The Professional Development of High School Chemistry Coordinators

Science.gov (United States)

Hofstein, Avi; Carmeli, Miriam; Shore, Relly

2004-02-01

The implementation of new content and pedagogical standards in science education necessitates intensive, long-term professional development of science teachers. In this paper, we describe the rationale and structure of a comprehensive and intensive professional development program of school-based leaders, namely school chemistry coordinators. The year-long program was designed so that the chemistry teachers who enrolled in the program were able to develop in three interrelated aspects: content knowledge, pedagogical content knowledge, and leadership ability. Several strategies for the development of these aspects were adopted from Loucks-Horsley, Hewson, Love, & Stiles (1998). The evaluation of the program focused on the changes that participating teachers underwent regarding their personal beliefs and their functioning as school chemistry coordinators in their schools.

Rhenium radioisotopes for therapeutic radiopharmaceutical development

International Nuclear Information System (INIS)

Knapp, F.F. Jr.; Beets, A.L.; Pinkert, J.; Kropp, J.; Lin, W.Y.; Wang, S.Y.

2001-01-01

Rhenium-186 and rhenium-188 represent two important radioisotopes which are of interest for a variety of therapeutic applications in oncology, nuclear medicine and interventional cardiology. Rhenium-186 is directly produced in a nuclear reactor and the 90 hour half-life allows distribution to distant sites. The relatively low specific activity of rhenium-186 produced in most reactors, however, permits use of phosphonates, but limits use for labelled peptides and antibodies. Rhenium-188 has a much shorter 16.9 hour half-life which makes distribution from direct reactor production difficult. However, rhenium-188 can be obtained carrier-free from a tungsten-188/rhenium-188 generator, which has a long useful shelf-life of several months which is cost-effective, especially for developing regions. In this paper we discuss the issues associated with the production of rhenium-186- and rhenium-188 and the development and use of various radiopharmaceuticals and devices labelled with these radioisotopes for bone pain palliation, endoradiotherapy of tumours by selective catheterization and tumour therapy using radiolabelled peptides and antibodies, radionuclide synovectomy and the new field of vascular radiation therapy. (author)

Non-traditional Oxidants in Preparative Coordination Chemistry

Science.gov (United States)

Kukushkin, Vadim Yu; Kukushkin, Yurii N.

1986-10-01

The application of nitrosonium and arenediazonium salts, carbenium, silver(I), and mercury(II) ions, protic acids, and amine oxides as oxidants in preparative coordination chemistry is examined. Specific examples illustrate which problems in the field of the synthesis and reactions of coordination compounds can be solved with the aid of these oxidants. The bibliography includes 158 references.

Coordination chemistry of technetium as related to nuclear medicine

International Nuclear Information System (INIS)

Srivastava, S.C.; Richards, P.

1982-01-01

Significant advances have been made in the area of technetium coordination chemistry during the last five years. The main driving force behind this recent surge of interest in the field has been due to the practical application of technetium-99m in the rapidly growing speciality of nuclear medicine. Technetium-99 is one of the products of nuclear fission reactions, but it was the development of the molybdenum-99-technetium-99m generator about two decades ago that provided the basis for the development of radiopharmaceuticals routinely used in modern diagnostic applications. The chemistry of this element has proven to be quite rich owing to its multiple oxidation states and variable geometry. This can be attributed to its position in the middle of the periodic table. Diagnostic radiopharmaceuticals comprise predominantly III, IV and V oxidation states of Tc and involve a variety of coordination complexes. Even though the chemistry of Tc has been slow to evolve, recent synthetic advances have provided a more scientific basis for the study of a number of compounds with diverse coordination geometries and structures. Ligands with oxygen, nitrogen and sulfur donor atoms have been utilized to elucidate various aspects of the coordination chemistry of Tc. Single crystal X-ray structural analysis has been extensively used to characterize Tc complexes and thus construct a firm foundation for the study of synthetic and mechanistic aspects of the chemistry of this element. (author)

Femtosecond Fluorescence and Intersystem Crossing in Rhenium(I) Carbonyl-Bipyridine Complexes

Czech Academy of Sciences Publication Activity Database

Cannizzo, A.; Blanco-Rodríguez, A. M.; Nahhas, A. E.; Šebera, Jakub; Záliš, Stanislav; Vlček, Antonín; Chergui, M.

2008-01-01

Roč. 130, č. 28 (2008), s. 8967-8974 ISSN 0002-7863 R&D Projects: GA MŠk 1P05OC068 Institutional research plan: CEZ:AV0Z40400503 Keywords : rhenium(I) * carbonyl-bipyridine * intersystem crossing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 8.091, year: 2008

Rhenium Re

International Nuclear Information System (INIS)

Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

1978-01-01

The basic methods for determining rhenium in various objects are presented. The gravimetric determination of rhenium is based on a quantitative precipitation of ReO 4 - ions with tetraphenylarsonium chloride. The determination is not hindered by tungstates and molybdates. The potentiometric determination of rhenium in alloys (>=0.5% Re) is based on perrhenate ion reduction to Re(4) with the titrated solution of the Cr(2) salt. Re(7) is titrated in a hot sulfuric acid solution in the presence of KJ. The relative error of the method is 1 to 3%. The photometric determination of rhenium is performed by the rhodamide method in molybdenum-and tungsten-containing alloys and catalytically, in rocks, after it has been separated in the form of sulfide. The extraction-photometric determination of rhenium is carried out with the aid of methyl violet (analysis of a stock with a high content of Mo, W, Ta, Nb, Ti ahd Zr) and thio-oxine (the determination of Re is hindered by Au, Pt, Pd, Ru, Os, Rh, Ir). Also described are methods for differential-spectrophotometric determination of Re with the aid of thiocarbamide, as well as with the aid of dimethylglyoxime in the presence of SnCl 2 in an acid medium when Re is determined in its alloys with niobium and hafnium. It takes 2 hours to analyze the Hf-Re alloy and 3 hours to analyze the Nb-Re alloy, the standard deviation being 0.005 at 30-50% Re and 0.027 to 0.019 at 10-50% Re

Forschungszentrum Rossendorf, Institute of Bioinorganic and Radiopharmaceutical Chemistry. Annual report 1995

International Nuclear Information System (INIS)

Johannsen, B.

1996-02-01

Research at the Institute of Bioinorganic and Radiopharmaceutical Chemistry of the Research Center Rossendorf is focused on radiotracers as molecular probes for diagnosis of disease. The research effort has two main components: -Positron emission tomography (PET) - technetium chemistry and radiopharmacology. The research activities of the Institute have been performed in three administratively classified groups. A PET tracer group is engaged in the chemistry and radiopharmacy of 11 C and 18 F compounds and in the setup of the PET center. A SPECT tracer group deals with the design, synthesis and chemical characterization of metal coordination compounds, primarily rhenium and technetium complexes. A biochemical group is working on SPECT and PET-relevant biochemical and biological projects. This includes the characterization and assessment of new compounds developed in the two synthetically oriented groups. The annual report presented here covers the research activities of the Institute of Bioinorganic and Radiopharmaceutical Chemistry in 1995. (orig.)

Electrochemical behaviour of rhenium-graphite electrode

International Nuclear Information System (INIS)

Varypaev, V.N.; Krasikov, V.L.

1980-01-01

Electrochemical behaviour of combination electrode from graphite with electrodeposited thin coating of electrolytic rhenium is studied. Solution of 0.5 m NaCl+0.04 m AlCl 3 served as an electrolite. Polarization galvanostatic curves of hydrogen evolution upon electrodes with conditional rhenium thickness of 3.5 and 0.35 μm, 35 and 3.5 nm are obtained. Possibility of preparation of rhenium-graphite cathode with extremely low rhenium consume, electro-chemical properties of which are simu-lar to purely rhenium cathode is shown. Such electrode is characterized with stable in time low cathode potential of hydrogen evolution in chloride electrolyte and during cathode polarization it is not affected by corrosion

Rhenium Rocket Manufacturing Technology

Science.gov (United States)

1997-01-01

The NASA Lewis Research Center's On-Board Propulsion Branch has a research and technology program to develop high-temperature (2200 C), iridium-coated rhenium rocket chamber materials for radiation-cooled rockets in satellite propulsion systems. Although successful material demonstrations have gained much industry interest, acceptance of the technology has been hindered by a lack of demonstrated joining technologies and a sparse materials property data base. To alleviate these concerns, we fabricated rhenium to C-103 alloy joints by three methods: explosive bonding, diffusion bonding, and brazing. The joints were tested by simulating their incorporation into a structure by welding and by simulating high-temperature operation. Test results show that the shear strength of the joints degrades with welding and elevated temperature operation but that it is adequate for the application. Rhenium is known to form brittle intermetallics with a number of elements, and this phenomena is suspected to cause the strength degradation. Further bonding tests with a tantalum diffusion barrier between the rhenium and C-103 is planned to prevent the formation of brittle intermetallics.

Near-Net Shape Powder Metallurgy Rhenium Thruster

Science.gov (United States)

Leonhardt, Todd; Hamister, Mark; Carlen, Jan C.; Biaglow, James; Reed, Brian

2001-01-01

This paper describes the development of a method to produce a near-net shape (NNS) powder metallurgy (PM) rhenium combustion chamber of the size 445 N (100 lbf) used in a high performance liquid apogee engine. These engines are used in low earth Orbit and geostationary orbit for satellite positioning systems. The developments in near-net shape powder metallurgy rhenium combustion chambers reported in this paper will reduce manufacturing cost of the rhenium chambers by 25 percent, and reduce the manufacturing time by 30 to 40 percent. The quantity of rhenium metal powder used to produce a rhenium chamber is reduced by approximately 70 percent and the subsequent reduction in machining schedule and costs is nearly 50 percent.

Directed light fabrication of rhenium components

Energy Technology Data Exchange (ETDEWEB)

Milewski, J.O.; Thoma, D.J.; Lewis, G.K.

1997-02-01

Directed Light Fabrication (DLF) is a direct metal deposition process that fuses powder, delivered by gas into the focal zone of a high powered laser beam to form fully dense near-net shaped components. This is accomplished in one step without the use of molds, dies, forming, pressing, sintering or forging equipment. DLF is performed in a high purity inert environment free from the contaminants associated with conventional processing such as oxide and carbon pickup, lubricants, binding agents, cooling or cleaning agents. Applications using rhenium have historically been limited in part by its workability and cost. This study demonstrates the ability to fuse rhenium metal powder, using a DLF machine, into free standing rods and describes the associated parameter study. Microstructural comparisons between DLF deposited rhenium and commercial rhenium sheet product is performed. This research combined with existing DLF technology demonstrates the feasibility of forming complex rhenium, metal shapes directly from powder.

Redox reactivity and coordination chemistry of uranium

International Nuclear Information System (INIS)

Nocton, G.

2009-09-01

The study and the understanding of actinides chemistry have important implications in the nuclear field both for the development of new actinides materials and the retreatment of the nuclear wastes. One of the major issues in that chemistry is that the actinides elements are known to undergo redox reaction and to form assemblies of different size and different topologies. In that context uranium can be a good model of the heavier radioelement because it is much less radioactive. So, this work concerns the synthesis and the study of the spectroscopy and the magnetic properties of several uranium based polymetallic assemblies synthesized by taking advantage of the redox properties and the coordination chemistry of uranium. The hydrolysis reactivity of trivalent uranium has been studied in absence of sterically hindered ligands and led to the synthesis of oxo/hydroxo uranium assemblies with different sizes by changing the starting complex or the reaction conditions. By following the same strategy, the controlled oxidation of trivalent uranium complexes led to an original azido/nitrido uranium complex. The coordination chemistry of the pentavalent uranyl polymer {[UO 2 py 5 ][KI 2 py 3 ]} n has also been studied with different ligand and in different conditions and led to several cation-cation complexes for which the stability is sufficient for studying there dismutation by proton NMR. By changing the ancillary ligands stable monomeric complexes of pentavalent uranyl complexes were also obtained. The magnetic properties of all the complexes, monomers and polymetallic complexes were studied and an antiferromagnetic coupling was observed for the cation-cation pentavalent uranyl dimer [UO 2 (dbm) 2 (K 18 C 6 )] 2 . (author)

Thermal conduction and linear expansion of sintered rhenium and tungsten-rhenium alloys at a temperature up to 1000 K

International Nuclear Information System (INIS)

Pozdnyak, N.Z.; Belyaev, R.A.; Vavilov, Yu.V.; Vinogradov, Yu.G.; Serykh, G.M.

1978-01-01

Preparation technology (by powder metallurgy methods) of sintered rhenium and tungsten-rhenium VR-5, VR-10, and VR-20 alloys is described. Thermal conduction of rhenium and VR-20 alloy has been measured in the temperature range from 300 to 1000 K. The value obtained turned out to be considerably less than those published elsewhere, this testifies to the great thermal contact resistance between the material grains. Also measured is the mean linear expansion coefficient for the mentioned above materials in the same temperature range. Linear expansion increases with rhenium content increase

Rhenium-osmium geochemistry: method and applications

International Nuclear Information System (INIS)

Luck, J.M.

1982-03-01

Experimental methods for chemical separation and isotopic analysis of rhenium-osmium are described. Accurate determinations are obtained for a quantity ratio around 10 -6 -10 -7 g. Development as a geochemical tracer is examined. Study of rhenium-osmium in meteorites allows the determination of solar system chronology and age of the galaxy. Rhenium-osmium chronology in meteorites is improved and osmium isotopes are used as petrogenetic and geological tracers. Molybdenites are studied through 187 Re- 187 Os dating [fr

Rhenium Nanochemistry for Catalyst Preparation

Directory of Open Access Journals (Sweden)

Vadim G. Kessler

2012-08-01

Full Text Available The review presents synthetic approaches to modern rhenium-based catalysts. Creation of an active center is considered as a process of obtaining a nanoparticle or a molecule, immobilized within a matrix of the substrate. Selective chemical routes to preparation of particles of rhenium alloys, rhenium oxides and the molecules of alkyltrioxorhenium, and their insertion into porous structure of zeolites, ordered mesoporous MCM matrices, anodic mesoporous alumina, and porous transition metal oxides are considered. Structure-property relationships are traced for these catalysts in relation to such processes as alkylation and isomerization, olefin metathesis, selective oxidation of olefins, methanol to formaldehyde conversion, etc.

Comprehensive coordination chemistry. The synthesis, reactions, properties and applications of coordination compounds. V.3. Main group and early transition elements

International Nuclear Information System (INIS)

Wilkinson, Geoffrey; Gillard, R.D.; McCleverty, J.A.

1987-01-01

Comprehensive coordination chemistry reviews the synthesis reactions and properties of coordination compounds. Their uses in such diverse fields as nuclear fuels, toxicology, medicine and biology are discussed. Volume three concentrates on the main group and early transition element coordination compounds. (UK)

Rhenium corrosion in chloride melts

International Nuclear Information System (INIS)

Stepanov, A.D.; Shkol'nikov, S.N.; Vetyukov, M.M.

1989-01-01

The results investigating rhenium corrosion in chloride melts containing sodium, potassium and chromium ions by a gravimetry potentials in argon atmosphere in a sealing quarth cell are described. Rhenium corrosion is shown to be rather considerable in melts containing CrCl 2 . The value of corrosion rate depending on temperature is determined

Near net shape of powder metallurgy rhenium parts

International Nuclear Information System (INIS)

Leonhardt, T.; Downs, J.

2001-01-01

In this paper, a description of the stages of processing necessary to produce a near-net shape (NNS) powder metallurgy (PM) rhenium component through the use of cold isostatic pressing (CIP) to form a complex shape will be explained. This method was primarily developed for the production of the 440 N and 490 N liquid apogee engine combustion chambers used in satellite positioning systems. The CIP to NNS process has been used in the manufacture and production of other rhenium aerospace components as well. Cold isostatic pressing (CIP) to a near net shape utilizing a one or two-part mandrel greatly reduces the quantity of rhenium required to produce the component, and also significantly reduces the number of secondary machining operations necessary to complete the manufacturing process. Further, the developments in near-net shape powder metallurgy rhenium manufacturing techniques have generated significant savings in the area of both time and budget. Overall, cost declined by as much as 35 % for the quantity of rhenium chambers, and manufacturing time was decreased by 30-40 %. The quantity of rhenium metal powder used to produce a rhenium chamber was reduced by approximately 70 %, with a subsequent reduction of nearly 50 % in secondary machining operation schedules. Thus, it is apparent that the overall savings provided by the production of near-net shape powder metallurgy rhenium components will be more than merely another aspect of any project involving high temperature applications, it will constitute significant benefit. (author)

Development of industrial hydrogenating catalyst on rhenium base

International Nuclear Information System (INIS)

Chistyakova, G.A.; Bat', I.I.; Rebrova, V.V.

1975-01-01

Processes for forming rhenium catalysts on carbon carrier and their catalytic properties in nitrobenzene (NB) reduction were studied. Application of an ammonia preparation to the carbon surface produced impregnated carbon saturated at room temperature with a water solution of the ammonia preparation, taken in a volume equal to the volumetric capacity of the carbon. With one impregnation, 2% rhenium was taken up. Catalysts containing more than 5% rhenium were obtained by impregnating the carbon with heating and use of more concentrated solutions. Catalysts made in this way and dried at 100 0 C had the composition Re 2 OH/carbon/. The most active catalysts were those reduced at 200-250 0 C; higher temperatures, up to 300-500 0 C, decreased the activity. Study of the catalytic properties of the rhenium catalysts in a liquid phase reduction of NB showed that the specific activity of rhenium depends only slightly on the content of the active component in the catalyst and is close to the specific activity of palladium and considerably exceeds that of nickel. Study of the effect of the NB concentration and hydrogen pressure on the activity and stability of the 5% rhenium catalyst indicated that with NB concentrations from 50 to 10% the process takes place at an essentially constant rate; the order of the reaction was close to zero with an apparent activation energy of about 7000 cal/mole. At pressures of 15-200 atm the yield with the 5% catalyst was proportional to the hydrogen pressure. A big advantage of the rhenium catalysts in the reduction of NB is their high selectivity. With a higher activity than palladium and nickel catalysts, 5% rhenium catalyst produces a high operating capacity in a wide range of contact charges, which has considerable significance for industrial use in contact apparatus of the column type. Comparison of the costs of rhenium catalysts and granular carbon carrier with those of nickel, platinum, and palladium showed that 5% rhenium catalyst can

Studies of technetium chemistry. Pt.8. The regularities of the bond length and configuration of rhenium and technetium complexes in crystals

International Nuclear Information System (INIS)

Liu Guozheng; Liu Boli

1995-01-01

Some bond length regularities in MO 6 , MO-4, MX 5 α and MX 4 αβ moieties of technetium and rhenium compounds are summarized and rationalized by cavity model. The chemical properties of technetium and rhenium are so similar that their corresponding complexes have almost the same configuration and M-X bond lengths when they are in cavity-controlled state. Technetium and Rhenium combine preferably with N, O, F, S, Cl and Br when they are in higher oxidation states (>3), but preferably with P, Se etc. when they are in lower oxidation states ( 4 αβ is approximately constant; (2) the average M-X bond length of MX 6 varies moderately with the oxidation state of M; (3) the bond length of M-X trans to M-α in MX 5 α has a linear relationship with the angle

Treatment of liver cancer with Rhenium-188 Lipiodol: Colombian experience

International Nuclear Information System (INIS)

Bernal, P.; Osorio, M.; Mendoza, M.; Esguerra, R.; Ucros, G.; Gutierrez, C.; Velez, O.; Cerquera, A.M.; Padhy, A.K.

2002-01-01

Aim:Trans-arterial Radio-conjugate therapy plays an important role in the palliative treatment of inoperable liver cancer. It also helps in reduction of the tumor to an operable state from an inoperable one. As a part of an IAEA sponsored coordinated research project, a new radiopharmaceutical, Rhenium-188 Lipiodol has been developed. The aim of this study was to establish the safety of the radiopharmaceutical and to find out the efficacy of treatment. Materials and Methods: Eight patients suffering from various forms of liver cancer (Hepatocellular carcinoma-4, Metastases from carcinoma of colon-3 and Carcinoid- 1) were treated with Rhenium -188 Lipiodol. Seven out of the eight patients were classified as ECOG- 1 and one as ECOG- 3. Labelling of Rhenium-188 with Lipiodol was carried out according to a protocol developed under the CRP and standardized in our service. Rhenium-188 Lipiodol was administered through the trans-arterial route by either selective (75%) or ultra selective (25%) hepatic arteriography. Administered therapeutic doses ranged between 170 MBq and 4181 MBq. Dosimetric evaluations were made using the IAEA developed dosimetry spreadsheet. All patients were followed up (1-5 months, average = 2 months) after treatment by clinical examination, liver function tests, haematological examinations and CT scans of liver to determine the size of hepatic tumor. Results: Rhenium-188 Lipiodol treatment was well tolerated by all patients. No immediate systemic complications were noted in any of the patients within 72 hrs. following therapy. Only two patients had mild rise in temperature in the immediate post-therapy period, which subsided subsequently. One patient who was classified as Child B and ECOG 3, developed encephalopathy on the seventh day after treatment. He died of hepatic failure. Another one present depressive syndrome, didn't accept food and died Follow-up CT scans in all the surviving (6/8) patients revealed significant reduction of the tumours

Perspectives of 99mTc chemistry and radiopharmacy: strategies, building blocks and targets

International Nuclear Information System (INIS)

Alberto, R.

2007-01-01

Technetium chemistry, both fundamental and applied are required to a larger extent in order to keep the essential role of this element in radiopharmacy alive. After an introduction, highlighting the situation in general from research and market aspects, new strategies will be proposed in which technetium and rhenium play an essential role which can not be taken over by other radionuclides such as 11 C or 18 F. Furthermore, currently available and potential future building blocks in technetium chemistry and their relationship to the new strategies as well as characteristics of new precursors will be discussed and compared to each other. Targets and targeting molecules, again in the context of strategies unique for technetium (and rhenium) are in the focus of the last part. With respect of retaining a unique role, it is obvious that any future technetium or rhenium labelled biomolecule should have potential to therapy or be applied in the immediate context of therapy, as e.g. for the early assessment of success in chemotherapy. All these aspects emphasize a role of inorganic technetium chemistry which goes far beyond simple labelling strategies. To underline the importance of fundamental chemistry, we will present and discuss some examples with nuclear targeting agents, amino acids and vitamin B12. (author)

Synthesis and physicochemical characterization of rhenium (V) complexes with bisbenzoylthiosemicarbazones

International Nuclear Information System (INIS)

Gagieva, S.Ch.; Gutnova, N.A.; Tsaloev, A.T.; Khubulov, A.B.; Arutyunyants, A.A.; Galimov, Yu.B.

2003-01-01

Rhenium (V) complexing with mono- and bis-benzoylthiosemicarbazones is studied in dependence on hydrohalic acids concentration changes. It is determined that in media with high concentration of hydrohalic acids (6 mol/l HCl, 7 mol/l HBr) in dependence on reaction conditions stable complexes with bi- and tridentate coordination of thiosemicarbazone are formed. In the case of hydrohalic acid concentration decreasing stable binuclear and oxohydroxycomplexes are formed. Composition and structure of the compounds obtained are determined by the methods of element analysis, IR spectroscopy, conductometry. Thermal investigations of the compounds obtained are done [ru

A coordination chemistry approach for modeling trace element adsorption

International Nuclear Information System (INIS)

Bourg, A.C.M.

1986-01-01

The traditional distribution coefficient, Kd, is highly dependent on the water chemistry and the surface properties of the geological system being studied and is therefore quite inappropriate for use in predictive models. Adsorption, one of the many processes included in Kd values, is described here using a coordination chemistry approach. The concept of adsorption of cationic trace elements by solid hydrous oxides can be applied to natural solids. The adsorption process is thus understood in terms of a classical complexation leading to the formation of surface (heterogeneous) ligands. Applications of this concept to some freshwater, estuarine and marine environments are discussed. (author)

Concentration of rhenium from dilute sodium chloride solutions

Directory of Open Access Journals (Sweden)

DRAGOLJUB M. LUKIC

2008-03-01

Full Text Available The conditions for the desorption of rhenium from the anion exchange resin Dowex 1-x8 by HNO3, HCl, H2SO4 and NaOH were determined. The solution (5.0´10-3 mol dm-3 Re in 0.15 mol dm-3 NaCl was passed through a column containing 0.10 g of the resin. The total sorbed amount of rhenium was 0.20 g/g of the resin. It was then eluted by the corresponding eluent in the concentration range up to about 3.0 mol dm-3. The highest elution efficiency and the most favourable elution profile were found with 3.0 mol dm-3 HNO3. Over 77 % of the sorbed rhenium was found in the first 5 ml of the eluate. Practically all the rhenium was recovered with 20 ml of the acid. Under the given experimental conditions, HCl and H2SO4 were less favourable while NaOH was not applicable, due to very low efficiency of rhenium elution.

Ambient aging of rhenium filaments used in thermal ionization mass spectrometry: Growth of oxo-rhenium crystallites and anti-aging strategies

Directory of Open Access Journals (Sweden)

Joseph M. Mannion

2017-01-01

Full Text Available Degassing is a common preparation technique for rhenium filaments used for thermal ionization mass spectrometric analysis of actinides, including plutonium. Although optimization studies regarding degassing conditions have been reported, little work has been done to characterize filament aging after degassing. In this study, the effects of filament aging after degassing were explored to determine a “shelf-life” for degassed rhenium filaments, and methods to limit filament aging were investigated. Zone-refined rhenium filaments were degassed by resistance heating under high vacuum before exposure to ambient atmosphere for up to 2 months. After degassing the nucleation and preferential growth of oxo-rhenium crystallites on the surface of polycrystalline rhenium filaments was observed by atomic force microscopy and scanning electron microscopy (SEM. Compositional analysis of the crystallites was conducted using SEM-Raman spectroscopy and SEM energy dispersive X-ray spectroscopy, and grain orientation at the metal surface was investigated by electron back-scatter diffraction mapping. Spectra collected by SEM-Raman suggest crystallites are composed primarily of perrhenic acid. The relative extent of growth and crystallite morphology were found to be grain dependent and affected by the dissolution of carbon into filaments during annealing (often referred to as carbonization or carburization. Crystallites were observed to nucleate in region specific modes and grow over time through transfer of material from the surface. Factors most likely to affect the rates of crystallite growth include rhenium substrate properties such as grain size, orientation, levels of dissolved carbon, and relative abundance of defect sites; as well as environmental factors such as length of exposure to oxygen and relative humidity. Thin (∼180 nm hydrophobic films of poly(vinylbenzyl chloride were found to slow the growth of oxo-rhenium crystallites on the filament

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.

Research program to investigate the fundamental chemistry of technetium

Energy Technology Data Exchange (ETDEWEB)

McKeown, David A.; Buechele, Andrew C.; Lukens, Wayne W.; Muller, Isabelle S.; Shuh, David K.; Pegg, Ian L.

2007-10-12

The objective of this research is to increase the knowledge of the fundamental technetium chemistry necessary to address challenges to the safe, long-term disposal of high-level nuclear waste posed by this element. The primary issues examined during the course of this project were the behavior of technetium and its surrogate rhenium during waste vitrification and glass corrosion. Since the redox behavior of technetium can play a large role in determining its volatility, one goal of this research was to better understand the behavior of technetium in glass as a function of the redox potential of the glass melt. In addition, the behavior of rhenium was examined, since rhenium is commonly used as a surrogate for technetium in waste vitrification studies. A number of glasses similar to Hanford Low Activity Waste (LAW) glasses were prepared under controlled atmospheres. The redox state of the glass was determined from the Fe(II)/Fe(III) ratio in the cooled glass, and the speciation of technetium and rhenium was determined by x-ray absorption fine structure (XAFS) spectroscopy. The behavior of rhenium and technetium during glass alteration was also examined using the vapor hydration test (VHT).

Linkable thiocarbamoylbenzamidines as ligands for bioconjugation of Rhenium and Technetium; Kopplungsfaehige Thiocarbamoylbenzamidine als Liganden zur Biokonjugation von Rhenium und Technetium

Energy Technology Data Exchange (ETDEWEB)

Castillo Gomez, Juan Daniel

2015-04-27

Bioconjugation reactions with Rhenium and Technetium are of high importance for the development of novel radiopharmaceuticals for nuclear medicine. In this thesis the possibilities for bioconjugation using linkable Thiocarmbamoylbenzamidines as ligands for the complexation of Rhenium and Technetium were examined.

The kinetics of anodic dissolution of rhenium in aqueous electrolyte solutions

International Nuclear Information System (INIS)

Atanasyants, A.G.; Kornienko, V.A.

1986-01-01

The kinetics of anodic rhenium dissolution was investigated by means of potentiodynamic and potentiostatic polarization curves recorded at temperature from 293 to 333 K in different media (NaOH, KOH, NaCl, NaBr, HCl, H 2 SO 4 ) using the rotating disc technique. It is shown that the kinetics of anodic rhenium dissolution and effective activation energy depend not only on the composition and pH value of the solutions but also on the structure of the dissolving rhenium surface. The investigation of the anodic behaviour of the rhenium monocrystal revealed the existence of anisotropy of the monocrystal electrochemical properties. The experimental results point to an important role of adsorption processes in anodic rhenium dissolution. Rhenium dissolution proceeds with formation of intermediate surface adsorption complexes between the metal and the components of the solution

Thermophysical measurements on solid and liquid rhenium

International Nuclear Information System (INIS)

Pottlacher, G.; Jager, H.; Neger, T.

1986-01-01

A fast resistive heating technique was used to measure such thermophysical data of solid and liquid rhenium as enthalpy, specific heat, thermal volume expansion, and electrical resistivity. The measurements are performed with heating rates of slightly more than 10 9 K s -1 up to states of superheated liquid rhenium (7500 K)

Effect of Temperature and Mole Ratio on the Synthesis Yield of Rhenium-Tetrofosmin

Directory of Open Access Journals (Sweden)

Widyastuti

2015-08-01

Full Text Available Technetium-99m (99mTc tetrofosmin is widely used in nuclear medicine as a diagnostic agent for myocardial perfusion and as a tumor imaging agent. As a parenteral preparation it requires an evaluation of its pharmacokinetics and stability in-vivo. Since 99mTc has a short half-life and is only available in very low concentrations, it is impossible to characterize its chemical properties and presence in the body. Due to this reason, only technetium-99 (T1/2 = 5 × 105 years, which is available in macro quantities, or natural rhenium can be used for this purpose. In this study rhenium-188 (188Re tetrofosmin will be synthesized and applied, because non-radioactive Re can be easily obtained. Synthesis and radiochemical purity analysis of carrier-added 188Re-tetrofosmin were carried out as a model to study the in-vivo stability of technetium-99m tetrofosmin. Rhenium-188 was used as a tracer to identify the formation of rhenium tetrofosmin. Rhenium gluconate was synthesized first prior to the formation of rhenium tetrofosmin. The quality of labeling for both rhenium gluconate and rhenium tetrofosmin was analyzed using paper- and thin-layer chromatography, respectively. Rhenium gluconate can be synthesized with high labeling yield within 1 hour, whereas rhenium tetrofosmin was synthesized both in room temperature and in an elevated temperature with various tetrofosmin-to-rhenium mole ratios.The results showed that heating at 95oC led to a higher yield of more than 90% within 30 minutes. Rhenium tetrofosmin could be produced in high radiochemical purity using an excess of tetrofosmin with mole ratio of 2000. It is concluded that rhenium tetrofosmin could be synthesized through the formation of rhenium gluconate, and a higher yield could be obtained in a shorter time by heating process.

Development of a radiochemical neutron activation analysis procedure for determination of rhenium in biological and environmental samples at ultratrace level

Czech Academy of Sciences Publication Activity Database

Kučera, Jan; Byrne, A. R.; Mizera, Jiří; Lučaníková, M.; Řanda, Zdeněk

2006-01-01

Roč. 269, č. 2 (2006), s. 251-257 ISSN 0236-5731 R&D Projects: GA ČR(CZ) GA203/04/0943 Institutional research plan: CEZ:AV0Z10480505 Keywords : radiochemical neutron activation analysis * rhenium * biological and environmental samples Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.509, year: 2006

Development of novel strategy for the synthesis of organometallic compounds usable as protein ligands: application to the human cyclophilin hCyp-18; Developpement de ligands de proteines par assemblage combinatoire autour d'un coeur de rhenium{sup V}: application a la cyclophiline hCyp-18

Energy Technology Data Exchange (ETDEWEB)

Clavaud, C

2006-02-15

This thesis describes a new strategy for the development of bioactive organometallic compounds, basing on the combinatorial assembly of sub-chemical libraries (A and B) independent but complementary and able to coordinate a metallic heart M to form A-M-B complex potential ligands of biomolecules. The coordination of metals, well adapted to the production of molecular variety is usually used in medicinal chemistry, in diagnostic and therapeutic nuclear medicine. Among the useful elements, the rhenium and the technetium are metals of choice for the development of the assembly strategy because of their chemical and radiochemical properties and of the structure analogy of their complexes. This strategy was validated in vitro. The protein chosen for this purpose was the cyclophilin hCyp-18. (N.C.)

Determination of rhenium in geologic samples of sandstone-type uranium deposit

International Nuclear Information System (INIS)

Li Yanan; Wang Xiuqin; Yin Jinshuang

1997-01-01

The thiourea colorimetry method suitable for the determination of samples with rhenium content higher than 5 μg/g is described. The method is characterized by many advantages: stability of analytical results, simplicity and cheapness of reagent, and wide range of analysed samples. The catalytic colorimetry is also applied to determine trace rhenium meeting the demand for comprehensive appraisal of prospecting and exploration, recovery and utilization of rhenium. This method can also be applied to analyse rhenium of other samples

Synthesis and characterization of organohydrazino complexes of technetium, rhenium, and molybdenum with the [M(η1-HxNNR)(η2-HyNNR)] core and their relationship to radiolabeled organohydrazine-derivatives chemotactic peptides with diagnostic applications

International Nuclear Information System (INIS)

Rose, D.J.; Maresca, K.P.; Nicholson, T.

1998-01-01

In this paper, the authors present the details of the preparation of the imaging agent and its imaging properties. In order to define some structural possibilities for the coordination chemistry relevant to these reagents, they also present the results of investigations of the syntheses and structures of Tc, Mo, and Re complexes with hydrazinopyridine, which not only establish the formation of the robust unit, but also implicate chelate formation through the pyridine nitrogen as a significant structural determinant. The structures of the parent (bis)hydrazino-trichlorometalate core compounds are presented, allowing analysis of structural changes that occur when (2) protonation sites on the ligand change, (2) a different metal is employed, and (3) a different chelating hydrazine is utilized. The structures of the thiolate substitution products of these parent compounds are also presented. These derivatives demonstrate that rhenium and technetium have analogous substitution chemistry

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.

Work function of carburized rhenium

International Nuclear Information System (INIS)

Pallmer, P.G. Jr.; Gordon, R.L.; Dresser, M.J.

1980-01-01

Variations of the electronic work function of carburized rhenium foils containing approximately 5 at.% carbon have been observed using the contact potential difference technique. Surface work function was observed to vary between 5.25 and 4.1 eV, with the work function of pure rhenium taken as 5.0 eV. Decrease in work function has been ascribed to the formation of graphitic layers on the surface at temperatures below the temperature of saturated solubility. The high work function surface was observed with all carbon in solution and has been ascribed to the presence of amorphous carbon near the surface

Accelerator Production and Separations for High Specific Activity Rhenium-186

Energy Technology Data Exchange (ETDEWEB)

Jurisson, Silvia S. [Univ. of Missouri, Columbia, MO (United States); Wilbur, D. Scott [Univ. of Washington, Seattle, WA (United States)

2016-04-01

Tungsten and osmium targets were evaluated for the production of high specific activity rhenium-186. Rhenium-186 has potential applications in radiotherapy for the treatment of a variety of diseases, including targeting with monoclonal antibodies and peptides. Methods were evaluated using tungsten metal, tungsten dioxide, tungsten disulfide and osmium disulfide. Separation of the rhenium-186 produced and recycling of the enriched tungsten-186 and osmium-189 enriched targets were developed.

Rhenium and technetium complexes with phenylbis(2-pyridyl)phosphine and tris(2-pyridyl)phosphine

Energy Technology Data Exchange (ETDEWEB)

Saucedo A, S. A. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Hagenbach, A.; Abram, U., E-mail: ssaucedo@uaz.edu.m [Institut fur Chemie und Biochemie, Freie Universitat Berlin, Fabeckstr. 34-36, D-14195, Berlin (Germany)

2010-10-15

Reactions of common technetium and rhenium precursors with 2-pyridyl phosphines produce novel, air stable tricarbonyl and oxo complexes. (NEt{sub 4}){sub 2}[Re(CO){sub 3}Br{sub 3}] or (NEt{sub 4}){sub 2}[Tc(CO){sub 3}Cl{sub 3}] react with phenylbis(2-pyridyl)phosphine (PPhpy{sub 2}) or tris(2-pyridyl)phosphine (Ppy{sub 3}) under formation of neutral tricarbonyl complexes of the composition [M(CO){sub 3}X(L)] (M = Re, X = Br; M = Tc, X = Cl, L = PPhpy{sub 2} or Ppy{sub 3}), where the ligands coordinate only with two for their nitrogen atoms. Removal of the bromo ligands from (NEt{sub 4}){sub 2}[Re(CO){sub 3}(Br){sub 3}] with AgNO{sub 3}, to force a tripodal coordination, and the subsequent reaction with the Ppy{sub 3} results in the formation of the complex [Re(CO){sub 3}(NO{sub 3})(Ppy{sub 3}{sup -}N,N{sup '})] with a monodentate coordinated nitrato ligand. (NBu{sub 4})[ReOCl{sub 4}] reacts with PPhpy{sub 2} to give the asymmetric, oxo-bridged rhenium (V) dimer (NBu{sub 4})[Re{sub 2}O{sub 2}Cl{sub 5}({mu}-PPhpy{sub 2}{sup -}P,N,N,N{sup '})({mu}-O)], while a similar reaction with (ReOCl{sub 3}(PPh{sub 3}){sub 2}] in boiling Thf results in reduction of the metal and gives (ReCl{sub 3}(OPPhpy{sub 2})(PPh{sub 3})]. The products have been characterized spectroscopically and by X-ray structure analyses. (Author)

Electrocatalysis of the hydrogen evolution reaction by rhenium oxides electrodeposited by pulsed-current

International Nuclear Information System (INIS)

Vargas-Uscategui, Alejandro; Mosquera, Edgar; Chornik, Boris; Cifuentes, Luis

2015-01-01

Highlights: • Rhenium oxides were produced by means of pulsed current electrodeposition over ITO. • The electrocatalytic behavior of rhenium oxides electrodeposited over ITO was studied. • Electrodeposited rhenium oxides showed electrocatalytic behavior increasing the rate of the hydrogen evolution reaction. • The electrocatalysis behavior was explained considering the relative abundance of Re species on the surface of the electrodeposited material. - Abstract: Rhenium oxides are materials of interest for applications in the catalysis of reactions such as those occurring in fuel cells and photoelectrochemical cells. This research work was devoted to the production of rhenium oxide by means of pulsed current electrodeposition for the electrocatalysis of the hydrogen evolution reaction (HER). Rhenium oxides were electrodeposited over a transparent conductive oxide substrate (Indium Tin-doped Oxide – ITO) in an alkaline aqueous electrolyte. The electrodeposition process allowed the production of rhenium oxides islands (200–600 nm) with the presence of three oxidized rhenium species: Re"I"V associated to ReO_2, Re"V"I associated to ReO_3 and Re"V"I"I associated to H(ReO_4)H_2O. Electrodeposited rhenium oxides showed electrocatalytic behavior over the HER and an increase of one order of magnitude of the exchange current density was observed compared to the reaction taking place on the bare substrate. The electrocatalytic behavior varied with the morphology and relative abundance of oxidized rhenium species in the electrodeposits. Finally, two mechanisms of electrocatalysis were proposed to explain experimental results.

Rhenium: a rare metal critical in modern transportation

Science.gov (United States)

John, David A.

2015-01-01

Rhenium is a silvery-white, metallic element with an extremely high melting point (3,180 degrees Celsius) and a heat-stable crystalline structure, making it exceptionally resistant to heat and wear. Since the late 1980s, rhenium has been critical for superalloys used in turbine blades and in catalysts used to produce lead-free gasoline.

Effect of rhenium addition on tungsten fuzz formation in helium plasmas

Energy Technology Data Exchange (ETDEWEB)

Khan, Aneeqa, E-mail: aneeqa.khan-3@postgrad.manchester.ac.uk [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, M13 9PL (United Kingdom); De Temmerman, Gregory [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046 - 13067 St Paul Lez Durance Cedex (France); Morgan, Thomas W. [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Partner in the Trilateral Euregio Cluster, Eindhoven (Netherlands); Ward, Michael B. [Institute for Materials Research, School of Chemical Process Engineering, University of Leeds, Leeds, LS2 9JT (United Kingdom)

2016-06-15

The effect of the addition of rhenium to tungsten on the formation of a nanostructure referred to as ‘fuzz’ when exposed to helium plasmas at fusion relevant ion fluxes was investigated in the Magnum and Pilot PSI devices at the FOM Institute DIFFER. The effect rhenium had on fuzz growth was seen to be dependent on time, temperature and flux. Initial fuzz growth was seen to be highly dependent on grain orientation, with rhenium having little effect. Once the fuzz was fully developed, the effect of grain orientation disappeared and the rhenium had an inhibiting effect on growth. This could be beneficial for inhibiting fuzz growth in a future fusion reactor, where transmutation of tungsten to rhenium is expected. It also appears that erosion or annealing of the fuzz is limiting growth of fuzz at higher temperatures in the range of ∼1340 °C.

Effect of rhenium addition on tungsten fuzz formation in helium plasmas

International Nuclear Information System (INIS)

Khan, Aneeqa; De Temmerman, Gregory; Morgan, Thomas W.; Ward, Michael B.

2016-01-01

The effect of the addition of rhenium to tungsten on the formation of a nanostructure referred to as ‘fuzz’ when exposed to helium plasmas at fusion relevant ion fluxes was investigated in the Magnum and Pilot PSI devices at the FOM Institute DIFFER. The effect rhenium had on fuzz growth was seen to be dependent on time, temperature and flux. Initial fuzz growth was seen to be highly dependent on grain orientation, with rhenium having little effect. Once the fuzz was fully developed, the effect of grain orientation disappeared and the rhenium had an inhibiting effect on growth. This could be beneficial for inhibiting fuzz growth in a future fusion reactor, where transmutation of tungsten to rhenium is expected. It also appears that erosion or annealing of the fuzz is limiting growth of fuzz at higher temperatures in the range of ∼1340 °C.

Minimizing core deposits radiation fields in PWRs by coordinated Li/B chemistry

International Nuclear Information System (INIS)

Roesmer, J.

1983-01-01

The effect of coolant chemistry on the buildup and composition of core deposits and on out-of-core radiation fields was investigated in the Beaver Valley and Trojan plants. Coordinated Li/B coolant chemistry led to an appreciable reduction of the surface concentration of core deposits, decreased greatly the formation of crud films on fresh fuel, and resulted in a reduction in the rate and level of radiation field buildup in the out-of-core regions of the primary circuits. (author)

Ultrafast Excited-State Dynamics of Rhenium(I) Photosensitizers [Re(Cl)(CO)3(N,N)] and [Re(imidazole)(CO)3(N,N)]+: Diimine Effects

Czech Academy of Sciences Publication Activity Database

Nahhas, A. E.; Consani, C.; Blanco-Rodríguez, A. M.; Lancaster, K. M.; Braem, O.; Cannizzo, A.; Towrie, M.; Clark, I. P.; Záliš, Stanislav; Chergui, M.; Vlček, Antonín

2011-01-01

Roč. 50, č. 7 (2011), s. 2932-2943 ISSN 0020-1669 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk(CZ) LD11082 Institutional research plan: CEZ:AV0Z40400503 Keywords : rhenium * photosynthesis * diimine effects Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.601, year: 2011

Determination of rhenium in ores of complex composition by the kinetic method

Energy Technology Data Exchange (ETDEWEB)

Pavlova, L G; Gurkina, T V [Kazakhskij Gosudarstvennyj Univ., Alma-Ata (USSR); Tsentral' naya Lab. Yuzhno-Kazakhstanskogo Geologicheskogo Upravleniya, Alma-Ata (USSR))

1979-09-01

The kinetic rhenium determination method is proposed based on rhenium catalytic effect in the reaction of malachite green with thiourea. The accompanying elements, excluding molybdenum, do not interfere with the rhenium determination at their concentration of up to 0.1 M. The interfering influence of molybdenum can be eliminated by addition of tartaric acid to the solution up to the concentration of 0.1 M. This enables to determine rhenium in presence of 1000-fold quantity of molybdenum. The method is applicable for the analysis of complex copper-zinc sulphide ores.

Nipponium, the element ascribable to rhenium from the modern chemical viewpoint

Energy Technology Data Exchange (ETDEWEB)

Yoshihara, H.K. [Japan Isotope Data Inst., Sendai (Japan)

1997-11-01

Though the discovery of nipponium by Ogawa in 1908 was judged to be false and his work was forgotten for many years, the new element he believed to have found should be ascribed to rhenium (z = 75) by the following reasons: (1) the spectral line of 4882 A agrees well with the present data of rhenium, (2) recalculation of the atomic weight of the element supports the value in the neighbourhood of 185 which is very close to the present value 186.2 of rhenium, and (3) rhenium is actually present in Japanese molybdenite he studied. Therefore, it is concluded that his discovery of the `new` element was correct, but assignment of z = 43 was wrong. (orig.)

Method of stably radiolabeling antibodies with technetium and rhenium

International Nuclear Information System (INIS)

Paik, C.H.; Reba, R.C.; Eckelman, W.C.

1987-01-01

A method is described for labeling antibodies or antibody fragments with radionuclides of technetium or rhenium to obtain stable labeling, comprising: reacting a reduced radioisotope of technetium or rhenium with an antibody or antibody fragment, or a diethylenetriaminepentaacetic acid conjugated antibody or antibody fragment, in the presence of free or carrier-bound diethylenetriaminepentaacetic acid (DTPA). The amount of DTPA is sufficient to substantially completely inhibit binding of the reduced technetium or rhenium to nonstable binding sites of the antibody or antibody fragment, or the DTPA-conjugated antibody or antibody fragment. The resultant stably labeled antibody or antibody fragment, or DTPA[conjugated antibody or antibody fragment is recovered

Complex chemistry

International Nuclear Information System (INIS)

Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

2006-06-01

This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

Crystal structures of a manganese(I and a rhenium(I complex of a bipyridine ligand with a non-coordinating benzoic acid moiety

Directory of Open Access Journals (Sweden)

Sheri Lense

2018-05-01

Full Text Available The structures of two facially coordinated Group VII metal complexes are reported, namely: fac-bromido[2-(2,2′-bipyridin-6-ylbenzoic acid-κ2N,N′]tricarbonylmanganese(I tetrahydrofuran monosolvate, [MnBr(C17H12N2O2(CO3]·C4H8O, I, and fac-[2-(2,2′-bipyridin-6-ylbenzoic acid-κ2N,N′]tricarbonylchloridorhenium(I tetrahydrofuran monosolvate, [ReCl(C17H12N2O2(CO3]·C4H8O, II. In both complexes, the metal ion is coordinated by three carbonyl ligands, a halide ion, and a 2-(2,2′-bipyridin-6-ylbenzoic acid ligand, in a distorted octahedral geometry. In manganese complex I, the tetrahydrofuran (THF solvent molecule could not be refined due to disorder. The benzoic acid fragment is also disordered over two positions, such that the carboxylic acid group is either positioned near to the bromide ligand or to the axial carbonyl ligand. In the crystal of I, the complex molecules are linked by a pair of C—H...Br hydrogen bonds, forming inversion dimers that stack up the a-axis direction. In the rhenium complex II, there is hydrogen bonding between the benzoic acid moiety and a disordered co-crystallized THF molecule. In the crystal, the molecules are linked by C—H...Cl hydrogen bonds, forming layers parallel to (100 separated by layers of THF solvent molecules.

Separation of Rhenium (VII) from Tungsten (VI)

International Nuclear Information System (INIS)

Vucina, J.; Lukic, D.; Stoiljkovic, M.; Milosevic, M.; Orlic, M.

2004-01-01

Examined were the conditions for an effective separation of tungsten (VI) and rhenium (VII) on alumina if the solution of 0.20 mol dm -3 NaCl, ph=2.6 is used as the aqueous phase. Under the given experimental conditions alumina was found to be much better adsorbent for tungsten than for rhenium. The breakthrough and saturation capacities of alumina at pH=2 are 24 and 78 mg W/g Al 2 O 3 , respectively. With the increase of pH these values decrease. So, at pH=6 they are only 4 and 13 mg W/g Al 2 O 3 respectively. The elution volume for rhenium for the given column dimensions and quantity of the adsorbent is about 16 ml. These results were confirmed by the experiments of the radiological separations. Tungsten-187 remains firmly bound to the alumina. The radionuclide purity of the eluted 186'188 Re at pH=2 is very high. (authors)

Determination of rhenium in molybdenite by neutron-activation analysis.

Science.gov (United States)

Terada, K; Yoshimura, Y; Osaki, S; Kiba, T

1967-01-01

A neutron-activation method is described for the determination of rhenium in molybdenite. Radiochemical separation by a carrier technique was carried out very rapidly by means of successive liquid-liquid extraction processes. The recovery of rhenium, which was determined by a spectrophotometric method, was about 93%. About 10 samples could be analysed within 6 hr in parallel runs.

Coordination Chemistry of Linear Oligopyrrolic Fragments Inspired by Heme Metabolites

Science.gov (United States)

Gautam, Ritika

Linear oligopyrroles are degradation products of heme, which is converted in the presence of heme oxygenase to bile pigments, such as biliverdin and bilirubin. These tetrapyrrolic oligopyrroles are ubiquitously present in biological systems and find applications in the fields of catalysis and sensing. These linear tetrapyrrolic scaffolds are further degraded into linear tripyrrolic and dipyrrolic fragments. Although these lower oligopyrroles are abundantly present, their coordination chemistry requires further characterization. This dissertation focuses mainly on two classes of bioinspired linear oligopyrroles, propentdyopent and tripyrrindione, and their transition metal complexes, which present a rich ligand-based redox chemistry. Chapter 1 offers an overview of heme degradation to different classes of linear oligopyrroles and properties of their transition metal complexes. Chapter 2 is focused on the tripyrrin-1,14-dione scaffold of the urinary pigment uroerythrin, which coordinates divalent transition metals palladium and copper with square planar geometry. Specifically, the tripyrrin-1, 14-dione ligand binds Cu(II) and Pd(II) as a dianionic organic radical under ambient conditions. The electrochemical study confirms the presence of ligand based redox chemistry, and one electron oxidation or reduction reactions do not alter the planar geometry around the metal center. The X-Ray analysis and the electron paramagnetic resonance (EPR) studies of the complexes in the solid and solution phase reveals intermolecular interactions between the ligand based unpaired electrons and therefore formation of neutral pi-pi dimers. In Chapter 3, the antioxidant activity and the fluorescence sensor properties of the tripyrrin-1,14-dione ligand in the presence of superoxide are described. We found that the tripyrrindione ligand undergoes one-electron reduction in the presence of the superoxide radical anion (O2•- ) to form highly fluorescent H3TD1•- radical anion, which emits

A comparative study of electrochemical and optical properties of rhenium deposited on gold and platinum

Energy Technology Data Exchange (ETDEWEB)

Zerbino, Jorge O.; Castro Luna, Ana M.; Martins, M. E. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina). Inst. de Investigaciones Fisico-Quimicas, Teoricas y Aplicadas (INIFTA)]. E-mail: mmartins@inifta.unlp.edu.ar; Zinola, Carlos F.; Mendez, Eduardo [Universidad de la Republica, Montevideo (Uruguay). Facultad de Ciencias. Lab. de Electroquimica Fundamental

2002-08-01

Rhenium-containing films were grown on gold and platinum after different potentiostatic and potentiodynamic polarizations in the - 0.20 V to 0.70 V range (vs rhe) in aqueous acid perrhenate. Experimental data were obtained using cyclic voltammetry and ellipsometry, from which the thickness and optical indices of the electrodeposited rhenium layer were calculated. Metallic rhenium deposition on gold takes place at potentials within the hydrogen evolution reaction. Rhenium oxide on platinum is formed in the hydrogen adatom potential domain, whereas metallic rhenium is deposited concurrently with the hydrogen adsorption and evolution reactions on the same metal. (author)

A comparative study of electrochemical and optical properties of rhenium deposited on gold and platinum

Directory of Open Access Journals (Sweden)

Zerbino Jorge O.

2002-01-01

Full Text Available Rhenium-containing films were grown on gold and platinum after different potentiostatic and potentiodynamic polarizations in the - 0.20 V to 0.70 V range (vs rhe in aqueous acid perrhenate. Experimental data were obtained using cyclic voltammetry and ellipsometry, from which the thickness and optical indices of the electrodeposited rhenium layer were calculated. Metallic rhenium deposition on gold takes place at potentials within the hydrogen evolution reaction. Rhenium oxide on platinum is formed in the hydrogen adatom potential domain, whereas metallic rhenium is deposited concurrently with the hydrogen adsorption and evolution reactions on the same metal.

Monoclonal Antibodies Radiolabeling with Rhenium-188 for Radioimmunotherapy

Science.gov (United States)

Martini, Petra; Pasquali, Micol

2017-01-01

Rhenium-188, obtained from an alumina-based tungsten-188/rhenium-188 generator, is actually considered a useful candidate for labeling biomolecules such as antibodies, antibody fragments, peptides, and DNAs for radiotherapy. There is a widespread interest in the availability of labeling procedures that allow obtaining 188Re-labeled radiopharmaceuticals for various therapeutic applications, in particular for the rhenium attachment to tumor-specific monoclonal antibodies (Mo)Abs for immunotherapy. Different approaches have been developed in order to obtain 188Re-radioimmunoconjugates in high radiochemical purity starting from the generator eluted [188Re]ReO4−. The aim of this paper is to provide a short overview on 188Re-labeled (Mo)Abs, focusing in particular on the radiolabeling methods, quality control of radioimmunoconjugates, and their in vitro stability for radioimmunotherapy (RIT), with particular reference to the most important contributions published in literature in this topic. PMID:28951872

Manufacture and properties of molybdenum-rhenium alloys

International Nuclear Information System (INIS)

Fischer, B.; Freund, D.

2001-01-01

It is necessary to measure strength and creep behavior to guarantee the safe and reliable usage of refractory alloys at extremely high temperatures. In the literature there is very little information available about the properties of Mo-Re alloys at temperatures higher than 1000 C. A special test facility has been designed and built for stress-rupture testing at very high temperatures (up to 3000 C) of refractory metals and alloys in inert atmospheres. - The stress-rupture strength as well as the creep behavior of molybdenum-rhenium alloys with rhenium contents between 41 and 51 wt.% have been determined at temperatures ranging from 1200 to 2000 C, and rupture times of up to 10 hours using this facility. Previous measurements of stress-rupture strength and creep behavior of pure rhenium have been compared with the measurement results of Mo-Re alloys. - The discussion of the values measured is based on metallographic test results and scanning electron microscopy (SEM) images of Mo-Re alloy samples after stress-rupture testing. (orig.) [de

Trinuclear rhenium(III) halide clusters with carboxylate ligands

Science.gov (United States)

Dougan, Jeffrey Steven

Four mono(carboxylato)trirhenium complexes and three bis(carboxylato)trirhenium complexes have been synthesized and characterized, principally by mass spectrometry, with supporting evidence from X-ray diffraction. These compounds represent the first trinuclear rhenium carboxylate complexes. The reactions generally proceed readily under comparatively mild conditions. Mass spectrometry has again proved its usefulness as a technique in the field of metal cluster chemistry, having provided the initial identification of the products of the reactions studied. These compounds provide a further base to which future mass spectra of metal cluster compounds can be compared. Re-examination of a reaction reported by Taha and Wilkinson has also cast considerable doubt onto the validity of a conversion widely reported in the literature that transforms (Re3Cl9) x into [Re2(O2CCH3)4Cl 2]. We believe that the literature result is a consequence of the purity of the metal precursor, and suggest that the starting material in the earlier work may have contained ReCl4 or ReCl5. The importance of mass spectrometry in the characterization of the new compounds synthesized in this project has led to a thorough study of calculated isotopic distributions. The information gathered suggests that for isotopically simple molecules, the choice of algorithm for computing an isotopic distribution is unimportant. However, it is important to compute the mass spectrum of an isotopically complex molecule using an algorithm that can, if desired, show the underlying isotopic fine structure of a peak of interest. In the last chapter of this thesis, the results of a project in chemistry education research are presented. Predicting the success of students in general chemistry has long been of interest to the chemistry education community, and several factors have been identified as contributing factors. An off-hand comment by a student inspired an examination of whether continuity with the same instructor for

Electrodialysis separation of rhenium from silicon

International Nuclear Information System (INIS)

Prasolova, O.D.; Borisova, L.V.; Ermakov, A.N.

1989-01-01

A method of separation of ruthenium from silicon by electrodialysis with heterogenuos ion-exchange membranes is developed. The effeciency of purification of rhenium from silicon depending on the number of dialyzer chambers, temperature and pH value of the dialyzate is studed. It is found that an addditional fourth chamber between the middle and anolytic ones causes the purification coefficient increase 50 times. It is necessary to cool the dialyzate in order to reduce silicon migration into the anolyte and reverse diffusion of perrhenate-ion from the anolyte into the dialyzate. The optimal pH value of diaizate is 5.5-6. The method developed has been used for separating rhenium from industrial solution of lead production with complex composition

A New Bioinspired Perchlorate Reduction Catalyst with Significantly Enhanced Stability via Rational Tuning of Rhenium Coordination Chemistry and Heterogeneous Reaction Pathway.

Science.gov (United States)

Liu, Jinyong; Han, Mengwei; Wu, Dimao; Chen, Xi; Choe, Jong Kwon; Werth, Charles J; Strathmann, Timothy J

2016-06-07

Rapid reduction of aqueous ClO4(-) to Cl(-) by H2 has been realized by a heterogeneous Re(hoz)2-Pd/C catalyst integrating Re(O)(hoz)2Cl complex (hoz = oxazolinyl-phenolato bidentate ligand) and Pd nanoparticles on carbon support, but ClOx(-) intermediates formed during reactions with concentrated ClO4(-) promote irreversible Re complex decomposition and catalyst deactivation. The original catalyst design mimics the microbial ClO4(-) reductase, which integrates Mo(MGD)2 complex (MGD = molybdopterin guanine dinucleotide) for oxygen atom transfer (OAT). Perchlorate-reducing microorganisms employ a separate enzyme, chlorite dismutase, to prevent accumulation of the destructive ClO2(-) intermediate. The structural intricacy of MGD ligand and the two-enzyme mechanism for microbial ClO4(-) reduction inspired us to improve catalyst stability by rationally tuning Re ligand structure and adding a ClOx(-) scavenger. Two new Re complexes, Re(O)(htz)2Cl and Re(O)(hoz)(htz)Cl (htz = thiazolinyl-phenolato bidentate ligand), significantly mitigate Re complex decomposition by slightly lowering the OAT activity when immobilized in Pd/C. Further stability enhancement is then obtained by switching the nanoparticles from Pd to Rh, which exhibits high reactivity with ClOx(-) intermediates and thus prevents their deactivating reaction with the Re complex. Compared to Re(hoz)2-Pd/C, the new Re(hoz)(htz)-Rh/C catalyst exhibits similar ClO4(-) reduction activity but superior stability, evidenced by a decrease of Re leaching from 37% to 0.25% and stability of surface Re speciation following the treatment of a concentrated "challenge" solution containing 1000 ppm of ClO4(-). This work demonstrates the pivotal roles of coordination chemistry control and tuning of individual catalyst components for achieving both high activity and stability in environmental catalyst applications.

Determination of rhenium in molybdenite by X-ray fluorescence: A combined chemical-spectrometric technique.

Science.gov (United States)

Solt, M W; Wahlberg, J S; Myers, A T

1969-01-01

Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 microg of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods.

Determination of rhenium in molybdenite by X-ray fluorescence. A combined chemical-spectrometric technique

Science.gov (United States)

Solt, M.W.; Wahlberg, J.S.; Myers, A.T.

1969-01-01

Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 ??g of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods. ?? 1969.

Molecular materials and devices: developing new functional systems based on the coordination chemistry approach

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Toma Henrique E.

2003-01-01

Full Text Available At the onset of the nanotechnology age, molecular designing of materials and single molecule studies are opening wide possibilities of using molecular systems in electronic and photonic devices, as well as in technological applications based on molecular switching or molecular recognition. In this sense, inorganic chemists are privileged by the possibility of using the basic strategies of coordination chemistry to build up functional supramolecular materials, conveying the remarkable chemical properties of the metal centers and the characteristics of the ancillary ligands. Coordination chemistry also provides effective self-assembly strategies based on specific metal-ligand affinity and stereochemistry. Several molecular based materials, derived from inorganic and metal-organic compounds are focused on this article, with emphasis on new supramolecular porphyrins and porphyrazines, metal-clusters and metal-polyimine complexes. Such systems are also discussed in terms of their applications in catalysis, sensors and molecular devices.

Clustering of transmutation elements tantalum, rhenium and osmium in tungsten in a fusion environment

Science.gov (United States)

You, Yu-Wei; Kong, Xiang-Shan; Wu, Xuebang; Liu, C. S.; Fang, Q. F.; Chen, J. L.; Luo, G.-N.

2017-08-01

The formation of transmutation solute-rich precipitates has been reported to seriously degrade the mechanical properties of tungsten in a fusion environment. However, the underlying mechanisms controlling the formation of the precipitates are still unknown. In this study, first-principles calculations are therefore performed to systemically determine the stable structures and binding energies of solute clusters in tungsten consisting of tantalum, rhenium and osmium atoms as well as irradiation-induced vacancies. These clusters are known to act as precursors for the formation of precipitates. We find that osmium can easily segregate to form clusters even in defect-free tungsten alloys, whereas extremely high tantalum and rhenium concentrations are required for the formation of clusters. Vacancies greatly facilitate the clustering of rhenium and osmium, while tantalum is an exception. The binding energies of vacancy-osmium clusters are found to be much higher than those of vacancy-tantalum and vacancy-rhenium clusters. Osmium is observed to strongly promote the formation of vacancy-rhenium clusters, while tantalum can suppress the formation of vacancy-rhenium and vacancy-osmium clusters. The local strain and electronic structure are analyzed to reveal the underlying mechanisms governing the cluster formation. Employing the law of mass action, we predict the evolution of the relative concentration of vacancy-rhenium clusters. This work presents a microscopic picture describing the nucleation and growth of solute clusters in tungsten alloys in a fusion reactor environment, and thereby explains recent experimental phenomena.

Effect of rhenium addition on tungsten fuzz formation in helium plasmas

NARCIS (Netherlands)

Khan, A.; De Temmerman, G.; Morgan, T. W.; M. B. Ward,

2016-01-01

The effect of the addition of rhenium to tungsten on the formation of a nanostructure referred to as ‘fuzz’ when exposed to helium plasmas at fusion relevant ion fluxes was investigated in the Magnum and Pilot PSI devices at the FOM Institute DIFFER. The effect rhenium had on fuzz growth was seen to

Neutron activation determination of rhenium in shales shales and molybdenites

International Nuclear Information System (INIS)

Zajtsev, E.I.; Radinovich, B.S.

1977-01-01

Described is the technique for neutron activation determination of rhenium in shales and molybdenites with its radiochemical extraction separation by methyl-ethyl ketone. The sensitivity of the analysis is 5x10 -7 %. Experimental checking of the developed technique in reference to the analysis of shales and molybdenites was carried out. Estimated is the possibility of application of X-ray gamma-spectrometer to instrumental determination of rhenium in molybdenites

Therapeutic applications of Rhenium-188 in nuclear medicine and oncology - Current status and expected future perspectives

International Nuclear Information System (INIS)

Knapp, F. F. Jr.

2005-01-01

Full text: The increasing use of unsealed radioactive targeting agents for cancer treatment requires the routine availability of cost-effective radioisotopes. Rhenium-188 (Re-188; half-life 16.9 hours) is a high-energy beta-emitter (E max 2.12 MeV), readily available no- max carrier-added from the alumina-based tungsten-188 (half-life 69 days)/rhenium-188 generator system. Rhenium-188 also emits a 155 keV (15%) gamma photon, permitting gamma camera imaging for biodistribution and dosimetry evaluation. The versatile chemistry of rhenium allows attachment to a wide variety of targeting molecules for Re-188 applications in nuclear oncology for both palliative metastatic treatment and targeted tumor therapy - radionuclide synovectomy, and coronary restenosis therapy. The long parent half-life and consistent performance provide an indefinite generator shelf-life of several months with high Re-188 elution yields (75-85 %) and consistently low W-188 parent breakthrough ( -6 ). Simple post-elution concentration methods have been developed which provide very high specific volume solution of Re-188 for radiolabeling (> 700 mCi/mL saline/1 Ci generator). Over 60 physician-sponsored clinical trials are currently in progress worldwide with applications in nuclear medicine, nuclear oncology and interventional cardiology. A variety of Re-188-labeled therapeutic radiopharmaceuticals and devices are being developed for clinical trials currently in progress for treatment of both benign and metastatic oncological disorders. Palliation of metastatic bone pain with Re-188-HEDP - prepared from a simple 'kit' - has been demonstrated as a cost-effective alternative to similar agents. Recent studies have in fact demonstrated the enhancement of progression-free interval and survival time by repeated Re-188-HEDP injections to patients with metastatic disease from prostate cancer. The use of the Re-188-labeled antiNCA95 (CD66) antibody in conjunction with external beam irradiation is an

Synthesis and study of rhenium (5) complexes with benzimidazole and rubeanic acid

Energy Technology Data Exchange (ETDEWEB)

Basitova, S M; Yurina, R D; Kotegov, K V; Amindzhanov, A A

1986-01-01

Mixed rhenium (5) oxohalide complex compounds with benzimidazole and rubeanic acid are synthesized. Composition of the compounds obtained is established by IR spectroscpy thermal and chemical analyses. It is shown that rhenium (5) chloride compound stability to pyrolysis is rather lower than that of the corresponding bromide derivatives.

Synthesis and study of rhenium (5) complexes with benzimidazole and rubeanic acid

International Nuclear Information System (INIS)

Basitova, S.M.; Yurina, R.D.; Kotegov, K.V.; Amindzhanov, A.A.

1986-01-01

Mixed rhenium (5) oxohalide complex compounds with benzimidazole and rubeanic acid are synthesized. Composition of the compounds obtained is established by IR spectroscpy thermal and chemical analyses. It is shown that rhenium (5) chloride compound stability to pyrolysis is rather lower than that of the corresponding bromide derivatives

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.

Rhenium Mechanical Properties and Joining Technology

Science.gov (United States)

Reed, Brian D.; Biaglow, James A.

1996-01-01

Iridium-coated rhenium (Ir/Re) provides thermal margin for high performance and long life radiation cooled rockets. Two issues that have arisen in the development of flight Ir/Re engines are the sparsity of rhenium (Re) mechanical property data (particularly at high temperatures) required for engineering design, and the inability to directly electron beam weld Re chambers to C103 nozzle skirts. To address these issues, a Re mechanical property database is being established and techniques for creating Re/C103 transition joints are being investigated. This paper discusses the tensile testing results of powder metallurgy Re samples at temperatures from 1370 to 2090 C. Also discussed is the evaluation of Re/C103 transition pieces joined by both, explosive and diffusion bonding. Finally, the evaluation of full size Re transition pieces, joined by inertia welding, as well as explosive and diffusion bonding, is detailed.

Coordination polymers: trapping of radionuclides and chemistry of tetravalent actinides (Th, U) carboxylates

International Nuclear Information System (INIS)

Falaise, Clement

2014-01-01

The use of nuclear energy obviously raises the question of the presence of radionuclides in the environment. Currently, their mitigation is a major issue associated with nuclear chemistry. This thesis focuses on both the trapping of radionuclides by porous solids called Metal-Organic Frameworks (MOF) and the crystal chemistry of the carboxylate of tetravalent actinides (AnIV). The academic knowledge of the reactivity of carboxylate of AnIV could help the understanding of actinides speciation in environment. We focused on the sequestration of iodine by aluminum based MOF. The functionalization (electron-donor group) of the MOF drastically enhances the iodine capture capacity. The removal of light actinides (Th and U) from aqueous solution was also investigated as well as the stability of (Al)-MOF under γ radiation. More than twenty coordination polymers based on tetravalent actinides have been synthesized and characterized by single crystal X-ray diffraction. The use of controlled hydrolysis promotes the formation of coordination polymers exhibiting polynuclear cluster ([U 4 ], [Th 6 ], [U 6 ] and [U 38 ]). In order to understand the formation of the largest cluster, the ex-situ study of the solvo-thermal synthesis of compound {U 38 } has also been investigated. (author)

Mechanistic Study of Oxygen Atom Transfer Catalyzed by Rhenium Compounds

Energy Technology Data Exchange (ETDEWEB)

Shan, Xiaopeng [Iowa State Univ., Ames, IA (United States)

2003-01-01

Two ionic and one neutral methyl(oxo)rhenium(V) compounds were synthesized and structurally characterized. They were compared in reactivity towards the ligands triphenylphosphane, pyridines, pyridine N-oxides. Assistance from Broensted bases was found on ligand displacement of ionic rhenium compounds as well as nucleophile assistance on oxidation of all compounds. From the kinetic data, crystal structures, and an analysis of the intermediates, a structural formula of PicH⁺3^- and mechanisms of ligand displacement and oxidation were proposed.

Lymph node scintigraphy with sup(99m)Tc-rhenium colloid

International Nuclear Information System (INIS)

Mitsuhata, Naoki; Suyama, Bunzo; Matsumura, Yosuke; Ohmori, Hiroyuki

1981-01-01

Lymph node scintigraphy with sup(99m)Tc-rhenium colloid in evaluation of nodal involvement by urological malignancy were performed on twelve cases (4 bladder cancer, 3 prostatic cancer, 2 penile cancer and 3 testicular tumor). These cases had been examined the extent of disease on the basis of findings at pedal lymphangiography, urography, computed tomography or laparotomy. sup(99m)Tc-rhenium colloid in a volume of 0.2 ml (2 mCi) was injected into the first interdigital webs of each foot without local anesthesia. In one case of penile cancer radioactive colloid was directly injected into the glans penis and prepuce including tumor area. Our clinical experience reported here reveals that lymph node scintigraphy with sup(99m)Tc-rhenium colloid can provide a useful method of investigating the lymphatic system. This technique is reproducible and can be performed in poor risk patients or pediatric patients readily and safely. (author)

Study of the electrodeposition of rhenium thin films by electrochemical quartz microbalance and X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Schrebler, R.; Cury, P.; Suarez, C.; Munoz, E.; Vera, F.; Cordova, R.; Gomez, H.; Ramos-Barrado, J.R.; Leinen, D.; Dalchiele, E.A.

2005-01-01

Rhenium thin films were prepared by electrodeposition from an aqueous solution containing 0.1 M Na 2 SO 4 +H 2 SO 4 , pH 2 in presence of y mM HReO 4 . As substrates polycrystalline gold (y=0.75 mM HReO 4 ) and monocrystalline n-Si(100) (y=40 mM HReO 4 ) were used. The electrochemical growth of rhenium was studied by cyclic voltammetry and electrochemical quartz microbalance on gold electrodes. The results found in the potential region before the hydrogen evolution reaction (her) showed that ReO 3 , ReO 2 and Re 2 O 3 with different hydration grades can be formed. In the potential region where the her is occurring, either on gold or n-Si(100) the electrodeposition of metallic rhenium takes place. On both substrates, rhenium films were formed by electrolysis at constant potential and X-ray photoelectron spectroscopy technique was used to characterise these deposits. It was concluded that the electrodeposited films were of metallic rhenium and only the uppermost atomic layer contained rhenium oxide species

High-temperature extraction of rhenium from sulfuric acid solutions with trialkylamines

International Nuclear Information System (INIS)

Gladyhev, V.P.; Andreeva, N.N.; Kim, E.M.; Kovaleva, S.V.

1985-01-01

This paper attempts to determine the possibility of conducting high-temperature extraction of rhenium from sulfuric acid solutions with trialkylamines (TAA) using higher hydrocarbon-paraffin mixtures as the diluent of the extraction system. Substitution of kerosene by paraffin in the extraction system would permit decreasing the danger of fire and explosions during he extraction process. In extracting rhenium from industrial solutions with a melt of higher paraffins containing TAA and alcohols, the extraction system can be continously heated in heat exchangers through which washing sulfuric acid passes and then goes to the extractor. This permits utilizing the heat and decreases the temperature of the solutions for extraction to the optimum temperatures. Extraction of rhenium with a melt of trioctylamine in paraffin obeys the same mechanisms as high-temperature extraction of ruthenium (IV) by amines in kerosene and aromatic hydrocarbons

Influence of nano-cluster compounds of rhenium drugs on the activity of liver enzymes in a tumor model

Directory of Open Access Journals (Sweden)

J. V. Suponko

2010-06-01

Full Text Available Enzymes’ level in rat’s hepatocytes under Guerin's carcinoma T8 development as well as after injection of rhenium compounds and cis-platin has been studied. It has been determined that the decrease of enzymatic activity to the level of the animals of control group was observed at the simultaneous injection of cis-platin and cluster rhenium compounds in nanoliposomal and water-soluble forms. That confirms possible hepatoprotective properties of the rhenium compounds. It has been shown that hepatoprotective properties of rhenium cluster compounds mostly don’t depend on the form of their injection and are detected regardless of anticancer properties. Rhenium-platinum system with β-alanine ligand in aqueous solution, has been found. Its injection is accompanied by the hepatoprotective effect.

Formation of a Six-Coordinate fac-[Re(Co)3]+ Complex by the N-C bond cleavage of a potentially tetradentate ligand

International Nuclear Information System (INIS)

Booysen, I.; Gerber, T. I. A.; Hosten, E.; Mayer, P.

2008-01-01

The rhenium(I) compound fac-[Re(CO) 3 (daa)]. Hpab.H 2 O (Hpab N,N'-(l,2-phenylene)bis(2'-aminobenzamide); Hdaa 2-amino-N-(2-aminophenyl)benzamide) was synthesized from the reaction of [Re(CO) 5 ,Br] with two equivalent of Hpab in toluene. The monoanionic tridentate ligand daa was formed by the rhenium-mediated cleavage of an amido N-C bond of the potentially tetradentate ligand Hpab. The compound was characterized by IR spectroscopy and X-ray crystallography, and daa is coordinated as a diamino amide via three nitrogen-donor atoms

Reductive coupling of carbon monoxide in a rhenium carbonyl complex with pendant Lewis acids.

Science.gov (United States)

Miller, Alexander J M; Labinger, Jay A; Bercaw, John E

2008-09-10

Phosphinoborane ligands impart unique reactivity to a rhenium carbonyl cation relative to simple phosphine complexes. Addition of either triethylborohydride or a platinum hydride (that can be formed from H2) forms a rhenium boroxycarbene. This carbene, which crystallizes as a dimer, disproportionates over a period of days to afford the starting cation and a structurally unprecedented boroxy(boroxymethyl)carbene, in which a new C-C bond has been formed between two reduced CO ligands. This product of C-C bond formation can be independently synthesized by addition of 2 equiv of hydride to the rhenium carbonyl cation.

Chemistry of Technetium

International Nuclear Information System (INIS)

Omori, Takashi

2001-01-01

Since the late 1970's the coordination chemistry of technetium has been developed remarkably. The background of the development is obviously related to the use of technetium radiopharmaceuticals for diagnosis in nuclear medicine. Much attention has also been denoted to the chemical behavior of environmental 99 Tc released from reprocessing plants. This review covers the several aspects of technetium chemistry, including production of radioisotopes, analytical chemistry and coordination chemistry. In the analytical chemistry, separation of technetium, emphasizing chromatography and solvent extraction, is described together with spectrophotometric determination of technetium. In the coordination chemistry of technetium, a characteristic feature of the chemistry of Tc(V) complexes is referred from the view point of the formation of a wide variety of highly stable complexes containing the Tc=O or Tc≡N bond. Kinetic studies of the preparation of Tc(III) complexes using hexakis (thiourea) technetium(III) ion as a starting material are summarized, together with the base hydrolysis reactions of Tc(III), Tc(IV) and Tc(V) complexes. (author)

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.

Use of cluster rhenium substances with alkyl ligands for inhibition of the Guerin carcinoma Growth

Directory of Open Access Journals (Sweden)

O. S. Voronkova

2007-04-01

Full Text Available Quantity and quality of erythrocytes, blood haemoglobin concentration, glucose levels in the erythrocytes and plasma, content of TBA-active products in blood plasma of rats were studied during development of the Guerin carcinoma, introduction of cis-platinum and cluster rhenium substances with organic ligands. It was shown that rhenium substances had essential antioxidant effects and changed the dynamic of tumour growth. The conclusion on perspectiveness of further investigations of rhenium substances with cluster fragment and organic ligands in experiments in vivo with changed redox-status of an organism was drawn.

A study of scandia and rhenium doped tungsten matrix dispenser cathode

Science.gov (United States)

Wang, Jinshu; Li, Lili; Liu, Wei; Wang, Yanchun; Zhao, Lei; Zhou, Meiling

2007-10-01

Scandia and rhenium doped tungsten powders were prepared by solid-liquid doping combined with two-step reduction method. The experimental results show that scandia was distributed evenly on the surface of tungsten particles. The addition of scandia and rhenium could decrease the particle size of doped tungsten, for example, the tungsten powders doped with Sc 2O 3 and Re had the average size of about 50 nm in diameter. By using this kind of powder, scandia and rhenium doped tungsten matrix with the sub-micrometer sized tungsten grains was obtained. This kind of matrix exhibited good anti-bombardment insensitivity at high temperature. The emission property result showed that high space charge limited current densities of more than 60 A/cm 2 at 900 °C could be obtained for this cathode. A Ba-Sc-O multilayer about 100 nm in thickness formed at the surface of cathode after activation led to the high emission property.

Characterization of rhenium compounds obtained by electrochemical synthesis after aging process

Energy Technology Data Exchange (ETDEWEB)

Vargas-Uscategui, Alejandro, E-mail: avargasuscat@ing.uchile.cl [Departamento de Ingeniería de Minas, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Tupper Av. 2069, Santiago (Chile); Mosquera, Edgar [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Tupper Av. 2069, Santiago (Chile); López-Encarnación, Juan M. [Department of Mathematics-Physics and Department of Chemistry, University of Puerto Rico at Cayey, 205 Ave. Antonio R. Barceló, Cayey, PR 00736, USA. (Puerto Rico); Chornik, Boris [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Blanco Encalada Av. 2008, Santiago (Chile); Katiyar, Ram S. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico San Juan, San Juan, PR 00931-3343 (United States); Cifuentes, Luis [Departamento de Ingeniería de Minas, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Tupper Av. 2069, Santiago (Chile)

2014-12-15

The proper identification of the molecular nature of the aged rhenium compound obtained by means of electrodeposition from an alkaline aqueous electrolyte was determined. Chemical, structural and vibrational experimental characterization of the aged Re compound showed agreement with quantum-computations, thereby allowing the unambiguous identification of the Re compound as H(ReO{sub 4})H{sub 2}O. - Graphical abstract: Rhenium oxides were electrodeposited on a copper surface and after environmental aging was formed the H(ReO{sub 4})H{sub 2}O compound. The characterization of the synthesized material was made through the comparison of experimental evidence with quantum mechanical computations carried out by means of density functional theory (DFT). - Highlights: • Aged rhenium compound obtained by means of electrodeposition was studied. • The study was made by combining experimental and DFT-computational information. • The aged electrodeposited material is consistent with the H(ReO{sub 4})H{sub 2}O compound.

Evaluation of oxide dispersion strengthened (ODS) molybdenum and molybdenum-rhenium alloys

International Nuclear Information System (INIS)

Mueller, A.J.; Bianco, R.; Buckman, R.W. Jr.

1999-01-01

Oxide dispersion strengthened (ODS) molybdenum alloys being developed for high temperature applications possess excellent high temperature strength and creep resistance. In addition they exhibit a ductile-to-brittle transition temperature (DBIT) in the worked and stress-relieved condition under longitudinal tensile load well below room temperature. However, in the recrystallized condition, the DBTT maybe near or above room temperature, depending on the volume fraction of oxide dispersion and the amount of prior work. Dilute rhenium additions (7 and 14 wt.%) to ODS molybdenum were evaluated to determine their effect on low temperature ductility. The addition of 7 wt.% rhenium to the ODS molybdenum did not significantly enhance the mechanical properties. However, the addition of 14 wt.% rhenium to the ODS molybdenum resulted in a DBTT well below room temperature in both the stress-relieved and recrystallized condition. Additionally, the tensile strength of ODS Mo-14Re is greater than the base ODS molybdenum at 1,000 to 1,250 C

Influence of cold rolling and strain rate on plastic response of powder metallurgy and chemical vapor deposition rhenium

International Nuclear Information System (INIS)

Koeppel, B.J.; Subhash, G.

1999-01-01

The plastic response of two kinds of rhenium processed via powder metallurgy (PM) and chemical vapor deposition (CVD) were investigated under uniaxial compression over a range of strain rates. The PM rhenium, further cold rolled to 50 and 80 pct of the original thickness, was also investigated to assess the influence of cold work on the plastic behavior. A strong basal texture was detected in all the preceding materials as a result of processing and cold work. Both CVD and PM rhenium exhibited an increase in yield strength and flow stress with increasing strain rate. In PM rhenium, cold work resulted in an increase in hardness and yield strength and a decrease in the work hardening rate. The deformed microstructures revealed extensive twinning in CVD rhenium. At large strains, inhomogeneous deformation mode in the form of classical cup and cone fracture was noticed

Effect of octanols structure on their extraction ability as regards to rhenium(VII) in sulfuric acid solutions

International Nuclear Information System (INIS)

Kasikov, A.G.; Petrova, A.M.

2007-01-01

It is established that extraction ability of octanols as regards to rhenium(VII) and sulfuric acid depends on the structure of alcohol, but if in passage from octanol-1 to octanol-3 as regard to rhenium(VII) it rises, then for H 2 SO 4 it falls. Dependence of the distribution function of rhenium from the concentration of the acid has maximums at 4-7 mol l 1- that the most distinctly it becomes apparent for secondary alcohols. Decreasing the extraction ability of octyl alcohols with the growth of H 2 SO 4 concentration more than 7 mol l 1- is connected with the change of extractant composition and forms of rhenium(VII) being in the solution [ru

3.3.1. Synthesis, Spectroscopy and Structural Analysis of Technetium and Rhenium Nitrosyl Complexes

Directory of Open Access Journals (Sweden)

Terrence\tNicholson*,\tEsther\tChunb, Ashfaq\tMahmood,\tPeter\tMueller,\tAlan\tDavisona\tand\tAlun\tG.\tJones

2015-11-01

Full Text Available Here we report an overview of our synthetic, spectroscopic and structural studies of technetium and rhenium nitrosyl complexes. We review the results from various notes and short papers reported over the past 15 years and discuss their significance in terms of radiopharmaceutical design.A single new complex is reported, the ReI-NO complex [ReICl2(NO(py-N(Et-py], in which the tridentate ligand di-(2-picolyl(N-ethylamine, (py-N(Et-py, is coordinated in a meridional manner. This complex was synthesized from the reaction of the ReI-nitrosyl complex ReCl2(NO(NCMe3] and the neutral tri-amine ligand py-N(Et-py in methylene chloride under argon. The bright red species was isolated chromatographically and recrystallized from CH2Cl2/MeOH under diethylether.A review of literature values for nitrosyl complexes with various ligands bound to the coordination sitetrans- to the nitrosyl group shows only minor variations in the M-N-O bond angle.

Forschungszentrum Rossendorf. Institute of Bioinorganic and Radiopharmaceutical Chemistry. Annual report 2002

Energy Technology Data Exchange (ETDEWEB)

Johannsen, B.; Seifert, S. (eds.)

2003-01-01

In 2002 the Institute of Bioinorganic and Radiopharmaceutical Chemistry, one of five institutes in the Forschungszentrum Rossendorf e.V., continued and further developed its basic and application-oriented research. Research was focused on radiotracers as molecular probes to make the human body biochemically transparent with regard to individual molecular reactions. While further pursuing and extending our chemical, biological and medical activities in the PET Centre and being engaged in the coordination chemistry and radiopharmacology of technetium, rhenium and other metals, new lines of activity have also been opened up recently. This involves bioactive substances as they are present in food. Such substances may cause a health risk or may exert effects not yet fully understood. New biotechnological procedures in food processing also give rise to new questions that can be addressed by PET. As illustrated by the majority of contributions in this report, the Institute is predominantly engaged in radiopharmaceutical chemistry of both radiometals and the PET nuclides carbon-11 and fluorine-18. The improvement of labelling methods continued to remain an area of considerable endeavour. The review article on radiochemistry with the short-lived positron emitters {sup 11}C and {sup 18}F is meant to emphasize this field of research and to help to classify our contribution to this area. As for the radiometals, our studies agree with the more and more demanding insight that the coordination has a not sufficiently predictable impact on the in vivo behaviour of the molecule into which the chelate unit is integrated. Therefore, attempts to better understand and adjust the in vivo behaviour of the radiotracers are being continued. In order to reflect on and identify trends and perspectives, the Institute organized on March 7-8, 2002, an international conference on advances and perspectives in radiotracer development. The Institute's chemically and radiopharmacologically

Forschungszentrum Rossendorf. Institute of Bioinorganic and Radiopharmaceutical Chemistry. Annual report 2002

International Nuclear Information System (INIS)

Johannsen, B.; Seifert, S.

2003-01-01

In 2002 the Institute of Bioinorganic and Radiopharmaceutical Chemistry, one of five institutes in the Forschungszentrum Rossendorf e.V., continued and further developed its basic and application-oriented research. Research was focused on radiotracers as molecular probes to make the human body biochemically transparent with regard to individual molecular reactions. While further pursuing and extending our chemical, biological and medical activities in the PET Centre and being engaged in the coordination chemistry and radiopharmacology of technetium, rhenium and other metals, new lines of activity have also been opened up recently. This involves bioactive substances as they are present in food. Such substances may cause a health risk or may exert effects not yet fully understood. New biotechnological procedures in food processing also give rise to new questions that can be addressed by PET. As illustrated by the majority of contributions in this report, the Institute is predominantly engaged in radiopharmaceutical chemistry of both radiometals and the PET nuclides carbon-11 and fluorine-18. The improvement of labelling methods continued to remain an area of considerable endeavour. The review article on radiochemistry with the short-lived positron emitters 11 C and 18 F is meant to emphasize this field of research and to help to classify our contribution to this area. As for the radiometals, our studies agree with the more and more demanding insight that the coordination has a not sufficiently predictable impact on the in vivo behaviour of the molecule into which the chelate unit is integrated. Therefore, attempts to better understand and adjust the in vivo behaviour of the radiotracers are being continued. In order to reflect on and identify trends and perspectives, the Institute organized on March 7-8, 2002, an international conference on advances and perspectives in radiotracer development. The Institute's chemically and radiopharmacologically oriented activities

THE SYNTHESIS OF BIOCONJUGATE BASED ON RHENIUM(I CARBONYL COMPLEX FOR VISUALIZATION OF PATHOLOGICAL PROCESS

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K. O. Piletska

2017-03-01

Full Text Available Tricarbonyl rhenium(I complexes have a great potential like biomarkers. It is caused their biological stability, low toxicity, large Stokes shifts, and long luminescence lifetimes. Rhenium tricarbonyl complexes fac-[Re(CO3(N^N], where N^N is a ligand with low π* orbitals are excellent candidates as imaging dyes. The method of obtaining potential biomarkers based on tricarbonyl rhenium(I complex with a 4-methyl-2,2’-bipyridine-4’-carboxylate by the addition of biomolecules by peptide synthesis was developed. The new complex [Re(CO3MebpyCOOHBr] was synthesized, composition and structure of which were established by mass spectrometry, IR and NMR spectroscopy. A selective attachment of receptor peptide enkephalin to complex [Re(CO3(MebpyCOOHBr] was performed. The formation of a new compound and its structure has been confirmed by HPLC and mass spectral analysis. The method which has been developed allows to connect various peptides to rhenium(I complex in the solution.

Structure and x-ray density of electrochemically deposited rhenium films

International Nuclear Information System (INIS)

Petrovich, V.A.; Fedenkov, A.L.; Shepurev, S.Yu.

1988-01-01

The electrodeposition of rhenium was carried out at a constant cathode-current density and room temperature. The backing was grade KEF-0.02 single-crystal silicon. The absorption coefficient μ of the film was determined for the K α radiation of the copper line. The investigation enabled us to conclude that electrochemically deposited rhenium films can be used as a material for the masking coatings of x-ray patterns, since the absorption coefficients of the x-ray radiation of the resultant films are superior to the similar parameters of traditionally employed materials, and surpass these materials in terms of corrosion resistance and simplicity of production

Determination coefficient distribution rhenium and tungsten using method extraction with solvent methyl ethyl ketone

International Nuclear Information System (INIS)

Riftanio Natapratama Hidayat; Maria Christina Prihatiningsih; Duyeh Setiawan

2015-01-01

Determination of the distribution coefficient (K d ) of the rhenium and tungsten conducted for the purpose of knowing the value of K d of the two elements. K d value determination is applied to the process of separation rhenium-188 from target of tungsten-188 for the purposes purification of radioisotopes that are made to meet the radionuclide and radiochemical purity. The K d value determination using solvent extraction with methyl ethyl ketone (MEK). Prior to the determination of K d values, determined beforehand the optimum conditions of extraction process based on the effect of agitation time, the volume of MEK, and the pH of the solution. Confirmation the results of the extraction was conducted using UV-Vis spectrophotometer with a complexing KSCN under acidic conditions and reductant SnCl 2 . The results showed that the optimum condition extraction process to feed each of 10 ppm is when the agitation for 10 minutes, the volume of MEK in 20 ml, and the pH below 5. Obtained the maximum recovery of rhenium are drawn to the organic phase as much as 9.545 ppm. However, the condition of the extraction process does not affect the migration of tungsten to the organic phase. Then the maximum K d values obtained at 2.7566 rhenium and tungsten maximum K d is 0.0873. Optimum conditions of extraction process can be further tested on radioactive rhenium and tungsten as an alternative to the separation of radioisotopes. (author)

Synthesis, reactivity, and properties of N-fused porphyrin rhenium(I) tricarbonyl complexes.

Science.gov (United States)

Toganoh, Motoki; Ikeda, Shinya; Furuta, Hiroyuki

2007-11-12

The thermal reactions of N-fused tetraarylporphyrins or N-confused tetraarylporphyrins with Re2(CO)10 gave the rhenium(I) tricarbonyl complexes bearing N-fused porphyrinato ligands (4) in moderate to good yields. The rhenium complexes 4 are characterized by mass, IR, 1H, and 13C NMR spectroscopy, and the structures of tetraphenylporphynato complex 4a and its nitro derivative 15 are determined by X-ray single crystal analysis. The rhenium complexes 4 show excellent stability against heat, light, acids, bases, and oxidants. The aromatic substitution reactions of 4 proceed without a loss of the center metal to give the nitro (15), formyl (16), benzoyl (17), and cyano derivatives (19), regioselectively. In the electrochemical measurements for 4, one reversible oxidation wave and two reversible reduction waves are observed. Their redox potentials imply narrow HOMO-LUMO band gaps of 4 and are consistent with their electronic absorption spectra, in which the absorption edges exceed 1000 nm. Theoretical study reveals that the HOMO and LUMO of the rhenium complexes are exclusively composed of the N-fused porphyrin skeleton. Protonation of 4 takes place at the 21-position regioselectively, reflecting the high coefficient of the C21 atom in the HOMO orbital. The skeletal rearrangement reaction from N-confused porphyrin Re(I) complex (8) to N-fused porphyrin Re(I) complex (4) is suggested from the mechanistic study as well as DFT calculations.

Extraction of rhenium(VII) by phosphorylated podands

International Nuclear Information System (INIS)

Turanov, A.N.; Karandashev, V.K.; Baulin, V.E.

2006-01-01

Interphase distribution of ReO 4 - between aqueous solutions of H 2 SO 4 and solutions of phosphoryl-containing podands in organic solvents is studied. Stoichiometry of the complexes extracted is determined. Effect of extractant structure and nature of organic solvent on efficiency of rhenium extraction into organic phase is determined [ru

Chromatographic separation of rhenium in alumina-methanol/sulfuric acid system

International Nuclear Information System (INIS)

Oguma, Koichi

1983-01-01

The adsorption behavior of a number of metals on alumina was surveyed in a methanol-(0.005 -- 0.5) M H 2 SO 4 (3 : 1 v/v) developing solvent by thin-layer chromatography. Over the acid concentration range tested, Re(VII) does not favor the alumina phase to any great extent while the most other metals are strongly adsorbed on alumina. These findings allowed to establish a column chromatographic technique for selective separation of rhenium in a methanol-0.05 M H 2 SO 4 (3 : 1 v/v) eluent. The separation technique thus established was applied to molybdenite analysis for rhenium. About 100-mg powdered sample containing ca. 100 ppm rhenium was decomposed with HNO 3 and then evaporated nearly to dryness. The residue was dissolved in NH 4 OH and the excess NH 4 OH was expelled by evaporation to dryness. The residue was dissolved in 2.5-ml 0.5 M H 2 SO 4 and 10-ml water, the insoluble materials filtered off, and the filtrate diluted to exactly 25 ml with water. A 10-ml aliquot of this solution was mixed with 30-ml methanol and the mixture was passed through a column (diameter 15 mm, bed height 30 mm) containing 5 g of alumina. The column was then washed with 20 ml of a methanol-0.05 M H 2 SO 4 (3 : 1 v/v) mixture. Rhenium was recovered from the loaded solution and the subsequent washings, and was determined spectrophotometrically with Methylene Blue as a chromogenic reagent. The values obtained from four samples of molybdenite are in good agreement with those obtained by neutron activation analysis. The relative standard deviation (n = 4; calculated from the range) was between 2.0 and 5.2 %. (author)

Homogeneous photocatalytic reactions with organometallic and coordination compounds--perspectives for sustainable chemistry.

Science.gov (United States)

Hoffmann, Norbert

2012-02-13

Since the time of Giacomo Ciamician at the beginning of the 20th century, photochemical transformations have been recognized as contributing to sustainable chemistry. Electronic excitation significantly changes the reactivity of chemical compounds. Thus, the application of activation reagents is frequently avoided and transformations can be performed under mild conditions. Catalysis plays a central role in sustainable chemistry. Stoichiometric amounts of activation reagents are often avoided. This fact and the milder catalytic reaction conditions diminish the formation of byproducts. In the case of homogeneous catalysis, organometallic compounds are often applied. The combination of both techniques develops synergistic effects in the sense of "Green Chemistry". Herein, metal carbonyl-mediated reactions are reported. These transformations are of considerable interest for the synthesis of complex polyfunctionalized compounds. Copper(I)-catalyzed [2+2] photocycloaddition gives access to a large variety of cyclobutane derivatives. Currently, a large number of publications deal with photochemical electron-transfer-induced reactions with organometallic and coordination compounds, particularly with ruthenium complexes. Several photochemically induced oxidations can easily be performed with air or molecular oxygen when they are catalyzed with organometallic complexes. Photochemical reaction conditions also play a certain role in C-H activation with organometallic catalysts, for instance, with alkanes, although such transformations are conveniently performed with a variety of other photochemical reactions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposition of rhenium from chloride melts: Electrochemical nature, structure and applied aspects

Directory of Open Access Journals (Sweden)

Vinogradov-Zhabrov O.N.

2003-01-01

Full Text Available Processes involved in the electrodeposition of rhenium from chloride melts have been studied over the temperature interval from 680 to 970 0C at a cathodic current density of 5 to 250 mA/cm2. It has been found that rhenium is deposited in the form of continuous layers. In addition to that the growth of deposits as separate single-crystal needles has also been noticed. Continuous layers had axial growth textures. The crystallographic direction of the textures is due to electrolysis conditions, such as concentration of oxygen-containing impurities, temperature, melt composition and cathodic current density. When the concentration of oxygen-containing impurities in the melt decreased, electrolysis temperature increased, the average radius of the supporting electrolyte cations became smaller, or cathodic current density diminished, the direction of the growth textures was changing as follows: (1010 →(1120 →(101L →(0001 →(0001needles. The microhardness of the deposits in this series is 900 to 250 kg/mm2. The growth of deposits on textured rhenium substrates and single crystals having different orientations, including bent substrates, was studied. It has been found that the epitaxial growth is virtually unlimited in depth if the orientation of the substrate coincides with the growth texture under given conditions. If the substrate orientation deviated from the growth texture, the epitaxial growth was nearly absent. Kinetic parameters were measured using the galvanostatic method. The exchange current density was determined over the interval of (0.01-0.1 A/cm2 depending on the concentration of oxygen-containing impurities, cation composition, type of the surface and its condition. The parameter α⋅Z, which was estimated by two methods, was equal to 2.1-3.1. The diffusion coefficient of rhenium ions has been found to be 2.8 ⋅10 −5 cm2/s at 790 0C and 3.5 ⋅10 −5 cm2/s at 840 0C. Galvanoplastic production of rhenium products, such as

Influence of the acid and basic properties of rhenium oxide supported on alumina catalyst on the catalytic performance in olefin metathesis; Influence des proprietes acido-basiques de l`oxyde de rhenium supporte sur les performances catalytiques en metathese des olefines

Energy Technology Data Exchange (ETDEWEB)

Nahama, F.

1996-11-30

The aim of this work is to study the influence of the acid-basic properties of rhenium oxide supported on alumina catalyst on the catalytic performance in olefin metathesis. The literature data indicate that the environment of the active site does possess acid properties. However, the nature of the acid sites is still matter of debate. Concerning the Re O{sub x} - Al{sub 2}O{sub 3} interactions, we have shown that perrhenate ions are electrostatically absorbed on alumina. The uptake of rhenium is favoured at acidic pH (below 4), and the absorbed rhenium is in equilibrium with rhenium in solution. The results of rhenium extraction by water strongly suggest that the surface compounds of the calcined Re{sub 2}O{sub 7}/Al{sub 2}O{sub 3} materials is aluminium perrhenate. Characterization of surface acidity of the catalyst by infrared spectroscopy reveals that the initiation of the metathesis reaction is governed essentially by Lewis acidity. This strongly supports the role of Lewis acidity, which is exalted by the increase of the rhenium content and the calcination temperature. Finally, we point out by ammonia adsorption-thermodesorption a band at 1320 cm{sup -1} characteristic of the Lewis acidity of aluminium perrhenate. This result is a second indication of the presence of aluminium perrhenate on the Re{sub 2}O{sub 7}/Al{sub 2}O{sub 3} catalyst surface. (author)

Development of unified X-ray fluorescent analysis to determine rhenium content in multicomponent oxide compositions

International Nuclear Information System (INIS)

Drobot, D.V.; Belyaev, A.V.; Kutvitskij, V.A.; Rysev, A.P.

1999-01-01

A procedure to prepare rhenium-containing glass-like specimens on the basis of bismuth and boron oxides is proposed. The glasses produced are studied by X-ray fluorescent analysis and routine spectrometric thiocyanate analysis. The results make it possible to determine rhenium in oxide mixtures in the range of its content 0.01 - 10% with S r = 0.03 [ru

A Study on the Trapping Characteristics of Rhenium Oxide Using Ca(OH)_2

International Nuclear Information System (INIS)

Lee, Tae-Kyo; Eun, Hee-Chul; Choi, Jung-Hoon; Lee, Ki-Rak; Han, Seung-Youb; Park, Hwan-Seo

2017-01-01

The objective of this study was to obtain basic data for trapping gaseous technetium (Tc) oxide generated from the voloxidation process in spent nuclear fuel pyroprocessing. Rhenium (Re) and Ca(OH)_2 were used as surrogates for the technetium and a trapping material, respectively. The trapping characteristics of rhenium oxide were investigated with changing temperatures and molar ratios of calcium (Ca) over rhenium, and the thermal behaviors of the trapping products were observed. The products following after the trapping test were identified as Ca(ReO_4)_2 and Ca_5Re_2O_1_2. The conversion to Ca_5Re_2O_1_2 was preferred with increasing temperatures, and the trapping products were completely converted into Ca5Re2O12 under conditions exceeding 800 ℃, or when maintained at 750 ℃ for 4 hr. The trapping efficiency at a molar ratio of 2.5 (Ca:Re=5:2) was significantly superior to that at the molar ratio of 2.

Synthesis and coordination chemistry of 1,1,1-tris-(pyrid-2-yl)ethane.

Science.gov (United States)

Santoro, Amedeo; Sambiagio, Carlo; McGowan, Patrick C; Halcrow, Malcolm A

2015-01-21

A new synthesis of 1,1,1-tris(pyrid-2-yl)ethane (L), and a survey of its coordination chemistry, are reported. The complexes [ML2](n+) (M(n+) = Fe(2+), Co(2+), Co(3+), Cu(2+) and Ag(+)), [PdCl2L] and [CuI(L)] have all been crystallographically characterised. Noteworthy results include an unusual square planar silver(i) complex [Ag(L)2]X (X(-) = NO3(-) and SbF6(-)); the oxidative fixation of aerobic CO2 by [CuI(L)] to yield [Cu2I(L)2(μ-CO3)]2[CuI3] and [Cu(CO3)(L)]; and, water/carbonato tape and water/iodo layer hydrogen bonding networks in hydrate crystals of two of the copper(ii) complexes. Cyclic voltammetric data on [Fe(L)2](2+) and [Co(L)2](2+/3+) imply that the peripheral methyl substituent has a weak influence on the ligand field exerted by L onto a coordinated metal ion.

Chemistry teacher initial formation under the eye of the coordinators of the courses

Directory of Open Access Journals (Sweden)

Roberta Guimarães Corrêa

2016-05-01

Full Text Available Despite the recognition of the need for change and the constant production of studies on initial formation, the degree courses still have questions that need to be discussed. These issues are related to the difficulty to overcome the lack of teachers in basic education and the type of formation offered in undergraduate courses, which does not seem to meet the current Brazilian educational demands. This paper presents data from a qualitative study conducted with coordinators of seven higher education institutions in the state of São Paulo. Despite the different institutional realities presented in this work, the difficulty of effectively contribute to the formation of chemistry teachers is common to all the institutions. Lack of interest in initial formation teacher’s courses, evasion problems, relationship between the initial formation of chemical teachers and chemistry’s professionals and the lack of commitment of teachers marked the reports of the coordinators of the courses.

Tungsten-rhenium composite tube fabricated by CVD for application in 18000C high thermal efficiency fuel processing furnace

International Nuclear Information System (INIS)

Svedberg, R.C.; Bowen, W.W.; Buckman, R.W. Jr.

1980-04-01

Chemical Vapor Deposit (CVD) rhenium was selected as the muffle material for an 1800 0 C high thermal efficiency fuel processing furnace. The muffle is exposed to high vacuum on the heater/insulation/instrumentation side and to a flowing argon-8 V/0 hydrogen gas mixture at one atmosphere pressure on the load volume side. During operation, the muffle cycles from room temperature to 1800 0 C and back to room temperature once every 24 hours. Operational life is dependent on resistance to thermal fatigue during the high temperature exposure. For a prototypical furnace, the muffle is approximately 13 cm I.D. and 40 cm in length. A small (about one-half size) rhenium closed end tube overcoated with tungsten was used to evaluate the concept. The fabrication and testing of the composite tungsten-rhenium tube and prototypic rhenium muffle is described

The coordination chemistry of the neutral tris-2-pyridyl silicon ligand [PhSi(6-Me-2-py)3].

Science.gov (United States)

Plajer, Alex J; Colebatch, Annie L; Enders, Markus; García-Romero, Álvaro; Bond, Andrew D; García-Rodríguez, Raúl; Wright, Dominic S

2018-05-22

Difficulties in the preparation of neutral ligands of the type [RSi(2-py)3] (where 2-py is an unfunctionalised 2-pyridyl ring unit) have thwarted efforts to expand the coordination chemistry of ligands of this type. However, simply switching the pyridyl substituents to 6-methyl-pyridyl groups (6-Me-2-py) in the current paper has allowed smooth, high-yielding access to the [PhSi(6-Me-2-py)3] ligand (1), and the first exploration of its coordination chemistry with transition metals. The synthesis, single-crystal X-ray structures and solution dynamics of the new complexes [{PhSi(6-Me-2-py)3}CuCH3CN][PF6], [{PhSi(6-Me-2-py)3}CuCH3CN][CuCl2], [{PhSi(6-Me-2-py)3}FeCl2], [{PhSi(6-Me-2-py)3}Mo(CO)3] and [{PhSi(6-Me-2-py)3}CoCl2] are reported. The paramagnetic Fe2+ and Co2+ complexes show strongly shifted NMR resonances for the coordinated pyridyl units due to large Fermi-contact shifts. However, magnetic anisotropy also leads to considerable pseudo-contact shifts so that both contributions have to be included in the paramagnetic NMR analysis.

Influence of ligand structure on anticancer and antioxidant properties of rhenium cluster compounds

Directory of Open Access Journals (Sweden)

I. V. Leus

2009-11-01

Full Text Available Under the model growth of T8 Guerin’s carcinoma in rats we studied the anticancer activity of the system rhenium-platinum, which includes cis-dicarboxylates of rhenium (III with different alkyl ligands, erythrocytes number and its morphological structure, erythrocytic stability, blood haemoglobin concentration, catalase activity and concentration of TBA-active products in the rats blood plasma. The renium-platinum system had considerable antioxidat effect and prevented the growth of tumour, that was maximal for a compound with the pivalate ligand.

Polynuclear complexes of copper(I) halides: coordination chemistry and catalytic transformations of alkynes

International Nuclear Information System (INIS)

Mykhalichko, B M; Mys'kiv, M G; Temkin, Oleg N

2000-01-01

Characteristic features of the coordination chemistry of Cu(I) and mechanisms of catalytic conversions of alkynes in the CuCl-MCl-H 2 O-HC≡CR system (MCl is alkali metal or ammonium chloride or amine hydrochloride; R=H, CH 2 OH, CH=CH 2 , etc.) are analysed based on studies of the compositions and structures of copper(I) chloride (bromide) complexes, alkyne π-complexes and ethynyl organometallic polynuclear compounds formed in this system in solutions and in the crystalline state. The role of polynuclear complexes in various reactions of alkynes is discussed. The bibliography includes 149 references.

Determination of rhenium (7) trace amounts by spectrophotometric titration in medium of mixed solvents

International Nuclear Information System (INIS)

Kuznetsov, V.V.; Samorukova, O.L.

1978-01-01

The method has been proposed of determining rhenium (7) microamounts by spectrophotometric titration in the medium water-dimethyl-sulphoxide with the reagent nitrochromazo. The method is based on the formation of ionic pairs K + ReO 4 - in water-organic solvents. The results of rhenium determination are satisfactory in a wide concentration range up to 0.3 mkg in 15 ml which makes the method proposed close in sensitivity to photometric methods and much better in reproducibility

Reductive Coupling of Carbon Monoxide in a Rhenium Carbonyl Complex with Pendant Lewis Acids

OpenAIRE

Miller, Alexander J. M.; Labinger, Jay A.; Bercaw, John E.

2008-01-01

Phosphinoborane ligands impart unique reactivity to a rhenium carbonyl cation relative to simple phosphine complexes. Addition of either triethylborohydride or a platinum hydride (that can be formed from H2) forms a rhenium boroxycarbene. This carbene, which crystallizes as a dimer, disproportionates over a period of days to afford the starting cation and a structurally unprecedented boroxy(boroxymethyl)carbene, in which a new C−C bond has been formed between two reduced CO ligands. This prod...

Tungsten - rhenium alloys wire: overview of thermomechanical processing and properties data

International Nuclear Information System (INIS)

Bryskin, B.

2001-01-01

The scope of this study encompasses the compositional modifications of the tungsten-rhenium dual system (W-3/5 Re up to W-27 Re) as well as some of the tungsten-molybdenum-rhenium ternary system. The alloys of interest are considered with a specific representation of powder metallurgy route based on doped or undoped tungsten vs. vacuum melted materials. This paper constitutes an in-depth review of structural and mechanical properties and systematic compilation of challenges necessary to provide the quality consistency of severely drawn filaments. The issue of thermomechanical processing trends is addressed as an important part of W-Re fabrication technology to achieve further improvement in design properties of rod and wire. (author)

Noncontact surface tension and viscosity measurements of rhenium in the liquid and undercooled states

International Nuclear Information System (INIS)

Ishikawa, Takehiko; Paradis, Paul-Francois; Yoda, Shinichi

2004-01-01

Surface tension and viscosity of liquid rhenium, which have hardly been measured due to the extremely high melting temperature of rhenium, were measured using an electrostatic levitation method combined with the oscillation drop technique. Sample position instability problems caused by the photon pressure of the heating lasers and by sample evaporation were solved by modifying the electrodes design. Good sample stability allowed the measurements of the surface tension and the viscosity over wide temperature ranges including the undercooled states. Over the 2800-3600 K interval, the surface tension of rhenium was measured as σ(T)=2.71x10 3 -0.23(T-T m ), where T m is the melting temperature, 3453 K. At T m , the datum agrees well with the literature values. Similarly, on the same temperature range, the viscosity was determined as η(T)=0.08 exp[1.33x10 5 /(RT)] (mPa s)

Chemistry and radiochemistry of As, Re and Rh isotopes relevant to radiopharmaceutical applications: high specific activity radionuclides for imaging and treatment.

Science.gov (United States)

Feng, Yutian; Phelps, Tim E; Carroll, Valerie; Gallazzi, Fabio; Sieckman, Gary; Hoffman, Timothy J; Barnes, Charles L; Ketring, Alan R; Hennkens, Heather M; Jurisson, Silvia S

2017-10-31

The chemistry and radiochemistry of high specific activity radioisotopes of arsenic, rhenium and rhodium are reviewed with emphasis on University of Missouri activities over the past several decades, and includes recent results. The nuclear facilities at the University of Missouri (10 MW research reactor and 16.5 MeV GE PETtrace cyclotron) allow research and development into novel theranostic radionuclides. The production, separation, enriched target recovery, radiochemistry, and chelation chemistry of 72,77 As, 186,188 Re and 105 Rh are discussed.

Monte Carlo criticality analysis of simple geometries containing tungsten-rhenium alloys engrained with uranium dioxide and uranium mononitride

International Nuclear Information System (INIS)

Webb, Jonathan A.; Charit, Indrajit

2011-01-01

Highlights: → The addition of rhenium to the tungsten matrix within W-UO 2 and W-UN CERMET materials can help reduce the risk of submersion criticality accidents while increasing the strength and ductility of tungsten based nuclear fuel elements. → The addition of rhenium up to 30 at.% to simple geometries containing W-UO 2 mixtures can increase the critical mass by 65 kg. → The addition of rhenium up to 30 at.% to simple geometries containing W-UN mixtures can increase the critical mass by 22 kg. → The addition of rhenium by up to 30 at.% to simple geometries containing W-UO 2 mixtures can reduce the change in reactivity change due to water submersion by $5.07. → The addition of rhenium by up to 30 at.% to simple geometries containing W-UN mixtures can reduce the change in reactivity due to water submersion by $3.24. - Abstract: The critical mass and dimensions of simple geometries containing highly enriched uranium dioxide (UO 2 ) and uranium mononitride (UN) encapsulated in tungsten-rhenium alloys are determined using MCNP5 criticality calculations. Spheres as well as cylinders with length to radius ratios of 1.82 are computationally built to consist of 60 vol.% fuel and 40 vol.% metal matrix. Within the geometries, the uranium is enriched to 93 wt.% uranium-235 and the rhenium content within the metal alloy was modeled over the range of 0-30 at.%. The spheres containing UO 2 were determined to have a critical radius of 18.29-19.11 cm and a critical mass ranging from 366 kg to 424 kg. The cylinders containing UO 2 were found to have a critical radius ranging from 17.07 cm to 17.84 cm with a corresponding critical mass of 406-471 kg. Spheres engrained with UN were determined to have a critical radius ranging from 14.82 cm to 15.19 cm and a critical mass between 222 kg and 242 kg. Cylinders which were engrained with UN were determined to have a critical radius ranging from 13.81 cm to 14.15 cm and a corresponding critical mass of 245-267 kg. The critical

Rhenium solubility in borosilicate nuclear waste glass: implications for the processing and immobilization of technetium-99.

Science.gov (United States)

McCloy, John S; Riley, Brian J; Goel, Ashutosh; Liezers, Martin; Schweiger, Michael J; Rodriguez, Carmen P; Hrma, Pavel; Kim, Dong-Sang; Lukens, Wayne W; Kruger, Albert A

2012-11-20

The immobilization of technetium-99 ((99)Tc) in a suitable host matrix has proven to be a challenging task for researchers in the nuclear waste community around the world. In this context, the present work reports on the solubility and retention of rhenium, a nonradioactive surrogate for (99)Tc, in a sodium borosilicate glass. Glasses containing target Re concentrations from 0 to 10,000 ppm [by mass, added as KReO(4) (Re(7+))] were synthesized in vacuum-sealed quartz ampules to minimize the loss of Re from volatilization during melting at 1000 °C. The rhenium was found as Re(7+) in all of the glasses as observed by X-ray absorption near-edge structure. The solubility of Re in borosilicate glasses was determined to be ~3000 ppm (by mass) using inductively coupled plasma optical emission spectroscopy. At higher rhenium concentrations, additional rhenium was retained in the glasses as crystalline inclusions of alkali perrhenates detected with X-ray diffraction. Since (99)Tc concentrations in a glass waste form are predicted to be wastes, assuming Tc as Tc(7+) and similarities between Re(7+) and Tc(7+) behavior in this glass system.

Effect of rhenium irradiations on the mechanical properties of tungsten for nuclear fusion applications

Energy Technology Data Exchange (ETDEWEB)

Khan, Aneeqa, E-mail: aneeqa.khan-3@postgrad.manchester.ac.uk [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, M13 9PL (United Kingdom); Elliman, Robert; Corr, Cormac [Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia); Lim, Joven J.H.; Forrest, Andrew [School of Materials, The University of Manchester, M13 9PL (United Kingdom); Mummery, Paul [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, M13 9PL (United Kingdom); Evans, Llion M. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom)

2016-08-15

As-received and annealed tungsten samples were irradiated at a temperature of 400 °C with Re and W ions to peak concentrations of 1600 appm (atomic parts per million) and damage levels of 40 dpa (displacements per atom). Mechanical properties were investigated using nanoindentation, and the orientation and depth dependence of irradiation damage was investigated using Electron Back Scatter Diffraction (EBSD). Following irradiation there was a 13% increase in hardness in the as received sheet and a 23% increase in the annealed material for both tungsten and rhenium irradiation. The difference between the tungsten and rhenium irradiated samples was negligible, suggesting that for the concentrations and damage levels employed, the presence of rhenium does not have a significant effect on the hardening mechanism. Energy dependent EBSD of annealed samples provided information about the depth distribution of the radiation damage in individual tungsten grains and confirmed that the radiation damage is orientation dependant.

Cisplatin coordination chemistry determination at hen egg white lysozyme His15 with ligand distances and angles, and their standard uncertainties, and also reporting a split occupancy effect

NARCIS (Netherlands)

Helliwell, John R.; Tanley, Simon W. M.; Schreurs, Antoine M. M.; Kroon - Batenburg, Louise

2016-01-01

Following the interest of L Messori and A Merlino 2016 Coordination Chemistry Reviews in the platinum ions coordination geometries in our PDB entries 4dd4 and 4dd6 we have extended our original analyses.

Submersion criticality safety of tungsten-rhenium urania cermet fuel for space propulsion and power applications

Energy Technology Data Exchange (ETDEWEB)

Craft, A.E., E-mail: aaron.craft@inl.gov [Center for Space Nuclear Research (CSNR), INL, Idaho Falls, ID (United States); O’Brien, R.C., E-mail: Robert.OBrien@inl.gov [Center for Space Nuclear Research (CSNR), INL, Idaho Falls, ID (United States); Howe, S.D., E-mail: Steven.Howe@inl.gov [Center for Space Nuclear Research (CSNR), INL, Idaho Falls, ID (United States); King, J.C., E-mail: kingjc@mines.edu [Nuclear Science and Engineering Program, Metallurgical and Materials Engineering Department, Colorado School of Mines, Golden, CO 80401 (United States)

2014-07-01

Highlights: • Criticality safety studies consider a generic space nuclear reactor in reentry scenarios. • Describes the submersion criticality behavior for a reactor fueled with a tungsten cermet fuel. • Study considers effects of varying fuel content, geometry, and other conditions. - Abstract: Nuclear thermal rockets are the preferred propulsion technology for a manned mission to Mars, and tungsten–uranium oxide cermet fuels could provide significant performance and cost advantages for nuclear thermal rockets. A nuclear reactor intended for use in space must remain subcritical before and during launch, and must remain subcritical in launch abort scenarios where the reactor falls back to Earth and becomes submerged in terrestrial materials (including seawater, wet sand, or dry sand). Submersion increases reflection of neutrons and also thermalizes the neutron spectrum, which typically increases the reactivity of the core. This effect is typically very significant for compact, fast-spectrum reactors. This paper provides a submersion criticality safety analysis for a representative tungsten/uranium oxide fueled reactor with a range of fuel compositions. Each submersion case considers both the rhenium content in the matrix alloy and the uranium oxide volume fraction in the cermet. The inclusion of rhenium significantly improves the submersion criticality safety of the reactor. While increased uranium oxide content increases the reactivity of the core, it does not significantly affect the submersion behavior of the reactor. There is no significant difference in submersion behavior between reactors with rhenium distributed within the cermet matrix and reactors with a rhenium clad in the coolant channels. The combination of the flooding of the coolant channels in submersion scenarios and the presence of a significant amount of spectral shift absorbers (i.e. high rhenium concentration) further decreases reactivity for short reactor cores compared to longer cores.

Separation of tungsten and rhenium on alumina

Directory of Open Access Journals (Sweden)

MILOVAN SM. STOILJKOVIC

2004-09-01

Full Text Available The conditions for the efficient separation of tungsten(VI and rhenium (VII on alumina were established. The distribution coefficients Kd for tungstate and perrhenate anions, as well as the separation factors a (a = KdWO42-/Kd ReO4- were determined using hydrochloric or nitric acid as the aqueous media. A solution of sodium chloride in the pH range 2–6 was also examined. Under all the tested experimental conditions, alumina is a much better adsorbent for tungsten than for rhenium. The obtained results indicated that the best separation of these two elements is achieved when 0.01– 0.1 mol dm-3 HCl or 1.0 mol dm-3 HNO3 are used as the aqueous media. If NaCl is used as the aqueous phase, the best separation is achieved with 0.20 mol dm-3 NaCl, pH 4–6. Under these experimental conditions, the breakthrough and saturation capacities of alumina for tungsten at pH 4 are 17 and 26 mg W/g Al2O3, respectively. With increasing pH, these values decrease. Thus, at pH 6 they are only 4 and 13 mg W/g Al2O3, respectively.

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.)

Separation of Rhenium from Lead-Rich Molybdenite Concentrate via Hydrochloric Acid Leaching Followed by Oxidative Roasting

Directory of Open Access Journals (Sweden)

Guanghui Li

2016-11-01

Full Text Available Lead-rich molybdenite is a typical rhenium-bearing molybdenum resource in China, which has not been efficiently utilized due to its high contents of lead and gangue minerals. In this study, hydrochloric acid was used for preliminarily removing lead and calcite from a lead-rich molybdenite concentrate. Oxidative roasting-ammonia leaching was then carried out for separation of rhenium and extraction of molybdenum. The hydrochloric acid leaching experiments revealed that 93.6% Pb and 97.4% Ca were removed when the leaching was performed at 95 °C for 10 min with HCl concentration of 8 wt. % and liquid-solid ratio of 5 (mL/g. The results of direct oxidative roasting indicated that 89.3% rhenium was volatilized from the raw concentrate after roasting at 600 °C for 120 min in air. In contrast, the rhenium volatilization was enhanced distinctly to 98.0% after the acid-leached concentrate (leaching residue was roasted at 550 °C for 100 min. By the subsequent ammonia leaching, 91.5% molybdenum was leached out from the calcine produced from oxidative roasting of the acid-leached concentrate, while only 79.3% Mo was leached from the calcine produced by roasting molybdenite concentrate without pretreatment.

Effect of operational parameters and internal recycle on rhenium solvent extraction from leach liquors using a mixer-settler

Directory of Open Access Journals (Sweden)

Mostafa Hosseinzadeh

2014-06-01

Full Text Available The extraction of rhenium from molybdenite roasting dust leach solution was performed using a mixer-settler extractor by tributyl phosphate (TBP diluted in kerosene as the extractant. In the single-stage extraction experiments, effect of the aqueous to organic phase ratios, Qa/Qo, and the number of extraction stages, N, on the rhenium extraction was studied. It was found that using the phase ratio of 1:1 in a two-stage extraction, 87.5% depletion of rhenium was obtained. The comparison of experimental results with the continuous co-current extraction showed a good agreement. The effect of internal recycle of organic phase was investigated in the phase ratio of 1:1 by changing the flow rate ratio of recycle-to-fresh organic phase, Qro/Qfo. The optimum performance was achieved in the phase ratio, Qro/Qfo, equal to 3:7. It was found that improvement in the performance of the mixer-settler for the rhenium-TBP system can be obtained in the phase ratio of 1:1when Qro/Qfo = 3:7.

Issues associated with the use of the Tungsten-188/Rhenium188 generator and concentrator system and preparation of Re-188 HDD: A report

International Nuclear Information System (INIS)

Knapp, F.F.Jr.; Turner, J.H.; Jeong, J.-M.; Padhy, A.K.

2004-01-01

The ready availability of no-carrier-added Rhenium-188 from the Tungsten-188/Rhenium-188 generator represents an important source of a therapeutic radioisotope for a broad range of therapeutic applications in nuclear medicine, oncology, rheumatology and interventional cardiology. The International Atomic Energy Agency (IAEA) is coordinating a clinical trial involving the use of Rhenium188-Lipiodol for therapy of hepatocellular carcinoma. This report summarizes the experience of investigators at ten participating centres associated with the use and performance of the Tungsten-188/Rhenium-188 generators and the preparation and handling of the Re-188 HDD agent. This evaluation has demonstrated the cost effective provision of on-site therapeutic activities of Rhenium-188 and recommendations are made for further development of the next generator prototype in light of this international experience. The high bolus volumes (20-40 ml) of the ORNL generator requires post elution concentration of the Re-188 bolus by passage through the tandem silver cation/anion column system. The high back pressure often encountered during generator elution through the silver cation/anion concentrator system has been identified as a potential problem. The details of a method involving in house preparation of the silver cation columns were provided and implementation of this method for Re-188 bolus concentration is recommended. It is also recommended that ORNL investigators reassess the possibility of increasing Tungsten generator loading capacity and the use of higher specific activity Tungsten-188, with a view to reducing the generator bolus volume. The Re-188 HDD/Lipiodol conjugate?;ate is used in this IAEA trial for radioembolytic therapy of primary liver cancer, and methods for preparation of Re-188 HDD and its extraction into Lipiodol are discussed. Since Re-188 HDD binds to glass surfaces, the recovery yields are variable and can be as low as 40-45%. In an effort to maximize the

A Study on the Trapping Characteristics of Rhenium Oxide Using Ca(OH){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Lee, Tae-Kyo; Eun, Hee-Chul; Choi, Jung-Hoon; Lee, Ki-Rak; Han, Seung-Youb; Park, Hwan-Seo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-01-15

The objective of this study was to obtain basic data for trapping gaseous technetium (Tc) oxide generated from the voloxidation process in spent nuclear fuel pyroprocessing. Rhenium (Re) and Ca(OH){sub 2} were used as surrogates for the technetium and a trapping material, respectively. The trapping characteristics of rhenium oxide were investigated with changing temperatures and molar ratios of calcium (Ca) over rhenium, and the thermal behaviors of the trapping products were observed. The products following after the trapping test were identified as Ca(ReO{sub 4}){sub 2} and Ca{sub 5}Re{sub 2}O{sub 12}. The conversion to Ca{sub 5}Re{sub 2}O{sub 12} was preferred with increasing temperatures, and the trapping products were completely converted into Ca5Re2O12 under conditions exceeding 800 ℃, or when maintained at 750 ℃ for 4 hr. The trapping efficiency at a molar ratio of 2.5 (Ca:Re=5:2) was significantly superior to that at the molar ratio of 2.

Data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (DAWAC). Report of a coordinated research project 2001-2005

International Nuclear Information System (INIS)

2006-06-01

This publication provides information on the current status and development trends in monitoring, diagnostics and control of water chemistry and corrosion of core and primary circuit materials in water cooled power reactors. It summarizes the results of an IAEA Coordinated Research Project and focuses on the methods for development, qualification and implementation of water chemistry expert systems at nuclear power plants. These systems are needed to have full benefit from using on-line sensors in real time mode when sensor signals, and other chemistry and operational data, are collected and continuously analysed with data acquisition and evaluation software. Technical knowledge was acquired in water chemistry control techniques (grab sampling, on-line monitoring, data collecting and processing, etc), plant chemistry and corrosion diagnostics, plant monitoring (corrosion, chemistry, activity) and plant chemistry improvement (analytical models and practices). This publication covers contributions from leading experts in water chemistry/corrosion, representing organizations from 16 countries with the largest nuclear capacities

sup(99m)Tc-sulfur-rhenium-colloid and 111In-indiumcitrate in the bone marrow scintigraphy

International Nuclear Information System (INIS)

Glaubitt, D.; Haberland, K.; Knoch, K.; Fejer, F.L.; Zachariah, S.; Staedtische Krankenanstalten Krefeld

1975-01-01

Bone marrow scintigraphy using 111 In-Indium-citrate and sup(99m)Tc-sulfur rhenium colloid was compared with each other in 6 male and 3 female patients. Our results in all patients were in favour of 111 In-citrate which caused a better delineation of morphological details than sup(99m)Tc-sulfur rhenium colloid did. In the first days after intravenous administration of 111 In-citrate, radioindium accumulated markedly in the pudendal region, this finding being more distinct in male patients than in female ones. On account of these results a considerable radiation dose has to be assumed in bone marrow scintigraphy using 111 In-citrate as long as the absorbed dose from 111 In has not been estimated under consideration of the radioindium accumulation in the pudendal region. 111 In-citrate should be applied in bone marrow scanning only exceptionally and sup(99m)Tc-sulfur rhenium colloid be preferred in the routine diagnostics of bone marrow. (orig.) [de

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.)

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.

Effect of deformation and annealing on mechanical properties of nickel-rhenium alloys

International Nuclear Information System (INIS)

Mashkova, V.M.

1978-01-01

Studied have been the mechanical properties of nickel-rhenium alloys, depending on the extent of deformation and heat treatment leading to softening. The mechanical properties of the alloys have been estimated by the results of the tensile tests of wire samples. The softening of the alloy at different temperatures is judged about by the variation in hardness. The results of the study indicate that the most abrupt reduction in the hardness of the cold-hardened metal occurs at 900-1,000 deg C and the hold-time of 1 min. Increase in the hold-time at such temperature almost does not reduce the hardness. It is established that in order to soften nickel-rhenium alloys in the process of the cold-deformation at brief annealings in the air the hold-time should not exceed 5 min at 800-900 deg C

The Breath of Chemistry

DEFF Research Database (Denmark)

Josephsen, Jens

The present preliminary text is a short thematic presentation in biological inorganic chemistry meant to illustrate general and inorganic (especially coordination) chemistry in biochemistry. The emphasis is on molecular models to explain features of the complicated mechanisms essential to breathing...

Highvalent and organometallic technetium and rhenium compounds

International Nuclear Information System (INIS)

Oehlke, Elisabeth

2010-01-01

Diagnostic methods in nuclear medicine allow a detailed description of morphological organ structures and their function. The beta emitting isotope Tc-99 has optimal physical properties (140 keV gamma rays, half-life 6 h) and is therefore used for radiopharmaceuticals. The thesis is concerned with the search for new technetium complexes and their reproducible production. The (TcO3) core is of main interest. The second part of the thesis deals with organometallic technetium and rhenium complexes with carbonyl ligands and N-heterocyclic carbenes that show stability in aerobic aqueous solutions.

Technetium chemistry

International Nuclear Information System (INIS)

Burns, C.; Bryan, J.; Cotton, F.; Ott, K.; Kubas, G.; Haefner, S.; Barrera, J.; Hall, K.; Burrell, A.

1996-01-01

Technetium chemistry is a young and developing field. Despite the limited knowledge of its chemistry, technetium is the workhorse for nuclear medicine. Technetium is also a significant environmental concern because it is formed as a byproduct of nuclear weapons production and fission-power generators. Development of new technetium radio-pharmaceuticals and effective environmental control depends strongly upon knowledge of basic technetium chemistry. The authors performed research into the basic coordination and organometallic chemistry of technetium and used this knowledge to address nuclear medicine and environmental applications. This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL)

Study on the application of crown ether for neutron activation analysis of rubidium and rhenium in rock samples

International Nuclear Information System (INIS)

Wang Xiaolin; Fu Yibei; Liu Yinong; Xiong Zonghua; Hao Fanhua

1996-01-01

The extraction behaviour of rubidium and rhenium with 18-crown-6 (18C6) and benzo-15-crown-5 (B15C5) in nitrobenzene from picric acid or potassium hydroxide solution are studied and methods for separation and determination are developed. The molar ratio of 18C6 to Rb and B15C5 to Re in the extracted species is probably 2:1. Rubidium and rhenium in rock samples are satisfactorily determined by neutron activation method

Active and passive vectorization of technetium99m and 188rhenium radiopharmaceuticals for medical imaging and radiotherapy

International Nuclear Information System (INIS)

Lepareur, N.

2003-11-01

Research for new molecules for nuclear medicine is a field in constant development. Over the past few years, development of new radiopharmaceuticals for radiotherapy has renewed interest for rhenium chemistry. Indeed, its two isotopes 186 Re and 188 Re, owing to their ideal properties and their similitude with 99m Tc, which is widely used as a radiotracer for diagnostic imaging, seem very promising for the preparation of radiopharmaceuticals. In the first part of this manuscript, the synthesis of rhenium and technetium-99 complexes, [M(RPhCS3)2(RPhCS2)] (M = Re, Tc), is described. The preparation of technetium 99m based radiopharmaceuticals, analogues to the pondered complexes, is also described. The stability/reactivity of these complexes has been studied by exchange reactions with potential ligands, specially dithiocarbamates, and also by UV-visible absorption spectroscopy and thermogravimetry. The reactivity of the complexes towards dithiocarbamates leads to the possibility to bind biomolecules to the metallic core, via the dithiocarbamate moiety. This method represents a potential alternative to current ones using the so-called bifunctional approach. In the second part of this manuscript, a new kit formulation for the 188 Re labeling of lipiodol is described, using a complex analogous to those described in the previous part. The labeled oil is a potential cure for hepatocellular carcinoma. The in vitro and in vivo stability of this 188 Re-SSS lipiodol and of its analogue 99m Tc-SSS lipiodol has been studied, and also their in vivo behavior in healthy pigs. This study has shown the quasi-exclusive hepatic fixation of the radiopharmaceutical, and has proven its good stability. Its selectivity for tumors remains to be shown before trying it on humans. (author)

Fabrication and use of zircaloy/tantalum-sheathed cladding thermocouples and molybdenum/rhenium-sheathed fuel centerline thermocouples

International Nuclear Information System (INIS)

Wilkins, S.C.; Sepold, L.K.

1985-01-01

The thermocouples described in this report are zircaloy/tantalum-sheathed and molybdenum/rhenium alloy-sheathed instruments intended for fuel rod cladding and fuel centerline temperature measurements, respectively. Both types incorporate beryllium oxide insulation and tungsten/rhenium alloy thermoelements. These thermocouples, operated at temperatures of 2000 0 C and above, were developed for use in the internationally sponsored Severe Fuel Damage test series in the Power Burst Facility. The fabrication steps for both thermocouple types are described in detail. A laser-welding attachment technique for the cladding-type thermocouple is presented, and experience with alternate materials for cladding and fuel therocouples is discussed

Active and passive vectorization of technetium{sup 99m} and {sup 188}rhenium radiopharmaceuticals for medical imaging and radiotherapy; Vectorisations active et passive de radiopharmaceutiques du technetium-99m et du rhenium-188 pour l'imagerie medicale et la therapie

Energy Technology Data Exchange (ETDEWEB)

Lepareur, N

2003-11-15

Research for new molecules for nuclear medicine is a field in constant development. Over the past few years, development of new radiopharmaceuticals for radiotherapy has renewed interest for rhenium chemistry. Indeed, its two isotopes {sup 186}Re and {sup 188}Re, owing to their ideal properties and their similitude with {sup 99m}Tc, which is widely used as a radiotracer for diagnostic imaging, seem very promising for the preparation of radiopharmaceuticals. In the first part of this manuscript, the synthesis of rhenium and technetium-99 complexes, [M(RPhCS3)2(RPhCS2)] (M = Re, Tc), is described. The preparation of technetium{sup 99m} based radiopharmaceuticals, analogues to the pondered complexes, is also described. The stability/reactivity of these complexes has been studied by exchange reactions with potential ligands, specially dithiocarbamates, and also by UV-visible absorption spectroscopy and thermogravimetry. The reactivity of the complexes towards dithiocarbamates leads to the possibility to bind biomolecules to the metallic core, via the dithiocarbamate moiety. This method represents a potential alternative to current ones using the so-called bifunctional approach. In the second part of this manuscript, a new kit formulation for the {sup 188}Re labeling of lipiodol is described, using a complex analogous to those described in the previous part. The labeled oil is a potential cure for hepatocellular carcinoma. The in vitro and in vivo stability of this {sup 188}Re-SSS lipiodol and of its analogue {sup 99m}Tc-SSS lipiodol has been studied, and also their in vivo behavior in healthy pigs. This study has shown the quasi-exclusive hepatic fixation of the radiopharmaceutical, and has proven its good stability. Its selectivity for tumors remains to be shown before trying it on humans. (author)

Active and passive vectorization of technetium{sup 99m} and {sup 188}rhenium radiopharmaceuticals for medical imaging and radiotherapy; Vectorisations active et passive de radiopharmaceutiques du technetium-99m et du rhenium-188 pour l'imagerie medicale et la therapie

Energy Technology Data Exchange (ETDEWEB)

Lepareur, N

2003-11-15

Research for new molecules for nuclear medicine is a field in constant development. Over the past few years, development of new radiopharmaceuticals for radiotherapy has renewed interest for rhenium chemistry. Indeed, its two isotopes {sup 186}Re and {sup 188}Re, owing to their ideal properties and their similitude with {sup 99m}Tc, which is widely used as a radiotracer for diagnostic imaging, seem very promising for the preparation of radiopharmaceuticals. In the first part of this manuscript, the synthesis of rhenium and technetium-99 complexes, [M(RPhCS3)2(RPhCS2)] (M = Re, Tc), is described. The preparation of technetium{sup 99m} based radiopharmaceuticals, analogues to the pondered complexes, is also described. The stability/reactivity of these complexes has been studied by exchange reactions with potential ligands, specially dithiocarbamates, and also by UV-visible absorption spectroscopy and thermogravimetry. The reactivity of the complexes towards dithiocarbamates leads to the possibility to bind biomolecules to the metallic core, via the dithiocarbamate moiety. This method represents a potential alternative to current ones using the so-called bifunctional approach. In the second part of this manuscript, a new kit formulation for the {sup 188}Re labeling of lipiodol is described, using a complex analogous to those described in the previous part. The labeled oil is a potential cure for hepatocellular carcinoma. The in vitro and in vivo stability of this {sup 188}Re-SSS lipiodol and of its analogue {sup 99m}Tc-SSS lipiodol has been studied, and also their in vivo behavior in healthy pigs. This study has shown the quasi-exclusive hepatic fixation of the radiopharmaceutical, and has proven its good stability. Its selectivity for tumors remains to be shown before trying it on humans. (author)

Rhenium(V) complexes with sulfur-containing amino acids

International Nuclear Information System (INIS)

Gagieva, S.Ch.; Tautieva, M.A.; Tsaloev, A.T.; Galimov, Yu.B.; Gagieva, L.Ch.; Belyaeva, T.N.

2007-01-01

Rhenium(V) complexes with 2-amino-4-(methylthio)butanoic acid (methionine, Met) and 2-amino-3-sulfopropionic acid (cysteine, Cys) have been synthesized. Depending on the initial reagent ratio, the resulting complexes contain one or two ligand molecules. On heating the compounds with one amino acid molecule, two hydrogen halide molecules are removed at 128-132 deg C to form a molecular complex. The composition, structure, and thermal stability of the complexes have been studied by elemental analysis, conductometry, IR spectroscopy, NMR, and mass spectrometry [ru

THERMIONIC EMISSION ENHANCEMENT FROM CESIUM COATED RHENIUM IN ELECTRIC FIELDS

Energy Technology Data Exchange (ETDEWEB)

de Steese, J. G.; Zollweg, R. J.

1963-04-15

The plasma-anode technique was used to observe anomalously high thermionic emission from a rhenium surface with small cesium coverage, where the work function of the composite surface is greater than the ionization potential of cesium. Data suggest that emission enhancement is caused by increased cesium coverage because of cesiumion trapping near the emitter surface under the influence of an ion-rich sheath. (auth)

Lattice strains in gold and rhenium under nonhydrostatic compression to 37 GPa

International Nuclear Information System (INIS)

Duffy, Thomas S.; Shen, Guoyin; Heinz, Dion L.; Shu, Jinfu; Ma, Yanzhang; Mao, Ho-Kwang; Hemley, Russell J.; Singh, Anil K.

1999-01-01

Using energy-dispersive x-ray diffraction techniques together with the theory describing lattice strains under nonhydrostatic compression, the behavior of a layered sample of gold and rhenium has been studied at pressures of 14-37 GPa. For gold, the uniaxial stress component t is consistent with earlier studies and can be described by t=0.06+0.015P where P is the pressure in GPa. The estimated single-crystal elastic moduli are in reasonable agreement with trends based on extrapolated low-pressure data. The degree of elastic anisotropy increases as α, the parameter which characterizes stress-strain continuity across grain boundaries, is reduced from 1.0 to 0.5. For rhenium, the apparent equation of state has been shown to be strongly influenced by nonhydrostatic compression, as evidenced by its dependence on the angle ψ between the diffracting plane normal and the stress axis. The bulk modulus obtained by inversion of nonhydrostatic compression data can differ by nearly a factor of 2 at angles of 0 degree sign and 90 degree sign . On the other hand, by a proper choice of ψ, d spacings corresponding to quasihydrostatic compression can be obtained from data obtained under highly nonhydrostatic conditions. The uniaxial stress in rhenium over the pressure range from 14-37 GPa can be described by t=2.5+0.09P. The large discrepancy between x-ray elastic moduli and ultrasonic data and theoretical calculations indicates that additional factors such as texturing or orientation dependence of t need to be incorporated to more fully describe the strain distribution in hexagonal-close-packed metals. (c) 1999 The American Physical Society

Study of technetium behaviour in radiopharmaceuticals. Characterization of sup(99m)Tc-pyrophosphate, sup(99m)Tc-dimercaptosuccinate, sup(99m)Tc-diethylenetriaminepentaacetate complexes and sup(99m)Tc-colloidal rhenium sulphide

International Nuclear Information System (INIS)

Saccavini, J.-C.

1980-12-01

The chemistry of technetium in extremely dilute solution was approached through the study of three complexing agents and a colloid. By the application of high-performance chromatographic techniques to the analysis of (Tc-pyro), (Tc-DTPA), (Tc-DMSA) complexes it was possible to isolate one or more chelates from a single complexing agent. Addition of pertechnetates to a solution of sodium pyrophosphates and stannous chloride at neutral pH leads to the formation of two complexes, both highly osteotropic. By the use of sup(117m)Sn it was shown that tin employed as reducing agent enters into the composition of one of the two complexes, either of which may be obtained preferentially by varying the (Sn)/(pyro) ratio. With technetium at acid pH (2.5) DMSA gives one or more chelates according to the concentration of the reagents present. DTPA with technetium at neutral pH gives a single complex for which a structure is proposed. The addition of calcium, indispensable for DTPA injection, leads to the appearance of a second bimetallic complex in very much smaller proportions than the first. The size distribution of some colloids was studied by ultrafiltration and permeation on gel. The preparation of colloidal rhenium sulphide and the technetium labelling conditions needed to obtain a very fine colloid were developed. The behaviour of technetium in the presence of colloidal rhenium sulphide and tin pyrophosphate was followed by sup(99m)Tc - sup(186)Re and sup(99m)Tc - sup(117m)Sn double-labelling tests. One reduced technetium fraction associates with the hydrolysed tin, the other follows the rhenium sulphide [fr

Intracellular distribution and stability of a luminescent rhenium(I) tricarbonyl tetrazolato complex using epifluorescence microscopy in conjunction with X-ray fluorescence imaging

International Nuclear Information System (INIS)

Wedding, Jason L.; Harris, Hugh H.; Bader, Christie A.; Plush, Sally E.; Mak, Rachel

2016-01-01

Optical fluorescence microscopy was used in conjunction with X-ray fluorescence microscopy to monitor the stability and intracellular distribution of the luminescent rhenium(I) complex fac-[Re(CO) 3 (phen)L], where phen = 1,10-phenathroline and L = 5-(4-iodophenyl)tetrazolato, in 22Rv1 cells. The rhenium complex showed no signs of ancillary ligand dissociation, a conclusion based on data obtained via X-ray fluorescence imaging aligning iodine and rhenium distributions. A diffuse reticular localisation was detected for the complex, in the nuclear/perinuclear region of cells, by either optical or X-ray fluorescence techniques. Furthermore, X-ray fluorescence also showed that the Re-I complex disrupted the homeostasis of some biologically relevant elements, such as chlorine, potassium and zinc.

Institute of Bioinorganic and Radiopharmaceutical Chemistry. Annual report 1993

International Nuclear Information System (INIS)

Johannsen, B.

1994-02-01

The subjects of the present report are described in this volume in 41 reports dealing with various aspects of radiotracers for nuclear medicine. This first part describes synthetic work on 11 C-tracers and precursors. The papers on technetium/rhenium chemistry describes the efforts to gain a deeper insight into the reactions taking place in intricate Tc/Re-ligand systems, to design more suitable and variable chelate units, and to start functionalizing these complexes in order to make them mimics of biochemical substrates or drugs. Progress has been achieved in the complexation of SH-containing peptides, mainly by the introduction of N-alkylation, which remarkably influences the properties of the complexes, by systematic alteration of the peptide chain length and derivatization. (orig./EF)

The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry.

Science.gov (United States)

Byrne, Joseph P; Kitchen, Jonathan A; Gunnlaugsson, Thorfinnur

2014-08-07

Ligands containing the btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] motif have appeared with increasing regularity over the last decade. This class of ligands, formed in a one pot ‘click’ reaction, has been studied for various purposes, such as for generating d and f metal coordination complexes and supramolecular self-assemblies, and in the formation of dendritic and polymeric networks, etc. This review article introduces btp as a novel and highly versatile terdentate building block with huge potential in inorganic supramolecular chemistry. We will focus on the coordination chemistry of btp ligands with a wide range of metals, and how it compares with other classical pyridyl and polypyridyl based ligands, and then present a selection of applications including use in catalysis, enzyme inhibition, photochemistry, molecular logic and materials, e.g. polymers, dendrimers and gels. The photovoltaic potential of triazolium derivatives of btp and its interactions with anions will also be discussed.

Transition metal chemistry of hydroxy(–OH)-rich molecules ...

Indian Academy of Sciences (India)

Administrator

Appropriately designed hydroxy(–OH) containing Schiff's base and Mannich base molecules have been recently found to be important for development of the coordination chemistry of a number of metal ions in the biomimetic chemistry of metalloenzymes. In this context, our group has studied the coordination role of these ...

Transuranic Computational Chemistry.

Science.gov (United States)

Kaltsoyannis, Nikolas

2018-02-26

Recent developments in the chemistry of the transuranic elements are surveyed, with particular emphasis on computational contributions. Examples are drawn from molecular coordination and organometallic chemistry, and from the study of extended solid systems. The role of the metal valence orbitals in covalent bonding is a particular focus, especially the consequences of the stabilization of the 5f orbitals as the actinide series is traversed. The fledgling chemistry of transuranic elements in the +II oxidation state is highlighted. Throughout, the symbiotic interplay of experimental and computational studies is emphasized; the extraordinary challenges of experimental transuranic chemistry afford computational chemistry a particularly valuable role at the frontier of the periodic table. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and crystal structure of carbonyltris (diethyldithiocarbamato) technetium (III): an unexpected source of co-ordinated carbon monoxide

International Nuclear Information System (INIS)

Baldas, J.; Bonnyman, J.; Pojer, P.M.; Williams, G.A.

1981-10-01

Tc(S 2 CNEt 2 ) 3 CO has been prepared by the reduction of NH 4 TcO 4 with formamidinesulphinic acid in the presence of NaS 2 CNEt 2 . It is suggested that the co-ordinated carbon monoxide is formed after co-ordination of formamidinesulphinic acid, or some decomposition product, with technetium. The crystal structure of Tc(S 2 CNEt 2 ) 3 CO has been determined by single-crystal X-ray diffraction methods at 17 deg. C. Diffractometry has provided significant Bragg intensities for 2045 independent reflections and the structure has been refined by full-matrix least-squares methods to R 0.049. The compound is isostructural with the rhenium analogue and consists of discrete Tc(S 2 CNEt 2 ) 3 CO molecules, each containing a terminal linear CO group. The technetium atom has a seven co-ordinate environment which is best described as a distorted pentagonal bipyramid

Water chemistry-related activities at the IAEA

International Nuclear Information System (INIS)

Cheng, H.; Onufriev, V.

2005-01-01

Water chemistry activities and publications in the past are listed. IAEA Coordinated Research Programmes, WWER-1000 SG water chemistry database, materials issues TM in Vienna, TC workshops and attendance of international meetings, publications. There is a list of IAEA publications related to water chemistry and corrosion. Finally water chemistry activities planned for 2006-2008 are detailed. (N.T.)

Effect of the method for rhenium neptasulfide preparation on its catalytic properties in hydrogenation of nitrobenzene and m-nitrobenzoic acid

International Nuclear Information System (INIS)

Pal'chevskaya, T.A.; Bogutskaya, L.V.; Belousov, V.M.

1988-01-01

The effect of conditions of rhenium heptasulfide synthesis by thiosulfate method on its physicochemical and catalytic properties during hydrogenation of nitrobenzene and m-nitrobenzoic acid has been studied. It is shown that the maximum yield of m-aminobenzoic acid can be attained on insoluble sulfide rhenium contacts, containing excessive amount of sulfur (3.5 %). Under certain conditions of catalyst synthesis particles of Re 2 S 7 soluble in dimethylformamide are formed, which possess selectivity towards amine

Synthesis, Characterization and Biological Studies of 99mTc and 188Re Peptides

Science.gov (United States)

Sanders, Vanessa

Radiopharmaceuticals are very powerful diagnostic tools for evaluation of a host of medical conditions. These drugs are labeled with radioactive isotopes, which are utilized to create pictures of areas of interest through absorption of the drug. They are currently in high demand due to their ability to image areas that traditional imaging devices cannot. The radioisotope 99mTc, with a half-life of 6.01 hours and a 140 keV gamma emission, is central to many radiopharmaceutical compounds. This isotope is easily obtained from a 99Mo-99mTc generator, through beta decay and column chromatography separations. Very little technetium, less than 6 ng, is needed to label the pharmaceuticals for use in-vivo. Another radioisotope 188Re is also important due to its ability to be used for therapy while being tracked throughout the body. Radiotherapy gives radiopharmaceuticals a huge advantage by their ability to destroy rapidly growing cells. One of the main reasons there is interest in rhenium pharmaceuticals is the chemical similarity between it and technetium. The 188Re isotope also has a considerably short half-life of approximately 17 hours and has emission energy of 155 keV. The 188Re isotope is separated from 188W-188Re generator, analogously to the 99Mo-99mTc generator. The ligand used in this work is a pentapepetide macrocyclic ligand. This ligand, KYCAR (lysyl-tyrosyl-cystyl-alanyl-arginine), has been designed as a potential chelating ligand for imaging and therapeutic in vivo agents. Ligands are chosen based on their in-situ biological behavior, and are used in the complexation with technetium and rhenium. Understanding and exploiting technetium and rhenium chemistry can provide insight into the reaction mechanisms and coordination chemistry of these compounds. The exploration of various oxidation states as a function of the ligands used and the reaction conditions can help develop novel radiopharmaceuticals. The investigations of the manipulation of oxidation states

Coordination chemistry insights into the role of alkali metal promoters in dinitrogen reduction.

Science.gov (United States)

Connor, Gannon P; Holland, Patrick L

2017-05-15

The Haber-Bosch process is a major contributor to fixed nitrogen that supports the world's nutritional needs and is one of the largest-scale industrial processes known. It has also served as a testing ground for chemists' understanding of surface chemistry. Thus, it is significant that the most thoroughly developed catalysts for N 2 reduction use potassium as an electronic promoter. In this review, we discuss the literature on alkali metal cations as promoters for N 2 reduction, in the context of the growing knowledge about cooperative interactions between N 2 , transition metals, and alkali metals in coordination compounds. Because the structures and properties are easier to characterize in these compounds, they give useful information on alkali metal interactions with N 2 . Here, we review a variety of interactions, with emphasis on recent work on iron complexes by the authors. Finally, we draw conclusions about the nature of these interactions and areas for future research.

Synthesis of novel '4+1' Tc(III)/Re(III) mixed-ligand complexes with dendritically modified ligands

International Nuclear Information System (INIS)

Gniazdowska, E.; Kuenstler, J.U.; Stephan, H.; Pietzsch, H.J.

2006-01-01

Coordination chemistry of technetium and rhenium attracts a considerable interest due to the nuclear medicine applications of their radionuclides. Inert, so-called '3+1' or '4+1' technetium/rhenium mixed-ligand complexes open a new way to application of 99 mTc/ 188 Re labeled compounds in tumor diagnosis and therapy. In the presented paper, authors describe the synthesis and study of novel 99 mTc/ 188 Re complexes with dendritically functionalized tetradentate (tripodal chelator 2,2',2''-nitrilotris(ethanethiol), NS 3 and carboxyl group-bearing ligand, NS 3 (COOH) 3 ) and monodentate (dendritically modified isocyanide, CN-R(COOMe) 3 and isocyanide-modified peptide, CN-GGY) ligands. To verify the identity of the prepared n.c.a. complexes, non-radioactive analogous '4+1' Re compounds were synthesized. The experimental data show that a dendritic modification of the tetradentate/monodentate ligands changes the complex lipophilicity and does not influence its stability

Neutron activation determination of rhenium in mineral raw materials of complex composition

International Nuclear Information System (INIS)

Shiryaeva, M.B.; Lyubimova, L.N.; Salmin, Yu.P.; Ryumina, K.N.; Tatarkin, M.A.

1984-01-01

The method of neutron-activation rhenium determination in mineral raw material of complex composition is developed, according to which easily hydrolized elements: scandium, iron, lanthanum, ytterbium, protactinium, hafnium and partially ruthenium and osmium are isolated in the form of hydroxides after smelting of a sample, which has been previously irradiated in nuclear reactor (thermal neutron flux 1.2x10 13 n/cm 2 xs for 22 hr) with sodium peroxide and leaching of the melt by water. To separate Re from other interfering elements extraction of perrhenate-ion by methylethylketone from alkali solution is used. Interfering effect of gold is eliminated by its extraction with TBP 30% solution in toluence or benzene from 1 M HNO 3 . Activity of rhenium preparations, singled out from samples of comparison, is measured, using multichannel γ-spectrometer with Ge(Li)-coaxial detector of high resolution (approximately 2.0-2.2 keV over the line 122 keV 5+ Co). Relative standard deviation in Re content range 5x10 -7 -5x10 -2 % does not exceed 0.3

Uranium chemistry research unit

International Nuclear Information System (INIS)

Anon.

1978-01-01

The initial field of research of this Unit, established in 1973, was the basic co-ordination chemistry of uranium, thorium, copper, cobalt and nickel. Subsequently the interest of the Unit extended to extractive metallurgy relating to these metals. Under the term 'co-ordination chemistry' is understood the interaction of the central transition metal ion with surrounding atoms in its immediate vicinity (within bonding distance) and the influence they have on each other - for example, structural studies for determining the number and arrangement of co-ordinated atoms and spectrophotometric studies to establish how the f electron energy levels of uranium are influenced by the environment. New types of uranium compounds have been synthesized and studied, and the behaviour of uranium ions in non-aqueous systems has also received attention. This work can be applied to the development and study of extractants and new extractive processes for uranium

Liquid kit for preparation of 188rhenium-etidronate

International Nuclear Information System (INIS)

Marczewski, Barbara; Dias, Carla Roberta; Moraes, Vanessa; Osso Junior, Joao Alberto

2005-01-01

The aim of this study was the preparation of a liquid kit for radiolabeling of 188 Re-HEDP (hydroxyethylidene diphosphonate). 188 Re was obtained from alumina based 188 W/ 188 Re generators. This paper reports the efficacy of a cold kit stored for more than two weeks, determined by the dependence of the radiolabeling yields of 188 Re-HEDP on the incubation time, reducing agent concentration, the effects of concentration of ligand, the p H of the reaction and the temperature. The cold kits showed a good stability when carrie-free rhenium-188 was added in the reaction mixture. (author)

Cermets based on rhenium and rare earth element oxides

International Nuclear Information System (INIS)

Varfolomeev, M.B.; Velichko, A.V.; Zajtseva, L.L.; Shishkov, N.V.

1977-01-01

The reduction of perrhenates of rare earth elements and of yttrium by hydrogen and the subsequent sintering have yielded cermets based on rhenium and rare earth element oxides inherent in which are more disperse and homogeneous structures than those of the ''molecular'' rare earth element-Tc cermets. The dispersity of cermets increases in the rare earth elements series from La to Lu. The microhardness of the Re phase in cermets is 490 kgf/mm 2 ; the total microhardness of a cermet is substantially higher

Endocavitary treatment of craniopharyngioma cysts by 186-rhenium. Traitement endocavitaire par le rhenium 186 des kystes de craniopharyngiomes

Energy Technology Data Exchange (ETDEWEB)

Berenger, N.; Lebtahi, R.; Piketty, M.L.; Merienne, L.; Turak, B.; Bok, R.; Askienazy, S. (Hopital Sainte-Anne, 75 - Paris (France)); Munari, C. (Centre Hospitalier Universitaire, 38 - Grenoble (France))

1993-01-01

Forty-three patients with craniopharyngioma cysts were treated by intracystic injection of 186-rhenium. Leakage of colloid isotope into the CSF spaces during the ''test'' or ''therapeutic'' injection was detected by scintigraphic follow-up (15 cases/58 intracystic injections). In fact the physical characteristics of [sup 186]Re are well adapted to the requirements of treatment and, with the gamma emission, also allows early detection of leakage, avoiding irradiation of neighbouring structures. Follow-up studies revealed that craniopharyngioma cysts were effectively treated, with cessation of fluid formation, progressive shrinkage of the cysts leading to total disappearance in 14 cases (10-156 months, mean 52.5) and a considerable decrease in 13 cases (5-53 months, mean 23).

Eleventh international symposium on radiopharmaceutical chemistry

International Nuclear Information System (INIS)

1995-01-01

This document contains abstracts of papers which were presented at the Eleventh International Symposium on Radiopharmaceutical Chemistry. Sessions included: radiopharmaceuticals for the dopaminergic system, strategies for the production and use of labelled reactive small molecules, radiopharmaceuticals for measuring metabolism, radiopharmaceuticals for the serotonin and sigma receptor systems, labelled probes for molecular biology applications, radiopharmaceuticals for receptor systems, radiopharmaceuticals utilizing coordination chemistry, radiolabelled antibodies, radiolabelling methods for small molecules, analytical techniques in radiopharmaceutical chemistry, and analytical techniques in radiopharmaceutical chemistry

Eleventh international symposium on radiopharmaceutical chemistry

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-31

This document contains abstracts of papers which were presented at the Eleventh International Symposium on Radiopharmaceutical Chemistry. Sessions included: radiopharmaceuticals for the dopaminergic system, strategies for the production and use of labelled reactive small molecules, radiopharmaceuticals for measuring metabolism, radiopharmaceuticals for the serotonin and sigma receptor systems, labelled probes for molecular biology applications, radiopharmaceuticals for receptor systems, radiopharmaceuticals utilizing coordination chemistry, radiolabelled antibodies, radiolabelling methods for small molecules, analytical techniques in radiopharmaceutical chemistry, and analytical techniques in radiopharmaceutical chemistry.

Complexes of technetium, rhenium, and rhodium with sexidentate Schiff-base ligands

International Nuclear Information System (INIS)

Hunter, G.; Kilcullen, N.

1989-01-01

The monocationic technetium (IV) and rhenium (IV) complexes with the sexidentate Schiff-base ligands tris[2-(2'-hydroxybenzylideneethyl)]amine and its substituted derivatives have been prepared and their electrochemical properties studied. The variable-temperature 90.6 MHz 13 C-{ 1 H} n.m.r. spectrum of the rhodium (III) complex of tris[2-(2-hydroxy-5'-isopropylbenzylideneethyl)-amine] has been observed, indicating fluxionality at temperatures above 218 K. (author)

Analysis of the Nuclear Structure of Rhenium-186 Using Neutron-Induced Reactions

Science.gov (United States)

2015-03-26

5 1.5 Methods ... radioisotope power source for use on the battlefield. 1 Re-Os Cosmochronometer. The isotope 187Re has a half-life in its ground state of 4.35⇥ 1010 years [2...187Os in meteorites permits one to date the nucleosynthesis of rhenium and osmium by high neutron flux events such as supernovae. The Re-Os radioactive

Development of novel strategy for the synthesis of organometallic compounds usable as protein ligands: application to the human cyclophilin hCyp-18

International Nuclear Information System (INIS)

Clavaud, C.

2006-02-01

This thesis describes a new strategy for the development of bioactive organometallic compounds, basing on the combinatorial assembly of sub-chemical libraries (A and B) independent but complementary and able to coordinate a metallic heart M to form A-M-B complex potential ligands of biomolecules. The coordination of metals, well adapted to the production of molecular variety is usually used in medicinal chemistry, in diagnostic and therapeutic nuclear medicine. Among the useful elements, the rhenium and the technetium are metals of choice for the development of the assembly strategy because of their chemical and radiochemical properties and of the structure analogy of their complexes. This strategy was validated in vitro. The protein chosen for this purpose was the cyclophilin hCyp-18. (N.C.)

Osmium and cobalt complexes incorporating facially coordinated N ...

Indian Academy of Sciences (India)

Administrator

coordinated N,N,O donor azo-imine ligands: Redox and catalytic properties. Poulami Pattanayak, a. Debprasad Patra, a. Jahar Lal Pratihar, a. Andrew Burrows,. Mary F. Mahon b and Surajit Chattopadhyay* a a. Department of Chemistry, University of Kalyani, Kalyani-741235, India b. Department of Inorganic Chemistry, ...

Rhenium-catalyzed dehydrogenative olefination of C(sp(3))-H bonds with hypervalent iodine(III) reagents.

Science.gov (United States)

Gu, Haidong; Wang, Congyang

2015-06-07

A dehydrogenative olefination of C(sp(3))-H bonds is disclosed here, by merging rhenium catalysis with an alanine-derived hypervalent iodine(III) reagent. Thus, cyclic and acyclic ethers, toluene derivatives, cycloalkanes, and nitriles are all successfully alkenylated in a regio- and stereoselective manner.

synthesis and optical properties of self-assembled coordination ...

African Journals Online (AJOL)

The coordination chemistry of the phenylmalonic acid and 4-1H- amino- 1,2,4- triazole with Zn(II) ions has been investigated. The coordination polymer was synthesized by slow evaporation method and characterized by FT-infrared spectroscopy, ultraviolet-visible measurements, scanning electron microscopy, Electron ...

New extraction chromatographic material for rhenium separation

International Nuclear Information System (INIS)

Lucanikova, M.; Czech Technical University, Prague; Kucera, J.; Czech Technical University, Prague; Sebesta, F.

2008-01-01

Three types of the extraction chromatographic materials, composed from Aliquat R 336 deposited in the polyacrylonitrile (PAN) beads and prepared by different procedures, were compared for extraction of rhenium. The best properties were exhibited when the solid extractant was prepared by impregnation of the ready-made PAN beads. Solid extractant prepared by direct coagulation of the beads from the suspension of Aliquat R 336 in solution of PAN in nitric acid differs only by lower capacity in dynamic conditions. Material prepared from the PAN solution in dimethylsulfoxide was the worst because Aliquat R 336 was washed out from the beads during coagulation of the polymer and the extraction capacity was low. As it is shown, the first two solid extractants are fully comparable with the commercial TEVA Resin. (author)

The process development of laser surface modification of commercially pure titanium (Grade 2) with rhenium

Science.gov (United States)

Kobiela, K.; Smolina, I.; Dziedzic, R.; Szymczyk, P.; Kurzynowski, T.; Chlebus, E.

2016-12-01

The paper presents the results of the process development of laser surface modification of commercially pure titanium with rhenium. The criterion of the successful/optimal process is the repetitive geometry of the surface, characterized by predictable and repetitive chemical composition over its entire surface as well as special mechanical properties (hardness and wear resistance). The analysis of surface geometry concluded measurements of laser penetration depth and heat affected zone (HAZ), the width of a single track as well as width of a clad. The diode laser installed on the industrial robot carried out the laser treatment. This solution made possible the continuous supply of powder to the substrate during the process. The aim of an investigation is find out the possibility of improving the tribological characteristics of the surface due to the rhenium alloying. The verification of the surface properties (tribological) concluded geometry measurements, microstructure observation, hardness tests and evaluation of wear resistance.

Chemistry of rhenium and technetium. II. Schiff base complexes with polyfunctional amino acids

International Nuclear Information System (INIS)

Du Preez, J.G.H.; Gerber, T.I.A.; Fourie, P.J.; Van Wyk, A.J.

1984-01-01

Amino acid Schiff base technetium(V) complexes of salicylaldehyde with l-cysteine, l-serine, l-histodine, l-threonine, l-glutamic acid and l-tryptophan have been preapred by direct reaction and by constituent combination. The amino acid part of the ligands coordinates to the technetium through the carboxylate group, while the other available functional group of the amino acids plays a more minor role as blocking group or in intramolecular bonding. 3 tables

Molybdenum: the element and aqueous solution chemistry

International Nuclear Information System (INIS)

Sykes, A.G.

1987-01-01

This chapter on the chemistry of the coordination compounds of molybdenum concentrates on the element itself, its recovery from ores and its use in the manufacture of steels. Most of the chapter is devoted to the aqueous solution chemistry of molybdenum in oxidation states II, III and IV. (UK)

Rhenium-186 direct labelling HIgG

International Nuclear Information System (INIS)

Lungu, V.; Mihailescu, G.; Dumitrescu, G.

2001-01-01

The aim of this study is to develop and improve existing radiolabelling techniques of peptides and monoclonal antibodies with 186 Re for achievement of potential agents for cancer targeted radiotherapy. There were selected methods and techniques for the direct labelling of intact HIgG by studding chemical and radiochemical processes of -S-S- bridges prereduction, reduction of 186 ReO 4 - and coupling reaction of rhenium with HIgG. The -S-S- bridges prereduction of HIgG to sulfhydryls was effected using different reducing agents: ascorbic acid, 2,3 dimercaptopropanol, cysteine, active hydrogen. The prereduction reactions are controlled by masic ratios of HIgG/reduction agent, pH, temperature and time of incubation. A pH=4.5 and a 24 hours incubation time are in the advantage of the prereduction yield. The labelling with 186 Re of prereduced HIgG with ascorbic acid or active hydrogen and 37 deg. C incubation in 22 hours releases 92% radiochemical purity. (author)

Liquid kit for preparation of {sup 188}rhenium-etidronate

Energy Technology Data Exchange (ETDEWEB)

Marczewski, Barbara; Dias, Carla Roberta; Moraes, Vanessa; Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Centro de Radiofarmacia]. E-mail: baszot@gmail.com

2005-10-15

The aim of this study was the preparation of a liquid kit for radiolabeling of {sup 188} Re-HEDP (hydroxyethylidene diphosphonate). {sup 188} Re was obtained from alumina based {sup 188} W/{sup 188} Re generators. This paper reports the efficacy of a cold kit stored for more than two weeks, determined by the dependence of the radiolabeling yields of {sup 188} Re-HEDP on the incubation time, reducing agent concentration, the effects of concentration of ligand, the p H of the reaction and the temperature. The cold kits showed a good stability when carrie-free rhenium-188 was added in the reaction mixture. (author)

Kinetics and mechanism of nitrobenzene hydrogenation to phenylhydroxylamine in rhenium thiocomplexes solutions

International Nuclear Information System (INIS)

Korenyako, G.I.; Belousov, V.M.

1985-01-01

A study was made on kinetics of nitrobenzene hydrogenation to phenylhydroxylamine in dimethylformamide solutions of rhenium thiocomplexes. The mechanism of hydrogenation was suggested. Formation of hydride catalyst complex represents the first stage of the process. Kinetic equation derived on the basis of suggested mechanism corresponds satisfactorily with experimental results. Thermodynamic parameters of separate process stages calculated on the basis of equilibrium constant values testify as well to the benefit of suggested mechanism

Formamidine sulfinic acid as reducing agent in technetium-99m rhenium sulfide labelling

Energy Technology Data Exchange (ETDEWEB)

Neves, M; Patricio, L [Laboratorio Nacional de Engenharia e Technologia Industrial, Sacavem (Portugal). Dept. de Radioisotopes; Ferronha, H [Laboratorio Nacional de Investigacao Veterinaria, Lisboa (Portugal)

1989-08-01

Labelling kinetic studies, radiochemical characterization and particle size evaluation of {sup 99m}Tc rhenium sulfide colloid using formamidine sulfinic acid as reducing agent are described. Comparison with the same colloid which makes use of Sn-sodium pyrophosphate complex as reducing agent showed higher labelling yields, simplification of labelling procedure and a longer shelf life when formamidine sulfinic acid was used. (author) 15 refs.; 7 figs.

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

Fundamental and Applied Bioorganometallic Chemistry of Technetium and Rhenium

International Nuclear Information System (INIS)

Alberto, R.; Braband, H.; Benz, M.; Can, D.; Imstepf, S.; Felber, M.; Spingler, B.

2016-01-01

Site directed accumulation is the base for therapy and imaging with inorganic medicinal compounds. To match selectively the structural properties of receptors, the topology of targeting complexes must be flexible and easily adaptable. For in vivo application, kinetic stability is desirable and in an advanced design, the complex itself can become part of the structure to be recognized by the receptor (3D structural space occupation concept).1 To match these requirements, we introduced the fac-{99mTcI(CO)3}+ building block many years ago. Many different complexes with this core were subjected to targeting studies and the organometallic chemistry of Tc developed rapidly beyond designs for molecular imaging. Some prominent examples will give insight into their structures and activities for molecular imaging. For complementing the fac-{99mTcI(CO)3}+ tag, we switched from low- to high-valent complexes. The isolobal fac-{99mTcVII(O)3}+ building block was introduced.2 Preparation of TcVII complexes is an example about how research is translated to routinely applicable conditions. For proceeding towards theranostics, homologous complexes with Re for therapy and with 99mTc complexes for imaging are mandatory. A new synthetic approach enabled the preparation of cyclopentadienyl complexes of both elements and based on pharmaceutically active lead structures.3 Newly introduced bis-arene complexes scopes at using these structures in analogy to ferrocene.4 The presentation exemplifies how questions from, ultimately practical, application lead to basic developments. Unexpected results in turn influence the discovery of new imaging and therapeutic agents.5 (1) Meggers, E. Curr. Opin. Chem. Biol. 2007, 11, 287. (2) Braband, H.; Tooyama, Y.; Fox, T.; Alberto, R. Chem. Eur. J. 2009, 15, 633. (3) Can, D.; Spingler, B.; Schmutz, P.; Mendes, F.; Raposinho, P.; Fernandes, C.; Carta, F.; Innocenti, A.; Santos, I.; Supuran, C. T.; Alberto, R. Angew. Chem. Int. Edit. 2012, 51, 3354. (4) Benz

Use of new tandem cation/anion exchange system with clinical-scale generators provides high specific volume solutions of technetium-99m and rhenium-188

International Nuclear Information System (INIS)

Knapp, F.F. Jr.; Beets, A.L.; Mirzadeh, S.; Guhlke, S.

1998-01-01

In this paper we describe the first application of our simple and inexpensive post-elution tandem cation/anion exchange column system which is based on generator elution with salts of weak acids such as ammonium acetate instead of saline solution to provide very high specific volume solutions of technetium-99m and rhenium-188 from clinical-scale molybdenum-99/technetium-99m generator prepared from low specific activity (n,y) molybdenum-99, and tungsten-188/rhenium-188 generators, respectively. Initial passage of the bolus through a strong cation exchange cartridge converts the ammonium acetate to acetic acid which is essentially not ionized at the acidic pH, allowing specific subsequent amine-type (QMA SepPak TM ) anion exchange cartridge column trapping of the microscopic levels of the pertechnetate or perrhenate. Subsequent elution of the anion cartridge with a small volume ( 500 mCi/mL) from the alumina-based tungsten-188/rhenium-188 generator. (author)

Thermal decomposition of rhenium (5) complexes with 1,2,4-triazole

International Nuclear Information System (INIS)

Amindzhanov, A.A.; Gagieva, S.Ch.; Kotegov, K.V.

1991-01-01

Processes of thermal decomposition of rhenium (5) complexes with 1,2,4-triazole were studied. Thermolysis products were identified on the basis of data of the element analysis, IR spectra, conductometry and other methods. It is ascertained that at the first stage of thermolysis of hydroxyl-containing monomer complexes removal of water molecules occurs, and at the second one - dimerization process with formation of Re-O-Re group. It is shown that the nature of halide ion practically does not affect the temperature of the start of intensive thermal decomposition of the complexes

The analysis of mechanism of rhenium-coated tools' wear-resistance rising

Directory of Open Access Journals (Sweden)

Daniel Petrosyan

2017-06-01

Full Text Available It is proposed to obtain wear-resistant layers on the hard-alloy materials by thermochemical treatment. In the different field of production – mechanical engineering, metallurgy and military technologies, with machine parts demanding high wearproof and corrosion-proof machinery parts on the surfaces of syntheses of diamonds, with metal surface thermal-diffusion with rhenium, to receive diffusion wearing layers for the first time. A method for thermochemical treatment of hard alloy plates has been investigated, allowing to raise the wear-resistance of cutting and mining tools.

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.

Invertase-labeling gold-dendrimer for in situ amplified detection mercury(II) with glucometer readout and thymine-Hg(2+)-thymine coordination chemistry.

Science.gov (United States)

Qiu, Zhenli; Shu, Jian; Jin, Guixiao; Xu, Mingdi; Wei, Qiaohua; Chen, Guonan; Tang, Dianping

2016-03-15

A simple, low-cost transducer with glucometer readout was designed for sensitive detection of mercury(II) (Hg(2+)), coupling with thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and invertase-functionalized gold-dendrimer nanospheres for the signal amplification. Initially, nanogold-encapsulated poly(amidoamine) dendrimers (Au DENs) were synthesized by in-situ reduction of gold(III). Thereafter, the as-prepared Au DENs were utilized for the labeling of invertase and T-rich signal DNA probe. In the presence of target Hg(2+), the functionalized Au DENs were conjugated to capture DNA probe-modified electrode via T-Hg(2+)-T coordination chemistry. Accompanying the Au DENs, the labeled invertase could hydrolyze sucrose into glucose, which could be quantitatively monitored by an external personal glucometer (PGM). The PGM signal increased with the increasing target Hg(2+) in the sample. Under the optimal conditions, our designed sensing platform exhibited good PGM responses toward target Hg(2+), and allowed the detection of Hg(2+) at a concentration as low as 4.2 pM. This sensing system also displayed remarkable specificity relative to target Hg(2+) against other competing ions, and could be applied for reliable monitoring of spiked Hg(2+) into the environmental water samples with satisfactory results. With the advantages of cost-effectiveness, simplicity, portability, and convenience, our strategy provides a tremendous potential to be a promising candidate for point-of-use monitoring of non-glucose targets by the public. Copyright © 2015 Elsevier B.V. All rights reserved.

Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

International Nuclear Information System (INIS)

Huang, Yongle; Bai, Shuxin; Zhang, Hong; Ye, Yicong

2015-01-01

Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm 2 min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm 2 min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating

Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

Energy Technology Data Exchange (ETDEWEB)

Huang, Yongle; Bai, Shuxin, E-mail: NUDT_MSE_501@163.com; Zhang, Hong; Ye, Yicong

2015-02-15

Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm{sup 2} min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm{sup 2} min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating.

High-resolution metallic magnetic calorimeters for β-spectroscopy on 187rhenium and position resolved X-ray spectroscopy

International Nuclear Information System (INIS)

Porst, Jan-Patrick

2011-01-01

This thesis describes the development of metallic magnetic calorimeters (MMCs) for high resolution spectroscopy. MMCs are energy dispersive particle detectors based on the calorimetric principle which are typically operated at temperatures below 100 mK. The detectors make use of a paramagnetic temperature sensor to transform the temperature rise upon the absorption of a particle in the detector into a measurable magnetic flux change in a dc-SQUID. The application of MMCs for neutrino mass measurements and their advantages with respect to other approaches are discussed. In view of this application the development of an MMC optimized for β-endpoint spectroscopy on 187 rhenium is presented. A fully micro-fabricated X-ray detector is characterized and performs close to design values. Furthermore, a new technique to more efficiently couple rhenium absorbers mechanically and thermally to the sensor was developed and successfully tested. By employing a metallic contact, signal rise times faster than 5 μs could be observed with superconducting rhenium absorbers. In addition to the single pixel detectors, an alternative approach of reading out multiple pixels was developed in this work, too. Here, the individual absorbers have a different thermal coupling to only one temperature sensor resulting in a distribution of different pulse shapes. Straightforward position discrimination by means of rise time analysis is demonstrated for a four pixel MMC and a thermal model of the detector is provided. Unprecedented so far, an energy resolution of less than ΔE FWHM <5 eV for 5.9 keV X-rays was achieved across all absorbers. (orig.)

Studies of the structures of rhenium complexes with sulphur-containing amino acids: cysteine and homocysteine

International Nuclear Information System (INIS)

Arkowska, A.; Wojciechowski, W.

1979-01-01

Two rhenium compounds have been synthesized: compound 1 with cysteine HS-CH 2 -CH-NH 2 -COOH and compound 2 with homocysteine HS-CH 2 -CH 2 -CH-NH 2 -COOH. On the basis of spectroscopic measurements (IR, far IR, Raman, VIS and UV spectra) and magnetic susceptibility measurements their probable electronic and molecular structures have been determined. (author)

Water chemistry guidelines for BWRs

International Nuclear Information System (INIS)

Bilanin, W.J.; Jones, R.L.; Welty, C.S.

1984-01-01

Guidelines for BWR water chemistry control have been prepared by a committee of experienced utility industry personnel sponsored by the BWR Owners Group on IGSCC Research and coordinated by the Electric Power Research Institute. The guidelines are based on extensive plant operational experience and laboratory research data. The purpose of the guidelines is to provide guidance to the electric utility industry on water chemistry control to help reduce corrosion, especially stress corrosion cracking, in boiling water reactors

Use of a new tandem cation/anion exchange system with clinical-scale generators provides high specific volume solutions of technetium-99m and rhenium-188

International Nuclear Information System (INIS)

Knapp, F.R. Jr.; Beets, A.L.; Mirzadeh, S.; Guhlke, S.; Univ. of Bonn

1998-03-01

In this paper the authors describe the first application of a simple and inexpensive post elution tandem cation-anion exchange column system which is based on generator elution with salts of weak acids such as ammonium acetate instead of saline solution to provide very high specific volume solutions of technetium-99m and rhenium-188 from clinical scale molybdenum-99/technetium-99m generator prepared from low specific activity (n,y) molybdenum-99, and tungsten-188/rhenium-188 generators, respectively. Initial passage of the bolus through a strong cation exchange cartridge converts the ammonium acetate to acetic acid which is essentially not ionized at the acidic pH, allowing specific subsequent amine type (QMA SepPak trademark) anion exchange cartridge column trapping of the microscopic levels of the pertechnetate or perrhenate. Subsequent elution of the anion cartridge with a small volume ( 500 mCi/mL) from the alumina-based tungsten-188/rhenium-188 generator

Progress in physical chemistry

CERN Document Server

Hempelmann, Rolf

2008-01-01

Progress in Physical Chemistry is a collection of recent ""Review Articles"" published in the ""Zeitschrift für Physikalische Chemie"". The second volume of Progress in Physical Chemistry is a collection of thematically closely related minireview articles written by the members of the Collaborative Research Centre (SFB) 277 of the German Research Foundation (DFG). These articles are based on twelve years of intense coordinated research efforts. Central topics are the synthesis and the characterization of interface-dominated, i.e. nanostructured materials, mainly in the solid state but also as

Inorganic chemistry and medicine

International Nuclear Information System (INIS)

Sadler, P.J.; Guo, Z.

1999-01-01

Inorganic chemistry is beginning to have a major impact on medicine. Not only does it offer the prospect of the discovery of truly novel drugs and diagnostic agents, but it promises to make a major contribution to our understanding of the mechanism of action of organic drugs too. Most of this article is concerned with recent developments in medicinal coordination chemistry. The role of metal organic compounds of platinum, titanium, ruthenium, gallium, bismuth, gold, gadolinium, technetium, silver, cobalt in the treatment or diagnosis of common diseases are briefly are examined

Rhenium (5) and molybdenum (5) complexes with 4',4''(5'')-ditretbutyldibenzo-24-crown-8

International Nuclear Information System (INIS)

Ashurova, N.Kh.; Yakubov, K.G.; Basitova, S.M.; Tashmukhamedova, A.K.; Sajfullina, N.Zh.

1989-01-01

Rhenium and molybdenum complexes in +5 oxidation degree with 4',4''(5'')-ditretbutyldibenzo-24-crown-8 (L) are synthesized with 75-95 % yield. Composition and structure of compounds produced are investigated using element analysis, conductometry, IR spectroscopy, thermogravimetry methods. Oxidation degree of complexer metal is determined. It is ascertained that the compound composition corresponds to the MOLX 3 formula, where M-Re, Mo; X-Cl - , Br -

Chalcogenhalide cluster rhenium- and molybdenum complexes

International Nuclear Information System (INIS)

Fedin, V.P.; Gubin, S.P.; Mishchenko, A.V.; Fedorov, V.E.

1984-01-01

The interaction of rhenium- and molybdenum chalcogenhalides with n-donor ligands (L) is studied. At heating Re 3 X 2 Hal 5 complexes up to 100 deg in DMSO in the L presence obtained are the complexes of the 1-6 composition Re 3 X 2 Hal 5 -x Lx DMSO (X=Se, Hal=Cl, L=Et 3 N(1); X=Se, Hal=Cl, L=Bipy(2); X=Se, Hal=Br, L=Et 3 N(3); X=Se, Hal=Br, L=Bipy(4); X=Te, Hal=Br, L=Et 3 N(5); X=Te, Hal=Br, L=(Me 2 NCH 2 ) 2 (6). In the course of boiling of Mo 3 S 7 Hal 4 with PPh 3 in MeCN the Mo 3 S 7 Hal 4 2PPh 3 complexes (Hal=Cl(7); Br(8)) are obtained. For 1 through 8 complexes the chemical analysis data and IR spectra are given. For 4 and 8 complexes the molecular mass is measured. A possible method of obtaining molecular trinuclear clusters from polymer clusters is discussed

Coordination-Assisted Bioorthogonal Chemistry: Orthogonal Tetrazine Ligation with Vinylboronic Acid and a Strained Alkene.

Science.gov (United States)

Eising, Selma; Xin, Bo-Tao; Kleinpenning, Fleur; Heming, Juriaan; Florea, Bogdan; Overkleeft, Herman; Bonger, Kimberly Michelle

2018-05-28

Bioorthogonal chemistry can be used for the selective modification of biomolecules without interfering with any other functionality present. Recent developments in the field provided orthogonal bioorthogonal reactions for modification of multiple biomolecules simultaneously. During our research, we have observed exceptional high reaction rates in the bioorthogonal inverse electron-demand Diels-Alder (iEDDA) reaction between non-strained vinylboronic acids (VBAs) and dipyridyl-s-tetrazines relative to that of tetrazines bearing a methyl or phenyl substituent. As VBAs are mild Lewis acids, we hypothesize that coordination of the pyridyl nitrogen to the boronic acid promotes the tetrazine ligation. Here, we explore the molecular basis and scope of the VBA-tetrazine ligation in more detail and benefit from its unique reactivity in the simultaneous orthogonal tetrazine labelling of two proteins modified with VBA and norbornene, a widely used strained alkene. We further show that the two orthogonal iEDDA reactions can be carried out in living cells by labelling of the proteasome using a non-selective probe equipped with a VBA and a subunit-selective one bearing a norbornene. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly(2-hydroxyethyl methacrylate) grafted halloysite nanotubes as a molecular host matrix for luminescent ions prepared by surface-initiated RAFT polymerization and coordination chemistry

Energy Technology Data Exchange (ETDEWEB)

Islam, Md. Rafiqul; Bach, Long Giang; Lim, Kwon Taek, E-mail: ktlim@pknu.ac.kr

2013-07-01

A fluorescent nanohybrid complex comprising of halloysite nanotubes (HNTs), poly(2-hydroxyethyl methacrylate) (PHEMA), and europium ions (Eu{sup 3+}) was synthesized by the combination of surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization and coordination chemistry. Initially, PHEMA was grafted from the HNTs by SI-RAFT and then reacted with succinic anhydride to provide carboxyl acid groups on the external layers of HNTs-g-PHEMA nanohybrids. The subsequent coordination of the nanohybrids with Eu{sup 3+} ions afforded photoluminescent Eu{sup 3+} tagged HNTs-g-PHEMA nanohybrid complexes (HNTs-g-PHEMA-Eu{sup 3+}). The structure, morphology, and fluorescence properties of the Eu{sup 3+} coordinated nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR, XPS, and EDS analyses suggested the formation of the HNTs-g-PHEMA-Eu{sup 3+} nanohybrids. FE-SEM images indicated the immobilization of polymer layers on HNTs. TGA scans further demonstrated the grafting of PHEMA onto HNTs surface. The optical properties of HNTs-g-PHEMA-Eu{sup 3+} nanohybrid complexes were investigated by photoluminescence spectroscopy.

Synthesis and structure of bivalent ytterbocenes and their coordination chemistry with pi-acceptor ligands

Energy Technology Data Exchange (ETDEWEB)

Schultz, Madeleine [Univ. of California, Berkeley, CA (United States)

2000-05-01

The bivalent lanthanide metallocenes [1,3-(Me₃C)₂C₅H₃]₂Yb and (Me₄C₅H)₂Yb have been synthesized and their structures have been determined by X-ray crystallography. Comparison with the known structures of (Me₅C₅)₂Yb and [1,3 -(Me₃Si)₂C₅H₃]₂Yb leads to an understanding of the role of intermolecular contacts in stabilizing these coordinatively unsaturated molecules. The optical spectra of the base-free ytterbocenes and their Lewis-base adducts have been measured; the position of the HOMO - LUMO transition can be correlated with the degree of bending of the complexes in solution according to a molecular orbital model. Electron - electron repulsion, resulting from additional σ-donor ligands, also affects the HOMO - LUMO transition by increasing the energy of the filled f-orbitals. The base-free metallocene (Me₅C₅)₂Yb coordinates carbon monoxide, resulting in a decrease in V_co relative to that of fi-ee carbon monoxide. This behavior is reminiscent of d-transition metallocene chemistry. Other base-free ytterbocenes also coordinate carbon monoxide and the degree of back-donation is related to the substituents on the cyclopentadienide rings. Isocyanides are coordinated in a 1:2 ratio by the ytterbocenes, giving complexes having v_cN higher than those of the free isocyanides. An electrostatic bonding model has been used to explain the changes in CN stretching frequencies. The optical spectra of the carbonyl and isocyanide complexes are consistent with the molecular orbital model of the variation in the HOMO - LUMO gap upon bending, and the increase in electron - electron repulsion due to the additional ligands. The complex (Me₅C₅)₂Yb(bipy) exhibits optical, infrared and NMIZ spectroscopy and an X-ray crystal

Convenient synthesis of bis(alkoxy)rhenium(VII) complexes

Energy Technology Data Exchange (ETDEWEB)

Zhu, Z.; Al-Ajlouni, A.M.; Espenson, J.H. [Iowa State Univ., Ames, IA (United States)

1996-02-28

The study of high-oxidation-state organorhenium compounds has been a field of continuing activity, thanks to the success of methylrhenium trioxide (CH{sub 3}ReO{sub 3} or MTO) in catalytic processes. This catalyst is effective in oxidations, olefin metathesis, the olefination of aldehydes, and the preparation of other compounds with three-membered rings. The syntheses of some rhenium compounds derived form MTO have been reported. Epoxide formation is a key reaction, and it bears directly on these findings reported here. Re(VII) complexes containing a chelated bis(diolate) ligand can be synthesized by refluxing MTO with 2,3-dimethyl-2,3-diol. Here, the authors report a more convenient method for this preparation. A different series of related compounds consists of chelated bis(diolates) of the Cp*Re-oxo series, Cp*ReO-(diolate).

High-resolution metallic magnetic calorimeters for {beta}-spectroscopy on {sup 187}rhenium and position resolved X-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Porst, Jan-Patrick

2011-02-01

This thesis describes the development of metallic magnetic calorimeters (MMCs) for high resolution spectroscopy. MMCs are energy dispersive particle detectors based on the calorimetric principle which are typically operated at temperatures below 100 mK. The detectors make use of a paramagnetic temperature sensor to transform the temperature rise upon the absorption of a particle in the detector into a measurable magnetic flux change in a dc-SQUID. The application of MMCs for neutrino mass measurements and their advantages with respect to other approaches are discussed. In view of this application the development of an MMC optimized for {beta}-endpoint spectroscopy on {sup 187}rhenium is presented. A fully micro-fabricated X-ray detector is characterized and performs close to design values. Furthermore, a new technique to more efficiently couple rhenium absorbers mechanically and thermally to the sensor was developed and successfully tested. By employing a metallic contact, signal rise times faster than 5 {mu}s could be observed with superconducting rhenium absorbers. In addition to the single pixel detectors, an alternative approach of reading out multiple pixels was developed in this work, too. Here, the individual absorbers have a different thermal coupling to only one temperature sensor resulting in a distribution of different pulse shapes. Straightforward position discrimination by means of rise time analysis is demonstrated for a four pixel MMC and a thermal model of the detector is provided. Unprecedented so far, an energy resolution of less than {delta}E{sub FWHM}<5 eV for 5.9 keV X-rays was achieved across all absorbers. (orig.)

RHENIUM SOLUBILITY IN BOROSILICATE NUCLEAR WASTE GLASS IMPLICATIONS FOR THE PROCESSING AND IMMOBILIZATION OF TECHNETIUM-99 (AND SUPPORTING INFORMATION WITH GRAPHICAL ABSTRACT)

Energy Technology Data Exchange (ETDEWEB)

AA KRUGER; A GOEL; CP RODRIGUEZ; JS MCCLOY; MJ SCHWEIGER; WW LUKENS; JR, BJ RILEY; D KIM; M LIEZERS; P HRMA

2012-08-13

The immobilization of 99Tc in a suitable host matrix has proved a challenging task for researchers in the nuclear waste community around the world. At the Hanford site in Washington State in the U.S., the total amount of 99Tc in low-activity waste (LAW) is {approx} 1,300 kg and the current strategy is to immobilize the 99Tc in borosilicate glass with vitrification. In this context, the present article reports on the solubility and retention of rhenium, a nonradioactive surrogate for 99Tc, in a LAW sodium borosilicate glass. Due to the radioactive nature of technetium, rhenium was chosen as a simulant because of previously established similarities in ionic radii and other chemical aspects. The glasses containing target Re concentrations varying from 0 to10,000 ppm by mass were synthesized in vacuum-sealed quartz ampoules to minimize the loss of Re by volatilization during melting at 1000 DC. The rhenium was found to be present predominantly as Re7 + in all the glasses as observed by X-ray absorption near-edge structure (XANES). The solubility of Re in borosilicate glasses was determined to be {approx}3,000 ppm (by mass) using inductively coupled plasma-optical emission spectroscopy (ICP-OES). At higher rhenium concentrations, some additional material was retained in the glasses in the form of alkali perrhenate crystalline inclusions detected by X-ray diffraction (XRD) and laser ablation-ICP mass spectrometry (LA-ICP-MS). Assuming justifiably substantial similarities between Re7 + and Tc 7+ behavior in this glass system, these results implied that the processing and immobilization of 99Tc from radioactive wastes should not be limited by the solubility of 99Tc in borosilicate LAW glasses.

Advances in Solid-State Transformations of Coordination Bonds: From the Ball Mill to the Aging Chamber

Directory of Open Access Journals (Sweden)

Cristina Mottillo

2017-01-01

Full Text Available Controlling the formation of coordination bonds is pivotal to the development of a plethora of functional metal-organic materials, ranging from coordination polymers, metal-organic frameworks (MOFs to metallodrugs. The interest in and commercialization of such materials has created a need for more efficient, environmentally-friendly routes for making coordination bonds. Solid-state coordination chemistry is a versatile greener alternative to conventional synthesis, offering quantitative yields, enhanced stoichiometric and topological selectivity, access to a wider range of precursors, as well as to molecules and materials not readily accessible in solution or solvothermally. With a focus on mechanochemical, thermochemical and “accelerated aging” approaches to coordination polymers, including pharmaceutically-relevant materials and microporous MOFs, this review highlights the recent advances in solid-state coordination chemistry and techniques for understanding the underlying reaction mechanisms.

Rhenium Alloys as Ductile Substrates for Diamond Thin-Film Electrodes.

Science.gov (United States)

Halpern, Jeffrey M; Martin, Heidi B

2014-02-01

Molybdenum-rhenium (Mo/Re) and tungsten-rhenium (W/Re) alloys were investigated as substrates for thin-film, polycrystalline boron-doped diamond electrodes. Traditional, carbide-forming metal substrates adhere strongly to diamond but lose their ductility during exposure to the high-temperature (1000°C) diamond, chemical vapor deposition environment. Boron-doped semi-metallic diamond was selectively deposited for up to 20 hours on one end of Mo/Re (47.5/52.5 wt.%) and W/Re (75/25 wt.%) alloy wires. Conformal diamond films on the alloys displayed grain sizes and Raman signatures similar to films grown on tungsten; in all cases, the morphology and Raman spectra were consistent with well-faceted, microcrystalline diamond with minimal sp 2 carbon content. Cyclic voltammograms of dopamine in phosphate-buffered saline (PBS) showed the wide window and low baseline current of high-quality diamond electrodes. In addition, the films showed consistently well-defined, dopamine electrochemical redox activity. The Mo/Re substrate regions that were uncoated but still exposed to the diamond-growth environment remained substantially more flexible than tungsten in a bend-to-fracture rotation test, bending to the test maximum of 90° and not fracturing. The W/Re substrates fractured after a 27° bend, and the tungsten fractured after a 21° bend. Brittle, transgranular cleavage fracture surfaces were observed for tungsten and W/Re. A tension-induced fracture of the Mo/Re after the prior bend test showed a dimple fracture with a visible ductile core. Overall, the Mo/Re and W/Re alloys were suitable substrates for diamond growth. The Mo/Re alloy remained significantly more ductile than traditional tungsten substrates after diamond growth, and thus may be an attractive metal substrate for more ductile, thin-film diamond electrodes.

Energetic lanthanide complexes: coordination chemistry and explosives applications

International Nuclear Information System (INIS)

Manner, V W; Barker, B J; Sanders, V E; Laintz, K E; Scott, B L; Preston, D N; Sandstrom, M; Reardon, B L

2014-01-01

Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

Epitaxial growth of rhenium with sputtering

Energy Technology Data Exchange (ETDEWEB)

Oh, Seongshik [National Institute of Standards and Technology, Boulder, CO 80305 (United States) and Department of Physics, University of Illinois, Urbana, IL 61801 (United States)]. E-mail: soh@boulder.nist.gov; Hite, Dustin A. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Cicak, K. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Osborn, Kevin D. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Simmonds, Raymond W. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); McDermott, Robert [University of California, Santa Barbara, CA 93106 (United States); Cooper, Ken B. [University of California, Santa Barbara, CA 93106 (United States); Steffen, Matthias [University of California, Santa Barbara, CA 93106 (United States); Martinis, John M. [University of California, Santa Barbara, CA 93106 (United States); Pappas, David P. [National Institute of Standards and Technology, Boulder, CO 80305 (United States)

2006-02-21

We have grown epitaxial Rhenium (Re) (0001) films on {alpha}-Al{sub 2}O{sub 3} (0001) substrates using sputter deposition in an ultra high vacuum system. We find that better epitaxy is achieved with DC rather than with RF sputtering. With DC sputtering, epitaxy is obtained with the substrate temperatures above 700 deg. C and deposition rates below 0.1 nm/s. The epitaxial Re films are typically composed of terraced hexagonal islands with screw dislocations, and island size gets larger with high temperature post-deposition annealing. The growth starts in a three dimensional mode but transforms into two dimensional mode as the film gets thicker. With a thin ({approx}2 nm) seed layer deposited at room temperature and annealed at a high temperature, the initial three dimensional growth can be suppressed. This results in larger islands when a thick film is grown at 850 deg. C on the seed layer. We also find that when a room temperature deposited Re film is annealed to higher temperatures, epitaxial features start to show up above {approx}600 deg. C, but the film tends to be disordered.

Alkene-glycol interconversion with technetium and rhenium oxo complexes

International Nuclear Information System (INIS)

Pearlstein, R.M.; Davison, Alan

1988-01-01

The trioxotechnetium(VII) complexes TcO 3 Cl(AA) (AA = phen, bpy, 5-NO 2 -phen, 3,4,7,8-Me 4 -phen) cleanly oxidize olefins (C 2 R 4 ) in solution at 22 0 C, forming in high yields the corresponding oxotechnetium(V) diolate complexes, TcOCl(OCR 2 CR 2 O)(AA). The complexes have been characterized by 1 H NMR, IR, elemental analysis, and fast atom bombardment mass spectrometry. The free diols isolated by hydrolysis of these diolate complexes with HCl were shown by capillary gas chromatography to represent syn addition of the two hydroxyl groups across the double bond. The related rhenium complex, ReOCl(OCH 2 CH 2 O)(phen) undergoes the reverse reaction when thermalized, releasing ethylene and producing ReO 3 Cl(phen). (author)

Actinyl chemistry at the Centre for Radiochemistry Research

International Nuclear Information System (INIS)

May, Iain; Copping, Roy; Cornet, Stephanie M.; Talbot-Eeckelears, Catherine E.; Gaunt, Andrew J.; John, Gordon H.; Redmond, Mike P.; Sharrad, Clint A.; Sutton, Andrew D.; Collison, David; Fox, O. Danny; Jones, Chris J.; Sarsfield, Mark J.; Taylor, Robin J.

2007-01-01

Increasing our basic chemical knowledge of the actinyl cations ({AnO 2 } 2+/+ , where An = U, Np, Pu or Am) is vital for underpinning the development of novel nuclear waste management and nuclear fuel processing technologies, as well as increasing our understanding of actinide behaviour in the environment. Over recent years there have been significant advances made in uranyl, neptunyl and plutonyl chemistry, with the main focus on uranyl. At the Centre for Radiochemistry Research (CRR), University of Manchester, there are ongoing projects investigating the coordination chemistry of the actinyl cations. These projects are undertaken at the CRR and at higher specific activity alpha facilities accessed through Nexia Solutions and the EU ACTINET programme, as well as concomitant computational chemistry projects at University College London. Recent discoveries have included the complexation of transuranic actinyl cations with tri-lacunary heteropolytungstate ligands and spectroscopic and structural evidence for the direct coordination of the pertechnetate anion to {UO 2 } 2+

Black Boxes in Analytical Chemistry: University Students' Misconceptions of Instrumental Analysis

Science.gov (United States)

Carbo, Antonio Domenech; Adelantado, Jose Vicente Gimeno; Reig, Francisco Bosch

2010-01-01

Misconceptions of chemistry and chemical engineering university students concerning instrumental analysis have been established from coordinated tests, tutorial interviews and laboratory lessons. Misconceptions can be divided into: (1) formal, involving specific concepts and formulations within the general frame of chemistry; (2)…

Novel bi-metallic uranyl complexes - Redox chemistry in aqueous solutions

International Nuclear Information System (INIS)

Yardeni, A.; Mizrahi, E.; Maimon, I.; Zilbermann, G.; Meyerstein, D.; Zehavi-cohen, A.Z.

2014-01-01

The synthesis of organic ligands which can accommodate two uranium atoms at different oxidation states, mixed valency being then achieved by redox chemistry at room temperature is definitely a challenge in coordination chemistry. The following complexes were synthesized and characterized by elemental analysis, NMR, MS, IR and UV-vis

Meso-Helical Ag(I) Coordination Polymer Based on a Pyridylimidazole Ligand

International Nuclear Information System (INIS)

Kang, Youngjin; Kim, Jinho; Lee, Eunji; Park, Ki-Min; Moon, Suk-Hee

2016-01-01

In the fields of material science and metallosupramolecular chemistry, coordination polymers with various helical types have been extensively explored because of their charming structures, and their potential applications in material chemistry. Among them, meso-helical coordination polymers consisting of achiral 1D strands, which are generally constructed by a crystallographic inversion symmetry, are relatively rare. The coordination polymer 1 exhibits a rare one-dimensional meso-helical chain topology constructed by its internal inversion symmetry. The skeleton of this meso-helical chain is preserved up to 300°C. The complexation of silver(I) ion to the free pyim ligand give rise to the enhanced photoluminescence intensity and slightly blue-shifted emission maximum, originated from intraligand (IL) π[BOND]π* transition and rigidochromic effect. Further exploration of complexation of this ligand with other transition metal ions is currently in progress

Broad Detection Range Rhenium Diselenide Photodetector Enhanced by (3-Aminopropyl)Triethoxysilane and Triphenylphosphine Treatment.

Science.gov (United States)

Jo, Seo-Hyeon; Park, Hyung-Youl; Kang, Dong-Ho; Shim, Jaewoo; Jeon, Jaeho; Choi, Seunghyuk; Kim, Minwoo; Park, Yongkook; Lee, Jaehyeong; Song, Young Jae; Lee, Sungjoo; Park, Jin-Hong

2016-08-01

The effects of triphenylphosphine and (3-aminopropyl)triethoxysilane on a rhenium diselenide (ReSe2 ) photodetector are systematically studied by comparing with conventional MoS2 devices. This study demonstrates a very high performance ReSe2 photodetector with high photoresponsivity (1.18 × 10(6) A W(-1) ), fast photoswitching speed (rising/decaying time: 58/263 ms), and broad photodetection range (possible above 1064 nm). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pyrazole complexes of rhenium. Synthesis and crystal structure of trans-[Re(O)(OMe)L4]Br2 · L · 4H2O (L - 3,5-dimethylpyrazole)

International Nuclear Information System (INIS)

Sokolov, M.N.; Fedorova, N.Eh.; Fedorov, V.E.; Virovets, A.V.; Nun'es, P.

2002-01-01

The first rhenium (V) mononuclear complex featuring composition [Re(O)(OMe)L 4 ]Br 2 (L = 3,5-dimethylpyrazole), which is resistant to hydrolysis in neutral aqueous solution, along with its molecular adduct of the composition [Re(O)(OMe)L 4 ]Br 2 · L · 4H 2 O were synthesized. The reaction products were characterized by the methods of elementary analysis, absorption spectroscopy in visible, UV and IR ranges, mass spectrometry. Besides, the adduct structure was studied by the method of X-ray diffraction analysis. It was ascertained that the adduct is crystallized in tetragonal crystal system with unit cell parameters as follows: a = 14.912 (3), c = 17.108 (4) A, sp. gr. I4/m, Z = 4. In the complex molecule linear grouping Re(O)(OMe)] 2+ (Re-O-C angle being equal to 180 deg) is coordinated by four L ligand molecules [ru

Development of pharmaceuticals with radioactive rhenium for cancer therapy. Production of {sup 186}Re and {sup 188}Re, synthesis of labeled compounds and their biodistributions

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Production of the radioactive rhenium isotopes {sup 186}Re and {sup 188}Re, and synthesis of their labeled compounds have been studied together with the biodistributions of the compounds. This work was carried out by the Working Group on Radioactive Rhenium, consisting of researchers of JAERI and some universities, in the Subcommittee for Production and Radiolabeling under the Consultative Committee of Research on Radioisotopes. For {sup 186}Re, production methods by the {sup 185}Re(n,{gamma}){sup 186}Re reaction in a reactor and by the {sup 186}W(p,n){sup 186}Re reaction with an accelerator, which can produce nocarrier-added {sup 186}Re, have been established. For {sup 188}Re, a production method by the double neutron capture reaction of {sup 186}W, which produces a {sup 188}W/{sup 188}Re generator, has been established. For labeling of bisphosphonate, DMSA, DTPA, DADS, aminomethylenephosphonate and some monoclonal antibodies with the radioactive rhenium isotopes, the optimum conditions, including pH, the amounts of reagents and so on, have been determined for each compound. The biodistributions of each of the labeled compounds in mice have been also obtained. (author)

Surveys of research in the Chemistry Division, Argonne National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Grazis, B.M. [ed.

1992-11-01

Research reports are presented on reactive intermediates in condensed phase (radiation chemistry, photochemistry), electron transfer and energy conversion, photosynthesis and solar energy conversion, metal cluster chemistry, chemical dynamics in gas phase, photoionization-photoelectrons, characterization and reactivity of coal and coal macerals, premium coal sample program, chemical separations, heavy elements coordination chemistry, heavy elements photophysics/photochemistry, f-electron interactions, radiation chemistry of high-level wastes (gas generation in waste tanks), ultrafast molecular electronic devices, and nuclear medicine. Separate abstracts have been prepared. Accelerator activites and computer system/network services are also reported.

Surveys of research in the Chemistry Division, Argonne National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Grazis, B.M. (ed.)

1992-01-01

Research reports are presented on reactive intermediates in condensed phase (radiation chemistry, photochemistry), electron transfer and energy conversion, photosynthesis and solar energy conversion, metal cluster chemistry, chemical dynamics in gas phase, photoionization-photoelectrons, characterization and reactivity of coal and coal macerals, premium coal sample program, chemical separations, heavy elements coordination chemistry, heavy elements photophysics/photochemistry, f-electron interactions, radiation chemistry of high-level wastes (gas generation in waste tanks), ultrafast molecular electronic devices, and nuclear medicine. Separate abstracts have been prepared. Accelerator activites and computer system/network services are also reported.

Coordination phenomena of cationic uranium(iv) complexes

International Nuclear Information System (INIS)

Rohwer, H.E.

1974-12-01

The coordination properties of the cationic uranium(IV) complexes UCl 3 + , UCl 2 2+ , UCl 3+ , and U 4+ were studied in a non-aqueous medium in the presence of perchlorate as counterion which, however, proved to coordinate to a much greater extent than expected. The strong neutral ligand, HMPA, could successively displace some of the perchlorates. An electrostatic model for the U(CIO 4 ) 4 -HMPA-acetone system compared favourably with the actual results. This emphasized the high ionic content in the bonding with actenoid cations, even with such a high charge as +4 . These conclusions are in agreement with studies 75 in which nitrate acts as counter ion. Correspondingly the uranium (IV) chemistry is characterized by the absence of typical 3d-organometallic chemistry, for example, strong bonding with CO, P(Phi) 3 etc, which strongly depends on covalent bonding. This stresses the fact that the d and f orbitals are not readily available for strong bond formation with the actenoids. 76

Spectroscopy and chemistry of uranium IV

International Nuclear Information System (INIS)

Folcher, G.; Rigny, P.

1980-06-01

Different fundamental research papers on uranium IV are presented, some were never edited. Molecular spectroscopy was used for identification and structural study of uranium IV in aqueous or organic solutions. The fields studied are: coordination, stereochemistry, electronic structure and chemical properties. For interpretation of results some studies were made with solid compounds or with thorium compounds or thorium complexes. Knowledge of actinides chemistry is improved, uranium and thorium being models for 5 f ions, extractive chemistry is better understood and new applications are possible [fr

Synthesis, molecular structure and magnetic properties of a rhenium(IV) compound with catechol

Science.gov (United States)

Cuevas, A.; Geis, L.; Pintos, V.; Chiozzone, R.; Sanchíz, J.; Hummert, M.; Schumann, H.; Kremer, C.

2009-03-01

A novel Re(IV) complex containing catechol as ligand has been prepared and characterized. The crystal structure of (HNEt 3)(NBu 4)[ReCl 4(cat)]·H 2cat was determined. The rhenium ion presents a distorted octahedral geometry, being bonded to a bidentate catecholate group and four chloride anions. The magnetic properties of the complex were studied, a /2 D/ (the energy gap between ±3/2 and ±1/2 Kramers doublets) value of 190(10) cm -1. This is the largest /2 D/ value reported for Re(IV) up to now.

Design criteria for rhenium-reduced nickel-based single-crystal alloys. Identification and computer-assisted conversion

International Nuclear Information System (INIS)

Goehler, Thomas

2016-01-01

In the present work, design criteria and property models for the creep strength optimization of rhenium-free nickel based single crystal Superalloys are investigated. The study focuses on a typical load condition of 1050 C and 150 MPa, which is representative for flight engine applications. Thereby the key aspect is to link chemical composition, manufacturing processes, microstructure formation and mechanistic understanding of dislocation creep through a computational materials engineering approach. Beside the positive effect of rhenium on solid solution hardening, a second mechanism in which rhenium increases high temperature creep strength is identified. It indirectly stabilizes precipitation hardening by reducing the coarsening kinetics of γ'-rafting. Five 1st and 2nd generation technical Superalloys show a comparable microstructure evolution for up to 2 % plastic elongation, while creep times differ by a factor of five. The application of a microstructure sensitive creep model shows that these coarsening processes can activate γ-cutting and thus lead to an increasing creep rate. Based on these calculations a threshold value of φ γ/γ' > 2,5 at 150 MPa is estimated. This ratio of matrix channel to raft thickness has been proofed for multiple positions by microstructure analysis of interrupted creep tests. The mechanism described previously can be decelerated by the enrichment of the γ-matrix with slow diffusing elements. The same principle also increases the solid solution strength of the γ-matrix. Therefore, the present work delivers an additional mechanistic explanation why creep properties of single phase nickel based alloys can be transferred to two phase technical Superalloys with rafted γ'-structure. Following, the best way to substitute both rhenium fundamental properties, namely a slow diffusion coefficient and a small solubility in g', has been investigated by means of CALPHAD-modeling. Only molybdenum and especially tungsten

Dynamic Combinatorial Chemistry with Diselenides, Disulfides, Imines and Metal Coordination

DEFF Research Database (Denmark)

Sørensen, Anne

combinatorial chemistry, namely the reversible diselenide exchange reaction. The first part of the thesis describes the development of a thermally induced OAr → SeAr migration reaction. Here, it was proven possible to rearrange a variety of substituted O-aryl selenocarbamates into the corresponding Se...

The Influence of Cobalt and Rhenium on the Behaviour of MCrAlY Coatings

OpenAIRE

Täck, Ulrike

2009-01-01

Superalloys are widely applied as materials for components in the hot section of gas turbines. As superalloys have a limited oxidation life, the application of a coating is vital. The most commonly applied coatings in stationary gas turbines are MCrAlY coatings. Since the turbine components are exposed to high cyclic thermal stresses, MCrAlY coatings must also show a high thermal fatigue resistance. In this thesis, the effect of Cobalt and Rhenium on microstructure, oxidation and thermal fati...

An introduction to the chemistry of complex compounds

CERN Document Server

Grinberg, Aleksander Abramovich; Trimble, R F

1962-01-01

An Introduction to the Chemistry of Complex Compounds discusses the fundamental concepts that are essential in understanding the underlying principles of complex compounds. The coverage of the book includes the compounds of the hexa, penta, and tetrammine type; compounds of the tri, dl, monoamine and hexacido types for the coordination number of 6; and complex compounds with a coordination number of 4. The text also covers the effects and chemical properties of complex compounds, such as the nature of the force of complex formation; the mutual effects of coordinated groups; and acid-base prope

The chemistry on a subnanometer scale of radiation-induced precipitation and segregation in fast-neutron irradiated tungsten-rhenium alloys

International Nuclear Information System (INIS)

Hershitz, R.; Seidman, D.N.

1984-01-01

The phenomena of radiation-induced precipitation and segregation have been investigated in W-10 at.% Re and W-25 at.% Re alloys, employing the atom-probe field-ion-microscope technique. The specimens had been irradiated to a fast-neutron fluence of approx.4x10 22 neutrons cm -2 (e>0.1 MeV) at 575, 625 and 675 deg C. This corresponds to 8.6 dpa and an average displacement rate, for the two year irradiation time of 1.4x10 -7 dpa s -1 . In the W-10 at.% Re alloy, coherent, semicoherent and possibly incoherent precipitates with the composition approx.WRe and a disc-shaped morphology -- one or two atomic planes thick -- were detected at a number density of approx.10 16 cm -3 , and a mean diameter of approx.57 A. In the W-25 at.% Re alloy the same precipitates with the composition approx.WRe 3 were detected at a number density of approx.10 17 cm -3 and a mean diameter of 40 A. The semicoherent WRe 3 precipitates were associated with 4 He atoms; that is, they may have been heterogeneously nucleated. None of the other precipitates were associated with either line or planar defects or with any impurity atoms. Therefore, a true homogeneous radiation-induced precipitation occurs in these alloys. In the W-25 at.% Re alloy a two dimensional WRe 3 phase has been observed at a grain boundary. The nucleation of both precipitates in the vicinity of displacement cascades might be produced by primary knock-on atoms. In both cases, the first step in the nucleation is due to the formation of tightly-bound mobile mixed dumbbells which react to form an immobile di-rhenium cluster. Point-defect mechanisms for all the other observations are also discussed

Reactor water chemistry relevant to coolant-cladding interaction

International Nuclear Information System (INIS)

1987-09-01

The report is a summary of the work performed in a frame of a Coordinated Research Program organized by the IAEA and carried out from 1981 till 1986. It consists of a survey on our knowledge on coolant-cladding interaction: the basic phenomena, the relevant parameters, their control and the modelling techniques implemented for their assessment. Based upon the results of this Coordinated Research Program, the following topics are reviewed on the report: role of water chemistry in reliable operation of nuclear power plants; water chemistry specifications and their control; behaviour of fuel cladding materials; corrosion product behaviour and crud build-up in reactor circuits; modelling of corrosion product behaviour. This report should be of interest to water chemistry supervisors at the power plants, to experts in utility engineering departments, to fuel designers, to R and D institutes active in the field and to the consultants of these organizations. A separate abstract was prepared for each of the 3 papers included in the Annex of this document. Refs, figs, tabs

High temperature on-line monitoring of water chemistry and corrosion control in water cooled power reactors. Report of a co-ordinated research project 1995-1999

International Nuclear Information System (INIS)

2002-07-01

This report documents the results of the Co-ordinated Research Project (CRP) on High Temperature On-line Monitoring of Water Chemistry and Corrosion in Water Cooled Power Reactors (1995-1999). This report attempts to provide both an overview of the state of the art with regard to on-line monitoring of water chemistry and corrosion in operating reactors, and technical details of the important contributions made by programme participants to the development and qualification of new monitoring techniques. The WACOL CRP is a follow-up to the WACOLIN (Investigations on Water Chemistry Control and Coolant Interaction with Fuel and Primary Circuit Materials in Water Cooled Power Reactors) CRP conducted by the IAEA from 1986 to 1991. The WACOLIN CRP, which described chemistry, corrosion and activity-transport aspects, clearly showed the influence of water chemistry on corrosion of both fuel and reactor primary-circuit components, as well as on radiation fields. It was concluded that there was a fundamental need to monitor water-chemistry parameters in real time, reliably and accurately. The objectives of the WACOL CRP were to establish recommendations for the development, qualification and plant implementation of methods and equipment for on-line monitoring of water chemistry and corrosion. Chief investigators from 18 organizations representing 15 countries provided a variety of contributions aimed at introducing proven monitoring techniques into plants on a regular basis and filling the gaps between plant operator needs and available monitoring techniques. The CRP firmly demonstrated that in situ monitoring is able to provide additional and valuable information to plant operators, e.g. ECP, high temperature pH and conductivity. Such data can be obtained promptly, i.e. in real time and with a high degree of accuracy. Reliable techniques and sensor devices are available which enable plant operators to obtain additional information on the response of structural materials in

Amidinate Ligands in Zinc coordination sphere: Synthesis and ...

Indian Academy of Sciences (India)

Amidinate Ligands in Zinc coordination sphere: Synthesis and structural diversity. SRINIVAS ANGA, INDRANI BANERJEE and TARUN K PANDA. ∗. Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi 502 285,. Sangareddy, Telangana, India e-mail: tpanda@iith.ac.in. MS received 25 February 2016; ...

Fate of rhenium in the environment as a chemical analogue of technetium

International Nuclear Information System (INIS)

Tagami, Keiko; Uchida, Shigeo

2007-01-01

Concentrations of rhenium, a chemical analogue of Tc, were measured in various environmental samples by ICP-MS to obtain information values on long-lived 99 Tc mobility in the environment. From the results, it was assumed that Re was removed from the rock and soil by water due to weathering and transport to the sea through rivers. The element would be retained in seawater for a long time, i.e., 2 x 10 5 to 7.5 x 10 5 y. The reservoirs of Re in the sea would be seaweeds, and anoxic and suboxic sediments, especially slightly below the water-sediment interface. (author)

Hot rocket plume experiment - Survey and conceptual design. [of rhenium-iridium bipropellants

Science.gov (United States)

Millard, Jerry M.; Luan, Taylor W.; Dowdy, Mack W.

1992-01-01

Attention is given to a space-borne engine plume experiment study to fly an experiment which will both verify and quantify the reduced contamination from advanced rhenium-iridium earth-storable bipropellant rockets (hot rockets) and provide a correlation between high-fidelity, in-space measurements and theoretical plume and surface contamination models. The experiment conceptual design is based on survey results from plume and contamination technologists throughout the U.S. With respect to shuttle use, cursory investigations validate Hitchhiker availability and adaptability, adequate remote manipulator system (RMS) articulation and dynamic capability, acceptable RMS attachment capability, adequate power and telemetry capability, and adequate flight altitude and attitude/orbital capability.

Substituent Effects on the Coordination Chemistry of Metal-Binding Pharmacophores

Energy Technology Data Exchange (ETDEWEB)

Craig, Whitney R. [Department; Baker, Tessa W. [Department; Marts, Amy R. [Department; DeGenova, Daniel T. [Department; Martin, David P. [Department; Reed, Garrett C. [Department; McCarrick, Robert M. [Department; Crowder, Michael W. [Department; Cohen, Seth M. [Department; Tierney, David L. [Department

2017-09-12

A combination of XAS, UV–vis, NMR, and EPR was used to examine the binding of a series of α-hydroxythiones to CoCA. All three appear to bind preferentially in their neutral, protonated forms. Two of the three clearly bind in a monodentate fashion, through the thione sulfur alone. Thiomaltol (TM) appears to show some orientational preference, on the basis of the NMR, while it appears that thiopyromeconic acid (TPMA) retains rotational freedom. In contrast, allothiomaltol (ATM), after initially binding in its neutral form, presumably through the thione sulfur, forms a final complex that is five-coordinate via bidentate coordination of ATM. On the basis of optical titrations, we speculate that this may be due to the lower initial pKa of ATM (8.3) relative to those of TM (9.0) and TPMA (9.5). Binding through the thione is shown to reduce the hydroxyl pKa by ~0.7 pH unit on metal binding, bringing only ATM’s pKa close to the pH of the experiment, facilitating deprotonation and subsequent coordination of the hydroxyl. The data predict the presence of a solvent-exchangeable proton on TM and TPMA, and Q-band 2-pulse ESEEM experiments on CoCA + TM suggest that the proton is present. ESE-detected EPR also showed a surprising frequency dependence, giving only a subset of the expected resonances at X-band.

State-of-the-art coordination chemistry of radioactive elements

International Nuclear Information System (INIS)

Kharisov, B I; Mendez-Rojas, Miguel A

2001-01-01

Modern procedures for the synthesis of coordination and organometallic compounds of actinides and technetium and the properties of these compounds are surveyed. Experimental techniques, including methods for the synthesis of actinide and technetium complexes from elemental metals (oxidative dissolution and direct electrosynthesis), salts and halide, carbonyl and other complexes are generalised. The bibliography includes 283 references.

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.

CO chemistry/research trends in CO chemistry in the US

Energy Technology Data Exchange (ETDEWEB)

Cantacuzene, M

1978-10-01

Research trends in CO chemistry in the U.S. include the development of stable and selective homogeneous catalysts which would facilitate the removal of the heat of reaction and be resistant to sulfur poisoning for the methanation reaction, methanol synthesis, and Fischer-Tropsch synthesis; development of low-temperature homogeneous water gas shift catalysts; and research on the coordination chemistry and photochemical conversions of CO/sub 2/. In 1977, the National Science Foundation awarded 16 contracts for a total of $720,000 to promote the research in this field, including studies on chemisorption and heterogeneous catalysis (four contracts) and on transition metal complexes (ten contracts, of which seven are dedicated to metal clusters). Carbon monoxide-based processes, including water gas shift reactions, CO reduction to alkanes and alcohols, hydroformylation, and homogeneous carbonylation processes, recently developed in the U.S. are listed.

Elementary steps of the catalytic oxidation of CO in a gas phase in the presence of rhenium cations with carbonyl and oxygen ligands: a comparison with heterogeneous catalysis

International Nuclear Information System (INIS)

Goncharov, V.B.; Fialko, E.F.; Shejnin, D.Eh.; Kikhtenko, A.V.

1997-01-01

Reactivity in a gaseous phase o rhenium (Re + ) and rhenium monocarbonyl (ReCO + ) in the reaction of CO oxidation in oxygen-containing reagents (NO, O 2 , H 2 O) is studied through the method of the ionic cyclotron resonance. It is shown that presence of carbonyl ligand essentially influences the ion reactivity. The effective channel of the metal monocarbonyl ions oxidation through molecular oxygen is found. Accounting for this stage makes of possible to explain the low-temperature activity of a number of oxide catalyzer Mo, W in the reaction of CO oxidation by molecular oxygen

Mass spectrometry of rhenium complexes: a comparative study by using LDI-MS, MALDI-MS, PESI-MS and ESI-MS.

Science.gov (United States)

Petroselli, Gabriela; Mandal, Mridul Kanti; Chen, Lee Chuin; Ruiz, Gustavo T; Wolcan, Ezequiel; Hiraoka, Kenzo; Nonami, Hiroshi; Erra-Balsells, Rosa

2012-03-01

A group of rhenium (I) complexes including in their structure ligands such as CF(3)SO(3)-, CH(3)CO(2)-, CO, 2,2'-bipyridine, dipyridil[3,2-a:2'3'-c]phenazine, naphthalene-2-carboxylate, anthracene-9-carboxylate, pyrene-1-carboxylate and 1,10-phenanthroline have been studied for the first time by mass spectrometry. The probe electrospray ionization (PESI) is a technique based on electrospray ionization (ESI) that generates electrospray from the tip of a solid metal needle. In this work, mass spectra for organometallic complexes obtained by PESI were compared with those obtained by classical ESI and high flow rate electrospray ionization assisted by corona discharge (HF-ESI-CD), an ideal method to avoid decomposition of the complexes and to induce their oxidation to yield intact molecular cation radicals in gas state [M](+·) and to produce their reduction yielding the gas species [M](-·). It was found that both techniques showed in general the intact molecular ions of the organometallics studied and provided additional structure characteristic diagnostic fragments. As the rhenium complexes studied in the present work showed strong absorption in the UV-visible region, particularly at 355 nm, laser desorption ionization (LDI) mass spectrometry experiments could be conducted. Although intact molecular ions could be detected in a few cases, LDI mass spectra showed diagnostic fragments for characterization of the complexes structure. Furthermore, matrix-assisted laser desorption ionization (MALDI) mass spectra were obtained. Nor-harmane, a compound with basic character, was used as matrix, and the intact molecular ions were detected in two examples, in negative ion mode as the [M](-·) species. Results obtained with 2-[(2E)-3-(4-tert-buthylphenyl)-2-methylprop-2-enylidene] malononitrile (DCTB) as matrix are also described. LDI experiments provided more information about the rhenium complex structures than did the MALDI ones. Copyright © 2012 John Wiley & Sons, Ltd.

Rhenium(5) and molybdenum(5) complexes with 4',4(5)-divaleryldibenzo-18-crown-6

International Nuclear Information System (INIS)

Ashurova, N.Kh.; Yakubov, K.G.; Tashmukhamedova, A.K.; Basitova, S.M.

1993-01-01

Methods for synthesizing oxohalide complexes of rhenium and molybdenum with +5 oxidation degree with 4',4 (5) -divaleryldibenzo-18-crown-6 were developed. Content and composition of prepared compounds were investigated by the methods of element analysis, crystal optics, conductometry, IR spectroscopy in the near and far regions, thermogravimetry. Oxidation degree of the complex-forming metal was determined. It was established that composition of the compounds coressponded to the general formula MOLX · H 2 O, where M - Re, Mo; L -4',4 (5) -divaleryldibenzo-18-crown-6; X -Cl - , Br -

Chemistry of supramolecular systems containing porphyrins and metal complexes

OpenAIRE

Araki, Koiti; Toma, Henrique Eisi

2002-01-01

Supramolecular chemistry is expected to keep a high developing pace in the next years, giving support to the advancement of molecular devices and nanotechnology. In this sense, porphyrins and their analogues should play a significant role as a consequence of their catalytic, electrocatalytic, photochemical and photoelectrochemical properties. In this review we focused on our own strategy based on coordination chemistry for the design and build-up of supermolecules and supramolecular structure...

Mechanical properties of tungsten following rhenium ion and helium plasma exposure

Directory of Open Access Journals (Sweden)

C.S. Corr

2017-08-01

Full Text Available Mechanical properties of Tungsten (W samples irradiated with 2 MeV Rhenium (Re ions and helium (He plasma were investigated using nanoindentation. It was found that there was an increase in hardness for all samples following separate irradiation with both Re ion and He plasma. A slight increase in hardness was obtained for combined exposures. A comparable increase in hardness was observed for a pure He plasma with a sample temperature of 473 K and 1273 K. Optical interferometry was employed to compare surface modification of the samples. Grazing incidence small angle x-ray scattering confirmed He nano-bubble formation of approximately 1 nm diameter in the higher temperature sample, which was not observed with samples at the lower temperatures.

Actinide chemistry in the far field

International Nuclear Information System (INIS)

Livens, F.R.; Morris, K.; Parkman, R.; Moyes, L.

1996-01-01

The environmental chemistry of the actinides is complicated due both to the extensive redox and coordination chemistry of the elements and also to the complexity of the reactive phases encountered in natural environments. In the far field, interactions with reactive surfaces, coatings and colloidal particles will play a crucial role in controlling actinide mobility. By virtue of both their abundance and reactivity; clays and other layer aluminosilicate minerals, hydrous oxides and organic matter (humic substances) are all identified as having the potential to react with actinide ions and some possible modes of interaction are described, together with experimental evidence for their occurrence. (author)

"Low-coordinate" 1,2-oxaphosphetanes - a new opportunity in coordination and main group chemistry.

Science.gov (United States)

Kyri, A W; Gleim, F; García Alcaraz, A; Schnakenburg, G; Espinosa Ferao, A; Streubel, R

2018-05-17

While 1,2σ5λ5-oxaphosphetanes are well known intermediates from the Wittig-reaction, no 1,2σ3λ3-oxaphosphetanes have been described, so far. Herein, we present the first synthesis of 1,2σ3λ3-oxaphosphetanes derived from their κP-Mo(CO)5 complexes and first investigations towards metal coordination and P-oxidation. Bonding, ring strain energy and potential retro-[2+2] cycloaddition reactions of the 1,2-oxaphosphetane ring were studied by DFT methods.

Rhenium Dichalcogenides: Layered Semiconductors with Two Vertical Orientations.

Science.gov (United States)

Hart, Lewis; Dale, Sara; Hoye, Sarah; Webb, James L; Wolverson, Daniel

2016-02-10

The rhenium and technetium diselenides and disulfides are van der Waals layered semiconductors in some respects similar to more well-known transition metal dichalcogenides (TMD) such as molybdenum sulfide. However, their symmetry is lower, consisting only of an inversion center, so that turning a layer upside-down (that is, applying a C2 rotation about an in-plane axis) is not a symmetry operation, but reverses the sign of the angle between the two nonequivalent in-plane crystallographic axes. A given layer thus can be placed on a substrate in two symmetrically nonequivalent (but energetically similar) ways. This has consequences for the exploitation of the anisotropic properties of these materials in TMD heterostructures and is expected to lead to a new source of domain structure in large-area layer growth. We produced few-layer ReS2 and ReSe2 samples with controlled "up" or "down" orientations by micromechanical cleavage and we show how polarized Raman microscopy can be used to distinguish these two orientations, thus establishing Raman as an essential tool for the characterization of large-area layers.

Magnetic relaxation in analytical, coordination and bioinorganic chemistry

International Nuclear Information System (INIS)

Mikhajlov, O.

1982-01-01

Nuclear magnetic relaxation is a special type of nuclear magnetic resonance in which the rate is measured of energy transfer between the excited nuclei and their molecular medium (spin-lattice relaxation) or the whole nuclear spin system (spin-spin relaxation). Nuclear magnetic relaxation relates to nuclei with a spin of 1/2, primarily H 1 1 , and is mainly measured in water solutions. It is suitable for (1) analytical chemistry because the relaxation time rapidly reduces in the presence of paramagnetic ions, (2) the study of complex compounds, (3) the study of biochemical reactions in the presence of different metal ions. It is also suitable for testing the composition of a flowing liquid. Its disadvantage is that it requires complex and expensive equipment. (Ha)

Superhard Rhenium/Tungsten Diboride Solid Solutions.

Science.gov (United States)

Lech, Andrew T; Turner, Christopher L; Lei, Jialin; Mohammadi, Reza; Tolbert, Sarah H; Kaner, Richard B

2016-11-02

Rhenium diboride (ReB 2 ), containing corrugated layers of covalently bonded boron, is a superhard metallic compound with a microhardness reaching as high as 40.5 GPa (under an applied load of 0.49 N). Tungsten diboride (WB 2 ), which takes a structural hybrid between that of ReB 2 and AlB 2 , where half of the boron layers are planar (as in AlB 2 ) and half are corrugated (as in ReB 2 ), has been shown not to be superhard. Here, we demonstrate that the ReB 2 -type structure can be maintained for solid solutions of tungsten in ReB 2 with tungsten content up to a surprisingly large limit of nearly 50 atom %. The lattice parameters for the solid solutions linearly increase along both the a- and c-axes with increasing tungsten content, as evaluated by powder X-ray and neutron diffraction. From micro- and nanoindentation hardness testing, all of the compositions within the range of 0-48 atom % W are superhard, and the bulk modulus of the 48 atom % solid solution is nearly identical to that of pure ReB 2 . These results further indicate that ReB 2 -structured compounds are superhard, as has been predicted from first-principles calculations, and may warrant further studies into additional solid solutions or ternary compounds taking this structure type.

Photocatalytic Conversion of CO2 to CO using Rhenium Bipyridine Platforms Containing Ancillary Phenyl or BODIPY Moieties

Science.gov (United States)

Andrade, Gabriel A.; Pistner, Allen J.; Yap, Glenn P.A.; Lutterman, Daniel A.; Rosenthal, Joel

2013-01-01

Harnessing of solar energy to drive the reduction of carbon dioxide to fuels requires the development of efficient catalysts that absorb sunlight. In this work, we detail the synthesis, electrochemistry and photophysical properties of a set of homologous fac-ReI(CO)3 complexes containing either an ancillary phenyl (8) or BODIPY (12) substituent. These studies demonstrate that both the electronic properties of the rhenium center and BODIPY chromophore are maintained for these complexes. Photolysis studies demonstrate that both assemblies 8 and 12 are competent catalysts for the photochemical reduction of CO2 to CO in DMF using triethanolamine (TEOA) as a sacrificial reductant. Both compounds 8 and 12 display TOFs for photocatalytic CO production upon irradiation with light (λex ≥ 400 nm) of ~5 hr−1 with TON values of approximately 20. Although structural and photophysical measurements demonstrate that electronic coupling between the BODIPY and fac-ReI(CO)3 units is limited for complex 12, this work clearly shows that the photoactive BODIPY moiety is tolerated during catalysis and does not interfere with the observed photochemistry. When taken together, these results provide a clear roadmap for the development of advanced rhenium bipyridine complexes bearing ancillary BODIPY groups for the efficient photocatalytic reduction of CO2 using visible light. PMID:24015374

(Chemistry of the global atmosphere)

Energy Technology Data Exchange (ETDEWEB)

Marland, G.

1990-09-27

The traveler attended the conference The Chemistry of the Global Atmosphere,'' and presented a paper on the anthropogenic emission of carbon dioxide (CO{sub 2}) to the atmosphere. The conference included meetings of the International Global Atmospheric Chemistry (IGAC) programme, a core project of the International Geosphere/Biosphere Programme (IGBP) and the traveler participated in meetings on the IGAC project Development of Global Emissions Inventories'' and agreed to coordinate the working group on CO{sub 2}. Papers presented at the conference focused on the latest developments in analytical methods, modeling and understanding of atmospheric CO{sub 2}, CO, CH{sub 4}, N{sub 2}O, SO{sub 2}, NO{sub x}, NMHCs, CFCs, and aerosols.

Physical chemistry of the interface between oxide and aqueous solution

International Nuclear Information System (INIS)

Jolivet, J.P.

1997-01-01

The behavior and properties of small oxide particles in aqueous suspension are dominated by the physico-chemistry of their surface. It is electrostatically charged and strongly solvated. The origin of the surface charge is discussed through the MUSIC model [Hiemstra 1996], allowing to estimate the acid-base behavior of surface oxygen atoms. The stability of aqueous dispersions of particles is analysed following the DLVO model, with a special attention on the hydration layers allowing the peptization of flocs. Different adsorption mechanisms of metal cations are presented in terms of coordination chemistry (outer- and inner-sphere complexes) emphasizing the coordinating ability of the surface towards metal complexes in solution. The anion adsorption is also studied in relation with some interesting consequences on spinel iron oxide nano-particles. (author)

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.

Applications of chiroptical spectroscopy to coordination compounds

Czech Academy of Sciences Publication Activity Database

Wu, Tao; You, X. Z.; Bouř, Petr

2015-01-01

Roč. 284, SI (2015), s. 1-18 ISSN 0010-8545 R&D Projects: GA ČR GA13-03978S; GA ČR GAP208/11/0105 Grant - others:GA AV ČR(CZ) M200550902 Institutional support: RVO:61388963 Keywords : chirality * coordination compounds * chiroptical spectroscopy * new materials Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.994, year: 2015

Moving Green Chemistry Forward: Networks as a Foundation

Science.gov (United States)

Carter, T.; Lough, G.

2014-12-01

Green chemistry is a growing discipline, but for a variety of reasons, it has not yet become integrated into science curriculum and the greater societal conscience. With its increasing economic benefits to many sectors including business, industry, and academia and its potential to make science more accessible not only to science students but also to the general citizenry, we suggested answers to the questions: Why has greater success not been realized? What are the particular barriers to wider implementation? And what are incentives and ways to move green chemistry forward? We suggest some strategies and options to both increase the use of green chemistry principles and to also increase stakeholders' understanding of the importance and utility of green chemistry in their daily lives. For example, our main suggestions are that an inclusive, multidisciplinary network would aid in coordinating data and in translating the science into user friendly tools, and that an educational component embedded in this greater effort would also serve to move green chemistry forward.

Coordination chemistry of the tiing tris(2-sallicilamidoetil)amina

International Nuclear Information System (INIS)

Fernandez Montalto, A. C.

1997-01-01

Synthesizes a new one tiing hexadented denominated tris (2-salicilamidoetil)amina, starting from the tris (2-aminoetil) amina and three equivalent of fenilo salicilato (salol). The aductos that are formed starting from this tiing with metallic ions of transition di- and trivalent, they are complex of the type LHM and LM respectively, showing a sphere of coordination pseudooctaedrica. The complex Lfe, Lcr and LHCu were synthesized, which were characterized by means of methods spectroscopy and magnetic [es

Catalytic transformation of functionalized carboxylic acids using multifunctional rhenium complexes.

Science.gov (United States)

Naruto, Masayuki; Agrawal, Santosh; Toda, Katsuaki; Saito, Susumu

2017-06-13

Carboxylic acids (CAs) are one of the most ubiquitous and important chemical feedstocks available from biorenewable resources, CO 2 , and the petrochemical industry. Unfortunately, chemoselective catalytic transformations of CH n CO 2 H (n = 1-3) groups into other functionalities remain a significant challenge. Herein, we report rhenium V complexes as extremely effective precatalysts for this purpose. Compared to previously reported heterogeneous and homogeneous catalysts derived from high- or low-valent metals, the present method involves a α-C-H bond functionalization, a hydrogenation, and a hydrogenolysis, which affords functionalized alcohols with a wide substrate scope and high chemoselectivity under relatively mild reaction conditions. The results represent an important step toward a paradigm shift from 'low-valent' to 'high-valent' metal complexes by exploring a new portfolio of selective functional group transformations of highly oxygenated organic substrates, as well as toward the exploitation of CAs as a valuable biorenewable feedstock.

Yearly scientific meeting: chemistry in human health and environment protection. Bialystok'92

International Nuclear Information System (INIS)

1992-01-01

The conference has been divided into 12 sections devoted to following topics: analytical chemistry; environmental chemistry; chemistry of natural compounds; chemistry of pharmaceutics and toxic compounds; chemistry in medicine; electrochemistry; young scientists forum; didactics and history of chemistry; chemistry and industry - technologies environment friendly; new trends in polymer science; crystallochemistry; pro-ecological actions in leather industry. Different analytical methods for determination of heavy methods and rare earths have been presented. Some of them have been successfully applied for the examination of environmental and biological materials. The basic chemical and physico-chemical studies including thermodynamic, crystal structure, coordination chemistry, sorption properties etc. have been extensively resented. The existence of radioactive elements in environment has been also investigated, especially in respect to municipal and industrial wastes and products of their processing. The radiation effects for different materials have been reported and discussed as well

Heterobimetallic coordination polymers involving 3d metal complexes and heavier transition metals cyanometallates

Energy Technology Data Exchange (ETDEWEB)

Peresypkina, Eugenia V. [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Samsonenko, Denis G. [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Vostrikova, Kira E., E-mail: vosk@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); LMI, Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France)

2015-04-15

The results of the first steps in the design of coordination polymers based on penta- and heptacyanometallates of heavier d transitions metals are presented. The 2D structure of the coordination polymers: [(Mn(acacen)){sub 2}Ru(NO)(CN){sub 5}]{sub n} and two complexes composed of different cyanorhenates, [Ni(cyclam)]{sub 2}[ReO(OH)(CN){sub 4}](ClO{sub 4}){sub 2}(H{sub 2}O){sub 1.25} and [Cu(cyclam)]{sub 2}[Re(CN){sub 7}](H{sub 2}O){sub 12}, was confirmed by single crystal XRD study, the rhenium oxidation state having been proved by the magnetic measurements. An amorphism of [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2} (M=Ni, Cu) polymers does not allow to define strictly their dimensionality and to model anisotropic magnetic behavior of the compounds. However, with high probability a honey-comb like layer structure could be expected for [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2} complexes, studied in this work, because such an arrangement is the most common among the bimetallic assemblies of hexa- and octacyanometallates with a ratio [M(cyclam)]/[M(CN){sub n}]=3/2. For the first time was prepared and fully characterized a precursor (n-Bu{sub 4}N){sub 2}[Ru(NO)(CN){sub 5}], soluble in organic media. - Graphical abstract: The very first results in the design of 2D coordination polymers based on penta- and heptacyanometallates of 4d and5d transitions metals are presented. - Highlights: • Design of coordination polymers based on penta- and heptacyanometallates. • New Ru and Re cyanide based heterobimetallic coordination complexes. • Hydrolysis and ox/red processes involving [Re(CN){sub 7}]{sup 3+} during crystallization. • High magnetic anisotropy of [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2}(H{sub 2}O){sub n}, M=Cu, Ni, complexes.

Experimental determination of the hydrothermal solubility of ReS2 and the Re–ReO2 buffer assemblage and transport of rhenium under supercritical conditions

Directory of Open Access Journals (Sweden)

Wood Scott A

2002-01-01

Full Text Available To understand the aqueous species important for transport of rhenium under supercritical conditions, we conducted a series of solubility experiments on the Re–ReO2 buffer assemblage and ReS2. In these experiments, pH was buffered by the K–feldspar–muscovite–quartz assemblage; in sulfur-free systems was buffered by the Re–ReO2 assemblage; and and in sulfur-containing systems were buffered by the magnetite–pyrite–pyrrhotite assemblage. Our experimental studies indicate that the species ReCl40 is dominant at 400°C in slightly acidic to near-neutral, and chloride-rich (total chloride concentrations ranging from 0.5 to 1.0 M environments, and ReCl3+ may predominate at 500°C in a solution with total chloride concentrations ranging from 0.5 to 1.5 M. The results also demonstrate that the solubility of ReS2 is about two orders of magnitude less than that of ReO2. This finding not only suggests that ReS2 (or a ReS2 component in molybdenite is the solubility-controlling phase in sulfur-containing, reducing environments but also implies that a mixing process involving an oxidized, rhenium-containing solution and a solution with reduced sulfur is one of the most effective mechanisms for deposition of rhenium. In analogy with Re, TcS2 may be the stable Tc-bearing phase in deep geological repositories of radioactive wastes.

Tracing oxidative weathering from the Andes to the lowland Amazon Basin using dissoved rhenium

Science.gov (United States)

Dellinger, M.; Hilton, R. G.; West, A. J.; Torres, M.; Burton, K. W.; Clark, K. E.; Baronas, J. J.

2016-12-01

Over long timescales (>105 yrs), the abundance of carbon dioxide (CO2) in the atmosphere is determined by the balance of the major carbon sources and sinks. Among the major carbon sources, the oxidation of organic carbon contained within sedimentary rocks ("petrogenic" carbon, or OCpetro) is thought to result in CO2 emission of similar magnitude to that released by volcanism. Rhenium (Re) has been proposed as a proxy for tracing OCpetro oxidation. Here we investigate the source, behavior and flux of dissolved and particulate rhenium (Re) in the Madre de Dios watershed (a major Andean tributary of the Amazon River) and the lowlands, aiming to characterize the behavior of Re in river water and quantify the flux of CO2 released by OCpetro oxidation. Measured Re concentrations in Andean rivers range from 0.07 to 1.55 ppt. In the Andes, Re concentration do not change significantly with water discharge, whereas in the lowlands, Re concentration decrease at high water discharge. Mass balance calculation show that more than 70% of the dissolved Re is sourced from the oxidation of OCpetro the Andes-floodplain system. We calculate dissolved Re flux over a hydrological year to estimate the rates of oxidative weathering, and the associated CO2 release from OCpetro. Rates are high in the Andean headwaters, consistent with estimates from other mountain rivers with similar rates of physical erosion. We find evidence that a significant amount of additional oxidation (Re flux) happens during floodplain transport. These results have important implications for improving our understanding of the source and processes controlling Re in rivers, and allowing us to quantify long-term OCpetro cycling in large river basins.

Unusual metal coordination chemistry from an amino-amide derivative of 4-nitrophenol, a surprising ligand

DEFF Research Database (Denmark)

McGinley, John; McKee, Vickie; Toftlund, Hans

2009-01-01

The simple ligand N-(2-aminoethyl)-2-hydroxy-5-nitrobenzamide () exhibits several coordination modes depending on the reaction conditions, acting as a zwitterion on its own or being ionic in the presence of acid and depending on the concentration of metal present in a reaction, it can coordinate...... to the metal in either a 1:1 or a 1:2 metal:ligand mode. Furthermore, the role of solvent plays an important role in these complexation reactions with both four and six coordinate copper complexes being obtained using water as solvent but only six coordinate copper complexes obtained using acetonitrile...

Correlation between catalytic activity and bonding and coordination number of atoms and molecules on transition metal surfaces: theory and experimental evidence

International Nuclear Information System (INIS)

Falicov, L.M.; Somorjai, G.A.

1985-01-01

Correlation between catalytic activity and low-energy local electronic fluctuation in transition metals is proposed. A theory and calculations are presented which indicate that maximum electronic fluctuants take place at high-coordination metal sites. Either (i) atomically rough surfaces that expose to the reactant molecules atoms with large numbers of nonmagnetic or weakly magnetic neighbors in the first or second layer at the surface or (ii) stepped and kinked surfaces are the most active in carrying out structure-sensitive catalytic reactions. The synthesis of ammonia from N 2 and H 2 over iron and rhenium surfaces, 1 H 2 / 2 H 2 exchange over stepped platinum crystal surfaces at low pressures, and the hydrogenolysis (C - C bond breaking) of isobutane at kinked platinum crystal surfaces are presented as experimental evidence in support of the theory

Effect of rhenium and osmium on mechanical properties of a 9Cr-2W-0.25V-0.07Ta-0.1C steel

International Nuclear Information System (INIS)

Klueh, R.L.; Alexander, D.J.; Sokolov, M.A.

2000-01-01

The nuclear transmutation of tungsten to rhenium and osmium in a tungsten-containing steel irradiated in a fission or fusion reactor will change the chemical composition of the steel. To determine the possible consequences of such compositional changes on the mechanical properties, tensile and Charpy impact properties were measured on five 9Cr-2W-0.25V-0.07Ta-0.1C steels that contained different amounts of rhenium, osmium, and tungsten. The mechanical properties changes caused by these changes in composition were minor. Observations were also made on the effect of carbon concentration. The effect of carbon on tensile behavior was minor, but there was a large effect on Charpy properties. Several of the steels showed little effect of tempering temperature on the Charpy transition temperature, a behavior that was tentatively attributed to the low silicon and/or manganese concentration of the experimental steels

Absorption behavior of technetium and rhenium through plant roots

International Nuclear Information System (INIS)

Tagami, K.; Uchida, S.

2004-01-01

The absorption behavior of technetium (Tc) and rhenium (Re) through plant roots was studied using nutrient solution culture. Radish samples, grown in culture solutions for 20-30 days in a green house, were transferred into plastic vessels containing nutrient solutions contaminated with multi-tracer solutions including Tc-95m and Re-183. The plant samples were grown individually for 1-7 days under laboratory conditions. The activities of radionuclides in nutrient solutions and oven-dried plant parts (roots, fleshy roots and leaves) were measured with Ge detecting systems. The concentrations of Tc-95m and Re-183 in the nutrient solutions after harvesting the plants were almost the same as those in the initial solution. Possibly, the radionuclides were taken up with water through plant roots. The distributions of Tc and Re in the plants showed no differences, thus, soluble Tc and Re absorption by plant samples were the same. It is suggested that Re could be used as a geochemical tracer of Tc in the soil environment. (author)

A tungsten-rhenium interatomic potential for point defect studies

Science.gov (United States)

Setyawan, Wahyu; Gao, Ning; Kurtz, Richard J.

2018-05-01

A tungsten-rhenium (W-Re) classical interatomic potential is developed within the embedded atom method interaction framework. A force-matching method is employed to fit the potential to ab initio forces, energies, and stresses. Simulated annealing is combined with the conjugate gradient technique to search for an optimum potential from over 1000 initial trial sets. The potential is designed for studying point defects in W-Re systems. It gives good predictions of the formation energies of Re defects in W and the binding energies of W self-interstitial clusters with Re. The potential is further evaluated for describing the formation energy of structures in the σ and χ intermetallic phases. The predicted convex-hulls of formation energy are in excellent agreement with ab initio data. In pure Re, the potential can reproduce the formation energies of vacancies and self-interstitial defects sufficiently accurately and gives the correct ground state self-interstitial configuration. Furthermore, by including liquid structures in the fit, the potential yields a Re melting temperature (3130 K) that is close to the experimental value (3459 K).

On the coordination chemistry of humic materials

International Nuclear Information System (INIS)

Grauer, R.

1989-01-01

Dissolved humic materials form ligands which can influence the speciation of certain radionuclides in natural waters and it is necessary to take account of this phenomenon in repository safety assessment model calculations. There are no models available which give a basic description of the wide range of complexation properties of humic materials with dissolved metals and which are based on a chemically meaningful background. All of these models make very drastic simplifications and, although capable of reproducing experimental data, they do not allow any extrapolation to ranges of concentration outside those covered by the experiments. Humic materials affect not only the solution chemistry of the metals but also their sorption onto minerals. The mineral surfaces are modified through adsorption of organic material which in turn alters their sorption properties. These processes are understood in qualitative terms. It is unlikely that a comprehensive predictive model of complexation by humic materials will be available in the foreseeable future. It is therefore suggested that experiments which provide an empirical description of the metal/humic material interaction using realistic pH values and metal/ligand ratios be carried out. Besides parameter studies and experiments in synthetic or formation waters, analogue studies could also serve as a useful tool. 132 refs., 51 figs., 12 tabs

Symposium on chemistry and biotechnology for national development. Proceedings

International Nuclear Information System (INIS)

Garba, A.; Ogunmola, G.B.

1998-01-01

This document is the full proceedings of the symposium on chemistry and biotechnology for national development held at SHESTCO in 1995. It contains the full texts of a forward, opening and special remarks, welcome and keynote addresses and abstracts and texts of 21 technical papers. The subjects covered included information technology,chemistry and biotechnology in agriculture, health care and industrial development. Additionally, the abstracts in respect of 19 other papers are included. We wish to thank the Coordinator of SHESTCO for making available this proceedings

Symposium on chemistry and biotechnology for national development. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Garba, A; Ogunmola, G B [eds.

1998-12-01

This document is the full proceedings of the symposium on chemistry and biotechnology for national development held at SHESTCO in 1995. It contains the full texts of a forward, opening and special remarks, welcome and keynote addresses and abstracts and texts of 21 technical papers. The subjects covered included information technology,chemistry and biotechnology in agriculture, health care and industrial development. Additionally, the abstracts in respect of 19 other papers are included. We wish to thank the Coordinator of SHESTCO for making available this proceedings.

The coordination chemistry of macrocyclic ligands II

International Nuclear Information System (INIS)

Klimes, J.; Knoechel, A.; Rudolph, G.

1977-01-01

Compounds of UO 2 (NO 3 ) 2 .6H 2 0 or Th(NO 3 ) 4 .5H 2 0 with five selected crown ethers were prepared according to the method described in Knoeckel et al., Inorg.Nucl.Chem.Lett.; 11:787 (1975). The products were characterized by chemical analysis, NMR, IR and Raman spectroscopy. The results are analyzed and discussed. It is shown that the NO 3 groups remain free after combination, and the H 2 0 groups form the bonds to the polyether. It is concluded that the polyether molecule is attached to two units of UO 2 (NO 3 ) 2 .2H 2 0 (or Th(NO 3 ) 4 .3H 2 0), one each side of the polyether. This would be contrary to the assumption in previous publications, that the U0 2 2+ and Th 4+ ions were coordinated inside the macrocyclic ligand structure. The present hypothesis, however, agrees with a recently published x-ray structure for the uranium compound. In view of the new proposed structure it is suggested that the compounds should be regarded as adducts rather than complexes. (U.K.)

Structure analysis in algorithms and programs. Generator of coordinates of equivalent points. (Collected programs)

International Nuclear Information System (INIS)

Matyushenko, N.N.; Titov, Yu.G.

1982-01-01

Programs of atom coordinate generation and space symmetry groups in a form of equivalent point systems are presented. Programs of generation and coordinate output from an on-line storage are written in the FORTRAN language for the ES computer. They may be used in laboratories specialized in studying atomic structure and material properties, in colleges and by specialists in other fields of physics and chemistry

Rhenium(V) and technetium(V) complexes of bis(o-hydroxyphenyl)phenylphosphine (PO22-) and (o-hydroxyphenyl)diphenylphosphine (PO-) ligands

International Nuclear Information System (INIS)

Luo, Hongyan; Setyawati, Ika; Rettig, S.J.; Orvig, C.

1995-01-01

The synthesis of several phosphine-based chelating compounds and chelates formed between these compounds and rhenium or technetium is discussed. Four categories of products result, (i) bis-(o-hydroxyphenyl) diphenylphosphine (PO) complexes, (ii) mono- (PO) complexes, (iii) bis-bis(o-hydroxyphenyl)-phenylphosphine (PO 2 ) complexes, and mixed-(PO) and (PO 2 ) complexes. Molecular structures of these compounds (including isomers) were probed by NMR, MS, and IR spectroscopies and by X-ray crystallography

Rhenium-188: Availability from the W-188/Re-188 Generator and Status of Current Applications

International Nuclear Information System (INIS)

Pillai, M.R.A.; Dash, A.; Knapp, Russ F. Jr.

2012-01-01

Rhenium-188 is one of the most readily available generator derived and useful radionuclides for therapy emitting β-particles (2.12 MeV, 71.1% and 1.965 MeV, 25.6%) and imageable gammas (155 KeV, 15.1%). The 188W/188Re generator is an ideal source for the long term (4-6 months) continuous availability of no carrier added (nca) 188Re suitable for the preparation of radiopharmaceuticals for radionuclide therapy. The challenges associated with the double neutron capture route of production of the parent 188W radionuclide have been a major impediment in the progress of application of 188Re. Tungsten-188 of adequate specific activity can be prepared only in 2-3 of the high flux reactors operating in the World. Several useful technologies have been developed for the preparation of clinical grade 188W/188Re generator. Since the specific activity of 188W used in the generator is relatively low (<5 Ci/g), the eluted 188ReO4- can have low radioactive concentration often insufficient for radiopharmaceutical preparation. However, several efficient post elution concentration techniques have been developed that yield clinically useful 188ReO4-. Rhenium-188 has been used for the preparation of therapeutic radiopharmaceuticals for the management of diseases such as bone metastasis, rheumatoid arthritis and primary cancers. Several early phase clinical studies using radiopharmaceuticals based on 188Re-labeled phosphonates, antibodies, peptides, lipiodol and particulates have been reported. This article reviews the availability, and use of188Re including a discussion of why broader use of 188Re has not progressed as ecpected as a popular radionuclide for therapy.

Amorphous infinite coordination polymer microparticles: a new class of selective hydrogen storage materials

Energy Technology Data Exchange (ETDEWEB)

Jeon, You-Moon; Heo, Jungseok; Mirkin, Chad A [Department of Chemistry, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL (United States); Armatas, Gerasimos S [Department of Chemistry, Northwestern University, Evanston, IL (United States); Kanatzidis, Mercouri G [Materials Science Division, Argonne National Laboratory, Argonne, IL (United States)

2008-06-04

A new class of micrometer-sized amorphous infinite coordination particles is selectively prepared from the coordination chemistry of a metallo-salen building block and Zn{sup 2+} ions. The particles show moderately high H{sub 2} uptake and almost no N{sub 2} adsorption, even though they are amorphous and do not have the well-defined channels typically used to explain such selectivity in metal-organic framework systems. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

PWR water chemistry controls: a perspective on industry initiatives and trends relative to operating experience and the EPRI PWR water chemistry guidelines

International Nuclear Information System (INIS)

Fruzzetti, K.; Choi, S.; Haas, C.; Pender, M.; Perkins, D.

2010-01-01

An effective PWR water chemistry control program must address the following goals: Minimize materials degradation (e.g., PWSCC, corrosion of fuel, corrosion damage of steam generator (SG) tubes); Maintain fuel integrity and good performance; Minimize corrosion product transport (e.g., transport and deposition on the fuel, transport into the SGs where it can foul tube surfaces and create crevice environments for the concentration of corrosive impurities); Minimize dose rates. Water chemistry control must be optimized to provide overall improvement considering the sometimes variant constraints of the goals listed above. New technologies are developed for continued mitigation of materials degradation, continued fuel integrity and good performance, continued reduction of corrosion product transport, and continued minimization of plant dose rates. The EPRI chemistry program, in coordination with other EPRI programs, strives to improve these areas through application of chemistry initiatives, focusing on these goals. This paper highlights the major initiatives and issues with respect to PWR primary and secondary system chemistry and outlines the recent, on-going, and proposed work to effectively address them. These initiatives are presented in light of recent operating experience, as derived from EPRI's PWR chemistry monitoring and assessment program, and EPRI's water chemistry guidelines. (author)

Synthesis, characterization, and photophysical properties of a thiophene-functionalized bis(pyrazolyl) pyridine (BPP) tricarbonyl rhenium(I) complex.

Science.gov (United States)

Lytwak, Lauren A; Stanley, Julie M; Mejía, Michelle L; Holliday, Bradley J

2010-09-07

A bromo tricarbonyl rhenium(I) complex with a thiophene-functionalized bis(pyrazolyl) pyridine ligand (L), ReBr(L)(CO)(3) (1), has been synthesized and characterized by variable temperature and COSY 2-D (1)H NMR spectroscopy, single-crystal X-ray diffraction, and photophysical methods. Complex 1 is highly luminescent in both solution and solid-state, consistent with phosphorescence from an emissive (3)MLCT excited state with an additional contribution from a LC (3)(pi-->pi*) transition. The single-crystal X-ray diffraction structure of the title ligand is also reported.

Evaluation of a new component used for isotopic lymphography: colloidal rhenium sulfide sup(99m)Tc labelled

International Nuclear Information System (INIS)

Pecking, A.; Le Mercier, N.; Gobin, R.; Bardy, A.; Najean, Y.

1978-01-01

We have studied for lymphatic scintigraphy a new radiopharmaceutical, sup(99m)Tc-labelled rhenium sulfocolloid. This preliminary study includes 20 adults patients with lymphomas and lymphoedemas. The principal advantage of this drug is its absence of toxicity and local pain, so that a rapid sub-cutaneous injection without local anesthesia is made possible. Good results have been obtained, as well in morphological studies of para-aortic and mammary lymph nodes as for kinetic studies of lymphatic flow in lymphoedemas. No liver and spleen uptake of radio-isotope was observed after foot injection [fr

Bio-organic chemistry at BARC

International Nuclear Information System (INIS)

Sharma, A.; Ghosh, S.K.; Chattopadhyay, S.

2009-01-01

Bioorganic chemistry plays a pivotal role of co-ordination amongst the research and developmental activities of physical, biological, material and nuclear sciences. Understandably, the domain of bioorganic chemistry encompasses overlapping scientific fields, and often involves multi-disciplinary subjects. The research activities of bioorganic research at BARC are, therefore directed with reference to deliverables, relevant to various nuclear and non-nuclear programmes of the department. Also, the activities of the division are fine tuned to address the contemporary needs. It is now well recognized that organic compounds are essential in various programmes of nuclear technology. These include solvents and membranes for the back-end process, carrier molecules for radiopharmaceuticals, optoelectrical materials and sensors for high tech applications etc. Coupled with this, bioorganics also form integral part of the departmental mission-oriented societal programmes in the areas of health and agriculture

Development of a Research-Oriented Inorganic Chemistry Laboratory Course

Science.gov (United States)

Vallarino, L. M.; Polo, D. L.; Esperdy, K.

2001-02-01

We report the development of a research-oriented, senior-level laboratory course in inorganic chemistry, which is a requirement for chemistry majors who plan to receive the ACS-approved Bachelor of Science degree and is a recommended elective for other chemistry majors. The objective of this course is to give all students the advantage of a research experience in which questions stemming from the literature lead to the formulation of hypotheses, and answers are sought through experiment. The one-semester Inorganic Chemistry Laboratory is ideal for this purpose, since for most students it represents the last laboratory experience before graduation and can assume the role of "capstone" course--a course where students are challenged to recall previously learned concepts and skills and put them into practice in the performance of an individual, original research project. The medium chosen for this teaching approach is coordination chemistry, a branch of chemistry that involves the interaction of inorganic and organic compounds and requires the use of various synthetic and analytical methods. This paper presents an outline of the course organization and requirements, examples of activities performed by the students, and a critical evaluation of the first five years' experience.

Polymer Photovoltaic Cells with Rhenium Oxide as Anode Interlayer.

Science.gov (United States)

Wei, Jinyu; Bai, Dongdong; Yang, Liying

2015-01-01

The effect of a new transition metal oxide, rhenium oxide (ReO3), on the performance of polymer solar cells based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend as buffer layer was investigated. The effect of the thickness of ReO3 layer on electrical characteristics of the polymer solar cells was studied. It is found that insertion of ReO3 interfacial layer results in the decreased performance for P3HT: PCBM based solar cells. In order to further explore the mechanism of the decreasing of the open-circuit voltage (Voc), the X-ray photoelectron spectroscopy (XPS) is used to investigate the ReO3 oxidation states. Kelvin Probe method showed that the work function of the ReO3 is estimated to be 5.13eV after thermal evaporation. The results indicated the fact that a portion of ReO3 decomposed during thermal evaporation process, resulting in the formation of a buffer layer with a lower work function. As a consequence, a higher energy barrier was generated between the ITO and the active layer.

Coordination Compounds of Co Ni , Cu , Zn , Cd and Hg with ...

African Journals Online (AJOL)

CLEMENT O BEWAJI

Bipin B. Mahapatra* and Saroj Ku. Panda. **. **P.G. Department of Chemistry, G.M. (Autonomous) College, Sambalpur – 768004 (Orissa). India. Telephone ..... Ferraro, J.R: Low Frequency Vibration of Inorganic and Co-ordination Compound Plenum press, New York. USA: (1971). 10. Sacconi. L: J. Inorg. Nucl. Chem., 18 ...

Primary water chemistry of VVERs-operating experience

International Nuclear Information System (INIS)

Kysela, Jan; Zmitko, Milan; Petrecky, Igor

1998-01-01

VVER units are operated in mixed boron-potassium-ammonia water chemistry. Several modifications of the water chemistry, differing in boron-potassium co-ordination and in the way how hydrogen concentration is produced and maintain in the coolant, is used. From the operational experience point of view VVER units do not show any significant problems connected with the primary coolant chemistry. The latest results indicate that dose rate levels are slowly returning to the former ones. An improvement of the radiation situation observed last two years is supported by the surface activity measurements. However, the final conclusion on the radiation situation can be made only after evaluation of the several following cycles. Further investigation is also needed to clarify a possible effect of modified water chemistry and shut-down chemistry on radioactivity build-up and dose rate level at Dukovany units. Structure materials composition has a significant effect on radiation situation in the units. It concerns mainly of cobalt content in SG material. There is no clear evidence of possible effect of the SG shut-down regimes on the radiation situation in the units even if the dose rate and surface activity data show wide spread for the individual reactor loops. (S.Y.)

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.

Influence of liposome forms of the rhenium compounds and cis-platin on thiol-disulfide coefficient in the rats’ blood

Directory of Open Access Journals (Sweden)

I. V. Klenina

2007-12-01

Full Text Available Thiol-disulfide coefficient (TDC and its different modifications in model in vivo were studied. Introduction of the liposome forms of cluster rhenium compounds with organic ligands (CROL leads to both TDC increasing and to the constancy of the TDC. Thus, CROLs aren’t toxic agents and some compounds could mobilize organisms’ thiol defence system. Liposome form of cis-platin leads to the TDC decreasing. Important CROL capacities for its future medical treatment practice were shown.

Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst

Directory of Open Access Journals (Sweden)

Dewi Tristantini

2016-03-01

Received: 10th November 2015; Revised: 10th February 2016; Accepted: 16th February 2016 How to Cite: Tristantini, D., Suwignjo, R.K. (2016. Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 84-92. (doi:10.9767/bcrec.11.1.424.84-92 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.424.84-92

new polythiophenes with oligo(oxyethylene) side chains

African Journals Online (AJOL)

USER

2Department of Chemistry, University of Port Elizabeth, P.O. Box 1600, 6000 Port ... applications of rhenium radiopharmaceuticals in nuclear medicine[5, 6]. ... This report deals with the synthesis of complexes II, and their reactions with 2-.

188Rhenium-HEDP in the treatment of pain in bone metastases

International Nuclear Information System (INIS)

Gaudiano, J.; Martinez, G.; Hermida, J.C.; Savio, E.; Verdera, S.; Robles, A.; Muniz, S.; Leon, A.; Knapp, F.F.

2001-01-01

Systemic use of radiopharmaceuticals is a recognised alternative method for the treatment of pain in patients with multiple bone metastases. A new option, 188 Re-HEDP is proposed, using generator-obtained 188 Rhenium (β energy = 2.1 MeV, γ energy = 155 keV, half-life = 16.9 hours). After establishing parameters of biodistribution, dosimetry and image acquisition in mice, rats and rabbits, Phase I and II studies were conducted on 12 patients with multiple metastases from carcinomas, with pain surpassing other analgesic options. More than 50% pain relief was found in 91% of the patients, with total relief during a variable period in 41% of them allowing opiate and other analgesic drugs to be decreased or withdrawn, and showing a lower bone marrow contribution to total absorbed dose than that reported for other similar radiopharmaceuticals. Further study of this option is recommended in order to determine higher dose protocols without toxic bone marrow reaction possibilities. (author)

188Rhenium-HEDP in the Treatment of Pain in Bone Metastases

International Nuclear Information System (INIS)

Gaudiano, J.; Savio, E.; Robles, A.; Muniz, S.; Leon, A.; Verdera, S.; Martinez, G.; Hermida, J.C.; Knapp, F.F. Jr.

1999-01-01

Systemic use of radiopharmaceuticals is a recognized alternative method for the treatment of pain in patients with multiple bone metastasis. A new option, 188 Re-HEDP is proposed, using generator-obtained 188 Rhenium (β energy = 2.1 MeV, γ energy = 155 keV, half-life = 16.9 hours). After establishing parameters of biodistribution, dosimetry and image acquisition in mice, rats and rabbits, Phase I and II studies were conducted on 12 patients with multiple metastasis from carcinomas, with pain surpassing other analgesic options. More than 50% pain relief was found in 91% of the patients, with total relief during a variable period in 41% of them allowing opiate and other analgesic drugs to be decreased or withdrawn, and showing a lower bone marrow contribution to total absorbed dose than that reported for other similar radiopharmaceuticals. Further study of this option is recommended in order to determine higher dose protocols without toxic bone marrow reaction possibilities

Studies on the preparation and isomeric composition of [sup 186]Re- and [sup 188]Re-pentavalent rhenium dimercaptosuccinic acid complex

Energy Technology Data Exchange (ETDEWEB)

Singh, J. (Canterbury Univ. (United Kingdom). Biological Lab.); Reghebi, K.; Lazarus, C.R.; Clarke, S.E.M. (Guy' s Hospital, London (United Kingdom)); Callahan, A.P.; Knapp, F.F. Jr. (Oak Ridge National Lab., TN (United States)); Blower, P.J. (Kent and Canterbury Hospital (United Kingdom))

1993-03-01

The preparative conditions for [sup 186]Re(V)DMSA and [sup 188]Re(V)DMSA (DMSA = meso-dimercaptosuccinic acid), [beta]-emitting radiopharmaceuticals that have been shown to localize in medullary thyroid carcinoma, require modification depending on the amount of carrier rhenium and the chemical form and medium in which the rhenium is supplied. Preparative conditions are described for use with carrier-free [sup 188]ReO[sub 4][sup -] in saline, and for use with [sup 186]ReO[sub 4][sup -] in saline, sodium hydroxide or nitric acid. Preparation of [sup 186]Re(V)DMSA (carrier present up to 2 mg per 2.5 ml reaction volume) requires a DMSA:SnCl[sub 2]:Re ratio of 10:5:1 at 100[sup o]C for 30 min. Addition of excess nitric acid or hydrochloric acid up to a concentration of 155 mM does not reduce the yield from 100%. A commercial DMSA kit vial (e.g. Amerscan DMSA) can be used for preparation of [sup 188]Re(V)DMSA (carrier free) provided the required is in a volume of less than 1 ml per vial. A convenient method of concentrating the [sup 188]Re generator eluate to the required volume is described. (Author).

The chemistry of PET imaging with zirconium-89.

Science.gov (United States)

Dilworth, Jonathan R; Pascu, Sofia I

2018-04-23

This Tutorial Review aims to provide an overview of the use of zirconium-89 complexes in biomedical imaging. Over the past decade there have been many new papers in this field, ranging from chemistry through to preclinical and clinical applications. Here we attempt to summarise the main developments that have occurred in this period. The primary focus is on coordination chemistry but other aspects such as isotope production, isotope properties, handling and radiochemical techniques and characterisation of cold and labelled complexes are included. Selected results from animal and human clinical studies are presented in the context of the stabilities and properties of the labelled bioconjugates.

Materials of the yearly scientific assembly of the Polish Chemical Society - Torun'93: chemistry of new materials

International Nuclear Information System (INIS)

1993-01-01

Scientific conference accompanied the assembly of Polish Chemical Society has been held in 1993 in Torun. The conference has been divided into 12 sections and 4 symposia covering the most important research fields in chemistry. The general view on scientific progress has been presented during the plenary session. Then proceedings have performed in specialist sessions on: contemporary methods in organic chemistry chemistry, chemistry and physico-chemistry of polymers, coordination chemistry state-of-the-art prospects, absorption and absorbents, new chemical technologies of organic compounds, new chemical technologies of inorganic compounds, environment protection, new methods in analytical chemistry, photochemistry and chemical kinetics, crystallochemistry, history of chemistry and didactics, new substances in health protection, membranes and membrane techniques, electroactive organic compounds, zeolites - material properties

Organic chemistry of elemental phosphorus

International Nuclear Information System (INIS)

Milyukov, V A; Budnikova, Yulia H; Sinyashin, Oleg G

2005-01-01

The principal achievements and the modern trends in the development of the chemistry of elemental phosphorus are analysed, described systematically and generalised. The possibilities and advantages of the preparation of organophosphorus compounds directly from white phosphorus are demonstrated. Attention is focused on the activation and transformation of elemental phosphorus in the coordination sphere of transition metal complexes. The mechanisms of the reactions of white phosphorus with nucleophilic and electrophilic reagents are discussed. Electrochemical approaches to the synthesis of organic phosphorus derivatives based on white phosphorus are considered.

Coordination symmetry determination of some lanthanide complexes by x-ray diffraction

International Nuclear Information System (INIS)

Oliveira Paiva Santos, C. de.

1983-01-01

The x-ray determination of the crystal and molecular structures of three lanthanide complexes is described. The work is a contribution to the study of the coordination chemistry of lanthanide ions with organic ligands and in particular, it aims to compare the observed point symmetry of the ion environment with spectroscopic predictions. (author)

EPRI BWR Water Chemistry Guidelines Revision

International Nuclear Information System (INIS)

Garcia, Susan E.; Giannelli, Joseph F.

2014-01-01

BWRVIP-190: BWR Water Chemistry Guidelines – 2008 Revision has been revised. The revision committee consisted of U.S. and non-U.S. utilities (members of the BWR Vessel and Internals Protection (BWRVIP) Mitigation Committee), reactor system manufacturers, fuel suppliers, and EPRI and industry experts. The revised document, BWRVIP-190 Revision 1, was completely reformatted into two volumes, with a simplified presentation of water chemistry control, diagnostic and good practice parameters in Volume 1 and the technical bases in Volume 2, to facilitate use. The revision was developed in parallel and in coordination with preparation of the Fuel Reliability Guidelines Revision 1: BWR Fuel Cladding Crud and Corrosion. Guidance is included for plants operating under normal water chemistry (NWC), moderate hydrogen water chemistry (HWC-M), and noble metal application (GE-Hitachi NobleChem™) plus hydrogen injection. Volume 1 includes significant changes to BWR feedwater and reactor water chemistry control parameters to provide increased assurance of intergranular stress corrosion cracking (IGSCC) mitigation of reactor materials and fuel reliability during all plant conditions, including cold shutdown (≤200°F (93°C)), startup/hot standby (>200°F (93°C) and ≤ 10%) and power operation (>10% power). Action Level values for chloride and sulfate have been tightened to minimize environmentally assisted cracking (EAC) of all wetted surfaces, including those not protected by hydrogen injection, with or without noble metals. Chemistry control guidance has been enhanced to minimize shutdown radiation fields by clarifying targets for depleted zinc oxide (DZO) injection while meeting requirements for fuel reliability. Improved tabular presentations of parameter values explicitly indicate levels at which actions are to be taken and required sampling frequencies. Volume 2 provides the technical bases for BWR water chemistry control for control of EAC, flow accelerated corrosion

Synthesis, structural characterization and photoluminescence properties of rhenium(I) complexes based on bipyridine derivatives with carbazole moieties.

Science.gov (United States)

Li, Hong-Yan; Wu, Jing; Zhou, Xin-Hui; Kang, Ling-Chen; Li, Dong-Ping; Sui, Yan; Zhou, Yong-Hui; Zheng, You-Xuan; Zuo, Jing-Lin; You, Xiao-Zeng

2009-12-21

Three N,N-bidentate ligands, 5,5'-dibromo-2,2-bipyridine (L1) and two carbazole containing ligands of 5-bromo-5'-carbazolyl-2,2-bipyridine (L2), 5,5'-dicarbazolyl-2,2'-bipyridine (L3), and their corresponding rhenium Re(CO)3Cl(L) complexes (ReL1-ReL3) have been successfully synthesized and characterized by elemental analysis, 1H NMR and IR spectra. Their photophysical properties and thermal analysis, along with the X-ray crystal structure analysis of L3 and complexes ReL1 and ReL3 are also described. In CH2Cl2 solution at room temperature, all complexes display intense absorption bands at ca. 220-350 nm, which can be assigned to spin-allowed intraligand (pi-->pi*) transitions, and the low energy broad bands in the 360-480 nm region are attributed to the metal to ligand charge-transfer d(Re)-->pi* (diimine) (MLCT). The introduction of carbazole moieties improves the MLCT absorption and molar extinction coefficient of these complexes. Upon excitation at the peak maxima, all complexes show strong emissions around 620 nm, which are assigned to d(Re)-->pi* (diimine) MLCT phosphorescence. The photoluminescence lifetime decay of Re(I) complexes were measured and the quantum efficiencies of the rhenium(I) complexes were calculated by using air-equilibrated [Ru(bpy)3]2+ x 2 Cl- aqueous solution as standard (phi(std) = 0.028). The complexes with appended carbazole moieties exhibit enhanced luminescence performances relative to ReL1.

Determination of rhenium traces in river water by Q-ICP-MS and HR-ICP-MS

International Nuclear Information System (INIS)

Uchida, S.; Tagami, K.; Saito, M.

2003-01-01

A simple separation method was applied to determine rhenium in river water using Q-ICP-MS and HR-ICP-MS. Re was concentrated from 420-925 ml river water using a TEVA resin minicolumn. Such extraction using a resin could separate Re from most sample matrices and trace elements. Almost 100% recovery was found throughout the method as determined with radioactive multitracers. The HR-ICP-MS was also used for the direct determination because of its low detection limit for Re (0.007 pg/ml). The Re concentration in the river water samples ranged from 0.9 to 6.5 pg/ml and the three analysis results showed good agreement with each other. (author)

Coordination-chemistry control of proton conductivity in the iconic metal-organic framework material HKUST-1.

Science.gov (United States)

Jeong, Nak Cheon; Samanta, Bappaditya; Lee, Chang Yeon; Farha, Omar K; Hupp, Joseph T

2012-01-11

HKUST-1, a metal-organic framework (MOF) material containing Cu(II)-paddlewheel-type nodes and 1,3,5-benzenetricarboxylate struts, features accessible Cu(II) sites to which solvent or other desired molecules can be intentionally coordinated. As part of a broader investigation of ionic conductivity in MOFs, we unexpectedly observed substantial proton conductivity with the "as synthesized" version of this material following sorption of methanol. Although HKUST-1 is neutral, coordinated water molecules are rendered sufficiently acidic by Cu(II) to contribute protons to pore-filling methanol molecules and thereby enhance the alternating-current conductivity. At ambient temperature, the chemical identities of the node-coordinated and pore-filling molecules can be independently varied, thus enabling the proton conductivity to be reversibly modulated. The proton conductivity of HKUST-1 was observed to increase by ~75-fold, for example, when node-coordinated acetonitrile molecules were replaced by water molecules. In contrast, the conductivity became almost immeasurably small when methanol was replaced by hexane as the pore-filling solvent. © 2011 American Chemical Society

Volatility literature of chlorine, iodine, cesium, strontium, technetium, and rhenium; technetium and rhenium volatility testing

International Nuclear Information System (INIS)

Langowski, M.H.; Darab, J.G.; Smith, P.A.

1996-03-01

A literature review pertaining to the volatilization of Sr, Cs, Tc (and its surrogate Re), Cl, I and other related species during the vitrification of Hanford Low Level Waste (LLW) streams has been performed and the relevant information summarized. For many of these species, the chemistry which occurs in solution prior to the waste stream entering the melter is important in dictating their loss at higher temperatures. In addition, the interactive effects between the species being lost was found to be important. A review of the chemistries of Tc and Re was also performed. It was suggested that Re would indeed act as an excellent surrogate for Tc in non-radioactive materials testing. Experimental results on Tc and Re loss from sodium aluminoborosilicate melts of temperatures ranging from 900--1350 degrees C performed at PNL are reported and confirm that Re behaves in a nearly identical manner to that of technetium

Lanthanide co-ordination frameworks: Opportunities and diversity

International Nuclear Information System (INIS)

Hill, Robert J.; Long, De-Liang; Hubberstey, Peter; Schroeder, Martin; Champness, Neil R.

2005-01-01

Significant successes have been made over recent years in preparing co-ordination framework polymers that show macroscopic material properties, but in the vast majority of cases this has been achieved with d-block metal-based systems. Lanthanide co-ordination frameworks also offer attractive properties in terms of their potential applications as luminescent, non-linear optical and porous materials. However, lanthanide-based systems have been far less studied to date than their d-block counterparts. One possible reason for this is that the co-ordination spheres of lanthanide cations are more difficult to control and, in the absence of design strategies for lanthanide co-ordination frameworks, it is significantly more difficult to target materials with specific properties. However, this article highlights some of the exciting possibilities that have emerged from the earliest investigations in this field with new topological families of compounds being discovered from relatively simple framework components, including unusual eight, seven and five-connected framework systems. Our own research, as well as others, is leading to a much greater appreciation of the factors that control framework formation and the resultant observed topologies of these polymers. As this understanding develops targeting particular framework types will become more straightforward and the development of designed polyfunctional materials more accessible. Thus, it can be seen that lanthanide co-ordination frameworks have the potential to open up previously unexplored directions for materials chemistry. This article focuses on the underlying concepts for the construction of these enticing and potentially highly important materials

Determination of rhenium in biological and environmental samples by radiochemical neutron activation analysis

International Nuclear Information System (INIS)

Kucera, J.; Mizera, J.; Randa, Z.; Byrne, A.R.; Lucanikova, M.

2006-01-01

Radiochemical neutron activation procedures using liquid-liquid extraction with tetraphenylarsonium chloride in chloroform from 1 M HCl and solid extraction with ALIQUAT 336 incorporated in a polyacrylonitrile binding matrix from 0.1 M HCl were developed for accurate determination of rhenium in biological and environmental samples at the sub-ng.g -1 level. Concentrations of Re in the range of 0.1 to 2.4 ng.g -1 were determined in several botanical reference materials (RM), while in a RM of road dust a value of approx. 10 ng.g -1 was found. Significantly elevated values of Re, up to 90 ng.g -1 , were found in seaweed (brown algae). Results for Re in the brown algae Fucus vesiculosus in which elevated 99 Tc values had previously been determined suggest possible competition between Re and Tc in the accumulation process. (author)

Coordination compounds in nuclear medicine

International Nuclear Information System (INIS)

Jurisson, S.; Berning, D.; Wei Jia; Dangshe Ma

1993-01-01

Radiopharmaceuticals, drugs containing a radionuclide, are used routinely in nuclear medicine departments for the diagnosis of disease and are under investigation for use in the treatment of disease. Nuclear medicine takes advantage of both the nuclear properties of the radionuclide and the pharmacological properties of the radiopharmaceutical. Herein lies the real strength of nuclear medicine, the ability to monitor biochemical and physiological functions in vivo. This review discusses the coordination chemistry that forms the basis for nuclear medicine applications of the FDA-approved radiopharmaceuticals that are in clinical use, and of the most promising diagnostic and therapeutic radiopharmaceuticals that are in various stages of development. 232 refs

Operational experience with PWR secondary water chemistry: a panel presentation San Onofre Unit 1

International Nuclear Information System (INIS)

Britt, R.D.; Millard, R.E.; DiFilippo, M.N.

1975-01-01

The three steam generators have been on phosphate chemistry since startup except for one brief period when volatile chemistry was attempted. Initially, coordinated pH-phosphate control was recommended by Westinghouse for the steam generators; however, after one year of operation, Westinghouse recommended changing to congruent control. From startup in 1967 until the end of 1970, the Na/PO 4 molar ratio was generally maintained in the 2.6 to 2.8 range, with a 5 to 10 ppM phosphate residual. A summary of steam generator chemistry from initial startup to the present is presented

A Study of Coordination Between Mathematics and Chemistry in the Pre-Technical Program.

Science.gov (United States)

Loiseau, Roger A.

This research was undertaken to determine whether the mathematics course offered to students taking courses in chemical technology was adequate. Students in a regular class and an experimental class were given mathematics and chemistry pretests and posttests. The experimental class was taught using a syllabus designed to maximize the coherence…

{sup 188}Rhenium-HEDP in the Treatment of Pain in Bone Metastases

Energy Technology Data Exchange (ETDEWEB)

Gaudiano, J.; Savio, E.; Robles, A.; Muniz, S.; Leon, A.; Verdera, S.; Martinez, G.; Hermida, J.C.; Knapp, F.F., Jr.

1999-01-18

Systemic use of radiopharmaceuticals is a recognized alternative method for the treatment of pain in patients with multiple bone metastasis. A new option, {sup 188}Re-HEDP is proposed, using generator-obtained {sup 188}Rhenium ({beta} energy = 2.1 MeV, {gamma} energy = 155 keV, half-life = 16.9 hours). After establishing parameters of biodistribution, dosimetry and image acquisition in mice, rats and rabbits, Phase I and II studies were conducted on 12 patients with multiple metastasis from carcinomas, with pain surpassing other analgesic options. More than 50% pain relief was found in 91% of the patients, with total relief during a variable period in 41% of them allowing opiate and other analgesic drugs to be decreased or withdrawn, and showing a lower bone marrow contribution to total absorbed dose than that reported for other similar radiopharmaceuticals. Further study of this option is recommended in order to determine higher dose protocols without toxic bone marrow reaction possibilities.

Accessing Specific Peptide Recognition by Combinatorial Chemistry

DEFF Research Database (Denmark)

Li, Ming

Molecular recognition is at the basis of all processes for life, and plays a central role in many biological processes, such as protein folding, the structural organization of cells and organelles, signal transduction, and the immune response. Hence, my PhD project is entitled “Accessing Specific...... Peptide Recognition by Combinatorial Chemistry”. Molecular recognition is a specific interaction between two or more molecules through noncovalent bonding, such as hydrogen bonding, metal coordination, van der Waals forces, π−π, hydrophobic, or electrostatic interactions. The association involves kinetic....... Combinatorial chemistry was invented in 1980s based on observation of functional aspects of the adaptive immune system. It was employed for drug development and optimization in conjunction with high-throughput synthesis and screening. (chapter 2) Combinatorial chemistry is able to rapidly produce many thousands...

EMODnet Thematic Lot n° 4 - Chemistry

DEFF Research Database (Denmark)

Beckers, Jean-Marie; Buga, Luminita; Debray, Noelie

2015-01-01

Data quality assurance and quality control (QA/QC) is an important issue in oceanographic data management, especially for the creation of multidisciplinary and comprehensive databases which include data from different and/or unknown origin covering long time periods. The data-collection methods i...... inconsistent data quality flags and the need for coordination and harmonization of practices. A dedicated workshop was organized to review the different practices and agree on a common methodology for data QA/QC and Diva products generation for EMODnet Chemistry....... will contribute considerably to the validation of large data collections. This report intends to be a reference manual for EMODnet Chemistry data QA/QC and the subsequent product generation. In fact, during the first data validation loop, each region adopted its own protocol and the results showed many...

Pore chemistry and size control in hybrid porous materials for acetylene capture from ethylene

KAUST Repository

Cui, X.; Chen, K.; Xing, H.; Yang, Q.; Krishna, R.; Bao, Z.; Wu, H.; Zhou, W.; Dong, Xinglong; Han, Y.; Li, B.; Ren, Q.; Zaworotko, M. J.; Chen, B.

2016-01-01

The trade-off between physical adsorption capacity and selectivity of porous materials is a major barrier for efficient gas separation and purification through physisorption. We report control over pore chemistry and size in metal coordination

Identification of rhenium donors and sulfur vacancy acceptors in layered MoS{sub 2} bulk samples

Energy Technology Data Exchange (ETDEWEB)

Brandão, F. D., E-mail: fdbrand@fisica.ufmg.br; Ribeiro, G. M.; Vaz, P. H.; González, J. C.; Krambrock, K. [Departamento de Física, Universidade Federal de Minas Gerais, CP 702, 30.123-970 Belo Horizonte, MG (Brazil)

2016-06-21

MoS{sub 2} monolayers, a two-dimensional (2D) direct semiconductor material with an energy gap of 1.9 eV, offer many opportunities to be explored in different electronic devices. Defects often play dominant roles in the electronic and optical properties of semiconductor devices. However, little experimental information about intrinsic and extrinsic defects or impurities is available for this 2D system, and even for macroscopic 3D samples for which MoS{sub 2} shows an indirect bandgap of 1.3 eV. In this work, we evaluate the nature of impurities with unpaired spins using electron paramagnetic resonance (EPR) in different geological macroscopic samples. Regarding the fact that monolayers are mostly obtained from natural crystals, we expect that the majority of impurities found in macroscopic samples are also randomly present in MoS{sub 2} monolayers. By EPR at low temperatures, rhenium donors and sulfur vacancy acceptors are identified as the main impurities in bulk MoS{sub 2} with a corresponding donor concentration of about 10{sup 8–12} defects/cm{sup 2} for MoS{sub 2} monolayer. Electrical transport experiments as a function of temperature are in good agreement with the EPR results, revealing a shallow donor state with an ionization energy of 89 meV and a concentration of 7 × 10{sup 15 }cm{sup −3}, which we attribute to rhenium, as well as a second deeper donor state with ionization energy of 241 meV with high concentration of 2 × 10{sup 19 }cm{sup −3} and net acceptor concentration of 5 × 10{sup 18 }cm{sup −3} related to sulfur vacancies.

Bibliographies on radiation chemistry

International Nuclear Information System (INIS)

Hoffman, M.Z.; Ross, A.B.

1986-01-01

The one-electron oxidation and reduction of metal ions and complexes can yield species in unusual oxidation states, and ligand-radicals coordinated to the central metal. These often unstable species can be mechanistically important intermediates in thermal, photochemical, and electrochemical reactions involving metal-containing substances. Their generation via radiolysis provides an alternate means of characterizing them using kinetic and spectroscopic techniques. We hope these bibliographies on the radiation chemistry of metal ions and complexes, presented according to periodic groups, will prove useful to researchers in metallo-redox chemistry. These bibliographies contain only primary literature sources; reviews are not included. However, a list of general review articles on the radiation chemistry of metal ions and complexes is presented here in the first section which covers cobalt, rhodium and iridium, Group 9 in the new IUPAC notation. Additional parts of the bibliography are planned, covering other periodic groups. Part A of the bibliography was prepared by a search of the Radiation Chemistry Data Center Bibliographic Data Base (RCDCbib) through January 1986 for papers on rhodium, iridium and cobalt compounds, and radiolysis (both continuous and pulsed). Papers in which the use of metal compounds was incidental to the primary objective of the study were excluded. Excluded also were publications in unrefereed and obscure sources such as meeting proceedings, internal reports, dissertations, and patents. The majority of the studies in the resultant compilation deal with experiments performed on solutions, mainly aqueous, although a substantial fraction is devoted to solid-state esr measurements. The references are listed in separate sections for each of the metals, and are presented in approximate chronological order. (author)

Hydrodeoxygenation of vicinal OH groups over heterogeneous rhenium catalyst promoted by palladium and ceria support.

Science.gov (United States)

Ota, Nobuhiko; Tamura, Masazumi; Nakagawa, Yoshinao; Okumura, Kazu; Tomishige, Keiichi

2015-02-02

Heterogeneous ReOx-Pd/CeO2 catalyst showed excellent performance for simultaneous hydrodeoxygenation of vicinal OH groups. High yield (>99%), turnover frequency (300 h(-1)), and turnover number (10,000) are achieved in the reaction of 1,4-anhydroerythritol to tetrahydrofuran. This catalyst can be applied to sugar alcohols, and mono-alcohols and diols are obtained in high yields (≥85%) from substrates with even and odd numbers of OH groups, respectively. The high catalytic performance of ReOx-Pd/CeO2 can be assigned to rhenium species with +4 or +5 valence state, and the formation of this species is promoted by H2/Pd and the ceria support. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photodetectors: Broad Detection Range Rhenium Diselenide Photodetector Enhanced by (3-Aminopropyl)Triethoxysilane and Triphenylphosphine Treatment (Adv. Mater. 31/2016).

Science.gov (United States)

Jo, Seo-Hyeon; Park, Hyung-Youl; Kang, Dong-Ho; Shim, Jaewoo; Jeon, Jaeho; Choi, Seunghyuk; Kim, Minwoo; Park, Yongkook; Lee, Jaehyeong; Song, Young Jae; Lee, Sungjoo; Park, Jin-Hong

2016-08-01

The effects of triphenylphosphine (PPh3 ) and (3-amino-propyl)triethoxysilane (APTES) on a rhenium diselenide (ReSe2 ) photodetector are systematically studied by J.-H. Park and co-workers on page 6711 in comparison with a conventional MoS2 device. A very high performance ReSe2 photodetector is demonstrated, which has a broad photodetection range, high photoresponsivity (1.18 × 10(6) A W(-1) ), and fast photoswitching speed (rising/decaying time: 58/263 ms). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of heat-treatment on microstructure and high-temperature deformation behavior of a low rhenium-containing single crystal nickel-based superalloy

International Nuclear Information System (INIS)

Sun, Nairong; Zhang, Lanting; Li, Zhigang; Shan, Aidang

2014-01-01

A low rhenium-containing [001] oriented single crystal nickel-based superalloy with different γ′ morphologies induced by various aging treatments was compressed from room temperature to 1000 °C. All the single crystal samples with different γ′ morphologies exhibit anomalous yield behavior. The sample first aged at 1180 °C has the widest anomalous temperature domain and highest yield strengths. The sample first aged at 1000 °C has the highest anomalous peak stress temperature

Fascinating chemistry or frustrating unpredictability : Observations in crystal engineering of metal–organic frameworks

NARCIS (Netherlands)

Goesten, M.G.; Kapteijn, F.; Gascon, J.

2013-01-01

Reticular design is a highly attractive concept, but coordination chemistry around the tectonic units of metal– organic frameworks (MOFs) and additional interplay with anionic and solvent species provide for dazzling complexity that effectively rules out structure prediction. We can however study

A Fluorine-18 Radiolabeling Method Enabled by Rhenium(I) Complexation Circumvents the Requirement of Anhydrous Conditions.

Science.gov (United States)

Klenner, Mitchell A; Pascali, Giancarlo; Zhang, Bo; Sia, Tiffany R; Spare, Lawson K; Krause-Heuer, Anwen M; Aldrich-Wright, Janice R; Greguric, Ivan; Guastella, Adam J; Massi, Massimiliano; Fraser, Benjamin H

2017-05-11

Azeotropic distillation is typically required to achieve fluorine-18 radiolabeling during the production of positron emission tomography (PET) imaging agents. However, this time-consuming process also limits fluorine-18 incorporation, due to radioactive decay of the isotope and its adsorption to the drying vessel. In addressing these limitations, the fluorine-18 radiolabeling of one model rhenium(I) complex is reported here, which is significantly improved under conditions that do not require azeotropic drying. This work could open a route towards the investigation of a simplified metal-mediated late-stage radiofluorination method, which would expand upon the accessibility of new PET and PET-optical probes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Actinide/crown ether chemistry

International Nuclear Information System (INIS)

Benning, M.M.

1988-01-01

A structural survey of actinide/crown ether compounds was conducted in order to investigate the solid state chemistry of these complexes. Several parameters - the metal size, crown type, counterion, solvent systems and reaction and crystallization conditions - were varied to correlate their importance in complexation. Under atmospheric conditions, two types of complexes were isolated, those containing only hydrogen-bonded crown interactions and instances where the crown interacts directly with the metal center. In both cases, water seems to play a very important role. When coordinated to the metal, water molecules exhibit the necessary donor properties required for the formation of hydrogen-bonded contacts. The water molecules also provide fierce competition with the crown ethers for metal-binding sites and in most cases prohibit the formation of complexes in which direct metal-ligand association exists. The results of this study indicate that direct interaction between the metal atoms and the crown ethers, in the presence of water, can only occur with polyether conformations which limit the steric replusions within the metal coordination sphere

Colloid and interface chemistry for nanotechnology

CERN Document Server

Kralchevsky, Peter; Ravera, Francesca

2016-01-01

Colloid and interface science dealt with nanoscale objects for nearly a century before the term nanotechnology was coined. An interdisciplinary field, it bridges the macroscopic world and the small world of atoms and molecules. Colloid and Interface Chemistry for Nanotechnology is a collection of manuscripts reflecting the activities of research teams that have been involved in the networking project Colloid and Interface Chemistry for Nanotechnology (2006-2011), Action D43, the European Science Foundation. The project was a part of the intergovernmental framework for Cooperation in Science and Technology (COST), allowing the coordination of nationally funded research across Europe. With contributions by leading experts, this book covers a wide range of topics. Chapters are grouped into three sections: "Nanoparticle Synthesis and Characterization," "New Experimental Tools and Interpretation," and "Nanocolloidal Dispersions and Interfaces." The topics covered belong to six basic research areas: (1) The synthes...

In-situ field-ion microscope study of the recovery behavior of heavy metal ion-irradiated tungsten, tungsten (rhenium) alloys and molybdenum

International Nuclear Information System (INIS)

Nielsen, C.H.

1977-06-01

Three field ion microscope (FIM) experiments were carried out to study the annealing behavior of heavy ion irradiated tungsten, tungsten (rhenium) alloys and molybdenum. The first experiment dealt with the stage I long-range migration of tungsten self interstitial atoms (SIAs) in high purity tungsten of resistivity ratio, R = 24,000 (R = rho 300 /rho 4 . 2 , where rho 300 and rho 4 . 2 are the room temperature and 0 0 C resistivities). The FIM specimens were irradiated in situ at 18 K with 30 keV W + ions to an average dose of 5 x 10 12 ions cm -2 and subsequently examined by the pulsed-field evaporation technique. The second experiment dealt with the phenomenon of impurity atom trapping of SIAs during long-range migration. It was shown that rhenium atoms in a tungsten matrix tend to capture tungsten SIAs and remain bound up to temperatures as high as 390 K. The final experiment was concerned with the low temperature annealing kinetics of irradiated molybdenum. High purity molybdenum of resistivity ratio R = 5700 was irradiated at 10 K with 30 keV Mo + ions to a dose of approximately 5 x 10 12 ions cm -2 . The results indicated that the electric field has only a minimal effect on the SIA annealing kinetics. This tends to strengthen the contention that the molybdenum SIA becomes mobile at 32 K

Crystal chemistry of uranyl carboxylate coordination networks obtained in the presence of organic amine molecules

Energy Technology Data Exchange (ETDEWEB)

Mihalcea, Ionut; Henry, Natacha; Loiseau, Thierry [Unite de Catalyse et Chimie du Solide (UCCS) - UMR CNRS 8181, Universite de Lille Nord de France, USTL-ENSCL, Villeneuve d' Ascq (France)

2014-03-15

Three uranyl isophthalates (1,3-bdc) and two uranyl pyromellitates (btec) of coordination-polymer type were hydrothermally synthesized (200 C for 24 h) in the presence of different amine-based molecules [1,3-diaminopropane (dap) or dimethylamine (dma) originating from the in situ decomposition of N,N-dimethylformamide]. (UO{sub 2}){sub 2}(OH){sub 2}(H{sub 2}O)(1,3-bdc).H{sub 2}O (1) is composed of inorganic tetranuclear cores, which are linked to each other through the isophthalato ligand to generate infinite neutral ribbons, which are intercalated by free H{sub 2}O molecules. The compounds (UO{sub 2}){sub 1.5}(H{sub 2}O)(1,3-bdc){sub 2}.0.5H{sub 2}dap.1.5H{sub 2}O (2) and UO{sub 2}(1,3-bdc){sub 1.5}.0.5H{sub 2}dap.2H{sub 2}O (3) consist of discrete uranyl-centered hexagonal bipyramids connected to each other by a ditopic linker to form a single-layer network for 2 or a double-layer network for 3. The protonated diamine molecules are located between the uranyl-organic sheets and balance the negative charge of the layered sub-networks. The phase (UO{sub 2}){sub 2}O(btec).2Hdma.H{sub 2}O (4) presents a 2D structure built up from tetranuclear units, which consist of two central sevenfold coordinated uranium centers and two peripheral eightfold coordinated uranium centers. The connection of the resulting tetramers through the pyromellitate molecules generates an anionic layerlike structure, in which the protonated dimethylammonium species are inserted. The compound UO{sub 2}(btec).2Hdma (5) is also a lamellar coordination polymer, which contains isolated eightfold coordinated uranium cations linked through pyromellitate molecules and intercalated by protonated dimethylammonium species. In both phases 4 and 5, the btec linker has non-bonded carboxyl oxygen atoms, which preferentially interact with the protonated amine molecules through a hydrogen-bond network. The different illustrations show the structural diversity of uranyl-organic coordination polymers with organic

Improved creep strength of nickel-base superalloys by optimized γ/γ′ partitioning behavior of solid solution strengthening elements

International Nuclear Information System (INIS)

Pröbstle, M.; Neumeier, S.; Feldner, P.; Rettig, R.; Helmer, H.E.; Singer, R.F.; Göken, M.

2016-01-01

Solid solution strengthening of the γ matrix is one key factor for improving the creep strength of single crystal nickel-base superalloys at high temperatures. Therefore a strong partitioning of solid solution hardening elements to the matrix is beneficial for high temperature creep strength. Different Rhenium-free alloys which are derived from CMSX-4 are investigated. The alloys have been characterized regarding microstructure, phase compositions as well as creep strength. It is found that increasing the Titanium (Ti) as well as the Tungsten (W) content causes a stronger partitioning of the solid solution strengtheners, in particular W, to the γ phase. As a result the creep resistance is significantly improved. Based on these ideas, a Rhenium-free alloy with an optimized chemistry regarding the partitioning behavior of W is developed and validated in the present study. It shows comparable creep strength to the Rhenium containing second generation alloy CMSX-4 in the high temperature / low stress creep regime and is less prone to the formation of deleterious topologically close packed (TCP) phases. This more effective usage of solid solution strengtheners can enhance the creep properties of nickel-base superalloys while reducing the content of strategic elements like Rhenium.

A randomised, phase II study of repeated rhenium-188-HEDP combined with docetaxel and prednisone versus docetaxel and prednisone alone in castration-resistant prostate cancer (CRPC) metastatic to bone; the Taxium II trial

Energy Technology Data Exchange (ETDEWEB)

Dodewaard-de Jong, Joyce M. van [VU University Medical Centre, Department of Medical Oncology, Amsterdam (Netherlands); Meander Medical Centre, Department of Medical Oncology, Amersfoort (Netherlands); Klerk, John M.H. de [Meander Medical Centre, Department of Nuclear Medicine, Amersfoort (Netherlands); Bloemendal, Haiko J. [Meander Medical Centre, Department of Medical Oncology, Amersfoort (Netherlands); University Medical Centre Utrecht, Department of Medical Oncology, Utrecht (Netherlands); Oprea-Lager, Daniela E.; Hoekstra, Otto S. [VU University Medical Centre, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Berg, H.P. van den [Tergooi Medical Hospital, Department of Medical Oncology, Hilversum (Netherlands); Los, Maartje [St Antonius Hospital Utrecht, Department of Medical Oncology, Utrecht (Netherlands); Beeker, Aart [Spaarne Gasthuis, Department of Medical Oncology, Hoofddorp (Netherlands); Jonker, Marianne A. [VU University Medical Centre, Department of Epidemiology and Biostatistics, Amsterdam (Netherlands); O' Sullivan, Joe M. [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast, Northern Ireland (United Kingdom); Verheul, Henk M.W.; Eertwegh, Alfons J.M. van den [VU University Medical Centre, Department of Medical Oncology, Amsterdam (Netherlands)

2017-08-15

Rhenium-188-HEDP is a beta-emitting radiopharmaceutical used for palliation of metastatic bone pain. We investigated whether the addition of rhenium-188-HEDP to docetaxel/prednisone improved efficacy of chemotherapy in patients with CRPC. Patients with progressive CRPC and osteoblastic bone metastases were randomised for first-line docetaxel 75 mg/m{sup 2} 3-weekly plus prednisone with or without 2 injections of rhenium-188-HEDP after the third (40 MBq/kg) and after the sixth (20 MBq/kg) cycle of docetaxel. Primary endpoint was progression-free survival (PFS), defined as either PSA, radiographic or clinical progression. Patients were stratified by extent of bone metastases and hospital. Forty-two patients were randomised for standard treatment and 46 patients for combination therapy. Median number of cycles of docetaxel was 9 in the control group and 8 in the experimental group. Median follow-up was 18.4 months. Two patients from the experimental group did not start treatment after randomisation. In the intention to treat analysis no differences in PFS, survival and PSA became apparent between the two groups. In an exploratory per-protocol analysis median overall survival was significantly longer in the experimental group (33.8 months (95%CI 31.75-35.85)) than in the control group (21.0 months (95%CI 13.61-28.39); p 0.012). Also median PFS in patients with a baseline phosphatase >220U/L was significantly better with combination treatment (9.0 months (95%CI 3.92-14.08) versus 6.2 months (95%CI 3.08-9.32); log rank p 0.005). As expected, thrombocytopenia (grade I/II) was reported more frequently in the experimental group (25% versus 0%). Combined treatment with rhenium-188-HEDP and docetaxel did not prolong PFS in patients with CRPC. The observed survival benefit in the per-protocol analysis warrants further studies in the combined treatment of chemotherapy and radiopharmaceuticals. (orig.)

Effects of Rhenium Addition on the Temporal Evolution of the Nanostructure and Chemistry of a Model Ni-Cr-Al Superalloy. 1; Experimental Observations

Science.gov (United States)

Yoon, Kevin E.; Noebe, Ronald D.; Seidman, David N.

2006-01-01

The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at.% Cr-10 at. % Al alloy, with the addition of 2 at.% Re, aged at 1073 K from 0.25 to 264 h, was studied. Transmission electron microscopy and atom-probe tomography were used to measure the number density and mean radius of the gamma prime (L1(sub 2) structure)-precipitates and the chemistry of the gamma prime-precipitates and the gamma (face-centered cubic)-matrix, including the partitioning behavior of all alloying elements between the gamma- and gamma prime-phases and the segregation behavior at gamma/gamma prime interfaces. The precipitates remained spheroidal for an aging time of up to 264 h and, unlike commercial nickel-based superalloys containing Re, there was not confined (nonmonotonic) Re segregation at the gamma/gamma prime interfaces.

Crystal chemistry, properties and synthesis of microporous silicates containing transition elements

International Nuclear Information System (INIS)

Chukanov, Nikita V; Pekov, Igor V; Rastsvetaeva, Ramiza K

2004-01-01

The review surveys and generalises recent data on synthesis methods, physicochemical properties and crystal chemistry of silicate microporous materials containing transition elements (amphoterosilicates). The frameworks of these materials, unlike those of usual aluminosilicate zeolites, are built from tetrahedrally coordinated atoms along with atoms of various elements (Ti, Nb, Zr, Ta, Sn, W, Fe, Mn, Zn, etc.) with coordination numbers of 6 or 5. Many amphoterosilicates possess ion-exchange properties and can serve as catalysts for redox reactions, sorbents, etc. The structural diversity of synthetic and natural amphoterosilicates provides the basis for the preparation of microporous materials with different properties.

Rhenium complexes of chromophore-appended dipicolylamine ligands: syntheses, spectroscopic properties, DNA binding and X-ray crystal structure

International Nuclear Information System (INIS)

Mullice, L.A.; Buurma, N.J.; Pope, S.J.A.; Laye, R.H.; Harding, L.P.

2008-01-01

The syntheses of two chromophore-appended dipicolylamine-derived ligands and their reactivity with penta-carbonyl-chloro-rhenium have been studied. The resultant complexes each possess the fac-Re(CO) 3 core. The ligands L 1 1-[bis(pyridine-2-yl-methyl)amino]methyl-pyrene and L 2 2-[bis(pyridine-2-yl-methyl)amino]methyl-quinoxaline were isolated via a one-pot reductive amination in moderate yield. The corresponding rhenium complexes were isolated in good yields and characterised by 1 H NMR, MS, IR and UV-Vis studies. X-Ray crystallographic data were obtained for fac-{Re(CO) 3 (L 1 )}(BF 4 ), C 34 H 26 BF 4 N 4 O 3 Re: monoclinic, P2(1)/c, a 18.327(2) Angstroms, α = 90.00 degrees, b 14.1537(14) Angstroms, β96.263(6) degrees, c = 23.511(3) Angstroms, γ 90.00 Angstroms, 6062.4(11) (Angstroms) 3 , Z=8. The luminescence properties of the ligands and complexes were also investigated, with the emission attributed to the appended chromophore in each case. Isothermal titration calorimetry suggests that fac-{Re(CO) 3 (L 1 )}(BF 4 ) self-aggregates cooperatively in aqueous solution, probably forming micelle-like aggregates with a cmc of 0.18 mM. Investigations into the DNA-binding properties of fac-{Re(CO) 3 (L 1 )}(BF 4 ) were undertaken and revealed that fac-{Re(CO) 3 (L 1 )}(BF 4 ) binding to fish sperm DNA (binding constant 1.5 ± 0.2 * 10 5 M -1 , binding site size 3.2 ± 0.3 base pairs) is accompanied by changes in the UV-Vis spectrum as typically observed for pyrene-based intercalators while the calorimetrically determined binding enthalpy (-14 ± 2 kcal mol -1 ) also agrees favourably with values as typically found for intercalators. (authors)

Phosphorene/rhenium disulfide heterojunction-based negative differential resistance device for multi-valued logic

Science.gov (United States)

Shim, Jaewoo; Oh, Seyong; Kang, Dong-Ho; Jo, Seo-Hyeon; Ali, Muhammad Hasnain; Choi, Woo-Young; Heo, Keun; Jeon, Jaeho; Lee, Sungjoo; Kim, Minwoo; Song, Young Jae; Park, Jin-Hong

2016-01-01

Recently, negative differential resistance devices have attracted considerable attention due to their folded current–voltage characteristic, which presents multiple threshold voltage values. Because of this remarkable property, studies associated with the negative differential resistance devices have been explored for realizing multi-valued logic applications. Here we demonstrate a negative differential resistance device based on a phosphorene/rhenium disulfide (BP/ReS2) heterojunction that is formed by type-III broken-gap band alignment, showing high peak-to-valley current ratio values of 4.2 and 6.9 at room temperature and 180 K, respectively. Also, the carrier transport mechanism of the BP/ReS2 negative differential resistance device is investigated in detail by analysing the tunnelling and diffusion currents at various temperatures with the proposed analytic negative differential resistance device model. Finally, we demonstrate a ternary inverter as a multi-valued logic application. This study of a two-dimensional material heterojunction is a step forward toward future multi-valued logic device research. PMID:27819264

Phosphorene/rhenium disulfide heterojunction-based negative differential resistance device for multi-valued logic

Science.gov (United States)

Shim, Jaewoo; Oh, Seyong; Kang, Dong-Ho; Jo, Seo-Hyeon; Ali, Muhammad Hasnain; Choi, Woo-Young; Heo, Keun; Jeon, Jaeho; Lee, Sungjoo; Kim, Minwoo; Song, Young Jae; Park, Jin-Hong

2016-11-01

Recently, negative differential resistance devices have attracted considerable attention due to their folded current-voltage characteristic, which presents multiple threshold voltage values. Because of this remarkable property, studies associated with the negative differential resistance devices have been explored for realizing multi-valued logic applications. Here we demonstrate a negative differential resistance device based on a phosphorene/rhenium disulfide (BP/ReS2) heterojunction that is formed by type-III broken-gap band alignment, showing high peak-to-valley current ratio values of 4.2 and 6.9 at room temperature and 180 K, respectively. Also, the carrier transport mechanism of the BP/ReS2 negative differential resistance device is investigated in detail by analysing the tunnelling and diffusion currents at various temperatures with the proposed analytic negative differential resistance device model. Finally, we demonstrate a ternary inverter as a multi-valued logic application. This study of a two-dimensional material heterojunction is a step forward toward future multi-valued logic device research.

Design, synthesis, and characterization of 0-D, 1-D, and 2-D Zinc–Adeninate coordination assemblies

Energy Technology Data Exchange (ETDEWEB)

An, Ji Hyun [Dept. of Chemistry Education, Seoul National University, Seoul (Korea, Republic of); Geib, Steven J. [Dept. of Chemistry, University of Pittsburgh, Pittsburgh (United States); Kim, Myung Gil [Dept. of Chemistry, Chungang University, Seoul (Korea, Republic of)

2015-08-15

In this study, we demonstrate the synthesis and characterization of zinc– adeninate coordination polymers with 0-D, 1-D, and 2-D structures. We describe methods for controlling the structure of these materials by applying different synthetic conditions and discuss their structural relationships. 0-D, 1-D, and 2-D zinc–adeninate coordination polymers with the same metal–adeninate coordination mode were synthesized and characterized. By controlling the temperature, a material with 0-D macrocycle or 1-D chain coordination polymer was prepared. A replacement of pyridine with bipyridine formed 2-D sheet structure by connecting 1-D chains with each other. They exhibited an interesting relationship between synthetic methods and structures. Further study of metal–adeninate coordination chemistry will render a precise control of the structure in synthesis and will open a new venue to new materials with fascinating properties.

Proceedings of the Third CSNI Workshop on Iodine Chemistry in Reactor Safety

International Nuclear Information System (INIS)

Ishigure, K.; Saeki, M.; Soda, K.; Sugimoto, J.

1992-03-01

The Third CSNI Workshop on Iodine Chemistry in Reactor Safety was held at Tokai Research Establishment of Japan Atomic Energy Research Institute at Tokai-mura, Ibaraki-ken, Japan, on September 11 to 13, 1991. About 60 experts attended the Workshop from 10 countries and 2 international organizations. In the Workshop, 29 papers were presented in five sessions on various aspects of iodine chemistry in reactor safety, such as radiolytic and surface reactions of iodine species, fundamental and integral tests, modeling and code developments. The information exchanged and the discussions followed resulted in extended and promoted understanding of iodine behavior in accidents of light water reactors and also gave a large expectation for the further progresses coming in the future. It should be emphasized that a most important and unique forum has been established through the Workshop for exchanging information and collaboratively solving the important problems in the field of the iodine chemistry in nuclear reactor safety. At the Workshop, an effort was made to integrate all information for better use by safety analysts. There is no doubt that a lot of information on iodine behaviour has been accumulated, but in many cases this information needs to be co-ordinated and well organised for safety analyses of nuclear reactors. It is essential that the results of laboratory studies and integral experiments together with modelling activities are well co-ordinated. Therefore, the goal was: - to review the knowledge and understanding of the chemistry of iodine of relevance to the prediction of its behaviour in nuclear reactors during a range of operational and accident conditions; - to define those areas of chemistry which are important but poorly understood and require further study. As shown by the conclusions of the Workshop, there is no doubt that this objective was widely attained

Thermal transformations of oxohalide complexes of rhenium(5) and molybdenum(5) with diazo-18-crown-6 in solid phase

International Nuclear Information System (INIS)

Ashurova, N.Kh.; Yakubov, K.G.

1992-01-01

Methods for synthesis and separation in solid state of the rhenium(5) and molybdenum(5) onium complexes with diaza-18-crown-6(L), the content of which according to the data of elementary analysis, IRS in the close and remote areas, thermogravimetry, conductometry and potentiometry corresponds to the (H 2 L)[EOX 5 ], where E = Re, Mo; X = Cl - , Br - . Thermotransformation of onium compounds is studied by methods of thermal methods (TG-DTG-DTA combined study). Their avility to be affected by solid-phase dehydrohalogenization, e.i. anderson regrouping. The thermolysis products, corresponding to the general formula (EOLX 3 ), are separated and studied

Rhenium-188 - advantages and clinical potential for use of a readily available, cost effective therapeutic radioisotope for applications in nuclear medicine, oncology and interventional cardiology

International Nuclear Information System (INIS)

Knapp, F.F. jr.

2002-01-01

Full text: Carrier-free rhenium-188 (Re-188) is readily available from the alumina-based tungsten-188/rhenium-188 generator system and has many attractive properties for a wide variety of therapeutic applications. The 16.9 h half-life, emission of the 2.2 MeV beta particle and versatile chemistry make Re-188 an important candidate for applications where high radiation penetration is required. In addition, emission of a gamma photon (155 KeV, 15 %) permits evaluation of biodistribution, pharmacokinetics and dosimetry estimates. The long physical half-life of the tungsten-188 (W-188) parent (t 1/2 69 days) and consistent generator performance - with high Re-188 yields and low W-188 parent breakthrough - result in an indefinite shelf-life of several months, dependent on the levels of Re-188 required. Post generator elution in-growth of 62 % of Re-188 after 24 hours in combination with high elution yields (75-85 %) result in 50 % daily yields of the maximal Re-188 available. In addition to research being conducted for the development of a wide variety of new therapeutic radiopharmaceuticals and devices, Re-188 is also being evaluated in physician-sponsored clinical trials in over 15 countries, with applications in nuclear medicine, oncology and interventional cardiology. One major current clinical application involves post-angiographic treatment of arterial segments following PTCA using Re-188 perrhenate or MAG3 liquid-filled balloons as an effective and cost-effective approach for inhibition of the hyperplastic response to vessel damage, which delivers uniform dose to the vessel wall. Re-188-HEDP is being used for palliation of metastatic bone pain palliation. This agent is readily prepared from a simple 'kit' and provides pain palliation as effective as other commercially available agents. The use of the Re-188-labeled Anti-NCA-95 antibody (BW 50/183; CD66 a,b,c,e) in conjunction which external beam irradiation and chemotherapy is an effective method for

Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

Energy Technology Data Exchange (ETDEWEB)

Even, Julia

2011-12-13

Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

The coordination chemistry of nitrosyl in cyanoferrates. An exhibit of bioinorganic relevant reactions.

Science.gov (United States)

Olabe, José A

2008-07-28

Sodium nitroprusside (SNP, Na(2)[Fe(CN)(5)(NO)].2H(2)O) is a widely used NO-donor hypotensive agent, containing the formally described nitrosonium (NO(+)) ligand, which may be redox-interconverted to the corresponding one-electron (NO) and two-electron (NO(-)/HNO) reduced bound species. Thus, the chemistry of the three nitrosyl ligands may be explored with adequate, biologically relevant substrates. The nitrosonium complex, [Fe(CN)(5)(NO)](2-), is formed through a reductive nitrosylation reaction of [Fe(III)(CN)(5)(H(2)O)](2-) with NO, or, alternatively, through the coordination of NO(2)(-) to [Fe(II)(CN)(5)(H(2)O)](3-) and further proton-assisted dehydration. It is extremely inert toward NO(+)-dissociation, and behaves as an electrophile toward different bases: OH(-), amines, thiolates, etc. Also, SNP releases NO upon UV-vis photo-activation, with formation of [Fe(III)(CN)(5)(H(2)O)](2-). The more electron rich [Fe(CN)(5)(NO)](3-) may be prepared from [Fe(II)(CN)(5)(H(2)O)](3-) and NO, and is also highly inert toward the dissociation of NO (k = 1.6 x 10(-5) s(-1), 25.0 degrees C, pH 10.2). It reacts with O(2) leading to SNP, with the intermediacy of a peroxynitrite adduct. The [Fe(CN)(5)(NO)](3-) ion is labile toward the release of trans-cyanide, forming the [Fe(CN)(4)(NO)](2-) ion. Both complexes exist in a pH-dependent equilibrium, and decompose thermally in the hours time scale, releasing cyanides and NO. The latter may further bind to [Fe(CN)(4)(NO)](2-) with formation of a singlet dinitrosyl species, [Fe(CN)(4)(NO)(2)](2-), which in turn is unstable toward disproportionation into SNP and N(2)O, and toward the parallel formation of a tetrahedral paramagnetic dinitrosyl compound, [Fe(CN)(2)(NO)(2)]. Emerging studies with the putative nitroxyl complex, [Fe(CN)(5)(HNO)](3-), should allow for a complete picture of the three nitrosyl ligands in the same pentacyano fragment. The present Perspective, based on an adequate characterization of structural and

Pyranopterin Coordination Controls Molybdenum Electrochemistry in Escherichia coli Nitrate Reductase.

Science.gov (United States)

Wu, Sheng-Yi; Rothery, Richard A; Weiner, Joel H

2015-10-09

We test the hypothesis that pyranopterin (PPT) coordination plays a critical role in defining molybdenum active site redox chemistry and reactivity in the mononuclear molybdoenzymes. The molybdenum atom of Escherichia coli nitrate reductase A (NarGHI) is coordinated by two PPT-dithiolene chelates that are defined as proximal and distal based on their proximity to a [4Fe-4S] cluster known as FS0. We examined variants of two sets of residues involved in PPT coordination: (i) those interacting directly or indirectly with the pyran oxygen of the bicyclic distal PPT (NarG-Ser(719), NarG-His(1163), and NarG-His(1184)); and (ii) those involved in bridging the two PPTs and stabilizing the oxidation state of the proximal PPT (NarG-His(1092) and NarG-His(1098)). A S719A variant has essentially no effect on the overall Mo(VI/IV) reduction potential, whereas the H1163A and H1184A variants elicit large effects (ΔEm values of -88 and -36 mV, respectively). Ala variants of His(1092) and His(1098) also elicit large ΔEm values of -143 and -101 mV, respectively. An Arg variant of His(1092) elicits a small ΔEm of +18 mV on the Mo(VI/IV) reduction potential. There is a linear correlation between the molybdenum Em value and both enzyme activity and the ability to support anaerobic respiratory growth on nitrate. These data support a non-innocent role for the PPT moieties in controlling active site metal redox chemistry and catalysis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Pyranopterin Coordination Controls Molybdenum Electrochemistry in Escherichia coli Nitrate Reductase*

Science.gov (United States)

Wu, Sheng-Yi; Rothery, Richard A.; Weiner, Joel H.

2015-01-01

We test the hypothesis that pyranopterin (PPT) coordination plays a critical role in defining molybdenum active site redox chemistry and reactivity in the mononuclear molybdoenzymes. The molybdenum atom of Escherichia coli nitrate reductase A (NarGHI) is coordinated by two PPT-dithiolene chelates that are defined as proximal and distal based on their proximity to a [4Fe-4S] cluster known as FS0. We examined variants of two sets of residues involved in PPT coordination: (i) those interacting directly or indirectly with the pyran oxygen of the bicyclic distal PPT (NarG-Ser719, NarG-His1163, and NarG-His1184); and (ii) those involved in bridging the two PPTs and stabilizing the oxidation state of the proximal PPT (NarG-His1092 and NarG-His1098). A S719A variant has essentially no effect on the overall Mo(VI/IV) reduction potential, whereas the H1163A and H1184A variants elicit large effects (ΔEm values of −88 and −36 mV, respectively). Ala variants of His1092 and His1098 also elicit large ΔEm values of −143 and −101 mV, respectively. An Arg variant of His1092 elicits a small ΔEm of +18 mV on the Mo(VI/IV) reduction potential. There is a linear correlation between the molybdenum Em value and both enzyme activity and the ability to support anaerobic respiratory growth on nitrate. These data support a non-innocent role for the PPT moieties in controlling active site metal redox chemistry and catalysis. PMID:26297003

Liaison activities with the Institute of Physical Chemistry, Russian Academy of Sciences: FY 1997

International Nuclear Information System (INIS)

Delegard, C.H.; Elovich, R.J.

1997-09-01

The Institute of Physical Chemistry of the Russian Academy of Sciences is conducting a program of fundamental and applied research into the chemistry of the actinides and technetium in alkaline media such as are present in the Hanford Site underground waste storage tanks. This work is being coordinated and the results disseminated through a technical liaison maintained at the Pacific Northwest National Laboratory. The technical liaison is performing laboratory studies on plutonium chemistry in alkaline media. The activities at the Institute of Physical Chemistry and through the liaison are pursued to improve understanding of the chemical behavior of key long-lived radioactive elements under current operating and proposed tank waste processing conditions. Both activities are supported by the Efficient Separations and Processing Crosscutting Program under the Office of Science and Technology of the U.S. Department of Energy

Annual reports in inorganic and general syntheses 1972

CERN Document Server

Niedenzu, Kurt

1973-01-01

Annual Reports in Inorganic and General Syntheses-1972 presents an organized annual summary of synthetic developments in inorganic chemistry and its related areas. The book discusses alkali and alkaline earth elements, alloys, silver, gold, zinc, cadmium, mercury, boron, aluminum, gallium, indium, thallium, yttrium, scandium, lanthanides, actinides, titanium, zirconium, hafnium, Group V and VI transition elements, manganese, technetium, rhenium, iron, cobalt, nickel, ruthenium, osmium, rhodium, and iridium. The text also describes the chemistry of palladium, platinum, silicon, germanium, tin,

Design criteria for rhenium-reduced nickel-based single-crystal alloys. Identification and computer-assisted conversion; Designkriterien fuer rheniumreduzierte Nickelbasis-Einkristalllegierungen. Identifikation und rechnergestuetzte Umsetzung

Energy Technology Data Exchange (ETDEWEB)

Goehler, Thomas

2016-06-17

In the present work, design criteria and property models for the creep strength optimization of rhenium-free nickel based single crystal Superalloys are investigated. The study focuses on a typical load condition of 1050 C and 150 MPa, which is representative for flight engine applications. Thereby the key aspect is to link chemical composition, manufacturing processes, microstructure formation and mechanistic understanding of dislocation creep through a computational materials engineering approach. Beside the positive effect of rhenium on solid solution hardening, a second mechanism in which rhenium increases high temperature creep strength is identified. It indirectly stabilizes precipitation hardening by reducing the coarsening kinetics of γ'-rafting. Five 1st and 2nd generation technical Superalloys show a comparable microstructure evolution for up to 2 % plastic elongation, while creep times differ by a factor of five. The application of a microstructure sensitive creep model shows that these coarsening processes can activate γ-cutting and thus lead to an increasing creep rate. Based on these calculations a threshold value of φ{sub γ/γ'} > 2,5 at 150 MPa is estimated. This ratio of matrix channel to raft thickness has been proofed for multiple positions by microstructure analysis of interrupted creep tests. The mechanism described previously can be decelerated by the enrichment of the γ-matrix with slow diffusing elements. The same principle also increases the solid solution strength of the γ-matrix. Therefore, the present work delivers an additional mechanistic explanation why creep properties of single phase nickel based alloys can be transferred to two phase technical Superalloys with rafted γ'-structure. Following, the best way to substitute both rhenium fundamental properties, namely a slow diffusion coefficient and a small solubility in g', has been investigated by means of CALPHAD-modeling. Only molybdenum and especially

Thermal decomposition of rhenium (5) complexes with 1,2,4-triazole. Termicheskoe razlozhenie kompleksov reniya (5) s 1,2,4-triazolom

Energy Technology Data Exchange (ETDEWEB)

Amindzhanov, A A; Gagieva, S Ch; Kotegov, K V [Tadzhikskij Gosudarstvennyj Univ., Dushanbe (Tajikistan)

1991-01-01

Processes of thermal decomposition of rhenium (5) complexes with 1,2,4-triazole were studied. Thermolysis products were identified on the basis of data of the element analysis, IR spectra, conductometry and other methods. It is ascertained that at the first stage of thermolysis of hydroxyl-containing monomer complexes removal of water molecules occurs, and at the second one - dimerization process with formation of Re-O-Re group. It is shown that the nature of halide ion practically does not affect the temperature of the start of intensive thermal decomposition of the complexes.

Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plant (FUWAC)

International Nuclear Information System (INIS)

2011-10-01

This report presents the results of the Coordinated Research Project (CRP) on Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plants (FUWAC, 2006-2009). It provides an overview of the results of the investigations into the current state of water chemistry practice and concerns in the primary circuit of water cooled power reactors including: corrosion of primary circuit materials; deposit composition and thickness on the fuel; crud induced power shift; fuel oxide growth and thickness; radioactivity buildup in the reactor coolant system (RCS). The FUWAC CRP is a follow-up to the DAWAC CRP (Data Processing Technologies and Diagnostics for Water Chemistry and Corrosion Control in Nuclear Power Plants 2001-2005). The DAWAC project improved the data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (NPPs). With the improved methods for controlling and monitoring water chemistry now available, it was felt that a review of the principles of water chemistry management should be undertaken in the light of new materials, more onerous operating conditions, emergent issues such as CIPS, also known as axial offset anomaly (AOA) and the ageing of operating power plant. In the framework of this CRP, water chemistry specialists from 16 nuclear utilities and research organizations, representing 15 countries, exchanged experimental and operational data, models and insights into water chemistry management. The CD-ROM attached to this IAEA-TECDOC includes the report itself, detailed progress reports of three Research Coordination Meetings (RCMs) (Annexes I-III) and the reports and presentations made during the project by the participants.

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

Directory of Open Access Journals (Sweden)

Vladislav Vasilenko

2016-04-01

Full Text Available We report the modular synthesis of three different types of neutral κ2-P,N-ligands comprising an imine and a phosphine binding site. These ligands were reacted with rhodium, iridium and palladium metal precursors and the structures of the resulting complexes were elucidated by means of X-ray crystallography. We observed that subtle changes of the ligand backbone have a significant influence on the binding geometry und coordination properties of these bidentate P,N-donors.

Highly effective synthesis of a cobalt(ii) metal-organic coordination polymer by using continuous flow chemistry.

Science.gov (United States)

Gong, Chunhua; Zhang, Junyong; Zeng, Xianghua; Xie, Jingli

2016-12-20

The coordination polymer [Co 2 L 4 (H 2 O) 2 ]·CH 3 CN·H 2 O (HL = (E)-2-[2-(4-chlorophenyl)vinyl]-8-hydroxyquinoline) has been achieved with 95% yield by using an Asia flow synthesis system (chip reactor). Compared with the conventional batch-type methods such as diffusion, reflux and solvothermal reactions, higher yielding reactions carried out in a flow reactor have demonstrated that this technique is a powerful strategy to obtain coordination compounds.

A polythreaded Ag(I) coordination polymer: A rare three-dimensional Pseudo-polyrotaxana constructed from the same components

Energy Technology Data Exchange (ETDEWEB)

Im, Han Su; Lee, Eunji; Lee, Shim Sung; Kim, Tae Ho; Park, Ki Min [Research Institute of Natural Science and Dept. of Chemistry, Gyeongsang National University, Jinju (Korea, Republic of); Moon, Suk Hee [Dept. of Food and Nutrition, Kyungnam College of Information and Technology, Busan (Korea, Republic of)

2017-01-15

In supramolecular chemistry, a lot of mechanically poly-threaded coordination polymers, such as polyrotaxanes, based on self-assembly of organic ligands and transition metal ions have attracted great attention over the past two decades because of their fascinating architectures as well as their potential application in material science. Among them, 1D + 2D → 3D pseudo-polyrotaxane constructed by the penetration of 1D coordination polymer chains into 1D channels formed by parallel stacking of 2D porous coordination layers is a quite rare topology. Until now, only a few examples of 1D + 2D → 3D pseudo-polyrotaxanes have been reported.

A polythreaded Ag(I) coordination polymer: A rare three-dimensional Pseudo-polyrotaxana constructed from the same components

International Nuclear Information System (INIS)

Im, Han Su; Lee, Eunji; Lee, Shim Sung; Kim, Tae Ho; Park, Ki Min; Moon, Suk Hee

2017-01-01

In supramolecular chemistry, a lot of mechanically poly-threaded coordination polymers, such as polyrotaxanes, based on self-assembly of organic ligands and transition metal ions have attracted great attention over the past two decades because of their fascinating architectures as well as their potential application in material science. Among them, 1D + 2D → 3D pseudo-polyrotaxane constructed by the penetration of 1D coordination polymer chains into 1D channels formed by parallel stacking of 2D porous coordination layers is a quite rare topology. Until now, only a few examples of 1D + 2D → 3D pseudo-polyrotaxanes have been reported

Relativistic effects in spectroscopy and photophysics of heavy-metal complexes illustrated by spin–orbit calculations of [Re(imidazole)(CO)3(phen)]+

Czech Academy of Sciences Publication Activity Database

Baková, Radka; Chergui, M.; Daniel, CH.; Vlček, Antonín; Záliš, Stanislav

2011-01-01

Roč. 255, 7-8 (2011), s. 975-989 ISSN 0010-8545 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk LD11086 Institutional research plan: CEZ:AV0Z40400503 Keywords : rhenium * carbonyl * diimine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.110, year: 2011

Die kunjugative Verbrückung metallorganischer Reaktionszentren Heterozweikernkomplexen [(OC)3ClRe(.mu.-L)MCl(C5Me5)]+, M=Rh oder Ir Spektroskopische Konsequenzen reduktiver Aktivierung

Czech Academy of Sciences Publication Activity Database

Kaim, W.; Scheiring, T.; Weber, M.; Fiedler, Jan

2004-01-01

Roč. 630, - (2004), s. 1883-1893 ISSN 0044-2313 R&D Projects: GA MŠk OC D15.10; GA MŠk OC D14.20 Institutional research plan: CEZ:AV0Z4040901 Keywords : electrochemistry * iridium * rhenium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.086, year: 2004

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.

Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

International Nuclear Information System (INIS)

Even, Julia

2011-01-01

Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

Coordination chemistry of nickel(II) nitrate with superbasic guanidines studied by electrospray mass spectrometry

Czech Academy of Sciences Publication Activity Database

Glasovac, Z.; Štrukil, V.; Eckert-Maksič, M.; Schröder, Detlef; Schlangen, M.; Schwarz, H.

2010-01-01

Roč. 290, č. 1 (2010), s. 22-31 ISSN 1387-3806 R&D Projects: GA ČR GA203/08/1487 Grant - others: ERC (XE) HORIZOMS AdG226373 Institutional research plan: CEZ:AV0Z40550506 Keywords : electrospray ionization * guanidine * ion association * nickel(II) nitrate * solvation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.009, year: 2010

Emission Data For Climate-Chemistry Interactions

Science.gov (United States)

Smith, S. J.

2012-12-01

Data on anthropogenic and natural emissions of reactive species are a critical input for studies of atmospheric chemistry and climate. The availability and characteristics of anthropogenic emissions data that can be used for such studies are reviewed and pathways for future work discuss Global and regional datasets for historical and future emissions are available, but their characteristics and applicability for specific studies differ. For the first time, a coordinated set of historical emissions (Lamarque et al 2010) and the future projections (van Vuurren et al. 2011) have been developed for use in the CMIP5 and ACCMIP long-term simulation comparison projects. These data have decadal resolution and were designed for long-term, global simulations. These data, however, lack finer-scale spatial and temporal detail that might be needed for some studies. Robust and timely updates of emissions data is generally lacking, although recent updates will be presented. While historical emission data is often treated as known, emissions are uncertain, even though this uncertainty is rarely quantified. Uncertainty varies by species and location. Inverse modeling is starting to indicate where emission data may be uncertain, which opens the way to improving these data overall. Further interaction between the chemistry modeling and inventory development communities are needed. Future projections are intrinsically uncertain, and while institutions and processes are in place to develop and review long-term century-scale scenarios, a need has remained for a wider range in shorter-term (e.g., several decade) projections. Emissions and scenario development communities have been working to fill this need. Communication across disciplines of the assumptions embedded in emissions projections remains a challenge. Atmospheric chemistry models are a central tool needed for studying chemistry-climate interactions. Simpler models, however, are also needed in order to examine interactions

Summary Report for April, May and June, 1951, Chemistry Division, Section C-1

Energy Technology Data Exchange (ETDEWEB)

Manning, W. M. [Argonne National Lab. (ANL), Argonne, IL (United States). Chemistry Division; Osborne, D. W. [Argonne National Lab. (ANL), Argonne, IL (United States). Chemistry Division

1951-08-01

This is a summary report for April, May and June, 1951, in the Chemistry Division, Section C-1 of Argonne National Laboratory. Topics include Nuclear Chemistry and Radiochemistry with specifics about the following: 1) U²³⁸ (n,2n) Cross Section WIthin a Uranium Slug, and 2) Possible Occurrence of Si³² in Nature. Basic Chemistry is also covered, going into the following subjects: 1) Heats of Solution of Salts in Organic Solvents, 2) Effect of Coordination on Absorption Spectra of Anions, 3) Entropy, Enthalpy, and Heat Capacity of Thorium Dioxide from 10 to 300°K, 4) The Thermodynamics of Neptunium Ions, 5) Migration of Ions in Ion-Exchange Resins During Electrolysis, and 5) Mutual Separation of Lanthanides and Actinides by Solvent Extraction Techniques.

Laser-induced breakdown spectroscopy measurement of a small fraction of rhenium in bulk tungsten

Science.gov (United States)

Nishijima, D.; Ueda, Y.; Doerner, R. P.; Baldwin, M. J.; Ibano, K.

2018-03-01

Laser-induced breakdown spectroscopy (LIBS) of bulk rhenium (Re) and tungsten (W)-Re alloy has been performed using a Q-switched Nd:YAG laser (wavelength = 1064 nm, pulse width ∼4-6 ns, laser energy = 115 mJ). It is found that the electron temperature, Te, of laser-induced Re plasma is lower than that of W plasma, and that Te of W-Re plasma is in between Re and W plasmas. This indicates that material properties affect Te in a laser-induced plasma. For analysis of W-3.3%Re alloy, only the strongest visible Re I 488.9 nm line is found to be used because of the strong enough intensity without contamination with W lines. Using the calibration-free LIBS method, the atomic fraction of Re, cRe, is evaluated as a function of the ambient Ar gas pressure, PAr. At PAr 10 Torr due to spectral overlapping of the Re I 488.9 nm line by an Ar II 488.9 nm line.

Prototype commercial electrooxidation cell for the recovery of molybdenum and rhenium from molybdenite concentrates

International Nuclear Information System (INIS)

Scheiner, B.J.; Pool, D.L.; Lindstrom, R.E.; McCleland, G.E.

1979-01-01

As part of the goal to maximize minerals and metals recovery from primary domestic resources, design factors associated with minimizing current leakage in bipolar cell configurations were studied as a means of improving the efficiency of bipolar electrooxidation cells. Initial studies that were conducted in a small bipolar cell operating at 140 to 145 volts and 15.4 A indicated how design factors could be employed to minimize current leakage around adjacent electrodes during cell operation. Based on these results, a 40-electrode, 108-kVA prototype of an industrial-sized cell was constructed and tested for extracting metal values from offgrade molybdenite concentrates. The feasibility of recovering molybdenum and rhenium from the oxidized pulp also was determined. Feed to the process sequence consisted of flotation concentrates containing 16 to 35% Mo as molybdenite and 6 to 15% Cu. Electrooxidation in the prototype cell results in 84 to 97% Mo and Re extraction with a corresponding energy consumption of 9 to 13 kWh/lb Mo extracted

Solvent-free porous framework resulted from 3D entanglement of 1D zigzag coordination polymer

KAUST Repository

Kole, Goutam Kumar Umar

2010-01-01

A solvent-free porous metal organic framework is constructed by the 3D entanglement of 1D zigzag coordination polymeric chains. The role of solvents and the effect of reaction conditions on such unique entanglement are addressed. © 2010 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

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

Organoactinide chemistry: synthesis, structure, and solution dynamics

International Nuclear Information System (INIS)

Brennan, J.G.

1985-12-01

This thesis considers three aspects of organoactinide chemistry. In chapter one, a bidentate phosphine ligand was used to kinetically stabilize complexes of the type Cp 2 MX 2 . Ligand redistribution processes are present throughout the synthetic work, as has often been observed in uranium cyclopentadienyl chemistry. The effects of covalent M-L bonding on the solution and solid state properties of U(III) coordination complexes are considered. In particular, the nature of the more subtle interaction between the metal and the neutral ligand are examined. Using relative basicity data obtained in solution, and solid state structural data (and supplemented by gas phase photoelectron measurements), it is demonstrated that the more electron rich U(III) centers engage in significant U → L π-donation. Trivalent uranium is shown to be capable of acting either as a one- or two-electron reducing agent toward a wide variety of unsaturated organic and inorganic molecules, generating molecular classes unobtainable via traditional synthetic approaches, as well as offering an alternative synthetic approach to molecules accessible via metathesis reactions. Ligand redistribution processes are again observed, but given the information concerning ligand lability, this reactivity pattern is applied to the synthesis of pure materials inaccessible from redox chemistry. 214 refs., 33 figs., 10 tabs

3,6-Bis(2-pyrazinyl)-1,2,4,5-tetrazin: Ein neuer mehrfunktioneller Ligand und sein syn,fac-konfigurierter Bis(tricarbonylchlororhenium)-Komplex

Czech Academy of Sciences Publication Activity Database

Sarkar, B.; Kaim, W.; Schleid, T.; Hartenbach, I.; Fiedler, Jan

2003-01-01

Roč. 629, - (2003), s. 1353-1357 ISSN 0044-2313 R&D Projects: GA MŠk OC D14.20; GA MŠk OC D15.10 Institutional research plan: CEZ:AV0Z4040901 Keywords : carbonyl ligands * heterocyclic ligands * rhenium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.127, year: 2003

Metal cyanides

International Nuclear Information System (INIS)

Wells, A.F.

1988-01-01

From the biewpoint of general crystal T chemistry principles and on the basis of modern data the structural chemistry of metal cyanites is presented. The features of the structure of the following compounds are considered: simple ionic alkali cyanides (Li-Cs) containing CN - ions; molybdenum (4,5), tungsten (4,5), rhenium (5,6) complexes etc, where-CN group is only connected with one metal atom; covalent cyanides of cadmium and other elements in which the CN-group serves as a bridge

Third Chemistry Conference on Recent Trends in Chemistry

International Nuclear Information System (INIS)

Saeed, M.M.; Wheed, S.

2011-01-01

The third chemistry conference 2011 on recent trends in chemistry was held from October 17-19, 2001 at Islamabad, Pakistan. More than 65 papers and oral presentation. The scope of the conference was wide open and provides and opportunity for participation of broad spectrum of chemists. This forum provided a platform for the dissemination of the latest research followed by discussion pertaining to new trends in chemistry. This con fence covered different aspects of subjects including analytical chemistry, environmental chemistry, polymer chemistry, industrial chemistry, biochemistry and nano chemistry etc. (A.B.)

SPS Fabrication of Tungsten-Rhenium Alloys in Support of NTR Fuels Development

International Nuclear Information System (INIS)

Webb, Jonathan A.; Charit, Indrajit; Sparks, Cory; Butt, Darryl P.; Frary, Megan; Carroll, Mark

2011-01-01

Tungsten metal slugs were fabricated via Spark Plasma Sintering (SPS) of powdered metals at temperatures ranging from 1575 K to 1975 K and hold times of 5 minutes to 30 minutes, using powders with an average diameter of 7.8 ?m. Sintered tungsten specimens were found to have relative densities ranging from 83 % to 94 % of the theoretical density for tungsten. Consolidated specimens were also tested for their Vickers Hardness Number (VHN), which was fitted as a function of relative density; the fully consolidated VHN was extrapolated to be 381.45 kg/mm2. Concurrently, tungsten and rhenium powders with average respective diameters of 0.5 ?m and 13.3 ?m were pre-processed either by High-Energy-Ball-Milling (HEBM) or by homogeneous mixing to yield W-25at.%Re mixtures. The powder batches were sintered at temperatures of 1975 K and 2175 K for hold times ranging from 0 minutes to 60 minutes yielding relative densities ranging from 94% to 97%. The combination of HEBM and sintering showed a significant decrease in the inter-metallic phases compared to that of the homogenous mixing and sintering.

Rhenium 188 labelling of peptide conjugates

International Nuclear Information System (INIS)

Melendez-Alafort, Laura

2001-01-01

Many human tumours express high levels, of somatostatin receptors. In order to make possible a radiotherapeutic treatment of this kind for tumour a series of somatostatin analogues that can tightly chelate beta emitting isotopes have been developed in recent years. The work carried out for this thesis has been aimed towards development of a new therapeutic radiopharmaceutical for treatment of somatostatin receptor positive tumours. The first chapters describe work with technetium-99m to establish the labelling and analytical conditions for a somatostatin analogue, [Tyr 3 ]-octreotide (TOC), as a precursor to undertaking labelling studies with the beta emitter rhenium-188. 6-Hydrazinopyridine-3-carboxylic acid (HYNIC) was conjugated to TOC and labelled with 99m using different coligands. Then the stability, receptor binding and biodistribution of each complex were assessed. 99m Tc-HYNIC-TOC using EDDA as coligand showed the best characteristics, and was superior for tumour imaging in humans than the commercially available 111 In-DTPA-octreotide. The conditions for labelling the HYNIC-TOC conjugate with 188 Re were then optimised using tricine as a co-ligand. A labelling yield of ∼80% was achieved. After purification however, the stability of the complex was low. The use of other coligand systems which had proved useful for 99m Tc labelling was explored, but yields were very poor. Other chelators such as diethylenetriamine pentaacetic acid (DTPA), dimercaptosuccinic acid (DMSA) and mercaptoacetyltriglycine (MAG 3 ) were studied as potential co-ligand agents to label the HYNIC-TOC conjugate with 188 Re but, again low yields of the labelled peptide complexes were achieved. A novel 188 Re-HYNIC complex was prepared in high yields using N-N-disubstituted dithiocarbamates as coligands. However to date, the specific activities achieved with this system are relatively low. The use of the [ 99m Tc(CO) 3 (H 2 O) 3 ] complex to label the HYNIC-TOC conjugate was investigated

Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

Science.gov (United States)

Lehn, Jean-Marie

2012-01-01

Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

Scientific conference on inorganic chemistry and radiochemistry devoted to centenary from birthday of academician V.I. Spitsyn. Program of conference and summary of reports

International Nuclear Information System (INIS)

2002-01-01

Program and summaries of reports of the Scientific conference on inorganic chemistry and radiochemistry devoted to the centenary from the birthday of academician V.I. Spitsyn are presented. The conference took place at the Chemical department of the Moscow State University named for M.V. Lomonosov 17 - 18 April, 2002. Part of the reports was devoted to the work of academician V.I. Spitsyn, his investigations into radiochemistry and radiation chemistry. Scientific explorations in the fields of solid chemistry, inorganic and coordination chemistry, radiochemistry and chemical technology are discussed [ru

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

Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plant (FUWAC). Additional Information

International Nuclear Information System (INIS)

2011-10-01

This report presents the results of the Coordinated Research Project (CRP) on Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plants (FUWAC, 2006-2009). It provides an overview of the results of the investigations into the current state of water chemistry practice and concerns in the primary circuit of water cooled power reactors including: corrosion of primary circuit materials; deposit composition and thickness on the fuel; crud induced power shift; fuel oxide growth and thickness; radioactivity buildup in the reactor coolant system (RCS). The FUWAC CRP is a follow-up to the DAWAC CRP (Data Processing Technologies and Diagnostics for Water Chemistry and Corrosion Control in Nuclear Power Plants 2001-2005). The DAWAC project improved the data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (NPPs). With the improved methods for controlling and monitoring water chemistry now available, it was felt that a review of the principles of water chemistry management should be undertaken in the light of new materials, more onerous operating conditions, emergent issues such as CIPS, also known as axial offset anomaly (AOA) and the ageing of operating power plant. In the framework of this CRP, water chemistry specialists from 16 nuclear utilities and research organizations, representing 15 countries, exchanged experimental and operational data, models and insights into water chemistry management. This CD-ROM attached to the printed IAEA-TECDOC includes the report itself, detailed progress reports of three Research Coordination Meetings (RCMs) (Annexes I-III) and the reports and presentations made during the project by the participants.

Radiation chemistry

International Nuclear Information System (INIS)

Rodgers, F.; Rodgers, M.A.

1987-01-01

The contents of this book include: Interaction of ionizing radiation with matter; Primary products in radiation chemistry; Theoretical aspects of radiation chemistry; Theories of the solvated electron; The radiation chemistry of gases; Radiation chemistry of colloidal aggregates; Radiation chemistry of the alkali halides; Radiation chemistry of polymers; Radiation chemistry of biopolymers; Radiation processing and sterilization; and Compound index

Phase stability, physical properties of rhenium diboride under high pressure and the effect of metallic bonding on its hardness

International Nuclear Information System (INIS)

Zhong, Ming-Min; Kuang, Xiao-Yu; Wang, Zhen-Hua; Shao, Peng; Ding, Li-Ping; Huang, Xiao-Fen

2013-01-01

Highlights: •The transition pressure P t between the ReB 2 –ReB 2 and MoB 2 –ReB 2 phases is firstly determinate. •The single-bonded B–B feather remains in ReB 2 compounds. •A semiempirical method to evaluate the hardness of crystals with partial metallic bond is presented. •The large hardness (39.1 GPa) of ReB 2 –ReB 2 indicate that it is a superhard material. •The zigzag interconnected B–Re and B–B covalent bonds underlie the ultraincompressibilities. -- Abstract: Using first-principles calculations, the elastic constants, thermodynamic property and structural phase transition of rhenium diboride under pressure are investigated by means of the pseudopotential plane-waves method, as well as the effect of metallic bond on its hardness. Eight candidate structures of known transition-metal compounds are chosen to probe for rhenium diboride ReB 2 . The calculated lattice parameters are consistent with the experimental and theoretical values. Based on the third order Birch–Murnaghan equation of states, the transition pressure P t between the ReB 2 –ReB 2 and MoB 2 –ReB 2 phases is firstly determinate. Elastic constants, shear modulus, Young’s modulus, Poisson’s ratio and Debye temperature are derived. The single-bonded B–B feather remains in ReB 2 compounds. Furthermore, according to Mulliken overlap population analysis, a semiempirical method to evaluate the hardness of multicomponent crystals with partial metallic bond is presented. Both strong covalency and a zigzag topology of interconnected bonds underlie the ultraincompressibilities. In addition, the superior performance and large hardness (39.1 GPa) of ReB 2 –ReB 2 indicate that it is a superhard material

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

Coordinated Implementation and Evaluation of Flipped Classes and Peer-Led Team Learning in General Chemistry

Science.gov (United States)

Robert, Jenay; Lewis, Scott E.; Oueini, Razanne; Mapugay, Andrea

2016-01-01

The research-based pedagogical strategy of flipped classes has been shown to be effective for increasing student achievement and retention in postsecondary chemistry classes. The purpose of flipped classes is to move content delivery (e.g., lecture) outside of the classroom, freeing more face-to-face time for active learning strategies. The…

Theoretical chemistry periodicities in chemistry and biology

CERN Document Server

Eyring, Henry

1978-01-01

Theoretical Chemistry: Periodicities in Chemistry and Biology, Volume 4 covers the aspects of theoretical chemistry. The book discusses the stably rotating patterns of reaction and diffusion; the chemistry of inorganic systems exhibiting nonmonotonic behavior; and population cycles. The text also describes the mathematical modeling of excitable media in neurobiology and chemistry; oscillating enzyme reactions; and oscillatory properties and excitability of the heart cell membrane. Selected topics from the theory of physico-chemical instabilities are also encompassed. Chemists, mechanical engin

Applying the Power of Reticular Chemistry to Finding the Missing alb-MOF Platform Based on the (6,12)-Coordinated Edge-Transitive Net

KAUST Repository

Chen, Zhijie

2017-02-05

Highly connected and edge-transitive nets are of prime importance in crystal chemistry and are regarded as ideal blueprints for the rational design and construction of metal-organic frameworks (MOFs). We report the design and synthesis of highly connected MOFs based on reticulation of the sole two edge-transitive nets with a vertex figure as double six-membered-ring (d6R) building unit, namely the (4,12)-coordinated shp net (square and hexagonal-prism) and the (6,12)-coordinated alb net (aluminum diboride, hexagonal-prism and trigonal-prism). Decidedly, the combination of our recently isolated 12-connected (12-c) rare-earth (RE) nonanuclear [RE(μ-OH)(μ-O)(OC-)] carboxylate-based cluster, points of extension matching the 12 vertices of hexagonal-prism d6R, with 4-connected (4-c) square porphyrinic tetracarboxylate ligand led to the formation of the targeted RE-shp-MOF. This is the first time that RE-MOFs based on 12-c molecular building blocks (MBBs), d6R building units, have been deliberately targeted and successfully isolated, paving the way for the long-awaited (6,12)-c MOF with alb topology. Indeed, combination of a custom-designed hexacarboxylate ligand with RE salts led to the formation of the first related alb-MOF, RE-alb-MOF. Intuitively, we successfully transplanted the alb topology to another chemical system and constructed the first indium-based alb-MOF, In-alb-MOF, by employing trinuclear [In(μ-O)(OC-)] as the requisite 6-connected trigonal-prism and purposely made a dodecacarboxylate ligand as a compatible 12-c MBB. Prominently, the dodecacarboxylate ligand was employed to transplant shp topology into copper-based MOFs by employing the copper paddlewheel [Cu(OC-)] as the complementary square building unit, affording the first Cu-shp-MOF. We revealed that highly connected edge-transitive nets such shp and alb are ideal for topological transplantation and deliberate construction of related MOFs based on minimal edge-transitive nets.

Applying the Power of Reticular Chemistry to Finding the Missing alb-MOF Platform Based on the (6,12)-Coordinated Edge-Transitive Net

KAUST Repository

Chen, Zhijie; Weselinski, Lukasz Jan; Adil, Karim; Belmabkhout, Youssef; Shkurenko, Aleksander; Jiang, Hao; Bhatt, Prashant; Guillerm, Vincent; Dauzon, Emilie; Xue, Dongxu; O’ Keeffe, Michael; Eddaoudi, Mohamed

2017-01-01

Highly connected and edge-transitive nets are of prime importance in crystal chemistry and are regarded as ideal blueprints for the rational design and construction of metal-organic frameworks (MOFs). We report the design and synthesis of highly connected MOFs based on reticulation of the sole two edge-transitive nets with a vertex figure as double six-membered-ring (d6R) building unit, namely the (4,12)-coordinated shp net (square and hexagonal-prism) and the (6,12)-coordinated alb net (aluminum diboride, hexagonal-prism and trigonal-prism). Decidedly, the combination of our recently isolated 12-connected (12-c) rare-earth (RE) nonanuclear [RE(μ-OH)(μ-O)(OC-)] carboxylate-based cluster, points of extension matching the 12 vertices of hexagonal-prism d6R, with 4-connected (4-c) square porphyrinic tetracarboxylate ligand led to the formation of the targeted RE-shp-MOF. This is the first time that RE-MOFs based on 12-c molecular building blocks (MBBs), d6R building units, have been deliberately targeted and successfully isolated, paving the way for the long-awaited (6,12)-c MOF with alb topology. Indeed, combination of a custom-designed hexacarboxylate ligand with RE salts led to the formation of the first related alb-MOF, RE-alb-MOF. Intuitively, we successfully transplanted the alb topology to another chemical system and constructed the first indium-based alb-MOF, In-alb-MOF, by employing trinuclear [In(μ-O)(OC-)] as the requisite 6-connected trigonal-prism and purposely made a dodecacarboxylate ligand as a compatible 12-c MBB. Prominently, the dodecacarboxylate ligand was employed to transplant shp topology into copper-based MOFs by employing the copper paddlewheel [Cu(OC-)] as the complementary square building unit, affording the first Cu-shp-MOF. We revealed that highly connected edge-transitive nets such shp and alb are ideal for topological transplantation and deliberate construction of related MOFs based on minimal edge-transitive nets.

The role of IAEA in coordinating research and transferring technology in radiation chemistry and processing of polymers

Energy Technology Data Exchange (ETDEWEB)

Haji-Saeid, M. [International Atomic Energy Agency (IAEA), Wagramer Strasse 5, A-1400 Vienna (Austria)], E-mail: M.Haji-Saeid@iaea.org; Sampa, M.H.; Ramamoorthy, N. [International Atomic Energy Agency (IAEA), Wagramer Strasse 5, A-1400 Vienna (Austria); Gueven, O. [Hacettepe University, Department of Chemistry, Ankara (Turkey); Chmielewski, A.G. [Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw (Poland)

2007-12-15

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through technical cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The technical cooperation (TC) programme helps Member States to realize their development priorities through the application of appropriate radiation technology. The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine. The IAEA extends cooperation to well-known international conferences dealing with radiation technology to facilitate participation of talented scientists from developing MS and building collaborations. The IAEA published technical documents, covering the findings of thematic technical meetings (TM) and coordinated research projects have been an important source of valuable practical information.

The role of IAEA in coordinating research and transferring technology in radiation chemistry and processing of polymers

International Nuclear Information System (INIS)

Haji-Saeid, M.; Sampa, M.H.; Ramamoorthy, N.; Gueven, O.; Chmielewski, A.G.

2007-01-01

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through technical cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The technical cooperation (TC) programme helps Member States to realize their development priorities through the application of appropriate radiation technology. The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine. The IAEA extends cooperation to well-known international conferences dealing with radiation technology to facilitate participation of talented scientists from developing MS and building collaborations. The IAEA published technical documents, covering the findings of thematic technical meetings (TM) and coordinated research projects have been an important source of valuable practical information

New twists and turns for actinide chemistry. Organometallic infinite coordination polymers of thorium diazide

Energy Technology Data Exchange (ETDEWEB)

Monreal, Marisa J.; Seaman, Lani A.; Goff, George S.; Michalczyk, Ryszard; Morris, David E.; Scott, Brian L.; Kiplinger, Jaqueline L. [Los Alamos National Laboratory, Los Alamos, NM (United States)

2016-03-07

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

Yearly scientific meeting: chemistry in human health and environment protection. Bialystok`92; Doroczny zjazd naukowy: chemia w ochronie zdrowia i srodowiska czlowieka. Bialystok`92

Energy Technology Data Exchange (ETDEWEB)

NONE

1992-12-31

The conference has been divided into 12 sections devoted to following topics: analytical chemistry; environmental chemistry; chemistry of natural compounds; chemistry of pharmaceutics and toxic compounds; chemistry in medicine; electrochemistry; young scientists forum; didactics and history of chemistry; chemistry and industry - technologies environment friendly; new trends in polymer science; crystallochemistry; pro-ecological actions in leather industry. Different analytical methods for determination of heavy methods and rare earths have been presented. Some of them have been successfully applied for the examination of environmental and biological materials. The basic chemical and physico-chemical studies including thermodynamic, crystal structure, coordination chemistry, sorption properties etc. have been extensively resented. The existence of radioactive elements in environment has been also investigated, especially in respect to municipal and industrial wastes and products of their processing. The radiation effects for different materials have been reported and discussed as well.

Yearly scientific meeting: chemistry in human health and environment protection. Bialystok`92; Doroczny zjazd naukowy: chemia w ochronie zdrowia i srodowiska czlowieka. Bialystok`92

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-12-31

The conference has been divided into 12 sections devoted to following topics: analytical chemistry; environmental chemistry; chemistry of natural compounds; chemistry of pharmaceutics and toxic compounds; chemistry in medicine; electrochemistry; young scientists forum; didactics and history of chemistry; chemistry and industry - technologies environment friendly; new trends in polymer science; crystallochemistry; pro-ecological actions in leather industry. Different analytical methods for determination of heavy methods and rare earths have been presented. Some of them have been successfully applied for the examination of environmental and biological materials. The basic chemical and physico-chemical studies including thermodynamic, crystal structure, coordination chemistry, sorption properties etc. have been extensively resented. The existence of radioactive elements in environment has been also investigated, especially in respect to municipal and industrial wastes and products of their processing. The radiation effects for different materials have been reported and discussed as well.

A rational route to SCM materials based on a 1-D cobalt selenocyanato coordination polymer.

Science.gov (United States)

Boeckmann, Jan; Näther, Christian

2011-07-07

Thermal annealing of a discrete complex with terminal SeCN anions and monodentate coligands enforces the formation of a 1D cobalt selenocyanato coordination polymer that shows slow relaxation of the magnetization. Therefore, this approach offers a rational route to 1D materials that might show single chain magnetic behaviour. This journal is © The Royal Society of Chemistry 2011

A contribution to the study of the structure, reactivity and bioinorganic chemistry of iron

International Nuclear Information System (INIS)

Toma, H.E.

1984-01-01

The research work on inorganic and biological chemistry of iron developed at the University of Sao Paulo (SP, Brazil) is reviewed. Considerations are made about: π interactions, electronic structure and spectroscopy of cyanoferrates; solvation studies and kinetics of substitution reactions involving iron complexes; reactivity of coordinating ligands and iron interactions with biomolecules. (C.L.B.) [pt

Application of rhenium 186 radiosynovectomy in elbow diffuse pigmented villonodular synovitis: Case report with multiple joint involvement

International Nuclear Information System (INIS)

Koca, Go Khan; Ozsoy, Ha Kan; Atilgan, Hasan Ikbal; Demirel, Koray; Dincel, Veysel Ercan; Korkmaz, Meliha

2012-01-01

After surgical therapy of diffuse pigmented villonodular synovitis (DPVNS), recurrence is seen in almost half of the patients. The effectiveness of radiosynovectomy (RSV)in preventing recurrence and complaints of DPVNS is well known. Elbow involvement in DPVNS is a very rare condition; therefore, RSV in elbow hasn't been experienced widely. The aim of this case report is to show the effectiveness of RSV with rhenium 186 (Re 186)sulfide colloid. We applied Re 186 sulfide colloid to the elbow joint of DPVNS patients six weeks after arthroscopic synovectomy. As a result, the patient did not have any complaints, and our findings are compatible with residue or recurrence on magnetic resonance imaging (MRI)in sixth and twentieth month controls after administration. We concluded that Re 186 is an effective adjuvant therapy for the prevention of recurrence and complaints

Surface grafting of a dense and rigid coordination polymer based on tri-para-carboxy-polychlorotriphenylmethyl radical and copper acetate

KAUST Repository

Mugnaini, Veró nica; Paradinas, Markos; Shekhah, Osama; Roques, Nans; Ocal, Carmen; Wö ll, Christof H.; Veciana, Jaume

2013-01-01

The step-by-step method is here presented as suitable to anchor on appropriately functionalized gold surfaces a metal-organic coordination polymer based on a non-planar trigonal tri-para-carboxy-polychlorotriphenylmethyl radical derivative and copper acetate. The structural characteristics of the grafted coordination polymer are derived during the step-wise growth from the real time changes in refractive index and oscillation frequency. The film thickness, as measured by scanning force microscopy, combined with the mass uptake value from the quartz crystal microbalance, are used to estimate an average density of the grafted metal-organic coordination polymer that suggests the formation of a dense and rather rigid thin film. This journal is © 2013 The Royal Society of Chemistry.

Comprehensive uranium thiophosphate chemistry: Framework compounds based on pseudotetrahedrally coordinated central metal atoms

International Nuclear Information System (INIS)

Neuhausen, Christine; Panthoefer, Martin; Tremel, Wolfgang; Hatscher, Stephan T.; Urland, Werner

2013-01-01

The new ternary compounds UP 2 S 6 , UP 2 S 7 , U(P 2 S 6 ) 2 , and U 3 (PS 4 ) 4 were prepared from uranium metal, phosphorus pentasulfide, and sulfur at 700 C. The crystal structures were determined by single-crystal X-ray diffraction methods. UP 2 S 6 (I) crystallizes in the ZrP 2 S 6 structure type [tetragonal, P4 2 /m, a = 6.8058(7) Aa, c = 9.7597(14) Aa, Z = 2], which consists of central uranium(IV) atoms coordinated by P 2 S 6 4- anions (staggered conformation). The anions are two-dimensional connectors for four uranium cations arranged in one plane. The structure of UP 2 S 7 (II) [orthorhombic, Fddd, a = 8.9966(15) Aa, b = 15.2869(2) Aa, c = 30.3195(5) Aa, Z = 16] is closely related to the monoclinic ZrP 2 S 7 structure type. It consists of U 4+ cations linked by P 2 S 7 4- ligands, the resulting 3D network contains large pores (diameter approx. 3.5 x 16.7 Aa). In the previously reported compound U(P 2 S 6 ) 2 (III) [I4 1 /a, a = 12.8776(9) Aa, c = 9.8367(10) Aa, Z = 2], the metal atoms are coordinated by four bidentate P 2 S 6 2- ligands. This arrangement can be considered as a pseudotetrahedral coordination of the uranium atoms by the linear ligands. Three of the resulting diamondoid frameworks are inseparably interwoven in order to optimize space filling. U 3 (PS 4 ) 4 (IV) [I4 1 /acd, a = 10.7440(9) Aa, c = 19.0969(2) Aa, Z = 2] crystallizes in a defect variant of the PrPS 4 structure type, with 50 % of the U2 sites statistically occupied with uranium atoms. The resulting stoichiometry is U 3 (PS 4 ) 4 with tetravalent uranium atoms. The structure of U 3 (PS 4 ) 4 consists of uranium atoms connected by PS 4 3- groups, each PS 4 group linking four central uranium atoms. Vibrational spectra, which were recorded for I-III, show good agreement between the obtained results and the expected values for the anionic units, while magnetic measurements confirm the presence of tetravalent uranium. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGa

Coordination chemistry of gadolinium complexes having pyridine carboxylate units in relation with the medical imagery

International Nuclear Information System (INIS)

Gateau, C.; Chatterton, N.; Nonat, A.; Mazzanti, M.; Pecaut, J.; Borel, A.; Merbach, A.; Heim, L.

2005-01-01

In order to study the influence of the coordination sphere on the properties which govern the relaxivity, ligands containing pyridine carboxylates units have been particularly studied. It has been shown that the tripodal ligand tpaa forms with gadolinium (III) a neutral complex having a relaxivity (r1p=13.3 mM -1 at 298 K and 60 MHz) which is three times superior to the contrast agents currently used in NMR Imaging. To explain this remarkably relaxivity, two new ligands analogous to the tpaa: the tpatcn and the bpeda containing pyridine carboxylate units bound to one or several aliphatic nitrogen have been studied in modulating the number of coordination sites and the symmetry degree. The study of the relaxivity of the corresponding gadolinium (III) complexes gives precious data on the understanding of the results in the case of the complex [Gd(tpaa)]. The synthesis and the properties of these gadolinium (III) complexes will be presented during this conference. (O.M.)

Coordination chemistry of oxovanadium(V) complexes with active Schiff bases: synthetic, spectral, and antimicrobial approach

International Nuclear Information System (INIS)

Garg, R; Fahmi, N.; Singh, R.V.

2007-01-01

The Schiff bases, 3-(indolin-2-one)hydrazinecarbothioamide, 3-(indolin-2-one)hydrazinecarboxamide, 5,6-dimethyl-3-(indolin-2-one)hydrazinecarbothioamide, and 5,6-dimethyl-3-(indolin-2-one)hydrazinecarboxamide, have been synthesized by the condensation of 1H-indol-2,3-dione and 5,6-dimethyl-1H-indol-2,3-dione with the corresponding hydrazinecarbothioamide and hydrazinecarboxamide, respectively. The complexes of oxovanadium and ligands have been characterized by elemental analyses, melting points, conductance measurements, molecular weight determinations, and IR, 1 H NMR and UV spectral studies. These studies showed that the ligands coordinated to the oxovanadium in a monobasic bidentate fashion through oxygen or sulfur and the nitrogen donor system. Thus, penta- and hexa coordinated environment around the vanadium atom has been proposed. All the complexes and their parent organic moieties have been screened for their biological activity on several pathogenic fungi and bacteria and were found to possess appreciable fungicidal and bactericidal properties [ru

Rhenium (5) and molybdenum (5) complexes with 4',4''(5'')-ditretbutyldibenzo-24-crown-8. Kompleksnye soedineniya reniya (5) i molibdena (5) s 4',4''(5'')-ditretbutildibenzo-24-kraun-8

Energy Technology Data Exchange (ETDEWEB)

Ashurova, N Kh; Yakubov, K G; Basitova, S M; Tashmukhamedova, A K; Sajfullina, N Zh [Tadzhikskij Gosudarstvennyj Univ., Dushanbe (USSR)

1989-10-01

Rhenium and molybdenum complexes in +5 oxidation degree with 4',4''(5'')-ditretbutyldibenzo-24-crown-8 (L) are synthesized with 75-95 % yield. Composition and structure of compounds produced are investigated using element analysis, conductometry, IR spectroscopy, thermogravimetry methods. Oxidation degree of complexer metal is determined. It is ascertained that the compound composition corresponds to the MOLX{sub 3} formula, where M-Re, Mo; X-Cl{sup -}, Br{sup -}.

Chemistry and physics

International Nuclear Information System (INIS)

Broerse, J.J.; Barendsen, G.W.; Kal, H.B.; Kogel, A.J. van der

1983-01-01

This book contains the extended abstracts of the contributions of the poster workshop sessions on chemistry and physics of the 7th international congress of radiation research. They cover the following main topics: primary processes in radiation physics and chemistry, general chemistry in radiation chemistry, DNA and model systems in radiation chemistry, molecules of biological interest in radiation chemistry, techniques in radiation chemistry, hot atom chemistry. refs.; figs.; tabs

$^{31}$Mg $\\beta$-NMR applied in chemistry and biochemistry

CERN Multimedia

Magnesium ions, Mg$^{2+}$, are essential in biological systems, taking part in practically all phosphate chemistry, in photosynthesis as an integral component of chlorophyll, and they are regulated via transport through selective membrane proteins. Nonetheless, the function of magnesium ions in biochemistry is difficult to characterize, as it is practically invisible to current experimental techniques. With this proposal we aim to advance the use of $^{31}$Mg $\\beta$-NMR to liquid samples, building on the experience from the successful Letter of Intent INTC-I-088 “$\\beta$-NMR as a novel technique for biological applications”. Initially a series of experiments will be conducted aiming to characterize the coordination chemistry of Mg$^{2+}$ in ionic liquids (ILs), demonstrating that it is possible within the lifetime of the radioisotope to achieve binding of Mg$^{2+}$ to a molecule dissolved in the IL. ILs are chosen as they display a very low vapor pressure, and are thus straightforwardly compatible with t...

New twists and turns for actinide chemistry: organometallic infinite coordination polymers of thorium diazide

Energy Technology Data Exchange (ETDEWEB)

Monreal, Marisa J.; Seaman, Lani A.; Goff, George S.; Michalczyk, Ryszard; Morris, David E.; Scott, Brian L.; Kiplinger, Jaqueline L. [Los Alamos National Laboratory, Los Alamos, NM (United States)

2016-03-07

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effects of Rhenium Addition on the Temporal Evolution of the Nanostructure and Chemistry of a Model Ni-Cr-Al Superalloy. 2; Analysis of the Coarsening Behavior

Science.gov (United States)

Yoon, Kevin E.; Noebe, Ronald D.; Seidman, David N.

2007-01-01

The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at.% Cr-10 at.% Al alloy with the addition of 2 at.% Re was studied using transmission electron microscopy and atom-probe tomography in order to measure the number density and mean radius of the y' (LIZ) precipitates and the chemistry of the y'-precipitates and the y (fcc)-matrix. In this article, the coarsening behavior of the y'-precipitates is discussed in detail and compared with the Umantsev-Olson model for multi-component alloys. In addition, the experimental results are evaluated with PrecipiCalc(TradeMark) simulations. The results show that the diffusivities of the solute elements play a major role in the coarsening behavior of the y'-precipitates and that the addition of Re retards the coarsening kinetics and stabilizes the spheroidal morphology of the precipitates by reducing the interfacial energy.

From hot atom chemistry to epithermal chemistry

International Nuclear Information System (INIS)

Roessler, K.

2004-01-01

The rise and fall of hot atom chemistry (HAC) over the years from 1934 to 2004 is reviewed. Several applications are discussed, in particular to astrophysics and the interaction of energetic ions and atoms in space. Epithermal chemistry (ETC) is proposed to substitute the old name, since it better fits the energy range as well as the non-thermal and non-equilibrium character of the reactions. ETC also avoids the strong connexion of HAC to nuclear chemistry and stands for the opening of the field to physical chemistry and astrophysics. (orig.)

Mathematical Chemistry

OpenAIRE

Trinajstić, Nenad; Gutman, Ivan

2002-01-01

A brief description is given of the historical development of mathematics and chemistry. A path leading to the meeting of these two sciences is described. An attempt is made to define mathematical chemistry, and journals containing the term mathematical chemistry in their titles are noted. In conclusion, the statement is made that although chemistry is an experimental science aimed at preparing new compounds and materials, mathematics is very useful in chemistry, among other things, to produc...

The global change research center atmospheric chemistry model

Energy Technology Data Exchange (ETDEWEB)

Moraes, Jr., Francis Perry [Oregon Graduate Inst. of Science and Technology, Portland, OR (United States)

1995-01-01

This work outlines the development of a new model of the chemistry of the natural atmosphere. The model is 2.5-dimensional, having spatial coordinates height, latitude, and, the half-dimension, land and ocean. The model spans both the troposphere and stratosphere, although the troposphere is emphasized and the stratosphere is simple and incomplete. The chemistry in the model includes the O_x, HO_x, NO_x, and methane cycles in a highly modular fashion which allows model users great flexibility in selecting simulation parameters. A detailed modeled sensitivity analysis is also presented. A key aspect of the model is its inclusion of clouds. The model uses current understanding of the distribution and optical thickness of clouds to determine the true radiation distribution in the atmosphere. As a result, detailed studies of the radiative effects of clouds on the distribution of both oxidant concentrations and trace gas removal are possible. This work presents a beginning of this study with model results and discussion of cloud effects on the hydroxyl radical.

Coherence of Physics and Chemistry Curricula in Terms of the Electron Concept

International Nuclear Information System (INIS)

Elena, Ivanova

2016-01-01

One of the major contradictions in subject teaching is the contradiction between the unity of the world and the discrete separated generalized content of natural sciences that study natural phenomena. These are physics, chemistry, biology and more. One can eliminate the conflict if opens the content's interdisciplinary links set by the events that are studied by different disciplines. The corresponding contexts of the phenomenon content arise depending on the discipline, and they are not enough coordinated. Obviously, we need a mechanism that allows establishing interdisciplinary links in the content quickly and without losing the logic of the material and assess their coherence in academic disciplines. This article uses a quantitative method of coherence assessment elaborated by T.N. Gnitetskaya. The definition of the concept of the semantic state introduced by the authors is given in this article. The method is applied to coherence assessment of physics and chemistry textbooks. The coherence of two pairs of chemistry and physics textbooks by different authors in different combinations was calculated. The most cohered pairs of textbooks (chemistry-physics) were identified. One can recommend using the pair of textbooks for eighth grade that we offered that favors the development of holistic understandings of the world around us. (paper)

Coherence of Physics and Chemistry Curricula in Terms of the Electron Concept

Science.gov (United States)

Elena, Ivanova

2016-08-01

One of the major contradictions in subject teaching is the contradiction between the unity of the world and the discrete separated generalized content of natural sciences that study natural phenomena. These are physics, chemistry, biology and more. One can eliminate the conflict if opens the content's interdisciplinary links set by the events that are studied by different disciplines. The corresponding contexts of the phenomenon content arise depending on the discipline, and they are not enough coordinated. Obviously, we need a mechanism that allows establishing interdisciplinary links in the content quickly and without losing the logic of the material and assess their coherence in academic disciplines. This article uses a quantitative method of coherence assessment elaborated by T.N. Gnitetskaya. The definition of the concept of the semantic state introduced by the authors is given in this article. The method is applied to coherence assessment of physics and chemistry textbooks. The coherence of two pairs of chemistry and physics textbooks by different authors in different combinations was calculated. The most cohered pairs of textbooks (chemistry-physics) were identified. One can recommend using the pair of textbooks for eighth grade that we offered that favors the development of holistic understandings of the world around us.

Two coordination polymers based on semicarbazone Schiff base and azide: synthesis, crystal structure, electrochemistry, magnetic properties and biological activity

Czech Academy of Sciences Publication Activity Database

Shaabani, B.; Khandar, A.A.; Dušek, Michal; Pojarová, Michaela; Mahmoudi, F.; Feher, A.; Kajňaková, M.

2013-01-01

Roč. 66, č. 5 (2013), s. 748-762 ISSN 0095-8972 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378271 Keywords : Schiff bases * semicarbazone * coordination polymer * structure analyses Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.224, year: 2013

Ftir study of CO interactions with Li+ ions in micro- and mesoporous matrices: coordination and localization of Li+ ions

Czech Academy of Sciences Publication Activity Database

Nachtigall, Petr; Frolich, K.; Drobná, H.; Bludský, Ota; Nachtigallová, Dana; Bulánek, R.

2007-01-01

Roč. 111, č. 30 (2007), s. 11353-11362 ISSN 1932-7447 R&D Projects: GA MŠk LC512; GA ČR GA203/06/0324; GA ČR GD203/03/H140 Institutional research plan: CEZ:AV0Z40550506 Keywords : zeolite * adsorption * coordination Subject RIV: CF - Physical ; Theoretical Chemistry

Non-Faradaic Li ⁺ Migration and Chemical Coordination across Solid-State Battery Interfaces

Energy Technology Data Exchange (ETDEWEB)

Gittleson, Forrest S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); El Gabaly, Farid [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2017-10-17

Efficient and reversible charge transfer is essential to realizing high-performance solid-state batteries. Efforts to enhance charge transfer at critical electrode–electrolyte interfaces have proven successful, yet interfacial chemistry and its impact on cell function remains poorly understood. Using X-ray photoelectron spectroscopy combined with electrochemical techniques, we elucidate chemical coordination near the LiCoO₂–LIPON interface, providing experimental validation of space-charge separation. Space-charge layers, defined by local enrichment and depletion of charges, have previously been theorized and modeled, but the unique chemistry of solid-state battery interfaces is now revealed. Here we highlight the non-Faradaic migration of Li+ ions from the electrode to the electrolyte, which reduces reversible cathodic capacity by ~15%. Inserting a thin, ion-conducting LiNbO₃ interlayer between the electrode and electrolyte, however, can reduce space-charge separation, mitigate the loss of Li+ from LiCoO₂, and return cathodic capacity to its theoretical value. This work illustrates the importance of interfacial chemistry in understanding and improving solid-state batteries.

Advances in technetium chemistry towards 99mTc receptor imaging agents

International Nuclear Information System (INIS)

Johannsen, B.; Spies, H.

1997-01-01

The development of the chemistry of technetium and its non-radioactive surrogate rhenium has been prompted by the trends and needs of nuclear medicine, which predominantly uses 99m Tc radiopharmaceuticals for a broad range of diagnostics. Technetium-99m is the ideal radioisotope for tomographic single-photon emission tomography (SPECT) imaging due to its nuclear properties (6.2 h, E γ 140 keV) and ready availability through generator systems. Transition metals offer many opportunities for designing molecules by modifying the environment around the core, allowing certain biological properties to be imposed upon the molecule. Whereas research in the past was mainly concerned with biological properties that allow relatively unspecific functional imaging, as in brain or myocardium perfusion studies, nuclear medicine is now requiring more and more biochemical information on low capacity, high specificity targets. Many research groups have become involved in the search for new technetium-based compounds, called the third generation of 99m Tc radiopharmaceuticals, that employ the principles of modern pharmacology to achieve biochemical specificity. There has been considerable interest in imaging CNS and other receptors with 99m Tc receptor-binding ligands. Such a 99m Tc CNS receptor-imaging agent is currently not yet in use because of the significant hurdles to be overcome in attaining this ambitious goal. However, some Tc and Re complexes of remarkable affinity in vitro, and the first high-affinity 99m Tc probes able to label the dopamine transporter in the brain by SPECT imaging prove the feasibility of this approach. (Author)

Atmospheric chemistry of CFCs and potential alternatives

International Nuclear Information System (INIS)

Watson, R.T.

1990-01-01

Since the discovery of the ozone hole, the knowledge of atmospheric chemistry related to ozone depletion and chlorofluorocarbons has increased significantly. Factors that result in large losses in ozone during the Antarctic spring are present in the Arctic, although a hole has not been observed. The latest science is discussed as it pertains to the Arctic and Antarctic regions. The ozone depletion potentials (ODP) and global warming potentials (GWP) of the most likely alternatives are presented and related to their environmental acceptability. NASA, NSF, NOAA, EPA and the industry sponsored AFEAS program are coordinating efforts to provide further scientific information to more fully understand the potential environmental effects of alternatives. A progress report is given

Industrial chemistry engineering

International Nuclear Information System (INIS)

1993-01-01

This book on industrial chemistry engineering is divided in two parts. The first part deals with industrial chemistry, inorganic industrial chemistry, organic industrial chemistry, analytical chemistry and practical questions. The last parts explain the chemical industry, a unit parts and thermodynamics in chemical industry and reference. It reveals the test subjects for the industrial chemistry engineering with a written examination and practical skill.

Advanced chemistry management system to optimize BWR chemistry control

International Nuclear Information System (INIS)

Maeda, K.; Nagasawa, K.

2002-01-01

BWR plant chemistry control has close relationships among nuclear safety, component reliability, radiation field management and fuel integrity. Advanced technology is required to improve chemistry control [1,3,6,7,10,11]. Toshiba has developed TACMAN (Toshiba Advanced Chemistry Management system) to support BWR chemistry control. The TACMAN has been developed as response to utilities' years of requirements to keep plant operation safety, reliability and cost benefit. The advanced technology built into the TACMAN allows utilities to make efficient chemistry control and to keep cost benefit. TACMAN is currently being used in response to the needs for tools those plant chemists and engineers could use to optimize and identify plant chemistry conditions continuously. If an incipient condition or anomaly is detected at early stage, root causes evaluation and immediate countermeasures can be provided. Especially, the expert system brings numerous and competitive advantages not only to improve plant chemistry reliability but also to standardize and systematize know-how, empirical knowledge and technologies in BWR chemistry This paper shows detail functions of TACMAN and practical results to evaluate actual plant. (authors)

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.)

Current organic chemistry

National Research Council Canada - National Science Library

1997-01-01

Provides in depth reviews on current progress in the fields of asymmetric synthesis, organometallic chemistry, bioorganic chemistry, heterocyclic chemistry, natural product chemistry, and analytical...

Aquatic Chemistry

International Nuclear Information System (INIS)

Kim, Dong Yeun; Kim, Oh Sik; Kim, Chang Guk; Park, Cheong Gil; Lee, Gwi Hyeon; Lee, Cheol Hui

1987-07-01

This book deals aquatic chemistry, which treats water and environment, chemical kinetics, chemical balance like dynamical characteristic, and thermodynamics, acid-base chemistry such as summary, definition, kinetics, and PH design for mixture of acid-base chemistry, complex chemistry with definition, and kinetics, precipitation and dissolution on summary, kinetics of precipitation and dissolution, and balance design oxidation and resolution with summary, balance of oxidation and resolution.

Combinatorial chemistry

DEFF Research Database (Denmark)

Nielsen, John

1994-01-01

An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds.......An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds....

Forensic Chemistry

Science.gov (United States)

Bell, Suzanne

2009-07-01

Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

International Nuclear Information System (INIS)

Ryan, R.R.

1981-05-01

This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research

Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

Energy Technology Data Exchange (ETDEWEB)

Ryan, R.R. (comp.)

1981-05-01

This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research.

The Brazilian medicinal chemistry from 1998 to 2008 in the Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters and European Journal of Medicinal Chemistry [A química medicinal brasileira de 1998 a 2008 nos periódicos Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters e European Journal of Medicinal Chemistry

OpenAIRE

Bárbara Vasconcellos da Silva; Renato Saldanha Bastos; Angelo da Cunha Pinto

2009-01-01

In this article we present the Brazilian publications, the research groups involved, the contributions per states and the main diseases studied from 1998 to 2008 in the following periodicals: Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters and European Journal of Medicinal Chemistry.

Thermal transformations of oxohalide complexes of rhenium(5) and molybdenum(5) with diazo-18-crown-6 in solid phase. Termicheskie prevrashcheniya oksogalogenidnykh kompleksov reniya(5) i molibdena(5) s diaza-18-kraun-6 v tverdoj faze

Energy Technology Data Exchange (ETDEWEB)

Ashurova, N Kh; Yakubov, K G [Tadzhikskij Gosudarstvennyj Univ., Dushanbe (Tajikistan)

1992-11-01

Methods for synthesis and separation in solid state of the rhenium(5) and molybdenum(5) onium complexes with diaza-18-crown-6(L), the content of which according to the data of elementary analysis, IRS in the close and remote areas, thermogravimetry, conductometry and potentiometry corresponds to the (H[sub 2]L)[EOX[sub 5

Structural studies of novel coordination compounds run in the Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences

International Nuclear Information System (INIS)

Antipin, M.Yu.; Starikova, Z.A.; Yanovskij, A.I.; Dolgushin, F.M.; Lysenko, K.A.; Khrustalev, V.N.; Vorontsov, I.I.; Korlyukov, A.A.; Andreev, G.B.; Neretin, I.S.

2001-01-01

The results of the investigation into structural chemistry of coordination compounds taking place in the X-ray Laboratory of the Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences are given. The review gives an idea on the tendencies to structural researches of complexes of varying categories of coordination compounds, among which are lithium, strontium, cadmium compounds, rare earth compounds, transuranium compounds, transition element compounds, carboranes, fullerenes. An attempt was made to prove the structure and reveal the novel structural and crystallochemical regularities in the studied series of relative compounds. The outlooks for the following progress of studies on this field are determined [ru

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

Bad chemistry

OpenAIRE

Petsko, Gregory A

2004-01-01

General chemistry courses haven't changed significantly in forty years. Because most basic chemistry students are premedical students, medical schools have enormous influence and could help us start all over again to create undergraduate chemistry education that works.

Poisson Coordinates.

Science.gov (United States)

Li, Xian-Ying; Hu, Shi-Min

2013-02-01

Harmonic functions are the critical points of a Dirichlet energy functional, the linear projections of conformal maps. They play an important role in computer graphics, particularly for gradient-domain image processing and shape-preserving geometric computation. We propose Poisson coordinates, a novel transfinite interpolation scheme based on the Poisson integral formula, as a rapid way to estimate a harmonic function on a certain domain with desired boundary values. Poisson coordinates are an extension of the Mean Value coordinates (MVCs) which inherit their linear precision, smoothness, and kernel positivity. We give explicit formulas for Poisson coordinates in both continuous and 2D discrete forms. Superior to MVCs, Poisson coordinates are proved to be pseudoharmonic (i.e., they reproduce harmonic functions on n-dimensional balls). Our experimental results show that Poisson coordinates have lower Dirichlet energies than MVCs on a number of typical 2D domains (particularly convex domains). As well as presenting a formula, our approach provides useful insights for further studies on coordinates-based interpolation and fast estimation of harmonic functions.

Positronium chemistry

CERN Document Server

Green, James

1964-01-01

Positronium Chemistry focuses on the methodologies, reactions, processes, and transformations involved in positronium chemistry. The publication first offers information on positrons and positronium and experimental methods, including mesonic atoms, angular correlation measurements, annihilation spectra, and statistical errors in delayed coincidence measurements. The text then ponders on positrons in gases and solids. The manuscript takes a look at the theoretical chemistry of positronium and positronium chemistry in gases. Topics include quenching, annihilation spectrum, delayed coincidence

Radiolabeling and biotinylation of internalizing monoclonal antibody chimeric BR96: Potential use of extracorporeal immunoadsorption with enhanced tumor radioactivity retention of Iodine, Indium and Rhenium

International Nuclear Information System (INIS)

Chen, JianQing.

1997-01-01

In this thesis, methodology of radiolabeling and simultaneous biotinylation for internalizing monoclonal antibody chimeric BR96 have been investigated by using three element groups of potential therapeutic radionuclides iodine, indium and rhenium, and their different labeling methods. The biodistribution and kinetics of biotinylated and radiolabeled chiBR96 have been studied in colon carcinoma isografted rats. The potential use of ECIA, based on the biotin-avidin concept, has been evaluated and compared with the approach of avidin 'chase' in the same animal tumor model with respect to an enhancement of tumor-to-normal tissue (T/N) activity ratio. 131 refs

Radiolabeling and biotinylation of internalizing monoclonal antibody chimeric BR96: Potential use of extracorporeal immunoadsorption with enhanced tumor radioactivity retention of Iodine, Indium and Rhenium

Energy Technology Data Exchange (ETDEWEB)

Chen, JianQing

1997-01-01

In this thesis, methodology of radiolabeling and simultaneous biotinylation for internalizing monoclonal antibody chimeric BR96 have been investigated by using three element groups of potential therapeutic radionuclides iodine, indium and rhenium, and their different labeling methods. The biodistribution and kinetics of biotinylated and radiolabeled chiBR96 have been studied in colon carcinoma isografted rats. The potential use of ECIA, based on the biotin-avidin concept, has been evaluated and compared with the approach of avidin `chase` in the same animal tumor model with respect to an enhancement of tumor-to-normal tissue (T/N) activity ratio. 131 refs.

Non-thermally activated chemistry

International Nuclear Information System (INIS)

Stiller, W.

1987-01-01

The subject is covered under the following headings: state-of-the art of non-thermally activated chemical processes; basic phenomena in non-thermal chemistry including mechanochemistry, photochemistry, laser chemistry, electrochemistry, photo-electro chemistry, high-field chemistry, magneto chemistry, plasma chemistry, radiation chemistry, hot-atom chemistry, and positronium and muonium chemistry; elementary processes in non-thermal chemistry including nuclear chemistry, interactions of electromagnetic radiations, electrons and heavy particles with matter, ionic elementary processes, elementary processes with excited species, radicalic elementary processes, and energy-induced elementary processes on surfaces and interfaces; and comparative considerations. An appendix with historical data and a subject index is given. 44 figs., 41 tabs., and 544 refs

Harvard-MIT research program in short-lived radiopharmaceuticals. Final report

International Nuclear Information System (INIS)

Adelstein, S.J.

1995-02-01

The Harvard-MIT Research Program in Short-lived Radiopharmaceuticals was established in 1977 to foster interaction among groups working in radiopharmaceutical chemistry at Harvard Medical School, the Massachusetts Institute of Technology, and the Massachusetts General Hospital. To this was added a group at The Childrens Hospital. From these collaborations and building upon the special strengths of the participating individuals, laboratories and institutions, it was hoped that original approaches would be found for the design of new, clinically useful, radiolabeled compounds. The original thrust of this proposal included: (a) examination of the coordination chemistry of technetium as a basis for rational radiopharmaceutical design, (b) development of an ultrashort-lived radionuclide generator for the diagnosis of congenital heart disease in newborns, (c) synthesis of receptor-site-directed halopharmaceuticals, (d) improved facile labeling of complex molecules with positron-emitting radionuclides. The authors' 1986 proposal was oriented toward organs and disease, emphasizing radiolabeled agents that delineate specific functions and the distribution of receptors in brain, heart, and tumors. In 1989, they further refined their purposes and focused on two major aims: (a) synthesis and utilization of neutral technetium and rhenium complexes of high specific activity, and (b) development of new approaches to the radiolabeling of proteins, peptides, immunoglobulins, and their fragments. In 1992, the authors amended this proposal to concentrate their efforts on biologically active peptides and proteins for targeted radiodiagnosis and therapy

Harvard-MIT research program in short-lived radiopharmaceuticals. Final report

Energy Technology Data Exchange (ETDEWEB)

Adelstein, S.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Office of Sponsored Programs

1995-02-01

The Harvard-MIT Research Program in Short-lived Radiopharmaceuticals was established in 1977 to foster interaction among groups working in radiopharmaceutical chemistry at Harvard Medical School, the Massachusetts Institute of Technology, and the Massachusetts General Hospital. To this was added a group at The Childrens Hospital. From these collaborations and building upon the special strengths of the participating individuals, laboratories and institutions, it was hoped that original approaches would be found for the design of new, clinically useful, radiolabeled compounds. The original thrust of this proposal included: (a) examination of the coordination chemistry of technetium as a basis for rational radiopharmaceutical design, (b) development of an ultrashort-lived radionuclide generator for the diagnosis of congenital heart disease in newborns, (c) synthesis of receptor-site-directed halopharmaceuticals, (d) improved facile labeling of complex molecules with positron-emitting radionuclides. The authors` 1986 proposal was oriented toward organs and disease, emphasizing radiolabeled agents that delineate specific functions and the distribution of receptors in brain, heart, and tumors. In 1989, they further refined their purposes and focused on two major aims: (a) synthesis and utilization of neutral technetium and rhenium complexes of high specific activity, and (b) development of new approaches to the radiolabeling of proteins, peptides, immunoglobulins, and their fragments. In 1992, the authors amended this proposal to concentrate their efforts on biologically active peptides and proteins for targeted radiodiagnosis and therapy.

Green chemistry: A tool in Pharmaceutical Chemistry

OpenAIRE

Smita Talaviya; Falguni Majumdar

2012-01-01

Green chemistry expresses an area of research developing from scientific discoveries about pollution awareness and it utilizes a set of principles that reduces or eliminates the use or generation of hazardous substances in all steps of particular synthesis or process. Chemists and medicinal scientists can greatly reduce the risk to human health and the environment by following all the valuable principles of green chemistry. The most simple and direct way to apply green chemistry in pharmaceut...

Chiral phosphites as ligands in asymmetric metal complex catalysis and synthesis of coordination compounds

International Nuclear Information System (INIS)

Gavrilov, Konstantin N; Bondarev, Oleg G; Polosukhin, Aleksei I

2004-01-01

The data published during the last five years on the application of chiral derivatives of phosphorous acid in coordination chemistry and enantioselective catalysis are summarised and discussed. The effect of the nature of these ligands on the structure of metal complexes and on the efficiency of catalytic organic syntheses is shown. Hydroformylation, hydrogenation, allylic substitution and conjugate addition catalysed by transition metal complexes with optically active phosphites and hydrophosphoranes are considered. The prospects for the development of this field of research are demonstrated.

An ideal teaching program of nuclear chemistry in the undergraduate chemistry curriculum

International Nuclear Information System (INIS)

Uenak, T.

2009-01-01

It is well known that several reports on the common educational problems of nuclear chemistry have been prepared by certain groups of experts from time to time. According to very important statements in these reports, nuclear chemistry and related courses generally do not take sufficient importance in undergraduate chemistry curricula and it was generally proposed that nuclear chemistry and related courses should be introduced into undergraduate chemistry curricula at universities worldwide. Starting from these statements, an ideal program in an undergraduate chemistry curriculum was proposed to be introduced into the undergraduate chemistry program at the Department of Chemistry, Ege University, in Izmir, Turkey during the regular updating of the chemistry curriculum. Thus, it has been believed that this Department of Chemistry has recently gained an ideal teaching program in the field of nuclear chemistry and its applications in scientific, industrial, and medical sectors. In this contribution, the details of this program will be discussed. (author)

Ligand substitution and selective surface coordination studies of iodine and 2,5-dihydroxythiophenol at platinum electrodes

International Nuclear Information System (INIS)

Berry, G.M.; Soriaga, M.P.

1989-01-01

The relative surface coordination strengths of 2,5-dihydroxythiophenol (DHT) and iodine at a smooth polycrystalline platinum electrode have been investigated by thin-layer electrochemical techniques. The competitive chemisorption was studied by exposing the Pt electrode to solutions of varying mole fractions of I and DHT. Studies of ligand substitution were carried out by the introduction of an iodine-coated Pt electrode into DHT solutions, and the introduction of a DHT-coated into I solutions. Surface coverage measurements indicated that DHT is preferentially adsorbed and will displace chemisorbed iodine at the Pt electrode. Chemisorbed DHT is not appreciably displaced by iodine. These results and their contribution to the trend in the selective surface coordination chemistry of platinum electrodes will be discussed

The oxidation of ReCl_5 with oleum: synthesis and crystal structure of Re_2O_4Cl_4(SO_4)

International Nuclear Information System (INIS)

Betke, Ulf; Wickleder, Mathias S.

2012-01-01

The reaction of ReCl_5 and fuming sulfuric acid (25 % SO_3) in a sealed glass tube at 200 C led to red, needle shaped single crystals of Re_2O_4Cl_4(SO_4) (monoclinic, C2/c, a = 1501.8(2) pm, b = 1545.9(2) pm, c = 945.18(8) pm, β = 98.761(9) , Z = 8). In the crystal structure the [ReO_2] moieties are linked by [SO_4]"2"- tetrahedra to chains along the [101] direction. Each sulfate ion connects four rhenium atoms, additional two chloride ions complete the octahedral coordination sphere of each rhenium atom according to "1_∞[ReO_2_/_1Cl_2_/_1(SO_4)_2_/_4]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

2010 INORGANIC CHEMISTRY GORDON RESEARCH CONFERENCE JUNE 20 - 25, 2010

Energy Technology Data Exchange (ETDEWEB)

JOHN LOCKEMEYER

2010-06-25

The Inorganic Chemistry GRC is one of the longest-standing of the GRCs, originating in 1951. Over the years, this conference has played a role in spawning many other GRCs in specialized fields, due to the involvement of elements from most of the periodic table. These include coordination, organometallic, main group, f-element, and solid state chemistries; materials science, catalysis, computational chemistry, nanotechnology, bioinorganic, environmental, and biomedical sciences just to name a few. The 2010 Inorganic Chemistry GRC will continue this tradition, where scientists at all levels from academic, industrial, and national laboratories meet to define the important problems in the field and to highlight emerging opportunities through exchange of ideas and discussion of unpublished results. Invited speakers will present on a wide variety of topics, giving attendees a look at areas both inside and outside of their specialized areas of interest. In addition to invited speakers, the poster sessions at GRCs are a key feature of the conference. All conferees at the Inorganic Chemistry GRC are invited to present a poster on their work, and here the informal setting promotes the free exchange of ideas and fosters new relationships. As in previous years, we will offer poster presenters the opportunity to compete for one of several program spots in which they can give an oral presentation based on the subject matter of their poster. This is a great way to get your work noticed by the scientists attending the meeting, especially for those early in their career path such as junior faculty members, postdoctoral fellows, and those at comparable ranks. Anyone interested in participating in the poster competition should bring an electronic slide presentation and a small hard copy of their poster to submit to the committee.

Analysis of Insertion of Environmental Issues in two Degree Course Chemistry of a Public University

Directory of Open Access Journals (Sweden)

Thiago do Nascimento Silva

2017-12-01

Full Text Available This work consists in a research on the inclusion of environmental matters in two degree courses of Chemistry in a public university. We started from the idea that discussing environmental issues in the academic context, in particular in the context of the Degree in Chemistry, is being very necessary nowadays, due to what society is going through, which is what we call "environmental crisis". Our main objective was to identify how the formation of the Chemistry teacher in these two courses has contemplated the inclusion of environmental issues as defined in the guidelines of official documents which they are subjected to. To structure all our discussion, we had as the theoretical background the production cycle of the curriculum policies developed by Ball and Bowe (1992, establishing this research in three main contexts presented by them (context influence, text production context and practice context. Therefore, a documental research in the national curriculum guidelines that drive the training of teachers / Chemistry teachers and educational projects of each course was conducted as well as interviews with coordinators and teachers of these courses, trying to understand the inclusion of discussions and questions that lead to an environmentally oriented education.

BWR Water Chemistry Guidelines: 1993 Revision, Normal and hydrogen water chemistry

International Nuclear Information System (INIS)

Karlberg, G.; Goddard, C.; Fitzpatrick, S.

1994-02-01

The goal of water chemistry control is to extend the operating life of the reactor and rector coolant system, balance-of-plant components, and turbines while simultaneously controlling costs to safeguard the continued economic viability of the nuclear power generation investment. To further this goal an industry committee of chemistry personnel prepared guidelines to identify the benefits, risks, and costs associated with water chemistry in BWRs and to provide a template for an optimized water chemistry program. This document replaces the BWR Normal Water Chemistry Guidelines - 1986 Revision and the BWR Hydrogen Water Chemistry Guidelines -- 1987 Revision. It expands on the previous guidelines documents by covering the economic implications of BWR water chemistry control

Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

International Nuclear Information System (INIS)

Ryan, R.R.

1982-05-01

This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research

Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

Energy Technology Data Exchange (ETDEWEB)

Ryan, R.R. (comp.)

1982-05-01

This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research.

Carbynes and carbenes in coordination chemistry: A new class of pentaammine and tetraammine complexes of osmium(II)

Energy Technology Data Exchange (ETDEWEB)

Hodges, L.M.; Sabat, M.; Harman, W.D. (Univ. of Virginia, Charlottesville (United States))

1993-02-17

Since their discovery by Fischer and co-workers in 1973, the study of transition-metal carbyne complexes and their role in alkyne metathesis has rapidly developed into a mature field. Although carbyne complexes are known for a diverse set of early- and mid-transition metals, the vast majority of these complexes contain carbon or phosphine [pi]-acids, or bulky alkoxide ligands, which limit the coordination number. We wish to report the first example of a carbyne species, as well as several heteroatom-carbene derivatives, in which the metal fragment, Os[sup II](NH[sub 3])[sub 5], provides a classical octahedral coordination environment. The carbyne [Os(NH[sub 3])[sub 5]([equivalent to]CPh)](OTf)[sub 3] (2) is synthesized in two steps from Os(NH[sub 3])[sub 5](OTf)[sub 3] and benzaledhyde dimethyl acetal.

Fundamentals of nuclear chemistry

International Nuclear Information System (INIS)

Majer, V.

1982-01-01

The author of the book has had 25 years of experience at the Nuclear Chemistry of Prague Technical University. In consequence, the book is intended as a basic textbook for students of this field. Its main objectives are an easily understandable presentation of the complex subject and in spite of the uncertainty which still characterizes the definition and subjects of nuclear chemistry - a systematic classification and logical structure. Contents: 1. Introduction (history and definition); 2. General nuclear chemistry (physical fundamentals, hot atom chemistry, interaction of nuclear radiation with matter, radioactive elements, isotope effects, isotope exchange, chemistry of radioactive trace elements); 3. Methods of nuclear chemistry of nuclear chemistry (radiochemical methods, activation, separation and enrichment chemistry); 4. Preparative nuclear chemistry (isotope production, labelled compounds); 5. Analytival nuclear chemistry; 6. Applied nuclear chemistry (isotope applications in general physical and analytical chemistry). The book is supplemented by an annex with tables, a name catalogue and a subject index which will facilitate access to important information. (RB) [de

Design of magnetic coordination complexes for quantum computing.

Science.gov (United States)

Aromí, Guillem; Aguilà, David; Gamez, Patrick; Luis, Fernando; Roubeau, Olivier

2012-01-21

A very exciting prospect in coordination chemistry is to manipulate spins within magnetic complexes for the realization of quantum logic operations. An introduction to the requirements for a paramagnetic molecule to act as a 2-qubit quantum gate is provided in this tutorial review. We propose synthetic methods aimed at accessing such type of functional molecules, based on ligand design and inorganic synthesis. Two strategies are presented: (i) the first consists in targeting molecules containing a pair of well-defined and weakly coupled paramagnetic metal aggregates, each acting as a carrier of one potential qubit, (ii) the second is the design of dinuclear complexes of anisotropic metal ions, exhibiting dissimilar environments and feeble magnetic coupling. The first systems obtained from this synthetic program are presented here and their properties are discussed.

Analysis of extreme ultraviolet spectra from laser produced rhenium plasmas

Science.gov (United States)

Wu, Tao; Higashiguchi, Takeshi; Li, Bowen; Suzuki, Yuhei; Arai, Goki; Dinh, Thanh-Hung; Dunne, Padraig; O'Reilly, Fergal; Sokell, Emma; Liu, Luning; O'Sullivan, Gerry

2015-08-01

Extreme ultraviolet spectra of highly-charged rhenium ions were observed in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a number of laser power densities. The maximum focused peak power density was 2.6 × 1014 W cm-2 for the former and 5.5 × 1012 W cm-2 for the latter. The Cowan suite of atomic structure codes and unresolved transition array (UTA) approach were used to calculate and interpret the emission properties of the different spectra obtained. The results show that n = 4-n = 4 and n = 4-n = 5 UTAs lead to two intense quasi-continuous emission bands in the 4.3-6.3 nm and 1.5-4.3 nm spectral regions. As a result of the different ion stage distributions in the plasmas induced by ps and ns laser irradiation the 1.5-4.3 nm UTA peak moves to shorter wavelength in the ps laser produced plasma spectra. For the ns spectrum, the most populated ion stage during the lifetime of this plasma that could be identified from the n = 4-n = 5 transitions was Re23+ while for the ps plasma the presence of significantly higher stages was demonstrated. For the n = 4-n = 4 4p64dN-4p54dN+1 + 4p64dN-14f transitions, the 4d-4f transitions contribute mainly in the most intense 4.7-5.5 nm region while the 4p-4d subgroup gives rise to a weaker feature in the 4.3-4.7 nm region. A number of previously unidentified spectral features produced by n = 4-n = 5 transitions in the spectra of Re XVI to Re XXXIX are identified.

Scientific Information Analysis of Chemistry Dissertations Using Thesaurus of Chemistry

Directory of Open Access Journals (Sweden)

Taghi Rajabi

2017-09-01

Full Text Available : Concept maps of chemistry can be obtained from thesaurus of chemistry. Analysis of information in the field of chemistry is done at graduate level, based on comparing and analyzing chemistry dissertations by using these maps. Therefore, the use of thesaurus for analyzing scientific information is recommended. Major advantage of using this method, is that it is possible to obtain a detailed map of all academic researches across all branches of science. The researches analysis results in chemical science can play a key role in developing strategic research policies, educational programming, linking universities to industries and postgraduate educational programming. This paper will first introduce the concept maps of chemistry. Then, emerging patterns from the concept maps of chemistry will be used to analyze the trend in the academic dissertations in chemistry, using the data collected and stored in our database at Iranian Research Institute for Information Science and Technology (IranDoc over the past 10 years (1998-2009.

Sorption of technetium and its analogue rhenium on bentonite material under aerobic conditions

International Nuclear Information System (INIS)

Koudelkova, M.; Vinsova, H.; Konirova, R.; Ernestova, M.; Jedinakova-Krizova, V.; Tereesha, M.

2003-01-01

The uptake of technetium on bentonite materials has been studied from the point of view of characterization of long-term radioactive elements behavior in nuclear waste repository. Bentonite R (locality Rokle, Czech Republic) and two types of model groundwater (granitic and bentonite) were selected for the sorption experiments. The aim of our research has been to find out the conditions suitable for the technetium sorption on selected bentonite under oxidizing condition. The sorption experiments with Tc-99 on bentonite have been carried out by batch method. The influence of the addition of different materials (e.g. activated carbon, graphite, Fe 2+ ) with bentonite, the effect of solid: aqueous phase ratio and a pH value on the percentage of technetium uptake and on the K d values were tested. Perrhenate was selected as an analogue of pertechnetate in non-active experiments of capillary electrophoresis (CE) and isotachophoresis (ITP). The percentage of rhenium sorbed on bentonite material was determined from the decrease of perrhenate peak area (CE) and from the shortening of the ITP zone corresponding to perrhenate. Both electromigration methods provided comparable results. The results obtained in this study with non-active material were compared to those of technetium acquired by radiometry and polarography. The 8 days kinetics of the perrhenate and pertechnetate sorption on bentonite was described mathematically with a tendency to predict long-term behavior of studied systems. (authors)

Clinical studies on the lymph flow of the esophagus by injecting sup(99m)Tc-rhenium colloid into the esophageal wall

International Nuclear Information System (INIS)

Baba, Masamichi; Tanabe, Gen; Nishi, Mitsumasa

1985-01-01

Using 29 operative cases lymph flow of the esophagus was investigated by injecting endoscopically sup(99m)Tc-Rhenium colloid. Rhenium colloid lymphoscintigraphy was made, and 30 -- 32 hours after injection RI up take (cpm/g) of resected lymph nodes was counted by scintillation counter. 1. RI up take of resected lymph nodes correspond with the lymphoscintigraphy of resected lymph nodes therefore, RI up take count was available to study the extra-mural lymph flow of the esophagus. 2. In the cases injected at upper part of the esophagus, the high counted RI up take was noted in bifurcation lymph nodes, upper mediastinal lymph nodes and bilateral supraclavicular lymph nodes. In the cases injected at middle part of the esophagus, bilateral supraclavicular lymph nodes, upper mediastinal lymph nodes and left gastric artery lymph nodes revealed the high RI up takes. In the cases injected at lower part of the esophagus, RI up take was highly noted in bifurcation lymph nodes, left gastric artery lymph nodes and celiac axis lymph nodes. In the cases injected at esophago-gastric junction, the high counted RI up take was noted in left gastric artery lymph nodes, celiac axis lymph nodes and the lymph nodes around the left renal vein. 3. In the cases injected at upper, middle parts of the esophagus, bilateral supraclavicular lymph nodes revealed the high RI up take. Some of these lymph nodes are regarded as directly connected with the extra-mural lymph vessls of the esophagus. Therefore, it was suggested that existence of ''direct lymph flow'' from which upper, middle intrathoracic esophagus directly connected to right supraclavicular lymph nodes. 4. It is important to perform bilateral modified neck dissection in case of upper, middle intrathoracic esophageal cancer and is important to dissect the lymph nodes around the left renal vein in case of esophago-gastric cancer and lower intrathoracic esophageal cancer. (J.P.N.)

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...

Stability and Reactivity of Cyclometallated Naphthylamine Complexes in Pd-C Bond Insertion Reactions with Coordinated Alkynylphosphanes

KAUST Repository

Chen, Shuli

2013-09-17

Phenylbis(phenylethynyl)phosphane PhP(C≡CPh)2 coordinates regiospecifically to the α-methyl-chiral ortho-platinated and -palladated naphthylamine units at the positions trans to the nitrogen donors. The P→Pt coordination bond is kinetically inert, whereas the P→Pd bond is labile. Upon heating of these phosphane complexes at 70 °C, one of the C≡C bonds in the coordinated PhP(C≡CPh)2 was activated towards an intermolecular Pd-C bond insertion reaction with an external ortho-palladated naphthylamine ring. No intramolecular insertion reaction occurred. In contrast to its palladium analogue, the ortho-platinated ring is not reactive towards coordinated PhP(C≡CPh)2, although it can promote the Pd-C bond insertion reaction. However, despite the high kinetic stability of the P→Pt coordination, the organoplatinum unit is a noticeably weaker activator than its organopalladium counterpart. The chirality of the reacting ortho-metallated naphthylamine ligand exhibited high stereochemical influence on the formation of the new stereogenic phosphorus center during the course of these C-C bond-formation reactions. The coordination chemistry and the absolute stereochemistry of the dimetallic products were determined by single-crystal X-ray crystallographic analysis. The asymmetric monoinsertion of PhP(C≡CPh)2 coordinated to a cyclometallated N,N-dimethyl naphthyl/benzylamine template into the Pd-C bonds of N,N-dimethylnaphthylamine palladacycles has been demonstrated for the synthesis of a variety of new P-stereogenic homo- or heterodimetallic complexes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Role of IAEA in Coordinating Research and Transferring Technology in Radiation Chemistry and Processing of Polymers

International Nuclear Information System (INIS)

Haji Saeid, M.

2006-01-01

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through Technical Cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The CRP brings together typically 10 - 15 groups of participants to share and complement core competencies and work on specific areas of development needed to benefit from an emerging radiation technique and its applications. The technical cooperation (TC) programme helps Member States realize their development priorities through the application of appropriate radiation technology. TC builds national capacities through training, expert advice and delivery of equipment. The impact of the IAEA's efforts is visible by the progress noticeable in adoption of radiation technology and/or growth in the range of activities in several MS in different regions. The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine. A number of technical cooperation projects have been implemented in this field to strengthen the capability of developing Member States and to create awareness in the industries about the technical

Exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology.

Science.gov (United States)

Ojima, Iwao

2013-07-05

Over the last three decades, my engagement in "fluorine chemistry" has evolved substantially because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of "fluorine chemistry" in the end of 1970s. I started exploring the interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, I have been exploring the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology, and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy.

Nuclear chemistry

International Nuclear Information System (INIS)

Vertes, A.; Kiss, I.

1987-01-01

This book is an introduction to the application of nuclear science in modern chemistry. The first group of chapters discuss the basic phenomena and concepts of nuclear physics with emphasis on their relation to chemical problems, including the main properties and the composition of atomic nuclei, nuclear reactions, radioactive decay and interactions of radiation with matter. These chapters provide the basis for understanding the following chapters which encompass the wide scope of nuclear chemistry. The methods of the investigation of chemical structure based on the interaction of nuclear radiation with matter including positronium chemistry and other exotic atoms is elaborated in particular detail. Separate chapters are devoted to the use of radioactive tracers, the chemical consequences of nuclear processes (i.e. hot atom chemistry), radiation chemistry, isotope effects and their applications, and the operation of nuclear reactors

Nuclear chemistry

International Nuclear Information System (INIS)

Vertes, A.; Kiss, I.

1987-01-01

This book is an introduction to the application of nuclear science in modern chemistry. The first group of chapters discuss the basic phenomena and concepts of nuclear physics with emphasis on their relation to chemical problems, including the main properties and the composition of atomic nuclei, nuclear reactions, radioactive decay and interactions of radiation with matter. These chapters provide the basis for understanding the following chapters which encompass the wide scope of nuclear chemistry. The methods of the investigation of chemical structure based on the interaction of nuclear radiation with matter including positronium chemistry and other exotic atoms is elaborated in particular detail. Separate chapters are devoted to the use of radioactive tracers, the chemical consequences of nuclear processes (i.e. hot atom chemistry), radiation chemistry, isotope effects and their applications, and the operation of nuclear reactors. (Auth.)

Coordination Chemistry of Life Processes: Bioinorganic Chemistry ...

Indian Academy of Sciences (India)

cannot be or can only poorly be rendered by organic compounds. The roles played ..... sweet potatoes or mushrooms are injured they turn brown. This is due to the .... complexes with terminal Mn v = ° moiety will certainly help and are valuable ...

Synthesis and investigation of CrB{sub 4}, MnB{sub 4} and new ternary chromium and rhenium manganese borides; Synthese und Untersuchung von CrB{sub 4}, MnB{sub 4} sowie neuen ternaeren Chrom- und Rheniummanganboriden

Energy Technology Data Exchange (ETDEWEB)

Knappschneider, Arno

2014-10-13

In the present work single crystals of the tetraborides of chromium and manganese have been grown and allowed a structure refinement of the compounds. Furthermore the physical characteristics for example hardness, electronic properties and magnetism were been determined. Also the ternary tetraboride phase of chromium and manganese was synthesized and a new ternary rhenium manganese diboride could be obtained.

Analytical Chemistry as Methodology in Modern Pure and Applied Chemistry

OpenAIRE

Honjo, Takaharu

2001-01-01

Analytical chemistry is an indispensable methodology in pure and applied chemistry, which is often compared to a foundation stone of architecture. In the home page of jsac, it is said that analytical chemistry is a learning of basic science, which treats the development of method in order to get usefull chemical information of materials by means of detection, separation, and characterization. Analytical chemistry has recently developed into analytical sciences, which treats not only analysis ...

Fundamentals of nuclear chemistry

International Nuclear Information System (INIS)

Majer, K.

1982-01-01

The textbook is a Czech-to-German translation of the second revised edition and covers the subject under the headings: general nuclear chemistry, methods of nuclear chemistry, preparative nuclear chemistry, analytical nuclear chemistry, and applied chemistry. The book is especially directed to students

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

Surface chemistry essentials

CERN Document Server

Birdi, K S

2013-01-01

Surface chemistry plays an important role in everyday life, as the basis for many phenomena as well as technological applications. Common examples range from soap bubbles, foam, and raindrops to cosmetics, paint, adhesives, and pharmaceuticals. Additional areas that rely on surface chemistry include modern nanotechnology, medical diagnostics, and drug delivery. There is extensive literature on this subject, but most chemistry books only devote one or two chapters to it. Surface Chemistry Essentials fills a need for a reference that brings together the fundamental aspects of surface chemistry w

Physico-chemistry of actinides and other radioelements in solutions and at the interfaces

International Nuclear Information System (INIS)

2000-01-01

This document provides the 61 papers (transparencies used during the presentations and posters) presented at the 1999 PRACTIS days, held February 17-18, 2000 in Villeneuve-les-Avignon. The content comprises 9 conferences dealing with 1)simulation of solvation, coordination and liquid-liquid extraction of rare earth and uranyl cations 2)overview on the complexation selectivity of actinides(III) and rare earths(III) by aromatic poly-nitrogenous ligands 3)detection, characterization and interaction between supramolecular aggregates of extractants: macroscopic consequences on the stability and on the macroscopic behaviour 4)chemistry of technetium in reducing medium: application to researches on radioactive waste management 5) separations by pyro-chemistry (CEA program) 6)overview on the Goethite operation 7)use of time-resolved luminescence spectroscopy to the determination of sorption sites at the interfaces 8)dissolution of uranium dioxide in an argillaceous water: results in oxidizing and reducing conditions 9)treatment and storage of radioactive wastes from weapon-grade plutonium production in Russia and other countries. A large part of the conference was devoted to poster sessions on the following topics: physico-chemistry in homogeneous solutions (22 posters), transfer kinetics of actinides and rare earths between liquid phases and separations (9 posters), physico-chemistry of the solid-solution interface (9 posters), simulation and molecular dynamics (5 posters), uranium dioxide and other oxides (1 poster), long-lived fission products (6 posters). (O.M.)

The New Color of Chemistry: Green Chemistry

Directory of Open Access Journals (Sweden)

Zuhal GERÇEK

2012-01-01

Full Text Available Green chemistry which is the new application of chemistry rules provides solutions to problems that mankind is faced with climate changes, sustainable agriculture, energy, toxics, depletion of natural sources e.g. designing new chemicals and processes that production and utilization of hazardous matters. So, it is the indispensible tool for sustainable development. Current and future chemists should consider the human health and ecological issues in their professional life. In order to provide a solution for this requirement, green chemistry rules and under standings should be primarily taken in the university curriculum and at all educational levels.

Pharmacokinetic properties of new antitumor radiopharmaceutical on the basis of diamond nanoporous composites labeled with rhenium-188

International Nuclear Information System (INIS)

Petriev, V M; Tishchenko, V K; Kuril’chik, A A; Skvortsov, V G

2017-01-01

Today the development of address therapeutic radionuclide delivery systems directly to tumor tissue is of current interest. It can be achieved by the design of drug containers of specific sizes and shapes from carbon-based composite materials. It will be allowed to enhance the efficacy of anticancer therapy and avoid serious side effects. In this work we studied the pharmacokinetic properties of nanodiamond nanoporous composite labeled with rhenium-188 in rats with hepatocholangioma PC-1 after intratumoral injection. It was established that substantial part of injected radioactivity remained in tumor tissue. Within three hours after 188 Re-nanoporous composites injection activity in tumor constituted 79.1–91.3% of injected dose (ID). Then activity level declined to 45.9% ID at 120 hours. No more than 1.34% ID entered the bloodstream. In soft organs and tissues, except thyroid gland, the content of compound didn’t exceed 0.3% ID/g. The highest activity in thyroid gland was 6.95% ID/g. In conclusion, received results suggest 188 Re-nanoporous composites can be promising radionuclide delivery systems for cancer treatment. (paper)

A Coordination Chemistry Approach to Fine-Tune the Physicochemical Parameters of Lanthanide Complexes Relevant to Medical Applications.

Science.gov (United States)

Le Fur, Mariane; Molnár, Enikő; Beyler, Maryline; Kálmán, Ferenc K; Fougère, Olivier; Esteban-Gómez, David; Rousseaux, Olivier; Tripier, Raphaël; Tircsó, Gyula; Platas-Iglesias, Carlos

2018-03-02

The geometric features of two pyclen-based ligands possessing identical donor atoms but different site organization have a profound impact in their complexation properties toward lanthanide ions. The ligand containing two acetate groups and a picolinate arm arranged in a symmetrical fashion (L1) forms a Gd 3+ complex being two orders of magnitude less stable than its dissymmetric analogue GdL2. Besides, GdL1 experiences a much faster dissociation following the acid-catalyzed mechanism than GdL2. On the contrary, GdL1 exhibits a lower exchange rate of the coordinated water molecule compared to GdL2. These very different properties are related to different strengths of the Gd-ligand bonds associated to steric effects, which hinder the coordination of a water molecule in GdL2 and the binding of acetate groups in GdL1. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

JACOB: An Enterprise Framework for Computational Chemistry

Science.gov (United States)

Waller, Mark P; Dresselhaus, Thomas; Yang, Jack

2013-01-01

Here, we present just a collection of beans (JACOB): an integrated batch-based framework designed for the rapid development of computational chemistry applications. The framework expedites developer productivity by handling the generic infrastructure tier, and can be easily extended by user-specific scientific code. Paradigms from enterprise software engineering were rigorously applied to create a scalable, testable, secure, and robust framework. A centralized web application is used to configure and control the operation of the framework. The application-programming interface provides a set of generic tools for processing large-scale noninteractive jobs (e.g., systematic studies), or for coordinating systems integration (e.g., complex workflows). The code for the JACOB framework is open sourced and is available at: http://www.wallerlab.org/jacob. © 2013 Wiley Periodicals, Inc. PMID:23553271

JACOB: an enterprise framework for computational chemistry.

Science.gov (United States)

Waller, Mark P; Dresselhaus, Thomas; Yang, Jack

2013-06-15

Here, we present just a collection of beans (JACOB): an integrated batch-based framework designed for the rapid development of computational chemistry applications. The framework expedites developer productivity by handling the generic infrastructure tier, and can be easily extended by user-specific scientific code. Paradigms from enterprise software engineering were rigorously applied to create a scalable, testable, secure, and robust framework. A centralized web application is used to configure and control the operation of the framework. The application-programming interface provides a set of generic tools for processing large-scale noninteractive jobs (e.g., systematic studies), or for coordinating systems integration (e.g., complex workflows). The code for the JACOB framework is open sourced and is available at: www.wallerlab.org/jacob. Copyright © 2013 Wiley Periodicals, Inc.

CINCH-II project. Next step in the coordination of education in nuclear- and radiochemistry in Europe

International Nuclear Information System (INIS)

John, Jan; Cuba, Vaclav; Nemec, Mojmir

2013-01-01

Any of the potential options for the nuclear power – both the renaissance, if any, or the phase out – will require significant numbers of the respective specialists, amongst others the nuclear and/or radiochemists. In parallel, a significant demand exists for these specialists in non-energy fields, such as environmental protection, radiopharmacy, nuclear medicine, biology, authorities, etc. Since the numbers of staff in teaching and the number of univerzities with facilities licensed for the work with open sources of ionizing radiation has decreased on or sometimes even below the critical level, coordination and collaboration are required to maintain the necessary teaching and training capabilities. The CINCH-II project, aiming at the Coordination of education and training In Nuclear CHemistry in Europe, will be a direct continuation of the CINCH-I project which, among others, identified the EuroMaster in Nuclear Chemistry quality label recognized and guaranteed by the European Chemistry Thematic Network Association as an optimum common mutual recognition system in the field of education in Nuclear Chemistry in Europe, surveyed the status of Nuclear Chemistry in industry / the needs of the end-users, developed an efficient system of education/training compact modular courses, or developed and tested two electronic tools as a basis of a future efficient distance learning system. In the first part of this paper, the achievements of the CINCH-I project will be described. This description will cover both the status review and the development activities of this Collaboration. In the status review field, the results of a detailed survey of the universities and curricula in nuclear- and radiochemistry in Europe and Russia will be presented. Another survey mapped the nuclear- and radiochemistry in industry – specifically the training and education needs of the end users. In the development activities field, the main achievements of the CINCH-project will be presented

Coordination chemistry of two heavy metals: I, Ligand preferences in lead(II) complexation, toward the development of therapeutic agents for lead poisoning: II, Plutonium solubility and speciation relevant to the environment

International Nuclear Information System (INIS)

Neu, M.P.

1993-11-01

The coordination chemistry and solution behavior of the toxic ions lead(II) and plutonium(IV, V, VI) have been investigated. The ligand pK a s and ligand-lead(II) stability constants of one hydroxamic acid and four thiohydroaxamic acids were determined. Solution thermodynamic results indicate that thiohydroxamic acids are more acidic and slightly better lead chelators than hydroxamates, e.g., N-methylthioaceto-hydroxamic acid, pK a = 5.94, logβ 120 = 10.92; acetohydroxamic acid, pK a = 9.34, logβ l20 = 9.52. The syntheses of lead complexes of two bulky hydroxamate ligands are presented. The X-ray crystal structures show the lead hydroxamates are di-bridged dimers with irregular five-coordinate geometry about the metal atom and a stereochemically active lone pair of electrons. Molecular orbital calculations of a lead hydroxamate and a highly symmetric pseudo octahedral lead complex were performed. The thermodynamic stability of plutonium(IV) complexes of the siderophore, desferrioxamine B (DFO), and two octadentate derivatives of DFO were investigated using competition spectrophotometric titrations. The stability constant measured for the plutonium(IV) complex of DFO-methylterephthalamide is logβ 110 = 41.7. The solubility limited speciation of 242 Pu as a function of time in near neutral carbonate solution was measured. Individual solutions of plutonium in a single oxidation state were added to individual solutions at pH = 6.0, T = 30.0, 1.93 mM dissolved carbonate, and sampled over intervals up to 150 days. Plutonium solubility was measured, and speciation was investigated using laser photoacoustic spectroscopy and chemical methods

David J. Triggle: Medicinal chemistry, to pharmacology, calcium channels, and beyond.

Science.gov (United States)

Walker, Michael J A

2015-11-15

David Triggle's scientific career began as a chemist, went through medicinal chemistry into pharmacology, and finally on to somewhat more philosophical interests in later years. It was a career marked by many contributions to all of those aspects of science. Chief amongst his many contributions, in addition to those in medicinal chemistry, was his work on the drugs known as calcium ion channel blockers or (calcium antagonists). In the calcium ion channel field he was a particularly instrumental figure in sorting out the mechanisms, actions and roles of the class of calcium channel blockers, known chemical and pharmacologically as the dihydropyridines (DHPs) in particular, as well as other calcium blockers of diverse structures. During the course of a long career, and extensive journeys into medicinal chemistry and pharmacology, he published voluminously in terms of papers, reviews, conference proceedings and books. Notably, many of his papers often had limited authorship where, as senior author it reflected his deep involvement in all aspects of the reported work. His work always helped clarify the field while his incisive reviews, together with his role in coordinating and running scientific meetings, were a great help in clarifying and organizing various fields of study. He has had a long and illustrious career, and is wellknown in the world of biomedical science; his contributions are appreciated, and well recognized everywhere. The following article attempts to chart a path through his work and contributions to medicinal chemistry, pharmacology, science, academia and students. Copyright © 2015 Elsevier Inc. All rights reserved.

Physical Chemistry '98: Fourth International Conference on Fundamental and Applied Aspects of Physical Chemistry - Papers

International Nuclear Information System (INIS)

Ribnikar, S.; Anic, S.

1998-01-01

The proceedings has following chapters: Plenary lectures; Chemical Thermodynamics; Spectroscopy, Molecular Structures, Physical Chemistry of Plasma; Kinetics, Catalysis, Nonlinear Dynamics; Electrochemistry; Biophysical Chemistry, Photochemistry, Radiation Chemistry; Radiochemistry, Nuclear Chemistry; Solid State Physical Chemistry, Material Science; Macromolecular Physical Chemistry; Environmental Protection; Phase Boundaries; Complex Compounds; General Physical Chemistry. A separated abstract was prepared for each of the 20 papers selected from the three chapters: Biophysical Chemistry, Photochemistry, Radiation Chemistry; Radiochemistry, Nuclear Chemistry. and Environmental Protection. Refs and figs

Rhenium and technetium: application of organometallic rhenium and technetium complexes in radiopharmacy. Evaluation of optimal anchor groups

International Nuclear Information System (INIS)

Alberto, R.; Schibli, R.; Egli, A.; Schaffland, A.; Rattat, D.; Mueller, J.; Iftimia, M.; Berke, H.; Kaden, T.A.; Abram, U.

1997-01-01

The coordinative properties of the '[fac-M(CO) 3 ] + ' moiety (M= 188 Re, Re, 99 Tc and 99m Tc) have been investigated in water and organic solvents in order to evaluate the anchor group attached to antibodies, small peptides and biologically active molecules. The preparation of [M(OH 2 ) 3 (CO) 3 ] + has been improved in a way that this complex can be prepared from a Kit formulation. The '[fac-M(CO) 3 ] + ' has been transformed to the '[fac-M(NO)(CO) 2 ] 2+ ' moiety to achieve higher direct labelling yields and faster incorporation kinetics. (author) 5 figs

Radiation chemistry

Energy Technology Data Exchange (ETDEWEB)

None

1973-07-01

Research progress is reported on radiation chemistry of heavy elements that includes the following topics: radiation chemistry of plutonium in nitric acid solutions (spectrophotometric analysis and gamma radiolysis of Pu(IV) and Pu(VI) in nitric acid solution); EPR studies of intermediates formed in radiolytic reactions with aqueous medium; two-phase radiolysis and its effect on the distribution coefficient of plutonium; and radiation chemistry of nitric acid. (DHM)

Environmental chemistry. Seventh edition

Energy Technology Data Exchange (ETDEWEB)

Manahan, S.E. [Univ. of Missouri, Columbia, MO (United States)

1999-11-01

This book presents a basic understanding of environmental chemistry and its applications. In addition to providing updated materials in this field, the book emphasizes the major concepts essential to the practice of environmental chemistry. Topics of discussion include the following: toxicological chemistry; toxicological chemistry of chemical substances; chemical analysis of water and wastewater; chemical analysis of wastes and solids; air and gas analysis; chemical analysis of biological materials and xenobiotics; fundamentals of chemistry; and fundamentals of organic chemistry.

Antiparallel Dynamic Covalent Chemistries.

Science.gov (United States)

Matysiak, Bartosz M; Nowak, Piotr; Cvrtila, Ivica; Pappas, Charalampos G; Liu, Bin; Komáromy, Dávid; Otto, Sijbren

2017-05-17

The ability to design reaction networks with high, but addressable complexity is a necessary prerequisite to make advanced functional chemical systems. Dynamic combinatorial chemistry has proven to be a useful tool in achieving complexity, however with some limitations in controlling it. Herein we introduce the concept of antiparallel chemistries, in which the same functional group can be channeled into one of two reversible chemistries depending on a controllable parameter. Such systems allow both for achieving complexity, by combinatorial chemistry, and addressing it, by switching from one chemistry to another by controlling an external parameter. In our design the two antiparallel chemistries are thiol-disulfide exchange and thio-Michael addition, sharing the thiol as the common building block. By means of oxidation and reduction the system can be reversibly switched from predominantly thio-Michael chemistry to predominantly disulfide chemistry, as well as to any intermediate state. Both chemistries operate in water, at room temperature, and at mildly basic pH, which makes them a suitable platform for further development of systems chemistry.

More Chemistry with Light! More Light in Chemistry!

Science.gov (United States)

Bach, Thorsten

2015-09-21

"…︁ Why is chemistry overlooked when talking about light? Is the photon a physical particle per se? Are all important light-induced processes biological? Maybe the role of light for chemistry and the role of chemistry for light may be far less important than a few eccentric scientists would like to believe. From the perspective of a synthetically oriented photochemist, however, the facts are different …︁" Read more in the Editorial by Thorsten Bach. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Medicinal Chemistry/Pharmacology in Sophomore Organic Chemistry.

Science.gov (United States)

Harrison, Aline M.

1989-01-01

Discussed is a series of lectures designed to illustrate the use of general organic chemical principles in molecular biology, introduce current research in interdisciplinary areas to the beginner, increase interest in organic chemistry, and bridge the gap between traditional organic chemistry, biology, and the consumer. An outline is presented.…

Power plant cycle chemistry - a currently neglected power plant chemistry discipline

International Nuclear Information System (INIS)

Bursik, A.

2005-01-01

Power plant cycle chemistry seems to be a stepchild at both utilities and universities and research organizations. It is felt that other power plant chemistry disciplines are more important. The last International Power Cycle Chemistry Conference in Prague may be cited as an example. A critical review of the papers presented at this conference seems to confirm the above-mentioned statements. This situation is very unsatisfactory and has led to an increasing number of component failures and instances of damage to major cycle components. Optimization of cycle chemistry in fossil power plants undoubtedly results in clear benefits and savings with respect to operating costs. It should be kept in mind that many seemingly important chemistry-related issues lose their importance during forced outages of units practicing faulty plant cycle chemistry. (orig.)

Chemistry

International Nuclear Information System (INIS)

Ferris, L.M.

1975-01-01

The chemical research and development efforts related to the design and ultimate operation of molten-salt breeder reactor systems are concentrated on fuel- and coolant-salt chemistry, including the development of analytical methods for use in these systems. The chemistry of tellurium in fuel salt is being studied to help elucidate the role of this element in the intergranular cracking of Hastelloy N. Studies were continued of the effect of oxygen-containing species on the equilibrium between dissolved UF 3 and dissolved UF 4 , and, in some cases, between the dissolved uranium fluorides and graphite, and the UC 2 . Several aspects of coolant-salt chemistry are under investigation. Hydroxy and oxy compounds that could be formed in molten NaBF 4 are being synthesized and characterized. Studies of the chemistry of chromium (III) compounds in fluoroborate melts were continued as part of a systematic investigation of the corrosion of structural alloys by coolant salt. An in-line voltammetric method for determining U 4+ /U 3+ ratios in fuel salt was tested in a forced-convection loop over a six-month period. (LK)

From trace chemistry to single atom chemistry

International Nuclear Information System (INIS)

Adloff, J.P.

1993-01-01

Hot atom chemistry in the vast majority of experimental works deals with the trace amount of radioactive matters. Accordingly, the concept of trace chemistry is at the heart of hot atom chemistry. Some aspects of the chemistry at trace scale and at subtrace scale are presented together with the related problems of speciation and the complication which may arise due to the formation of radio colloids. The examples of 127 I(n,γ) 128 I and 132 Te (β - ) 132 I are shown, and the method based on radioactivity was used. The procedure of separating the elements in pitchblende is shown as the example of the chemistry of traces. 13 27 Al+ 2 4 He→ 0 1 n+ 15 30 P and 15 30 P→ 14 30 Si+e + +V are shown, and how to recognize the presence of radioactive colloids is explained. The formation of radiocolloids is by the sorption of a trace radioelement on pre-existing colloidal impurity or the self-condensation of monomeric species. The temporal parameters of the nature of reactions at trace concentration are listed. The examples of Class A and Class B reactions are shown. The kinetics of reactions at trace level, radon concentration, anthropogenic Pu and natural Pu in environment, the behavior of Pu atoms and so on are described. (K.I.)

Organic chemistry

International Nuclear Information System (INIS)

2003-08-01

This book with sixteen chapter explains organic chemistry on linkage isomerism such as alkane, cycloalkane, alkene, aromatic compounds, stereo selective isomerization, aromatic compounds, stereo selective isomerization, organic compounds, stereo selective isomerization, organic halogen compound, alcohol, ether, aldehyde and ketone, carboxylic acid, dicarboxylic acid, fat and detergent, amino, carbohydrate, amino acid and protein, nucleotide and nucleic acid and spectroscopy, a polymer and medical chemistry. Each chapter has introduction structure and characteristic and using of organic chemistry.

Preparative radiation chemistry

International Nuclear Information System (INIS)

Drawe, H.

1978-01-01

Preparative synthesis of compounds with the aid of radiation chemistry is increasingly used in laboratories as well as on a technical scale. A large number of new compounds has been produced with the methods of radiation chemistry. With the increasing number of available radiation sources, also the number of synthesis metods in radiation chemistry has increased. This paper can only briefly mention the many possible ways of synthesis in radiation chemistry. (orig./HK) [de

Development of a radiochemical neutron activation analysis procedure for determination of rhenium in biological and environmental samples at ultratrace level

International Nuclear Information System (INIS)

Kucera, J.; Lucanikova, M.; Czech Technical Univ., Prague

2006-01-01

Radiochemical neutron activation procedures using liquid-liquid extraction with tetraphenylarsonium chloride in chloroform from 1M HCl and solid extraction with ALIQUAT 336 incorporated in a polyacrylonitrile binding matrix from 0.1M HCl were developed for accurate determination of rhenium in biological and environmental samples at the sub-ng x g -1 level. Concentrations of Re in the range of 0.1 to 2.4 ng x g -1 were determined in several botanical reference materials (RM), while in a RM of road dust a value of ∼ 10 ng x g -1 was found. Significantly elevated values of Re, up to 90 ng x g -1 were found in seaweed (brown algae). Results for Re in the brown algae Fucus vesiculosus in which elevated 99 Tc values had previously been determined suggested possible competition between Re and Tc in the accumulation process. (author)

Safety and Efficacy of 188-Rhenium-Labeled Antibody to Melanin in Patients with Metastatic Melanoma

Directory of Open Access Journals (Sweden)

M. Klein

2013-01-01

Full Text Available There is a need for effective “broad spectrum” therapies for metastatic melanoma which would be suitable for all patients. The objectives of Phase Ia/Ib studies were to evaluate the safety, pharmacokinetics, dosimetry, and antitumor activity of 188Re-6D2, a 188-Rhenium-labeled antibody to melanin. Stage IIIC/IV metastatic melanoma (MM patients who failed standard therapies were enrolled in both studies. In Phase Ia, 10 mCi 188Re-6D2 were given while unlabeled antibody preload was escalated. In Phase Ib, the dose of 188Re-6D2 was escalated to 54 mCi. SPECT/CT revealed 188Re-6D2 uptake in melanoma metastases. The mean effective half-life of 188Re-6D2 was 12.4 h. Transient HAMA was observed in 9 patients. Six patients met the RECIST criteria for stable disease at 6 weeks. Two patients had durable disease stabilization for 14 weeks and one for 22 weeks. Median overall survival was 13 months with no dose-limiting toxicities. The data demonstrate that 188Re-6D2 was well tolerated, localized in melanoma metastases, and had antitumor activity, thus warranting its further investigation in patients with metastatic melanoma.

Organic chemistry experiment

International Nuclear Information System (INIS)

Mun, Seok Sik

2005-02-01

This book deals with organic chemistry experiments, it is divided five chapters, which have introduction, the way to write the experiment report and safety in the laboratory, basic experiment technic like recrystallization and extraction, a lot of organic chemistry experiments such as fischer esterification, ester hydrolysis, electrophilic aromatic substitution, aldol reaction, benzoin condensation, wittig reaction grignard reaction, epoxidation reaction and selective reduction. The last chapter introduces chemistry site on the internet and way to find out reference on chemistry.

The latest general chemistry

International Nuclear Information System (INIS)

Ryu, Geun Bae; Choi, Se Yeong; Kim, Chin Yeong; Yoon, Gil Jung; Lee, Eun Seok; Seo, Moon Gyu

1995-02-01

This book deals with the latest general chemistry, which is comprised of twenty-three chapters, the contents of this book are introduction, theory of atoms and molecule, chemical formula and a chemical reaction formula, structure of atoms, nature of atoms and the periodic table, structure of molecule and spectrum, gas, solution, solid, chemical combination, chemical reaction speed, chemical equilibrium, thermal chemistry, oxidation-reduction, electrochemistry, acid-base, complex, aquatic chemistry, air chemistry, nuclear chemistry, metal and nonmetal, organic chemistry and biochemistry. It has exercise in the end of each chapter.

Rhenium(5) and molybdenum(5) complexes with 4',4[sup (]5[sup )]-divaleryldibenzo-18-crown-6. Kompleksnye soedineniya reniya(5) i molibdena(5) s 4',4[sup (]5[sup )]-divalerildibenzo-18-kraun-6

Energy Technology Data Exchange (ETDEWEB)

Ashurova, N Kh; Yakubov, K G; Tashmukhamedova, A K; Basitova, S M [Tadzhikskij Gosudarstvennyj Univ., Dushanbe (Tajikistan)

1993-02-01

Methods for synthesizing oxohalide complexes of rhenium and molybdenum with +5 oxidation degree with 4',4[sup (5)]-divaleryldibenzo-18-crown-6 were developed. Content and composition of prepared compounds were investigated by the methods of element analysis, crystal optics, conductometry, IR spectroscopy in the near and far regions, thermogravimetry. Oxidation degree of the complex-forming metal was determined. It was established that composition of the compounds coressponded to the general formula MOLX [sub [center dot

Analytical chemistry instrumentation

International Nuclear Information System (INIS)

Laing, W.R.

1986-01-01

In nine sections, 48 chapters cover 1) analytical chemistry and the environment 2) environmental radiochemistry 3) automated instrumentation 4) advances in analytical mass spectrometry 5) fourier transform spectroscopy 6) analytical chemistry of plutonium 7) nuclear analytical chemistry 8) chemometrics and 9) nuclear fuel technology

Is Chemistry Attractive for Pupils? Czech Pupils' Perception of Chemistry

Science.gov (United States)

Kubiatko, Milan

2015-01-01

Chemistry is an important subject due to understanding the composition and structure of the things around us. The main aim of the study was to find out the perception of chemistry by lower secondary school pupils. The partial aims were to find out the influence of gender, year of study and favorite subject on the perception of chemistry. The…

Towards "Bildung"-Oriented Chemistry Education

Science.gov (United States)

Sjöström, Jesper

2013-01-01

This paper concerns "Bildung"-oriented chemistry education, based on a reflective and critical discourse of chemistry. It is contrasted with the dominant type of chemistry education, based on the mainstream discourse of chemistry. "Bildung"-oriented chemistry education includes not only content knowledge in chemistry, but also…

Green Chemistry Metrics with Special Reference to Green Analytical Chemistry

Directory of Open Access Journals (Sweden)

Marek Tobiszewski

2015-06-01

Full Text Available The concept of green chemistry is widely recognized in chemical laboratories. To properly measure an environmental impact of chemical processes, dedicated assessment tools are required. This paper summarizes the current state of knowledge in the field of development of green chemistry and green analytical chemistry metrics. The diverse methods used for evaluation of the greenness of organic synthesis, such as eco-footprint, E-Factor, EATOS, and Eco-Scale are described. Both the well-established and recently developed green analytical chemistry metrics, including NEMI labeling and analytical Eco-scale, are presented. Additionally, this paper focuses on the possibility of the use of multivariate statistics in evaluation of environmental impact of analytical procedures. All the above metrics are compared and discussed in terms of their advantages and disadvantages. The current needs and future perspectives in green chemistry metrics are also discussed.

Green Chemistry Metrics with Special Reference to Green Analytical Chemistry.

Science.gov (United States)

Tobiszewski, Marek; Marć, Mariusz; Gałuszka, Agnieszka; Namieśnik, Jacek

2015-06-12

The concept of green chemistry is widely recognized in chemical laboratories. To properly measure an environmental impact of chemical processes, dedicated assessment tools are required. This paper summarizes the current state of knowledge in the field of development of green chemistry and green analytical chemistry metrics. The diverse methods used for evaluation of the greenness of organic synthesis, such as eco-footprint, E-Factor, EATOS, and Eco-Scale are described. Both the well-established and recently developed green analytical chemistry metrics, including NEMI labeling and analytical Eco-scale, are presented. Additionally, this paper focuses on the possibility of the use of multivariate statistics in evaluation of environmental impact of analytical procedures. All the above metrics are compared and discussed in terms of their advantages and disadvantages. The current needs and future perspectives in green chemistry metrics are also discussed.

Tracking chemistry self-efficacy and achievement in a preparatory chemistry course

Science.gov (United States)

Garcia, Carmen Alicia

Self-efficacy is a person's own perception about performing a task with a certain level of proficiency (Bandura, 1986). An important affective aspect of learning chemistry is chemistry self-efficacy (CSE). Several researchers have found chemistry self-efficacy to be a fair predictor of achievement in chemistry. This study was done in a college preparatory chemistry class for science majors exploring chemistry self-efficacy and its change as it relates to achievement. A subscale of CAEQ, Chemistry Attitudes and Experiences Questionnaire (developed by Dalgety et al, 2003) as well as student interviews were used to determine student chemistry self-efficacy as it changed during the course. The questionnaire was given to the students five times during the semester: in the first class and the class before each the four tests taken through the semester. Twenty-six students, both men and women, of the four major races/ethnicities were interviewed three times during the semester and events that triggered changes in CSE were followed through the interviews. HLM (hierarchical linear modeling) was used to model the results of the CSE surveys. Among the findings, women who started at significantly lower CSE than men accomplished a significant gain by the end of the semester. Blacks' CSE trends through the semester were found to be significantly different from the rest of the ethnicities.

Green Chemistry Pedagogy

Science.gov (United States)

Kolopajlo, Larry

2017-02-01

This chapter attempts to show how the practice of chemistry teaching and learning is enriched by the incorporation of green chemistry (GC) into lectures and labs. To support this viewpoint, evidence from a wide range of published papers serve as a cogent argument that GC attracts and engages both science and nonscience students, enhances chemistry content knowledge, and improves the image of the field, while preparing the world for a sustainable future. Published pedagogy associated with green and sustainable chemistry is critically reviewed and discussed.

The renaissance of non-aqueous uranium chemistry

Energy Technology Data Exchange (ETDEWEB)

Liddle, Stephen T. [School of Chemistry, University of Nottingham (United Kingdom)

2015-07-20

Prior to the year 2000, non-aqueous uranium chemistry mainly involved metallocene and classical alkyl, amide, or alkoxide compounds as well as established carbene, imido, and oxo derivatives. Since then, there has been a resurgence of the area, and dramatic developments of supporting ligands and multiply bonded ligand types, small-molecule activation, and magnetism have been reported. This review (1) introduces the reader to some of the specialist theories of the area, (2) covers all-important starting materials, (3) surveys contemporary ligand classes installed at uranium, including alkyl, aryl, arene, carbene, amide, imide, nitride, alkoxide, aryloxide, and oxo compounds, (4) describes advances in the area of single-molecule magnetism, and (5) summarizes the coordination and activation of small molecules, including carbon monoxide, carbon dioxide, nitric oxide, dinitrogen, white phosphorus, and alkanes. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The changing role of chemistry in the power industry

International Nuclear Information System (INIS)

Caris, N.B.

2006-01-01

Corrosion costs the U.S. electricity industry between five and ten billion dollars a year. In steam generating plants it is estimated that over half the forced outages are caused by corrosion, and in the U.S. industry, corrosion increases the cost of electricity more than it increases the cost of any other product, adding over 10% to its price. The total cost of corrosion to U.S. industry is in excess of dollar 276 billion annually, of which more than 30% could be prevented through the use of optimum corrosion management practices. In order to effectively deal with these issues it will require a coordinated approach throughout the industry, in which chemistry has a major role to play. Chemistry has effectively moved from being a problem to being a solution for materials and corrosion issues, and judging by the current advances and initiatives, will continue to do so. The window of opportunity to positively influence the entire industry is here. This will be especially challenging for us as chemists in Eskom, with an ageing fleet and lack of excess generating capacity. The spin-off of taking up this challenge to 'get our chemistry right' and take a quantum step forward would be a significant positive effect on the unit capability factor (UCF) and the forced loss rate (UCLF) for the Generation Division. This could, in turn, influence issues as far reaching as the cost of electricity for the South African consumer and when the construction of new generating plant is scheduled. (orig.)

How students learn to coordinate knowledge of physical and mathematical models in cellular physiology

Science.gov (United States)

Lira, Matthew

This dissertation explores the Knowledge in Pieces (KiP) theory to account for how students learn to coordinate knowledge of mathematical and physical models in biology education. The KiP approach characterizes student knowledge as a fragmented collection of knowledge elements as opposed to stable and theory-like knowledge. This dissertation sought to use this theoretical lens to account for how students understand and learn with mathematical models and representations, such as equations. Cellular physiology provides a quantified discipline that leverages concepts from mathematics, physics, and chemistry to understand cellular functioning. Therefore, this discipline provides an exemplary context for assessing how biology students think and learn with mathematical models. In particular, the resting membrane potential provides an exemplary concept well defined by models of dynamic equilibrium borrowed from physics and chemistry. In brief, membrane potentials, or voltages, "rest" when the electrical and chemical driving forces for permeable ionic species are equal in magnitude but opposite in direction. To assess students' understandings of this concept, this dissertation employed three studies: the first study employed the cognitive clinical interview to assess student thinking in the absence and presence of equations. The second study employed an intervention to assess student learning and the affordances of an innovative assessment. The third student employed a human-computer-interaction paradigm to assess how students learn with a novel multi-representational technology. Study 1 revealed that students saw only one influence--the chemical gradient--and that students coordinated knowledge of only this gradient with the related equations. Study 2 revealed that students benefited from learning with the multi-representational technology and that the assessment detected performance gains across both calculation and explanation tasks. Last, Study 3 revealed how students

A new amperometric glucose biosensor based on screen printed carbon electrodes with rhenium(IV - oxide as a mediator

Directory of Open Access Journals (Sweden)

ALBANA VESELI

2012-11-01

Full Text Available Rhenium(IV-oxide, ReO2, was used as a mediator for carbon paste (CPE and screen printed carbon (SPCE electrodes for the catalytic amperometric determination of hydro-gen peroxide, whose overpotential for the reduction could be lowered to -0.1 V vs. Ag/AgCl in flow injection analysis (FIA using phosphate buffer (0.1 M, pH=7.5 as a carrier. For hydrogen peroxide a detection limit (3σ of 0.8 mg L-1 could be obtained.ReO2-modified SPCEs were used to design biosensors with a template enzyme, i.e. glucose oxidase, entrapped in a Nafion membrane. The resulting glucose sensor showed a linear dynamic range up to 200 mg L-1 glucose with a detection limit (3σ of 0.6 mg L-1. The repeatability was 2.1 % RSD (n = 5 measurements, the reproducibility 5.4 % (n = 5 sensors. The sensor could be applied for the determination of glucose in blood serum in good agreement with a reference method.

Chemistry Notes

Science.gov (United States)

School Science Review, 1976

1976-01-01

Described are eight chemistry experiments and demonstrations applicable to introductory chemistry courses. Activities include: measure of lattice enthalpy, Le Chatelier's principle, decarboxylation of soap, use of pocket calculators in pH measurement, and making nylon. (SL)

Fundamentals of nuclear chemistry

International Nuclear Information System (INIS)

Matel, L.; Dulanska, S.

2013-01-01

This text-book is an introductory text in nuclear chemistry and radiochemistry, aimed on university undergraduate students in chemistry and related disciplines (physics, nuclear engineering). It covers the key aspects of modern nuclear chemistry. The text begins with basic theories in contemporary physics. It relates nuclear phenomena to key divisions of chemistry such as atomic structure, spectroscopy, equilibria and kinetics. It also gives an introduction to sources of ionizing radiation, detection of ionizing radiation, nuclear power industry and accident on nuclear installations as well as basic knowledge's of radiobiology. This book is essential reading for those taking a first course in nuclear chemistry and is a useful companion to other volumes in physical and analytical chemistry. It will also be of use to those new to working in nuclear chemistry or radiochemistry.

Coordinate measuring machines

DEFF Research Database (Denmark)

De Chiffre, Leonardo

This document is used in connection with three exercises of 2 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercises concern three aspects of coordinate measuring: 1) Measuring and verification of tolerances on coordinate measuring machines, 2) Traceabilit...... and uncertainty during coordinate measurements, 3) Digitalisation and Reverse Engineering. This document contains a short description of each step in the exercise and schemes with room for taking notes of the results.......This document is used in connection with three exercises of 2 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercises concern three aspects of coordinate measuring: 1) Measuring and verification of tolerances on coordinate measuring machines, 2) Traceability...

Handbook of heterocyclic chemistry

National Research Council Canada - National Science Library

Katritzky, Alan R

2010-01-01

... Heterocyclic Chemistry I (1984) Comprehensive Heterocyclic Chemistry II (1996) Comprehensive Heterocyclic Chemistry III (2008) Comprehensive Organic Functional Group Transformations I (1995) Compreh...

Binuclear complexes of technetium. Evidence for bis(terdentate)bidentate coordination by the bridging ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine to technetium(V)

International Nuclear Information System (INIS)

Du Preez, J.G.H.; Gerber, T.I.A.; Gibson, M.L.; Geyser, R.

1990-01-01

The authors have used the potentially bis(terdentate) nitrogen aromatic heterocyclic ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz) to prepare mono- and bimetallic technetium(V) complexes bound to tppz. The stimulus for the development of the coordination chemistry of the man-made element technetium is provided by the use of complexes of this element as anatomical imaging agents in nuclear medicine. Although the chemistry of technetium(V) with nitrogen donor ligands is well understood, no complexes have been prepared using potentially terdentate neutral nitrogen donor ligands of this metal in the +5 oxidation state

Analysis of extreme ultraviolet spectra from laser produced rhenium plasmas

International Nuclear Information System (INIS)

Wu, Tao; Dunne, Padraig; O’Reilly, Fergal; Sokell, Emma; Liu, Luning; O’Sullivan, Gerry; Higashiguchi, Takeshi; Suzuki, Yuhei; Arai, Goki; Dinh, Thanh-Hung; Li, Bowen

2015-01-01

Extreme ultraviolet spectra of highly-charged rhenium ions were observed in the 1–7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a number of laser power densities. The maximum focused peak power density was 2.6 × 10 14 W cm −2 for the former and 5.5 × 10 12 W cm −2 for the latter. The Cowan suite of atomic structure codes and unresolved transition array (UTA) approach were used to calculate and interpret the emission properties of the different spectra obtained. The results show that n = 4-n = 4 and n = 4-n = 5 UTAs lead to two intense quasi-continuous emission bands in the 4.3–6.3 nm and 1.5–4.3 nm spectral regions. As a result of the different ion stage distributions in the plasmas induced by ps and ns laser irradiation the 1.5–4.3 nm UTA peak moves to shorter wavelength in the ps laser produced plasma spectra. For the ns spectrum, the most populated ion stage during the lifetime of this plasma that could be identified from the n = 4-n = 5 transitions was Re 23+ while for the ps plasma the presence of significantly higher stages was demonstrated. For the n = 4-n = 4 4p 6 4d N -4p 5 4d N+1  + 4p 6 4d N−1 4f transitions, the 4d-4f transitions contribute mainly in the most intense 4.7–5.5 nm region while the 4p-4d subgroup gives rise to a weaker feature in the 4.3–4.7 nm region. A number of previously unidentified spectral features produced by n = 4-n = 5 transitions in the spectra of Re XVI to Re XXXIX are identified. (paper)

Investigating the pharmacodynamic and magnetic properties of pyrophosphate-bridged coordination complexes

Science.gov (United States)

Ikotun, Oluwatayo (Tayo) F.

The multidentate nature of pyrophosphate makes it an attractive ligand for complexation of metal cations. The participation of pyrophosphate in a variety of biological pathways and its metal catalyzed hydrolysis has driven our investigation into its coordination chemistry. We have successfully synthesized a library of binuclear pyrophosphate bridge coordination complexes. The problem of pyrophosphate hydrolysis to phosphate in the presence of divalent metal ions was overcome by incorporating capping ligands such as 1,10-phenanthroline and 2,2'-bipyridine prior to the addition of the pyrophosphate. The magnetic properties of these complexes was investigated and magneto-structural analysis was conducted. The biological abundance of pyrophosphate and the success of metal based drugs such as cisplatin, prompted our investigation of the cytotoxic properties of M(II) pyrophosphate dimeric complexes (where M(II) is CoII, CuII, and NiII) in adriamycin resistant human ovarian cancer cells. Thess compounds were found to exhibit toxicity in the nanomolar to picomolar range. We conducted in vitro stability studies and the mechanism of cytoxicity was elucidated by performing DNA mobility and binding assays, enzyme inhibition assays, and in vitro oxidative stress studies.

Coordination chemistry of two heavy metals: I, Ligand preferences in lead(II) complexation, toward the development of therapeutic agents for lead poisoning: II, Plutonium solubility and speciation relevant to the environment

Energy Technology Data Exchange (ETDEWEB)

Neu, Mary Patricia [Univ. of California, Berkeley, CA (United States)

1993-11-01

The coordination chemistry and solution behavior of the toxic ions lead(II) and plutonium(IV, V, VI) have been investigated. The ligand pK_as and ligand-lead(II) stability constants of one hydroxamic acid and four thiohydroaxamic acids were determined. Solution thermodynamic results indicate that thiohydroxamic acids are more acidic and slightly better lead chelators than hydroxamates, e.g., N-methylthioaceto-hydroxamic acid, pK_a = 5.94, logβ₁₂₀ = 10.92; acetohydroxamic acid, pK_a = 9.34, logβ₁₂₀ = 9.52. The syntheses of lead complexes of two bulky hydroxamate ligands are presented. The X-ray crystal structures show the lead hydroxamates are di-bridged dimers with irregular five-coordinate geometry about the metal atom and a stereochemically active lone pair of electrons. Molecular orbital calculations of a lead hydroxamate and a highly symmetric pseudo octahedral lead complex were performed. The thermodynamic stability of plutonium(IV) complexes of the siderophore, desferrioxamine B (DFO), and two octadentate derivatives of DFO were investigated using competition spectrophotometric titrations. The stability constant measured for the plutonium(IV) complex of DFO-methylterephthalamide is logβ₁₂₀ = 41.7. The solubility limited speciation of ²⁴²Pu as a function of time in near neutral carbonate solution was measured. Individual solutions of plutonium in a single oxidation state were added to individual solutions at pH = 6.0, T = 30.0, 1.93 mM dissolved carbonate, and sampled over intervals up to 150 days. Plutonium solubility was measured, and speciation was investigated using laser photoacoustic spectroscopy and chemical methods.