The discrete mixed [TeBrxCl6-x](2-) anions in their disordered crystal structures have been identified by using the phases prepared by the reaction of 1-butyl-2,3-dimethylimidazolium halogenides (bdmim)X with tellurium tetrahalogenides TeX4 (X = Cl, Br) as examples. Homoleptic (bdmim)(2)[TeX6] [X = Cl (1), Br (2)] and mixed (bdmim)(2)[TeBr2Cl4] (3), and (bdmim)(2)[TeBr4Cl2] (4) are formed depending on the choice of the reagents, and their crystal structures have been determined by single-crystal X-ray diffraction. The coordination environments of tellurium in all hexahalogenidotellurates are almost octahedral. Because of the crystallographic disorder, the mixed [TeBr2Cl4](2-) and [TeBr4Cl2](2-) anions in 3 and 4 cannot be identified in their crystal structures. Fawley refinement of the X-ray powder diffraction patterns of 1-4 indicates the presence of single phases in all four products. The solid state Raman spectra of 1-4 were assigned with help of OFT calculations that were performed both for the discrete anions in vacuum and for the complete crystal structures employing periodic boundary conditions. The fundamental vibrations of the homoleptic [TeX6](2-) (X = Cl, Br) anions could be well reproduced by the solid-state OFT computations and enabled a complete assignment of the Raman spectra. While the presence of cis-isomers in both [TeBr2Cl4](2-) and [TeBr4Cl2](2-) could be inferred by the computed fundamental vibrations, that of trans-isomers among the reaction products is, however, also possible. The pathway of the formation of [TeX4Y2](2-) isomers from TeX4 and Y- (X, Y = Cl, Br) was also explored by OFT calculations both in vacuum and in solution and indicated that both reactions afforded 80 mol% of cis-isomers and 20 mol% of trans-isomers. (C) 2013 Elsevier B.V. All rights reserved.
|Julkaisu||SPECTROCHIMICA ACTA PART A: MOLECULAR AND BIOMOLECULAR SPECTROSCOPY|
|DOI - pysyväislinkit|
|Tila||Julkaistu - 3 tammikuuta 2014|
|OKM-julkaisutyyppi||A1 Julkaistu artikkeli, soviteltu|