Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

Title: Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

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Abstract

Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol,more »« less

Authors:: McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

Publication Date:: Wed Jan 01 00:00:00 EST 2014

Research Org.:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC)

OSTI Identifier:: 1166994

Report Number(s):: LBNL-6690E

DOE Contract Number:: DE-AC02-05CH11231

Resource Type:: Journal Article

Journal Name:: European Journal of Inorganic Chemistry

Additional Journal Information:: Journal Name: European Journal of Inorganic Chemistry

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Technetium, POM, polyoxometallate

Citation Formats


                    McGregor, Donna, Burton-Pye, Benjamin P., Lukens, Wayne W., Howell, Robertha C., and Francesconi, Lynn C. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds.  United States: N. p., 2014. 
        Web.

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                    McGregor, Donna, Burton-Pye, Benjamin P., Lukens, Wayne W., Howell, Robertha C., & Francesconi, Lynn C. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds.  United States.

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                    McGregor, Donna, Burton-Pye, Benjamin P., Lukens, Wayne W., Howell, Robertha C., and Francesconi, Lynn C. 2014.  
        "Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds".  United States.  https://www.osti.gov/servlets/purl/1166994.

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@article{osti_1166994,

  title        = {Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds},

  author       = {McGregor, Donna and Burton-Pye, Benjamin P. and Lukens, Wayne W. and Howell, Robertha C. and Francesconi, Lynn C.},

  abstractNote = {Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/1166994},
  journal      = {European Journal of Inorganic Chemistry},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Wed Jan 01 00:00:00 EST 2014},

  month        = {Wed Jan 01 00:00:00 EST 2014}

}

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