Synthetic and Coordination Chemistry of the Heavier Trivalent Technetium Binary Halides: Uncovering Technetium Triiodide

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• 作者：Erik V. Johnstone ; Frederic Poineau ; Jenna Starkey ; Thomas Hartmann ; Paul M. Forster ; Longzhou Ma ; Jeremy Hilgar ; Efrain E. Rodriguez ; Romina Farmand ; Kenneth R. Czerwinski ; Alfred P. Sattelberger
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：December 16, 2013
• 年：2013
• 卷：52
• 期：24
• 页码：14309-14316
• 全文大小：417K
• 年卷期：v.52,no.24(December 16, 2013)
• ISSN：1520-510X

文摘

Technetium tribromide and triiodide were obtained from the reaction of the quadruply Tc鈥揟c-bonded dimer Tc₂(O₂CCH₃)₄Cl₂ with flowing HX(g) (X = Br, I) at elevated temperatures. At 150 and 300 掳C, the reaction with HBr(g) yields TcBr₃ crystallizing with the TiI₃ structure type. The analogous reactions with flowing HI(g) yield TcI₃, the first technetium binary iodide to be reported. Powder X-ray diffraction (PXRD) measurements show the compound to be amorphous at 150 掳C and semicrystalline at 300 掳C. X-ray absorption fine structure spectroscopy indicates TcI₃ to consist of face-sharing TcI₆ octahedra. Reactions of technetium metal with elemental iodine in a sealed Pyrex ampules in the temperature range 250鈥?00 掳C were performed. At 250 掳C, no reaction occurred, while the reaction at 400 掳C yielded a product whose PXRD pattern matches the one of TcI₃ obtained from the reaction of Tc₂(O₂CCH₃)₄Cl₂ and flowing HI(g). The thermal stability of TcBr₃ and TcI₃ was investigated in Pyrex and/or quartz ampules at 450 掳C under vacuum. Technetium tribromide decomposes to Na{[Tc₆Br₁₂]₂Br} in a Pyrex ampule and to technetium metal in a quartz ampule; technetium triiodide decomposes to technetium metal in a Pyrex ampule.