A new one-step solvothermal synthesis route for reduction of pertechnetate salts to low valent technetium metal-metal bonded dimers will be presented. The reaction of potassium pertechnetate with glacial acetic acid plus either halo acids or halo salts under in-situ hydrogen production by sodium borohydride at various temperatures yields multiple products consisting of tetraacetate Tc-Tc (II,III) and Tc-Tc (III,III) paddle wheel dimers. Solid products isolated and analyzed via Single Crystal X-ray Diffraction (SC-XRD) in these reactions consist of polymeric chains Tc2+5 core: Tc2(�-O2CCH3)4(O2CCH3), Tc2(�-O2CCH3)4Cl, Tc2(�-O2CCH3)4Br, Tc2(�-O2CCH3)4I, molecular Tc2+5 core: Tc2(�-O2CCH3)3Cl2(H2O)2�H2O, K[Tc2(�-O2CCH3)4Br2], and molecular Tc2+6 core: Tc2(�-O2CCH3)4Cl2, Tc2(�-O2CCH3)4Br2. Of the compounds listed four are newly discovered using the one-step technique and two more additions to crystal database. Additional spectroscopic (X-ray Absorbance Fine Structure, UV-Vis, and FT-IR) characterization of the new compounds will be shown and used to propose a mechanism. Analysis of the mother liquor of each reaction by UV-Vis and formation of crystals over time due to oxidation of solutions affords a possible insight into mechanism of the Tc2+5 to Tc2+6 core formation. The oxidation states of Tc-Tc dimers formed is also dependent on temperature and pH of the starting solutions and will be explained in extensive detail. These one step reactions of reducing Tc(VII) to low valent technetium provides high yield intermediates for potential waste forms, use in nuclear fuel cycle separations, and radiopharmaceuticals.

Preparation of low valent technetium metal-metal bonded species via solvothermal reduction of pertechnetate salts

246th National Meeting (2013)

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