharmacies should evaluate whether continued stocking of Na2EDTA is necessary, given the established risk for hypocalcemia, the availability of less toxic alternatives, and an ongoing safety review by the Food and Drug Administration (FDA). Health-care providers and pharmacists should ensure that Na2EDTA is not administered to children during chelation therapy.

  13. A study on the adsorption and subsurface transport of radioactive solutes in the presence of chelating agents

    International Nuclear Information System (INIS)

    Baik, Min Hoon

    1994-02-01

    In this study, adsorption and transport models were developed to analyze the effect of chelating agents on the adsorption and subsurface transport of radioactive solutes. The effect of chelating agents on the adsorption of radioactive solutes was analyzed by developing an adsorption model based upon the extended concept of distribution coefficient reflecting the presence of chelating agents. Also, a batch adsorption experiment was conducted in order to validate the developed adsorption model and to investigate the effect of chelating agent on the adsorption of radioactive metal solutes. In this experiment, a Cobalt(II)/EDTA/Bentonite system was considered as a representative chelation/adsorption system. It was found from the results that the presence of chelating agents significantly reduced the adsorbing capacity of geologic media such as clay minerals and soils. Thus it was concluded that the presence of chelating agents even in a small amount could contribute to the mobilization of radioactive solutes from radioactive waste burial sites by reducing the adsorbing capacity of geologic media. The effect of chelating agents on the transport of radioactive solutes in subsurface porous media was analyzed by formulating an advective-dispersive transport model which incorporated chelate formation, adsorption, decay, and degradations and by introducing the concept of a tenad. Particularly the governing equation for the tenad of radioactive solutes, M, was presented as a linear partial differential form by introducing the extended distribution coefficient, K D . The calculated results from the model showed that the transport rate of the chelated radionuclides was much greater than that of the free ionic radionuclides. This much faster transport of the chelated radionuclides was found to be due to the lower retardation factor of the chelated radionuclides than the free ionic radionuclides. The effect of parameters on the transport of radioactive solutes was also analyzed

  14. Studies on effect of Microbial Iron Chelators on Candida Albican

    International Nuclear Information System (INIS)

    Rehmani, Fouzia S.; Milicent, S.; Zaheer-Uddin

    2005-01-01

    Iron is an essential for the life of all microbe cells. It generally exists in the oxidized form Fe(III). Even under anaerobic reducing condition the metal appear to be taken up as Fe(III). Thus free-living microorganisms require specific and effective ferric ion transport system to cope with low availability of the metal. In iron deficient environment they produce a low molecular weight specific chelators called siderphores or microbial iron chelators. Siderphores compete for limited supplied of iron. These compounds came out of the cell but can not re-enter without iron due to high affinity of these siderphores often have more than one catechol/hydroxamate functions and are multidentate (usually hexadentate ligands). The aim of the present research is to check the effect of iron chelators, namely gallic acid and salisyl hydroxamate on the growth of Candida albican in vitro. C. albican is the opportunistic paltogen present as the normal flora inside human body. In vivo the growth of C. albican is distributed by the use of antibiotics and immuno suppressers. In cases of iron over-dosage in human being, the patients are treated with certain a-iron chelators. Hence an attempt is made to notice the effect that might be inhibition or enhancement of the organism in vitro. (author)

  15. Chelation of thallium by combining deferasirox and desferrioxamine in rats.

    Science.gov (United States)

    Saljooghi, Amir Shokooh; Babaie, Maryam; Mendi, Fatemeh Delavar; Zahmati, Maliheh; Saljooghi, Zoheir Shokouh

    2016-01-01

    The hypothesis that two known chelators deferasirox (4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) and desferrioxamine (DFO) might be more efficient as combined treatment than as monotherapies in removing thallium from the body was tested in a new acute rat model. 7-week-old male Wistar rats received chelators: deferasirox (orally), DFO (intraperitoneal; i.p.), or deferasirox + DFO as 75 or 150 mg/kg dose half an hour after a single i.p. administration of 8 mg thallium/kg body weight in the form of chloride. Serum thallium concentration, urinary thallium, and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level, while DFO was more effective than deferasirox in enhancing urinary thallium excretion, deferasirox was more effective than DFO in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the DFO effect on thallium and DFO did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of thallium chelators. Urinary values were more useful because of the high variability of serum results. © The Author(s) 2013.

  16. Solvent extraction: the coordination chemistry behind extractive metallurgy.

    Science.gov (United States)

    Wilson, A Matthew; Bailey, Phillip J; Tasker, Peter A; Turkington, Jennifer R; Grant, Richard A; Love, Jason B

    2014-01-07

    The modes of action of the commercial solvent extractants used in extractive hydrometallurgy are classified according to whether the recovery process involves the transport of metal cations, M(n+), metalate anions, MXx(n-), or metal salts, MXx into a water-immiscible solvent. Well-established principles of coordination chemistry provide an explanation for the remarkable strengths and selectivities shown by most of these extractants. Reagents which achieve high selectivity when transporting metal cations or metal salts into a water-immiscible solvent usually operate in the inner coordination sphere of the metal and provide donor atom types or dispositions which favour the formation of particularly stable neutral complexes that have high solubility in the hydrocarbons commonly used in recovery processes. In the extraction of metalates, the structures of the neutral assemblies formed in the water-immiscible phase are usually not well defined and the cationic reagents can be assumed to operate in the outer coordination spheres. The formation of secondary bonds in the outer sphere using, for example, electrostatic or H-bonding interactions are favoured by the low polarity of the water-immiscible solvents.

  17. High-Relaxivity MRI Contrast Agents: Where Coordination Chemistry Meets Medical Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Eric J.; Datta, Ankona; Jocher, Christoph J.; Raymond, Kenneth N.

    2008-01-15

    The desire to improve and expand the scope of clinical magnetic resonance imaging (MRI) has prompted the search for contrast agents of higher efficiency. The development of better agents requires consideration of the fundamental coordination chemistry of the gadolinium(III) ion and the parameters that affect its efficacy as a proton relaxation agent. In optimizing each parameter, other practical issues such as solubility and in vivo toxicity must also be addressed, making the attainment of safe, high-relaxivity agents a challenging goal. Here we present recent advances in the field, with an emphasis on the hydroxypyridinone family of Gd{sup III} chelates.

  18. Making the invisible visible: improved electrospray ion formation of metalloporphyrins/-phthalocyanines by attachment of the formate anion (HCOO(-)).

    Science.gov (United States)

    Hitzenberger, Jakob Felix; Dammann, Claudia; Lang, Nina; Lungerich, Dominik; García-Iglesias, Miguel; Bottari, Giovanni; Torres, Tomás; Jux, Norbert; Drewello, Thomas

    2016-02-21

    A protocol is developed for the coordination of the formate anion (HCOO(-)) to neutral metalloporphyrins (Pors) and -phthalocyanines (Pcs) containing divalent metals as a means to improve their ion formation in electrospray ionization (ESI). This method is particularly useful when the oxidation of the neutral metallomacrocycle fails. While focusing on Zn(II)Pors and Zn(II)Pcs, we show that formate is also readily attached to Mn(II), Mg(II) and Co(II)Pcs. However, for the Co(II)Pc secondary reactions can be observed. Upon collision-induced dissociation (CID), Zn(II)Por/Pc·formate supramolecular complexes can undergo the loss of CO2 in combination with transfer of a hydride anion (H(-)) to the zinc metal center. Further dissociation leads to electron transfer and hydrogen atom loss, generating a route to the radical anion of the Zn(II)Por/Pc without the need for electrochemical reduction, although the Zn(II)Por/Pc may have a too low electron affinity to allow electron transfer directly from the formate anion. In addition to single Por molecules, multi Por arrays were successfully analyzed by this method. In this case, multiple addition of formate occurs, giving rise to multiply charged species. In these multi Por arrays, complexation of the formate anion occurs by two surrounding Por units (sandwich). Therefore, the maximum attainment of formate anions in these arrays corresponds to the number of such sandwich complexes rather than the number of porphyrin moieties. The same bonding motif leads to dimers of the composition [(Zn(II)Por/Pc)2·HCOO](-). In these, the formate anion can act as a structural probe, allowing the distinction of isomeric ions with the formate bridging two macrocycles or being attached to a dimer of directly connected macrocycles.

  19. Retention data of bile acids and their oxo derivatives in characterization of pharmacokinetic properties and in silico ADME modeling.

    Science.gov (United States)

    Trifunović, Jovana; Borčić, Vladan; Vukmirović, Saša; Kon, Svetlana Goločorbin; Mikov, Momir

    2016-09-20

    Information on ADME properties of examined bile acids and their oxo derivatives are scarce, although the interest for bile acids and their use in nanochemistry and macromolecular chemistry is increasing. The purpose of this research was to evaluate the lipophilicity, a crucial physicochemical parameter for describing ADME properties of selected bile acids and their oxo derivatives, and to compare two approaches: experimentally determined hydrophobicity parameters and calculated logP values. Commercially available bile acids - deoxycholic, chenodeoxycholic, hyodeoxycholic and ursodeoxycholic acid were used to synthesize oxo derivatives. Lipophilicity was evaluated in two solvent systems: toluene/ethanol and toluene/butanol. Retention parameters were acquired by normal-phase TLC. The correlations between calculated logP values obtained using five different software and experimentally determined hydrophobicity parameters (RM(0)(tol/eth), RM(0)(tol/but), b(tol/eth) and b(tol/but)) were examined. Correlation analysis confirmed significant dependence between experimental RM(0) values and software calculated parameters. Results suggest satisfactory intestinal absorption after oral administration for all of the examined compounds as well as low volumes of distribution, and high affinity for binding with plasma proteins. Penetration through blood-brain barrier and skin is not satisfactory. All of the examined compounds show high affinity for binding with G-protein coupled receptors and consequently inhibition of ionic channels. Results also suggest possible binding with nuclear receptors. Established lipophilicity testing model of studied compounds showed excellent predictive ability and might represent significant tool in development of relations between chromatographic behavior and ADME properties. Compounds 3α-hydroxy-7,12-dioxo-5β-cholanoic and 12α-hydroxy-3,7-dioxo-5β-cholanoic acid might be the most suitable candidates for further development studies (satisfactory

  20. Design, synthesis, and evaluation of polyhydroxamate chelators for selective complexation of actinides

    International Nuclear Information System (INIS)

    Gopalan, A.; Jacobs, H.; Koshti, N.; Stark, P.; Huber, V.; Dasaradhi, L.; Caswell, W.; Smith, P.; Jarvinen, G.

    1995-01-01

    Specific chelating polymers targeted for actinides have much relevance to problems involving remediation of nuclear waste. Goal is to develop polymer supported, ion specific extraction systems for removing actinides and other hazardous metal ions from wastewaters. This is part of an effort to develop chelators for removing actinide ions such as Pu from soils and waste streams. Selected ligands are being attached to polymeric backbones to create novel chelating polymers. These polymers and other water soluble and insoluble polymers have been synthesized and are being evaluated for ability to selectively remove target metal ions from process waste streams

  1. Synthesis of novel bifunctional chelators and their use in preparing monoclonal antibody conjugates for tumor targeting

    International Nuclear Information System (INIS)

    Westerberg, D.A.; Carney, P.L.; Rogers, P.E.; Kline, S.J.; Johnson, D.K.

    1989-01-01

    Bifunctional derivatives of the chelating agents ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, in which a p-isothiocyanatobenzyl moiety is attached at the methylene carbon atom of one carboxymethyl arm, was synthesized by reductive alkylation of the relevant polyamine with (p-nitrophenyl)pyruvic acid followed by carboxymethylation, reduction of the nitro group, and reaction with thiophosgene. The resulting isothiocyanate derivatives reacted with monoclonal antibody B72.3 to give antibody-chelator conjugates containing 3 mol of chelator per mole of immunoglobulin, without significant loss of immunological activity. Such conjugates, labeled with the radioisotopic metal indium-111, selectively bound a human colorectal carcinoma implanted in nude mice when given intravenously. Uptake into normal tissues was comparable to or lower than that reported for analogous conjugates with known bifunctional chelators. It is concluded that substitution with a protein reactive group at this position in polyaminopolycarboxylate chelators does not alter the chelating properties of these molecules to a sufficient extent to adversely affect biodistribution and thus provides a general method for the synthesis of such chelators

  2. Metal-chelating compounds produced by ectomycorrhizal fungi collected from pine plantations.

    Science.gov (United States)

    Machuca, A; Pereira, G; Aguiar, A; Milagres, A M F

    2007-01-01

    To investigate the in vitro production of metal-chelating compounds by ectomycorrhizal fungi collected from pine plantations in southern Chile. Scleroderma verrucosum, Suillus luteus and two isolates of Rhizopogon luteolus were grown in solid and liquid modified Melin-Norkans (MMN) media with and without iron addition and the production of iron-chelating compounds was determined by Chrome Azurol S (CAS) assay. The presence of hydroxamate and catecholate-type compounds and organic acids was also investigated in liquid medium. All isolates produced iron-chelating compounds as detected by CAS assay, and catecholates, hydroxamates as well as oxalic, citric and succinic acids were also detected in all fungal cultures. Scleroderma verrucosum produced the greatest amounts of catecholates and hydroxamates whereas the highest amounts of organic acids were detected in S. luteus. Nevertheless, the highest catecholate, hydroxamate and organic acid concentrations did not correlate with the highest CAS reaction which was observed in R. luteolus (Yum isolate). Ectomycorrhizal fungi produced a variety of metal-chelating compounds when grown in liquid MMN medium. However, the addition of iron to all fungi cultures reduced the CAS reaction, hydroxamate and organic acid concentrations. Catecholate production was affected differently by iron, depending on the fungal isolate. The ectomycorrhizal fungi described in this study have never been reported to produce metal-chelating compound production. Moreover, apart from some wood-rotting fungi, this is the first evidence of the presence of catecholates in R. luteolus, S. luteus and S. verrucosum cultures.

  3. Effect of other metals on iron bioavailability in presence of a selective chelator

    International Nuclear Information System (INIS)

    Rehman, F.S.

    1995-01-01

    Iron (III) is generally very easily chelated by a number of chelators in the biological environment, either supplied by food or already present there. One of the these chelator is gallic acid. The stability constants of the complexes formed between gallic acid and other trace metals have been determined by a potentiometric method. The data obtained was computed with the help of computer program B est . The resulted Beta values were compared with already known values of iron gallic acid complexes. (author)

  4. Solvent extraction of anionic chelate complexes of lanthanum(III), europium(III), lutetium(III), scandium(III), and indium(III) with 2-thenoyltrifluoroacetone as ion-pairs with tetrabutylammonium ions

    International Nuclear Information System (INIS)

    Noro, Junji; Sekine, Tatsuya.

    1992-01-01

    The solvent extraction of lanthanum(III), europium(III), lutetium(III), scandium(III), and indium(III) in 0.1 mol dm -3 sodium nitrate solutions with 2-thenoyltrifluoroacetone (Htta) in the absence and presence of tetrabutylammonium ions (tba + ) into carbon tetrachloride was measured. The extraction of lanthanum(III), europium(III), and lutetium(III) was greatly enhanced by the addition of tba + ; this could be explained in terms of the extraction of a ternary complex, M(tta) 4 - tba + . However, the extractions of scandium(III) and indium(III) were nearly the same when tba + was added. The data were treated on the basis of the formation equilibrium of the ternary complex from the neutral chelate, M(tta) 3 , with the extracted ion-pairs of the reagents, tta - tba + , in the organic phase. It was concluded that the degree of association of M(tta) 3 with the ion-pair, tta - tba + , is greater in the order La(tta) 3 ≅ Eu(tta) 3 > Lu(tta) 3 , or that the stability of the ternary complex in the organic phase is higher in the order La(tta) 4 - tba + ≅ Eu(tta) 4 - tba + > Lu(tta) 4 - tba + . This is similar to those of adduct metal chelates of Htta with tributylphosphate (TBP) in synergistic extraction systems. (author)

  5. Chelation therapy in intoxications with mercury, lead and copper

    DEFF Research Database (Denmark)

    Cao, yang; Skaug, Marit Aralt; Andersen, Ole

    2015-01-01

    In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively...... mobilize deposits of mercury as well as of lead into the urine. These drugs can be administered orally and have relatively low toxicity compared to the classical antidote dimercaptopropanol (BAL). d-Penicillamine has been widely used in copper overload, although 2,3-dimercaptosuccinic acid...

  6. New compounds bearing [M(S_2O_7)_3]"2"- anions (M = Si, Ge, Sn): Syntheses and characterization of A_2[Si(S_2O_7)_3] (A = Na, K, Rb), A_2[Ge(S_2O_7)_3] (A = Li, Na, K, Rb, Cs), A_2[Sn(S_2O_7)_3] (A = Na, K), and the unique germanate Hg_2[Ge(S_2O_7)_3]Cl_2 with cationic "1_∞[HgCl_2_/_2]"+ chains

    International Nuclear Information System (INIS)

    Logemann, Christian; Witt, Julia; Wickleder, Mathias S.; Gunzelmann, Daniel; Senker, Juergen

    2012-01-01

    The reaction of the group 14 tetrachlorides MCl_4 (M = Si, Ge, Sn) with oleum (65 % SO_3) at elevated temperatures led to the unique anionic complexes [M(S_2O_7)_3]"2"- that show the central M atoms in coordination of three chelating S_2O_7"2"- groups. The mean distances M-O within the complexes increase from 175 pm (M = Si) via 186 pm (M = Ge) up to 200 pm (M = Sn). The charge balance for the [M(S_2O_7)_3]"2"- anions is achieved by alkaline metal ions A"+ (A = Li, Na, K, Rb, Cs) which were implemented in the syntheses in form of their sulfates. The size of the A"+ ions, i.e. their coordination requirement causes the crystallographic differences in the crystal structures, while the structure of the complex [M(S_2O_7)_3]"2"- anions remains essentially unaffected. Furthermore, we were able to characterize the unique germanate Hg_2[Ge(S_2O_7)_3]Cl_2 which forms when HgCl_2 is added as a source for the counter cation. The Hg"2"+ and the Cl"- ions form infinite cationic chains according to "1_∞[HgCl_2_/_2]"+ which take care for the charge compensation. For selected examples of the compounds the thermal behavior has been monitored by means of thermal analyses and X-ray powder diffraction. For A being an alkaline metal the decomposition product is a mixture of the sulfates A_2SO_4 and the dioxides MO_2, whereas Hg_2[Ge(S_2O_7)_3]Cl_2 shows a more complicated decomposition. The tris-(disulfato)-silicate Na_2[Si(S_2O_7)_3] has additionally been examined by solid state "2"9Si and "2"3Na NMR spectroscopic measurements. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Coordination compounds of metals with imidazoles and benzimidazoles

    International Nuclear Information System (INIS)

    Novikova, G.A.; Molodkin, A.K.; Kukalenko, S.S.

    1988-01-01

    Methods of preparation, composition and structure of UO 2 2+ , Th 4+ , Mo 3+ , Cd 2+ , Ln 3+ metal ion complexes with imidazoles and benzimidazoles are considered in reviews of native and foreign literature of up to 1985. Complexes are customarily prepared by direct interaction of ligands with inorganic salts in different organic solvents. Complex composition is defined by the nature of complexing metal and inorganic salt anion, ligand volume and basicity, as well as solvent characteristics. Effect of R substituent in imidazole and benzimidazole side chain on composition of coordination compounds is considered

  8. Study of the simultaneous complexation of a cation and of an anion using functionalized calixarenes; Etude de la complexation simultanee d'un cation et d'un anion par des calixarenes fonctionnalises

    Energy Technology Data Exchange (ETDEWEB)

    Moli, Ch. [CEA Cadarache, Dept. d' Etudes des Dechets, DED, 13 - Saint Paul lez Durance (France)]|[Universite Louis Pasteur, 67 - Strasbourg (France)

    2002-03-01

    The chemical reprocessing of irradiated nuclear fuels leads to the production of high-level radioactive liquid wastes which contain long-lived toxic radioelements. In the framework of the long-term management of these wastes, important research work is carried out for the separation of these radioelements for their further transmutation or immobilization inside specific matrices. These radioelements are present in acid solutions of fission products in the form of cations (cesium), anions (technetium, selenium) and molecules (iodine). Crown calixarenes have been successfully used for the extraction of cesium thanks to their exceptional selectivities. This work is mainly based on the use of the chelating properties of calixarenes for the extraction of anionic radioelements. Calixarenes functionalized by amino-carbon chains have been selected. The synthesis of amine calix[4]arenes and calix[6]arenes is described and their extractive and ionophoretic properties with respect to radioelements are shown using aqueous selective separation techniques like the liquid-liquid extraction and the supported liquid membrane transport. Technetium and selenium are extracted by amine calixarenes from a 10{sup -2} M aqueous solution of nitric acid. At this acidity, no selenium transport is observed, while technetium transport is efficient: the solution is quasi-totally decontaminated in 6 hours. Molecular iodine is efficiently extracted with a simple organic diluent, the 1,2-nitro-phenyl-hexyl-ether, from a strongly concentrated aqueous solution of nitric acid (HNO{sub 3} = 3 M). The transport of iodine becomes faster and more efficient when its concentration in the solution is higher. (J.S.)

  9. Effect of cation-anion interactions on the structural and vibrational properties of 1-buthyl-3-methyl imidazolium nitrate ionic liquid

    Science.gov (United States)

    Kausteklis, Jonas; Aleksa, Valdemaras; Iramain, Maximiliano A.; Brandán, Silvia Antonia

    2018-07-01

    The cation-anion interactions present in the 1-butyl-3-methylimidazolium nitrate ionic liquid [BMIm][NO3] were studied by using density functional theory (DFT) calculations and the experimental FT-Raman spectrum in liquid phase and its available FT-IR spectrum. For the three most stable conformers found in the potential energy surface and their 1-butyl-3-methylimidazolium [BMIm] cation, the atomic charges, molecular electrostatic potentials, stabilization energies, bond orders and topological properties were computed by using NBO and AIM calculations and the hybrid B3LYP level of theory with the 6-31G* and 6-311++G** basis sets. The force fields, force constants and complete vibrational assignments were also reported for those species by using their internal coordinates and the scaled quantum mechanical force field (SQMFF) approach. The dimeric species of [BMIm][NO3] were also considered because their presence could probably explain the most intense bands observed at 1344 and 1042 cm-1 in both experimental FT-IR and FT-Raman spectra, respectively. The geometrical parameters suggest monodentate cation-anion coordination while the studies by charges, NBO and AIM calculations support bidentate coordinations between those two species. Additionally several quantum chemical descriptors were also calculated in order to interpret various molecular properties such as electronic structure, reactivity of those species and predict their gas phase behaviours.

  10. Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

    Energy Technology Data Exchange (ETDEWEB)

    Fatimah, Soja Siti, E-mail: soja-sf@upi.edu [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Bahti, Husein H.; Hastiawan, Iwan [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Permanasari, Anna [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia)

    2016-02-08

    The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, ({sup 1}H, and {sup 13}C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

  11. Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

    Science.gov (United States)

    Fatimah, Soja Siti; Bahti, Husein H.; Hastiawan, Iwan; Permanasari, Anna

    2016-02-01

    The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

  12. The assessment of pellicular anion-exchange resins for the determination of anions by ion chromatography

    International Nuclear Information System (INIS)

    Pohlandt, C.

    1981-01-01

    Because pellicular anion-exchange resins suitable for the determination, by ion chromatography, of anions with alkaline eluents were unavailable in South Africa at the inception of this work, an attempt was made to prepare such resins. In this study it is shown that the pellicular resins produced are more efficient than the surface-aminated resins used previously. The simultaneous separation and determination of five common anions is demonstrated. The method was applied to the analysis of uranium leach liquors, effluent samples, and a solid sample of ferric oxide (goethite)

  13. Chelating extractants of improved selectivity. Progress report, September 1, 1976--October 31, 1977

    International Nuclear Information System (INIS)

    Freiser, H.

    1977-07-01

    New means of characterizing metal chelating reagent selectivity have been developed and incorporated into a theoretical factor analysis of the chelate stability constants of 24 metal ions with 14 ligands of the EDTA family. The factor analysis will be extended to extracting ligand families. A computer-controlled automated metal chelate stability constant apparatus has been assembled and successfully tested. A high performance liquid chromatograph has been set up and preliminary examination of comparison of reversed phase chromatographic separation of metal ions with their solvent extraction behavior begun

  14. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

    International Nuclear Information System (INIS)

    Wang, Lai-Sheng

    2015-01-01

    Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent development in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES

  15. Oxidative degradation stability and hydrogen sulfide removal performance of dual-ligand iron chelate of Fe-EDTA/CA.

    Science.gov (United States)

    Miao, Xinmei; Ma, Yiwen; Chen, Zezhi; Gong, Huijuan

    2017-09-05

    Catalytic oxidation desulfurization using chelated iron catalyst is an effective method to remove H 2 S from various gas streams including biogas. However, the ligand of ethylenediaminetetraacetic acid (EDTA), which is usually adopted to prepare chelated iron catalyst, is liable to be oxidative degraded, and leads to the loss of desulfurization performance. In order to improve the degradation stability of the iron chelate, a series of iron chelates composed of two ligands including citric acid (CA) and EDTA were prepared and the oxidative degradation stability as well as desulfurization performance of these chelated iron catalysts were studied. Results show that the iron chelate of Fe-CA is more stable than Fe-EDTA, while for the desulfurization performance, the situation is converse. For the dual-ligand iron chelates of Fe-EDTA/CA, with the increase of mol ratio of CA to EDTA in the iron chelate solution, the oxidative degradation stability increased while the desulfurization performance decreased. The results of this work showed that Fe-EDTA/CA with a mol ratio of CA:EDTA = 1:1 presents a relative high oxidative degradation stability and an acceptable desulfurization performance with over 90% of H 2 S removal efficiency.

  16. Mathematical modeling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

    International Nuclear Information System (INIS)

    Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E.; Reed, D.T.

    1998-01-01

    Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems

  17. Mathematical modelling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

    International Nuclear Information System (INIS)

    Banaszak, J.E.; VanBriesen, J.M.; Rittmann, B.E.; Reed, D.T.

    1998-01-01

    Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and hence, the mobility of actinides in subsurface environments. We combined mathematical modelling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bioutilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modelling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems. (orig.)

  18. High precision isotopic ratio analysis of volatile metal chelates

    International Nuclear Information System (INIS)

    Hachey, D.L.; Blais, J.C.; Klein, P.D.

    1980-01-01

    High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

  19. Carbonate formation within a nickel dimer: synthesis of a coordinatively unsaturated bis(mu-hydroxo) dinickel complex and its reactivity toward carbon dioxide.

    Science.gov (United States)

    Wikstrom, Jeffrey P; Filatov, Alexander S; Mikhalyova, Elena A; Shatruk, Michael; Foxman, Bruce M; Rybak-Akimova, Elena V

    2010-03-14

    The tridentate aminopyridine ligand bearing a bulky tert-butyl substituent at the amine nitrogen, tert-butyl-dipicolylamine (tBuDPA), occupies three coordination sites in six-coordinate complexes of nickel(ii), leaving the remaining three sites available for additional ligand binding and activation. New crystallographically characterized complexes include two mononuclear species with 1:1 metal:ligand complexation: a trihydrate solvate (1.3H(2)O) and a monohydrate biacetonitrile solvate (1.H(2)O.2CH(3)CN). Complexation in the presence of sodium hydroxide results in a bis(mu-hydroxo) complex (2), the bridging hydroxide anions of which are labile and become displaced by methoxide anions in methanol solvent, affording bis-methoxo-bridged (4). Nickel(II) centers in 2 are five-coordinate and antiferromagnetically coupled (with J = -31.4(5) cm(-1), H = -2JS(1)S(2), in agreement with Ni-O-Ni angle of 103.7 degrees). Bridging hydroxide or alkoxide anions in coordinatively unsaturated dinuclear nickel(II) complexes with tBuDPA react as active nucleophiles. 2 readily performs carbon dioxide fixation, resulting in the formation of a bis(mu-carbonato) tetrameric complex (3), which features a novel binding geometry in the form of an inverted butterfly-type nickel-carbonate core. Temperature-dependent magnetic measurements of tetranuclear carbonato-bridged revealed relatively weak antiferromagnetic coupling (J(1) = -3.1(2) cm(-1)) between the two nickel centers in the core of the cluster, as well as weak antiferromagnetic pairwise interactions (J(2) = J(3) = -4.54(5) cm(-1)) between central and terminal nickel ions.

  20. Red Blood Cell Transfusion Independence Following the Initiation of Iron Chelation Therapy in Myelodysplastic Syndrome

    Directory of Open Access Journals (Sweden)

    Maha A. Badawi

    2010-01-01

    Full Text Available Iron chelation therapy is often used to treat iron overload in patients requiring transfusion of red blood cells (RBC. A 76-year-old man with MDS type refractory cytopenia with multilineage dysplasia, intermediate-1 IPSS risk, was referred when he became transfusion dependent. He declined infusional chelation but subsequently accepted oral therapy. Following the initiation of chelation, RBC transfusion requirement ceased and he remained transfusion independent over 40 months later. Over the same time course, ferritin levels decreased but did not normalize. There have been eighteen other MDS patients reported showing improvement in hemoglobin level with iron chelation; nine became transfusion independent, nine had decreased transfusion requirements, and some showed improved trilineage myelopoiesis. The clinical features of these patients are summarized and possible mechanisms for such an effect of iron chelation on cytopenias are discussed.