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News Article | February 23, 2017
Site: www.eurekalert.org

PULLMAN, Wash. - A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods. The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy. "The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.


News Article | February 24, 2017
Site: www.rdmag.com

A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods. The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy. "The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.


News Article | February 23, 2017
Site: phys.org

The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy."The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds. More information: Jamie Weaver et al, Chemical Trends in Solid Alkali Pertechnetates, Inorganic Chemistry (2017). DOI: 10.1021/acs.inorgchem.6b02694


This breakthrough may allow the use of hybrid metal-DNA molecules for applications in the fields of biotechnology and biomedicine, given that the DNA structure remains practically unaltered and the metallic ions offer new properties to DNA molecules, including fluorescence, conductivity, magnetism or catalytic properties. The research, published in Angewandte Chemie, has been conducted in the department of Inorganic Chemistry at the UGR. The formation of these metal-DNA hybrids has been achieved carrying out slight chemical modifications in some of the DNA molecules' components—in particular, replacing adenine units with 7-deazaadenine units, which maintains their auto-recognition properties and facilitates the incorporation of metallic ions. The research team from the UGR has transformed Watson-Crick bondings into similar bondings with silver metallic ions. This creates hybrid, highly stable DNA molecules capable of holding metallic ions in specific controlled positions within the DNA molecules. As a result, for the first time, researchers can obtain big DNA molecules that keep their base complementarity, and whose metallic ions are distributed along the whole DNA molecule. As professor Miguel A. Galindo Cuesta explains, "Until now, the international scientific community had only managed to introduce a small amount of metallic ions in some sections of the DNA structure using sophisticated chemical alterations that made it lose its natural properties, thus limiting possible applications." The research team is currently expanding this strategy in collaboration with Javier Martínez from the Centre for Genomics and Oncological Research (GENyO), in order to prepare metal-DNA, nanometric systems with well-defined structures by using enzymatic DNA replication methods. The goal is to develop metal-DNA hybrids with potential biotechnological applications aimed at medicine and nanotechnology. Explore further: New class of catalysts to transform cheap, widely available hydrocarbons into industrial molecules More information: Noelia Santamaría-Díaz et al. Highly Stable Double-Stranded DNA Containing Sequential Silver(I)-Mediated 7-Deazaadenine/Thymine Watson-Crick Base Pairs, Angewandte Chemie International Edition (2016). DOI: 10.1002/anie.201600924


News Article | February 25, 2017
Site: www.techtimes.com

Washington State University conducted tests to study the effects of the chemical substance known as technetium-99. The study was led by John McCloy, an associate professor in the School of Mechanical and Materials Engineering along with Jamie Weaver, a chemistry graduate student. They worked in collaboration with researchers from the Office of River Protection and Lawrence Berkeley National Laboratory and Pacific Northwest National Laboratory. Technetium-99 is the chemical by-product derived as a result of plutonium weapon production. It is being considered a major problem as scientists are trying to find new methods of disposing the nuclear waste. In fact, there exists about 2000 pounds of technetium-99 which is stored in 177 storage tanks at the Hanford nuclear site in Washington. The element is readily soluble in water and so poses an intense risk. Due to its volatility, it can easily contaminate water streams which would cause major health issues. Nuclear wastes are generated from nuclear power plants in significant amounts and thus, it needs to be managed and disposed of properly. The most important issue concerning the nuclear waste is the management of its toxic nature, so that it poses no risk to the workers or the general public. The Washington State University conducted the study of technetium-99 in PNNL's highly specialized Radiochemical Processing Laboratory. Researchers carried out various tests with the compound. Their aim was to precisely observe technetium-99 and determine how it may be stored. They found that the sodium reacts differently in the compound than in any other alkalis, which may go a long way in defining why technetium-99 is so reactive with water. This may also reveal the reason behind its volatility. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. Currently, U.S. Department of Energy at Hanford is in the act of constructing a waste treatment plant. They aim to store threatening nuclear waste in a glass. However, researchers have to find an alternative as the entire technetium-99 cannot be incorporated in a glass. The volatilized gas would also be needed to be recycled back into the system. These innovative ideas may pave the way for a safer future. However, for now the threat of nuclear contamination due to the high volume of nuclear waste being produced seems to be looming. It has become essential to come up with a reliable way to dispose these wastes of. The study has been published in the journal Inorganic Chemistry. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | November 21, 2016
Site: www.eurekalert.org

LOGAN, UTAH, USA -- Utah State University professor Lisa Berreau has been named a Fellow of the American Association for the Advancement of Science, one of the nation's top national science honors. One of 391 honorees recognized nationwide, she will be formally honored in a Feb. 18 ceremony during the association's 2017 annual meeting in Boston. An inorganic chemist, Berreau, who serves as executive associate dean for USU's College of Science, is recognized for her innovative work in understanding reaction involving metals and dioxygen that lead to carbon-carbon bond cleavage and the influence of hydrogen bonding on metal-centered reactivity. Her work investigates the role metal ions play in human health, the environment and catalysis. "Designation as an AAAS fellow is a distinct honor reserved for the nation's top scientists," says USU President Stan Albrecht. "It's not only an honor for Dr. Berreau to be recognized for her outstanding contributions, but also for Utah State University." "Dr. Berreau is a most deserving awardee and we are thrilled she is receiving this prestigious recognition," says Maura Hagan, dean of USU's College of Science. "She promotes the role of science not only as an accomplished researcher, but also as a dedicated educator and administrator." In addition to her administrative and research efforts, Berreau, a professor in the Department of Chemistry and Biochemistry, teaches and mentors a team of graduate and undergraduate students in research. She also serves as treasurer of the American Chemical Society Division of Inorganic Chemistry. Berreau, who joined USU's faculty in 1998, received the prestigious National Science Foundation CAREER Research Fellowship and was also named a Herman Frasch Foundation Fellow. In 2006, she was named "Undergraduate Research Mentor of the Year" for USU's College of Science. A native of Brewster, Minn., Berreau earned a bachelor's degree from Mankato State University in 1990 and completed a doctorate from Iowa State University in 1994. She returned to her home state in 1995, where she served as a postdoctoral fellow at the University of Minnesota until 1998. At USU, she advanced to full professor in 2011 and served as interim dean for the College of Science from 2014-2015. Berreau joins fellow USU AAAS Fellows James "Jim" MacMahon, emeritus trustee professor of biology and former dean of the College of Science; Lance Seefeldt, professor in the Department of Chemistry and Biochemistry and Patricia Lambert, professor in the Department of Sociology, Social Studies and Anthropology. The AAAS is the world's largest general scientific society and publisher of a number of academic journals, including the association's flagship publication Science.


When it comes to making phosphorus compounds, chemists have traditionally relied on white phosphorus, P , a tetrahedral-shaped allotrope of the element. The one downside with white phosphorus is that it’s toxic and flammable. Red phosphorus, an air-stable amorphous oligomeric allotrope, is a safer alternative. But chemists have had difficulty processing the relatively inert material in large quantities without resorting to high temperature and strong reducing agents. Florida State University chemists have now solved that problem by discovering an easy way to convert red phosphorus to soluble polyphosphides (Angew. Chem. Int. Ed. 2016, DOI: 10.1002/anie.201511186). Alina Dragulescu-Andrasi, a postdoctoral researcher in Michael Shatruk’s group, provided details of the approach during a Division of Inorganic Chemistry symposium on Monday at the American Chemical Society national meeting in San Diego. The team simply passes a solution of inexpensive potassium ethoxide in an organic solvent through red phosphorus under mild heating to produce P –, P 2-, and P 3-. These variously sized clusters, which the researchers isolate as potassium or tetrabutylammonium salts, could be used to synthesize phosphorus compounds or to make two-dimensional semiconductors and lithium-ion battery anodes. Taking the process a step further, the researchers adapted it to run as a continuous-flow reaction by passing potassium ethoxide through a stainless-steel column packed with red phosphorus, generating multigram amounts of the soluble polyphosphides. The Florida State team’s work is funded in part by a Small Business Innovation Research grant in collaboration with Chemring Ordnance, a Florida-based munitions company. “This appears to be a relatively safe and convenient methodology for generating soluble salts of polyphosphide anions,” commented MIT’s Christopher C. Cummins, who builds new compounds from elemental phosphorus. “It should open the door to more widespread study and application of these interesting little bits of reduced phosphorus.”


Among the elements, cesium, located in the lower left corner of the periodic table, and fluorine, in the upper right corner, are among the largest electropositive and smallest electronegative elements, respectively. When chemists look at possible ways to get the two elements together, something interesting is bound to happen. And it has. Klaus-Richard Pörschke, David Pollak, and Richard Goddard of the Max Planck Institute for Coal Research have prepared a molecule in which a central cesium atom is coordinated by 16 fluorine atoms—achieving a perfect score for the maximum number of bonds possible and establishing a new precedent for bonding in the process. Pörschke announced the team’s discovery in a Division of Inorganic Chemistry symposium at the American Chemical Society national meeting yesterday in San Diego. Going beyond 12 bonds is rare because of the limited space available around the central atom of a molecule and electrostatic repulsion between the ligands. Chemists have flirted with 16-coordinate compounds for years, reporting isolated 15- and 16-coordinate Th-H molecules and a gas-phase 16-coordinate Co-B species. For Pörschke and coworkers, pairing the large singly charged Cs+ cation with the weakly coordinating [H NB (C F ) ]– anion allowed them to go beyond 12 bonds in a complex for the first time without using hydrogen as a ligand. The team prepared Cs[H NB (C F ) ] by using ultrasound to agitate a solution of [Na(OCH CH ) ][H NB (C F ) ] and CsF in dichloromethane. The researchers concentrated the solution and isolated crystals to study by X-ray crystallography. The poor aqueous solubility of the new compound suggested to the researchers that [H NB (C F ) ]– could be a good scavenger of Cs+ in water, which they demonstrated with a set of experiments. Pörschke says that the anion might therefore be useful to pull 134Cs and 137Cs from nuclear waste solutions, as a treatment for 134Cs and 137Cs radiation poisoning, or to prepare implantable 131Cs and 137Cs seeds for radiation therapy. “Pörschke and coworkers have plumbed the limits of coordination chemistry by a careful matching of cation and anion properties,” commented Warren E. Piers, of the University of Calgary, an expert in coordination chemistry. “In addition to the sheer beauty of the molecule, they demonstrate exciting possibilities for radioactive cesium ion sequestration.”


News Article | December 2, 2016
Site: www.csmonitor.com

Four new elements have been added to the periodic table, though each of the synthetic metals can only exist in reality for fractions of a second. Kosuke Morita of Riken Nishina Center for Accelerator-Based Science points at the periodic table of the elements during a press conference in Wako, Saitama prefecture, near Tokyo, on Dec. 31, 2015. Nihonium (Nh), moscovium (Mc), tennessine (Ts), and oganesson (Og): Welcome to the periodic table. The International Union of Pure and Applied Chemistry (IUPAC) approved the names and symbols for four new elements earlier this week. After verifying their discovery last December, the IUPAC suggested names for these four elements in June, pending a five-month review period for public comment. Nh, Mc, Ts, and Og – officially designated as elements 113, 115, 117, and 118, respectively – will complete the seventh period (or row) on the table, making them some of the heaviest metals on the table. These elements are synthetic, or man-made, and they only exist for fractions of a second in a lab before breaking apart into other elements. These are the first elements added to the centuries-old periodic table since 2011, when heavy metal band members livermorium (element 116) and flerovium (element 114) were added to the table. Adding new names to the table is not something scientists – or the general public – take lightly, as the five-month process suggests. “Overall, it was a real pleasure to realize that so many people are interested in the naming of the new elements, including high-school students, making essays about possible names and telling how proud they were to have been able to participate in the discussions,” said Jan Reedijk, president of the Inorganic Chemistry Division at IUPAC, in a press release. “It is a long process from initial discovery to the final naming, and IUPAC is thankful for the cooperation of everyone involved.” However, the naming process is not entirely open to the public. Although numerous comments and petitions were received, the suggestions “could not be accepted,” IUPAC explains, because only the elements' discoverers “have the right to propose names and symbols.” The four new elements follow IUPAC’s guidelines, which dictate that all elements be named after a place, scientist, property, mineral, or mythological concept. Oganesson honors Armenian nuclear physicist and element hunter Yuri Oganessian, who is also known as “the grandfather of superheavy elements.” Nihonium, moscovium, and tennessine are all named for the locations where they were discovered: Japan (Nihon is a way to say Japan in Japanese), Moscow, and the US state of Tennessee. “It used to be that when a discovery was made, when you thought you had one, you named it something,” Janan Hayes, professor emeritus at Merced College in California and former chair of the American Chemical Society’s Division of History of Chemistry, told The Christian Science Monitor’s Lisa Suhay. “But this was very confusing because you could end up with three or four names for an element as three or four different groups or laboratories claimed discovery. What makes the naming important internationally is that the name is accepted internationally.” And considering that new elements come along so infrequently, it makes sense that chemists take their naming seriously. “Biologists get to do all those sorts of things, more whimsical namings, because they have so much more to work with,” added Dr. Hayes. “In chemistry, we have so little that we really need to put deeper thought into it every time.”


News Article | March 1, 2017
Site: phys.org

The study, published in Inorganic Chemistry, used a range of experimental techniques and ab Initio calculations to characterise a family of lanthanoid-polyoxometalate single-molecule magnets (Ln-SMMs). Inelastic neutron scattering at ANSTO provided measurements of crystal field excitations in the series that showed good agreement with theoretical computations. "It is the biggest, most comprehensive, combined study of these interesting molecules using excellent samples, good quality measurements and outstanding simulations," said Pelican instrument scientist Dr Richard Mole, who with co-author Dr Dehong Yu is based at the Australian Centre for Neutron Scattering. The investigation was led by chemist Associate Professor Colette Boskovic and dr Alessandro Soncini from the University of Melbourne, including lead author Michele Vonci, who completed some of his PhD research at ANSTO. "Inelastic neutron scattering is a very effective way to see very weak excitations because you are probing what the individual ions are doing, in contrast to magnetic susceptibility measurements which determine so-called bulk properties," said Mole. In the Ln-SMMs, a lanthanoid ion sits in the middle of a cluster of tungsten and oxygen anions, surrounded by a network of water coordinated sodium cations. Although neutron scattering has been used to study the SMMs, there have only been a handful of papers on single ion lanthanoid SMMs. "Unlike conventional bulk magnets, in which there is collective long range ordering of magnetic moments, every metal atom knows where its neighbours are and they all line up, the SMMs rely on a pure quantum effect," said Mole. The lowest lying energy levels in the geometric structure of the lanthanoid ions binding with polyoxometalate ligands are dominated by crystal field splitting of the f-orbitals. The crystal field splitting can result in a slow relaxation of magnetisation, even at relatively high temperature. The quantum tunnelling of a particle's spin through a potential energy barrier from one orientation to another (reversing direction) was first observed in lanthanoid single molecule magnets in 2003. Since then much a larger body of research has focused on how the quantum nature of this ground state of these Ln-SMM's can be used as qubits in quantum computers. Mole and Yu and collaborators were building on previous research (published in Chemical Communications in December 2015) that elucidated the sensitivity of the electronic structure of the ground and excited states of a terbium analogue to small structural distortions from axial symmetry. In the first magnetisation study on Pelican, the researchers discovered a polymorphism, in which the same molecule has a different crystal structure, in the terbium analog. They found the polymorphism when trying to resolve a discrepancy in the neutron data, which observed four well resolved peaks (transitions) instead of the predicted two peaks. "One possible explanation was the presence of multiple species in the sample," said Mole. Calculations and X-ray diffraction data enabled them to determine that the INS spectra had captured two distinct co-crystallised polymorphic phases. After synthesising the samples separately and repeating the INS measurements, they confirmed the ground state transitions for each phase and energy shifts. Minute differences in crystal structure, like one or two degrees in the torsion angle, give a 1 meV difference in energy. "A 1 meV in energy is equivalent about 10 K in temperature, which is significant when you think about operating temperature and power requirements for quantum computers," said Mole. Understanding the interaction, that such a small change in coordination geometry can have on electronic structure, was important and led the group to a more comprehensive further investigation of the Ln-SMMs. "This is a huge project which involved the synthesis and characterisation of neodymium, dysprosium, holmium, and terbium analogues," said Mole. Experimental techniques included single crystal X-ray diffraction, magnetic measurements, deuteration, INS with data analysis and refinement, theoretical calculations and ab initio calculations of magnetic properties and INS spectral simulations. There have been relatively few neutron scattering measurements of the lanthanoid-polyoxotungstates, because they absorb neutrons to a greater or lesser degree and are also very difficult to make in pure forms. "Nonetheless we were able to get a signal from all the compounds except the dysprosium, which has an extremely high absorption of neutrons," said Mole. Explore further: Pelican instrument provides crucial experimental evidence of unusual quantum state More information: Michele Vonci et al. Magnetic Excitations in Polyoxotungstate-Supported Lanthanoid Single-Molecule Magnets: An Inelastic Neutron Scattering and ab Initio Study, Inorganic Chemistry (2017). DOI: 10.1021/acs.inorgchem.6b02312

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