Syntheses; 77Se, 203Tl, and 205Tl NMR; and Theoretical Studies of the Tl2Se66-, Tl3Se65-, and Tl
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- 作者：Ayaaz M. Pirani ; Hé ; lè ; ne P. A. Mercier ; Reijo J. Suontamo ; Gary J. Schrobilgen ; David P. Santry ; and Horst Borrmann
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：November 28, 2005
- 年：2005
- 卷：44
- 期：24
- 页码：8770 - 8785
- 全文大小：439K
- 年卷期：v.44,no.24(November 28, 2005)
- ISSN：1520-510X
文摘
The 2,2,2-crypt salts of the Tl4Se84- and [Tl2Se42-MG SRC="/isubscribe/journals/inocaj/44/i24/eqn/ic0510922e10001.gif"> anions have been obtained by extraction of the ternary alloyNaTl0.5Se in ethylenediamine (en) in the presence of 2,2,2-crypt and 18-crown-6 followed by vapor-phase diffusionof THF into the en extract. The [2,2,2-crypt-Na]4[Tl4Se8]·en crystallizes in the monoclinic space group P21/n, withZ = 2 and a = 14.768(3) Å, b = 16.635(3) Å, c = 21.254(4) Å, 
mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 94.17(3)mages/entities/deg.gif"> at -123 mages/entities/deg.gif">C, and the [2,2,2-crypt-Na]2[Tl2Se4
·en crystallizes in the monoclinic space group P21/c, with Z = 4 and a = 14.246(2) Å, b =14.360(3) Å, c = 26.673(8) Å, mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 99.87(3)mages/entities/deg.gif"> at -123 mages/entities/deg.gif">C. The TlIII anions, Tl2Se66- and Tl3Se75-, and the mixedoxidation state TlI/TlIII anion, Tl3Se65-, have been obtained by extraction of NaTl0.5Se and NaTlSe in en, in thepresence of 2,2,2-crypt and/or in liquid NH3, and have been characterized in solution by low-temperature 77Se,203Tl, and 205Tl NMR spectroscopy. The 1J(203,205Tl-77Se) and 2J(203,205Tl-203,205Tl) couplings of the three anionshave been used to arrive at their solution structures by detailed analyses and simulations of all spin multiplets thatcomprise the 205,203Tl NMR subspectra arising from natural abundance 205,203Tl and 77Se isotopomer distributions.The structure of Tl2Se66- is based on a Tl2Se2 ring in which each thallium is bonded to two exo-selenium atomsso that these thalliums are four-coordinate and possess a formal oxidation state of +3. The Tl4Se84- anion isformally derived from the Tl2Se66- anion by coordination of each pair of terminal Se atoms to the TlIII atom of aTlSe+ cation. The structure of the [Tl2Se42-
anion is comprised of edge-sharing distorted TlSe4 tetrahedra thatform infinite, one-dimensional [Tl2Se42-
chains. The structures of Tl3Se65- and Tl3Se75- are derived from Tl4Se4-cubes in which one thallium atom has been removed and two and three exo-selenium atoms are bonded to thalliumatoms, respectively, so that each is four-coordinate and possesses a formal oxidation state of +3 with the remainingthree-coordinate thallium atom in the +1 oxidation state. Quantum mechanical calculations at the MP2 level oftheory show that the Tl2Se66-, Tl3Se65-, Tl3Se75-, and Tl4Se84- anions exhibit true minima and display geometriesthat are in agreement with their experimental structures. Natural bond orbital and electron localization functionanalyses were utilized in describing the bonding in the present and previously published Tl/Se anions, and showedthat the Tl2Se66-, Tl3Se65-, Tl3Se75-, and Tl4Se84- anions are electron-precise rings and cages.
·en crystallizes in the monoclinic space group P21/c, with Z = 4 and a = 14.246(2) Å, b =14.360(3) Å, c = 26.673(8) Å, anion is comprised of edge-sharing distorted TlSe4 tetrahedra thatform infinite, one-dimensional [Tl2Se42- chains. The structures of Tl3Se65- and Tl3Se75- are derived from Tl4Se4-cubes in which one thallium atom has been removed and two and three exo-selenium atoms are bonded to thalliumatoms, respectively, so that each is four-coordinate and possesses a formal oxidation state of +3 with the remainingthree-coordinate thallium atom in the +1 oxidation state. Quantum mechanical calculations at the MP2 level oftheory show that the Tl2Se66-, Tl3Se65-, Tl3Se75-, and Tl4Se84- anions exhibit true minima and display geometriesthat are in agreement with their experimental structures. Natural bond orbital and electron localization functionanalyses were utilized in describing the bonding in the present and previously published Tl/Se anions, and showedthat the Tl2Se66-, Tl3Se65-, Tl3Se75-, and Tl4Se84- anions are electron-precise rings and cages.