BTBP

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Core chemical structure of a bis-triazinyl bipyridine Bis-triazinyl bipyridine.png
Core chemical structure of a bis-triazinyl bipyridine

The bis-triazinyl bipyridines (BTBPs) are a class of chemical compounds which are tetradentate ligands similar in shape to quaterpyridine. The BTBPs are made by the reaction of hydrazine and a 1,2-diketone (such as hexane-3,4-dione) with 6,6'-dicyano-2,2'-bipyridine. The dicyanobipy can be made by reacting 2,2'-bipy with hydrogen peroxide in acetic acid, (followed by the addition of acetone) to form 2,2'-bipyridine-N,N-dioxide. [1] The 2,2'-bipyridine-N,N-dioxide is then converted into the dicyano compound [2] by treatment with potassium cyanide and benzoyl chloride in a mixture of water and THF. [3]

The BTBPs were first reported as synthetic intermediates in the synthesis of quaterpyridines by a Diels-Alder reaction of the triazine ring with tributylstannylacetylene or norbornadiene, [4] after the Diels-Alder reaction a series of other reactions cause the adjunct to lose a molecule of nitrogen and a molecule of cyclopentadiene to form the pyridine ring.

The BTBPs are related to the BTPs, the BTPs are the bis-triazinyl pyridines which were introduced to solvent extraction by Z. Kolarik. [5] By extending the central part of the BTPs the BTBPs were created.

The synthesis of the BTBPs as solvent extraction reagents was a development of the chemistry at Reading in Berkshire which was done during the PARTNEW EU funded project on advanced nuclear reprocessing, the hemi-BTPs had been made from 2,2'-bipyridine-N-oxide [6] this chemistry was then extended to form the BTBPs. The research continued during the EUROPART integrated project and in the ACSEPT project. With lanthanides the BTBPs bind with four nitrogens to form complexes, the trinitrate complexes of most of the lanthanides have been characterised by X-ray crystallography, with a smaller metal such as nickel the BTBPs are may bind with three nitrogens in some complexes. The perchlorate salts of both the 1:1 and 1:2 complexes of nickel and a BTBP have been characterised by crystallography. [7] The 1:1 complex has a single BTBP which binds through four nitrogen atoms to the metal atom, the four BTBP nitrogens form an equatorial plane and two acetonitrile molecules occupy the two axial sites. Two BTBP molecules each bind with three nitrogens in the 1:2 complex to provide the nickel with a distorted octahedral coordination environment. Uranium(VI) binds to BTBP to form a 1:1 complex, where the axial sites are occupied with the uranyl oxygen atoms. [8] The BTBPs are also able to bind to cyclopentadienyl complexes of uranium. [9]

In recent years the BTBPs have been investigated as reagents for the selective extraction of post-plutonium metals such as americium from nitric acid solutions containing large amounts of lanthanides. [10] Already one of the BTBPs has been shown to be able to selectively extract the americium and curium from a genuine mixture formed from used MOX fuel. [11] The MOX fuel was dissolved in nitric acid, the bulk of the uranium and plutonium were removed by means of a PUREX type extraction using tributyl phosphate in a hydrocarbon, the lanthanides and the remaining actinides were then separated from the aqueous residue (raffinate) by a diamide based extraction to give, after stripping, a mixture of trivalent actinides and lanthanides.

Related Research Articles

Americium Chemical element, symbol Am and atomic number 95

Americium is a synthetic radioactive chemical element with the symbol Am and atomic number 95. It is a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas.

The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide.

Curium Chemical element, symbol Cm and atomic number 96

Curium is a transuranic, radioactive chemical element with the symbol Cm and atomic number 96. This element of the actinide series was named after eminent scientists Marie and Pierre Curie, both known for their research on radioactivity. Curium was first intentionally made by the team of Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso in 1944, using the cyclotron at Berkeley. They bombarded a piece of the newly discovered element plutonium with alpha-particles. This was then sent to the Metallurgical Laboratory at the University of Chicago where a tiny sample of curium was eventually separated and identified. The discovery was kept secret until after the end of the World War II. The news was released to the public in November 1947. Most curium is produced by bombarding uranium or plutonium with neutrons in nuclear reactors – one tonne of spent nuclear fuel contains about 20 grams of curium.

Terpyridine Chemical compound

Terpyridine is a heterocyclic compound derived from pyridine. It is a white solid that is soluble in most organic solvents. The compound is mainly used as a ligand in coordination chemistry.

Triazine Aromatic, heterocyclic compound

Triazines are a class of nitrogen-containing heterocycles. The parent molecules' molecular formula is C3H3N3. They exist in three isomeric forms, 1,3,5-triazines being common.

PUREX Spent fuel reprocessing process for plutonium and uranium recovery

PUREX is a chemical method used to purify fuel for nuclear reactors or nuclear weapons. PUREX is the de facto standard aqueous nuclear reprocessing method for the recovery of uranium and plutonium from used nuclear fuel. It is based on liquid–liquid extraction ion-exchange.

Liquid–liquid extraction (LLE), also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an organic solvent (non-polar). There is a net transfer of one or more species from one liquid into another liquid phase, generally from aqueous to organic. The transfer is driven by chemical potential, i.e. once the transfer is complete, the overall system of chemical components that make up the solutes and the solvents are in a more stable configuration. The solvent that is enriched in solute(s) is called extract. The feed solution that is depleted in solute(s) is called the raffinate. LLE is a basic technique in chemical laboratories, where it is performed using a variety of apparatus, from separatory funnels to countercurrent distribution equipment called as mixer settlers. This type of process is commonly performed after a chemical reaction as part of the work-up, often including an acidic work-up.

Uranyl

The uranyl ion is an oxycation of uranium in the oxidation state +6, with the chemical formula UO2+
2. It has a linear structure with short U–O bonds, indicative of the presence of multiple bonds between uranium and oxygen. Four or more ligands may be bound to the uranyl ion in an equatorial plane around the uranium atom. The uranyl ion forms many complexes, particularly with ligands that have oxygen donor atoms. Complexes of the uranyl ion are important in the extraction of uranium from its ores and in nuclear fuel reprocessing.

Coordination sphere

In coordination chemistry, the first coordination sphere refers to the array of molecules and ions directly attached to the central metal atom. The second coordination sphere consists of molecules and ions that attached in various ways to the first coordination sphere.

Uranocene, U(C8H8)2, is an organouranium compound composed of a uranium atom sandwiched between two cyclooctatetraenide rings. It was one of the first organoactinide compounds to be synthesized. It is a green air-sensitive solid that dissolves in organic solvents. Uranocene, a member of the "actinocenes," a group of metallocenes incorporating elements from the actinide series. It is the most studied bis[8]annulene-metal system, although it has no known practical applications.

Organoactinide chemistry

Organoactinide chemistry is the science exploring the properties, structure and reactivity of organoactinide compounds, which are organometallic compounds containing a carbon to actinide chemical bond.

2,2′-Bipyridine Chemical compound

2,2′-Bipyridine (bipy or bpy, pronounced ) is an organic compound with the formula C10H8N2. This colorless solid is an important isomer of the bipyridine family. It is a bidentate chelating ligand, forming complexes with many transition metals. Ruthenium and platinum complexes of bipy exhibit intense luminescence, which may have practical applications.

The plutonyl ion is an oxycation of plutonium in the oxidation state +6, with the chemical formula PuO2+
2. It is isostructural with the uranyl ion, compared to which it has a slightly shorter M–O bond. It is easily reduced to plutonium(III). The plutonyl ion forms many complexes, particularly with ligands that have oxygen donor atoms. Complexes of the plutonyl ion are important in nuclear fuel reprocessing.

Actinide chemistry Branch of nuclear chemistry

Actinide chemistry is one of the main branches of nuclear chemistry that investigates the processes and molecular systems of the actinides. The actinides derive their name from the group 3 element actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide. All but one of the actinides are f-block elements, corresponding to the filling of the 5f electron shell; lawrencium, a d-block element, is also generally considered an actinide. In comparison with the lanthanides, also mostly f-block elements, the actinides show much more variable valence. The actinide series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.

Jaqueline Kiplinger American inorganic chemist

Jaqueline Kiplinger is an American inorganic chemist who specializes in organometallic actinide chemistry. Over the course of her career, she has done extensive work with fluorocarbons and actinides. She is currently a Fellow of the Materials Synthesis and Integrated Devices group in the Materials Physics and Applications Division of Los Alamos National Laboratory (LANL). Her current research interests are focused on the development of chemistry for the United States’ national defense and energy needs.

Transition metal pyridine complexes

Transition metal pyridine complexes encompass many coordination complexes that contain pyridine as a ligand. Most examples are mixed-ligand complexes. Many variants of pyridine are also known to coordinate to metal ions, such as the methylpyridines, quinolines, and more complex rings.

David P. Mills British chemist

David Paul Mills is a British chemist and a Professor in the Department of Chemistry at The University of Manchester. His research typically investigates the chemistry of the lanthanide and actinide f-block elements. This is generally based on the synthesis of new f-block complexes, structural and bonding properties and their uses in different fields including in nuclear fuel cycles, energy and single molecule magnets.

The advanced reprocessing of spent nuclear fuel is a potential key to achieve a sustainable nuclear fuel cycle and to tackle the heavy burden of nuclear waste management. In particular, the development of such advanced reprocessing systems may save natural resources, reduce waste inventory and enhance the public acceptance of nuclear energy. This strategy relies on the recycling of major actinides and the transmutation of minor actinides in appropriate reactors. In order to fulfill this objective, selective extracting agents need to be designed and developed by investigating their complexation mechanism.

Marinella Mazzanti Italian chemist

Marinella Mazzanti is an Italian inorganic chemist specialized in coordination chemistry. She is a professor at EPFL and the head of the group of Coordination Chemistry at EPFL's School of Basic Sciences.

Transition metal complexes of 2,2'-bipyridine are coordination complexes containing one or more 2,2'-bipyridine ligands. Complexes have been described for all of the transition metals. Although few have any practical value, these complexes have been influential. 2,2'-Bipyridine is classified as a diimine ligand. Unlike the structures of pyridine complexes, the two rings in bipy are coplanar, which facilitates electron delocalization. As a consequence of this delocalization, bipy complexes often exhibit distinctive optical and redox properties.

References

  1. ↑ Simpson, P. G.; Quagliano, J. V.; Vinciguerra, A. (1963). "The Donor Properties of 2,2'-Bipyridine N,N'-Dioxide". Inorganic Chemistry. 2 (2): 282–286. doi:10.1021/ic50006a009.
  2. ↑ Baxter, P. N. W.; Connor, J. A.; Schweizer, W. B.; Wallis, J. D. (1992). "Novel Tetra-Dentate and Hexa-Dentate Ligands from 6,6'-Dicyano-2,2'-Bipyridine". Dalton Transactions . 1992 (20): 3015–3019. doi:10.1039/DT9920003015.
  3. ↑ Foreman, M. R. S.; Hudson, M. J.; Drew, M. G. B.; Hill, C.; Madic, C. (2006). "Complexes formed between the quadridentate, heterocyclic molecules 6,6'-bis-(5,6-dialkyl-1,2,4-triazin-3-yl)-2,2'-bipyridine (BTBP) and lanthanides(III): implications for the partitioning of actinides(III) and lanthanides(III)". Dalton Transactions . 2006 (13): 1645–1653. doi:10.1039/B511321K. PMID   16547539.
  4. ↑ Pabst, G. R.; Pfuller, O. C.; Sauer, J. (1999). "The new and simple 'LEGO' system: Synthesis and reactions of thienyl-substituted 4-tributylstannyl-2,6-oligopyridines". Tetrahedron. 55 (16): 5047–5066. doi:10.1016/S0040-4020(99)00178-7.
  5. ↑ Kolarik, Z. (2003). "Extraction of selected mono- to tetravalent metal ions by 2,6-di-(5,6-dialkyl-1,2,4-triazin-3-yl)pyridines". Solvent Extraction and Ion Exchange. 21 (3): 381–397. doi:10.1081/SEI-120020217.
  6. ↑ Hudson, M. J.; Drew, M. G. B.; Foreman, M. R. S.; Hill, C.; Huet, N.; Madic, C.; Youngs, T. G. A. (2003). "The coordination chemistry of 1,2,4-triazinyl bipyridines with lanthanide(III) elements - implications for the partitioning of americium(III)". Dalton Transactions . 2003 (9): 1675–1685. doi:10.1039/b301178j.
  7. ↑ Ekberg, C.; Dubois, I.; Fermvik, A.; Retegan, T.; Skarnemark, G.; Drew, M. G. B.; Foreman, M. R. S.; Hudson, M. J. (2007). "Extraction Behavior of Nickel(II) using some of the BTBP-Class Ligands". Solvent Extraction and Ion Exchange. 25 (5): 603–617. doi:10.1080/07366290701512634.
  8. ↑ Berthet, J. C.; Thuery, P.; Foreman, M. R. S.; Ephritikhine, M. (2008). "First 5f-element complexes with the tetradentate BTBP ligand. Synthesis and crystal structure of uranyl(VI) compounds with CyMe4BTBP". Radiochimica Acta. 96 (4–5): 189–197. doi:10.1524/ract.2008.1478.
  9. ↑ Berthet, J. C.; Maynadie, J.; Thuery, P.; Ephritikhine, M. (2010). "Linear uranium metallocenes with polydentate aromatic nitrogen ligands". Dalton Transactions . 39 (29): 6801–6807. doi:10.1039/C002279A.
  10. ↑ Ekberg, C.; Fermvik, A.; Retegan, T.; Skarnemark, G.; Foreman, M. R. S.; Hudson, M. J.; Englund, S.; Nilsson, M. (2008). "An overview and historical look back at the solvent extraction using nitrogen donor ligands to extract and separate An(III) from Ln(III)". Radiochimica Acta. 96 (4–5): 225–233. doi:10.1524/ract.2008.1483.
  11. ↑ Magnusson, D.; Christiansen, B.; Foreman, M. R. S.; Geist, A.; Glatz, J. P.; Malmbeck, R.; Modolo, G.; Serrano-Purroy, D.; Sorel, C. (2009). "Demonstration of a SANEX Process in Centrifugal Contactors using the CyMe4-BTBP Molecule on a Genuine Fuel Solution". Solvent Extraction and Ion Exchange. 27 (2): 97–106. doi:10.1080/07366290802672204.
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