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Title: Spectroscopic Characterization of Aqua [ fac-Tc(CO) 3] + Complexes at High Ionic Strength

Abstract

Understanding fundamental Tc chemistry is important to both the remediation of nuclear waste and the reprocessing of nuclear fuel; however, current knowledge of the electronic structure and spectral signatures of low-valent Tc compounds significantly lags behind the remainder of the d-block elements. In particular, identification and treatment of Tc speciation in legacy nuclear waste is challenging due to the lack of reference data especially for Tc compounds in the less common oxidation states (I–VI). In an effort to establish a spectroscopic library corresponding to the relevant conditions of extremely high ionic strength typical for the legacy nuclear waste, compounds with the general formula of [ fac-Tc(CO) 3(OH 2) 3–n(OH) n] 1–n (where n = 0–3) were examined by a range of spectroscopic techniques including 99Tc/ 13C NMR, IR, XPS, and XAS. In the series of monomeric aqua species, stepwise hydrolysis results in the increase of the Tc metal center electron density and corresponding progressive decrease of the Tc–C bond distances, Tc electron binding energies, and carbonyl stretching frequencies in the order [ fac-Tc(CO) 3(OH 2) 3] > [ fac-Tc(CO) 3(OH 2) 2(OH)] > [ fac-Tc(CO) 3(OH 2)(OH) 2] . These results correlate with established trends of the 99Tc upfield chemicalmore » shift and carbonyl 13C downfield chemical shift. The lone exception is [ fac-Tc(CO) 3(OH)] 4 which exhibits a comparatively low electron density at the metal center attributed to the μ 3-bridging nature of the –OH ligands causing less σ-donation and no π-donation. As a result, this work also reports the first observations of these compounds by XPS and [ fac-Tc(CO) 3Cl 3] 2– by XAS. The unique and distinguishable spectral features of the aqua [ fac-Tc(CO) 3] + complexes lay the foundation for their identification in the complex aqueous matrixes.« less

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [2];  [3]; ORCiD logo [1]; ORCiD logo [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Environmental Management (EM); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1466384
Alternate Identifier(s):
OSTI ID: 1528899
Grant/Contract Number:  
AC02-06CH11357; AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 57; Journal Issue: 12; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES

Citation Formats

Chatterjee, Sayandev, Hall, Gabriel B., Engelhard, Mark H., Du, Yingge, Washton, Nancy M., Lukens, Wayne W., Lee, Sungsik, Pearce, Carolyn I., and Levitskaia, Tatiana G. Spectroscopic Characterization of Aqua [fac-Tc(CO)3]+ Complexes at High Ionic Strength. United States: N. p., 2018. Web. doi:10.1021/acs.inorgchem.8b00490.
Chatterjee, Sayandev, Hall, Gabriel B., Engelhard, Mark H., Du, Yingge, Washton, Nancy M., Lukens, Wayne W., Lee, Sungsik, Pearce, Carolyn I., & Levitskaia, Tatiana G. Spectroscopic Characterization of Aqua [fac-Tc(CO)3]+ Complexes at High Ionic Strength. United States. doi:10.1021/acs.inorgchem.8b00490.
Chatterjee, Sayandev, Hall, Gabriel B., Engelhard, Mark H., Du, Yingge, Washton, Nancy M., Lukens, Wayne W., Lee, Sungsik, Pearce, Carolyn I., and Levitskaia, Tatiana G. Tue . "Spectroscopic Characterization of Aqua [fac-Tc(CO)3]+ Complexes at High Ionic Strength". United States. doi:10.1021/acs.inorgchem.8b00490. https://www.osti.gov/servlets/purl/1466384.
@article{osti_1466384,
title = {Spectroscopic Characterization of Aqua [fac-Tc(CO)3]+ Complexes at High Ionic Strength},
author = {Chatterjee, Sayandev and Hall, Gabriel B. and Engelhard, Mark H. and Du, Yingge and Washton, Nancy M. and Lukens, Wayne W. and Lee, Sungsik and Pearce, Carolyn I. and Levitskaia, Tatiana G.},
abstractNote = {Understanding fundamental Tc chemistry is important to both the remediation of nuclear waste and the reprocessing of nuclear fuel; however, current knowledge of the electronic structure and spectral signatures of low-valent Tc compounds significantly lags behind the remainder of the d-block elements. In particular, identification and treatment of Tc speciation in legacy nuclear waste is challenging due to the lack of reference data especially for Tc compounds in the less common oxidation states (I–VI). In an effort to establish a spectroscopic library corresponding to the relevant conditions of extremely high ionic strength typical for the legacy nuclear waste, compounds with the general formula of [fac-Tc(CO)3(OH2)3–n(OH)n]1–n (where n = 0–3) were examined by a range of spectroscopic techniques including 99Tc/13C NMR, IR, XPS, and XAS. In the series of monomeric aqua species, stepwise hydrolysis results in the increase of the Tc metal center electron density and corresponding progressive decrease of the Tc–C bond distances, Tc electron binding energies, and carbonyl stretching frequencies in the order [fac-Tc(CO)3(OH2)3] > [fac-Tc(CO)3(OH2)2(OH)] > [fac-Tc(CO)3(OH2)(OH)2]–. These results correlate with established trends of the 99Tc upfield chemical shift and carbonyl 13C downfield chemical shift. The lone exception is [fac-Tc(CO)3(OH)]4 which exhibits a comparatively low electron density at the metal center attributed to the μ3-bridging nature of the –OH ligands causing less σ-donation and no π-donation. As a result, this work also reports the first observations of these compounds by XPS and [fac-Tc(CO)3Cl3]2– by XAS. The unique and distinguishable spectral features of the aqua [fac-Tc(CO)3]+ complexes lay the foundation for their identification in the complex aqueous matrixes.},
doi = {10.1021/acs.inorgchem.8b00490},
journal = {Inorganic Chemistry},
number = 12,
volume = 57,
place = {United States},
year = {2018},
month = {6}
}

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