Sammanfattning

At the dissolution of solid anhydrous thallium(III) trifluoromethanesulfonate, Tl(CF3SO3)3, or thallium(III) trifluoroacetate, Tl(CF3COO)3, in dimethylsulfoxide (dmso) or N,N,N',N'-tetramethylurea (tmu), intensely redcolored complexes are formed. This red thallium complex is stable for years in dmso, while it is reduced fairly rapidly to thallium(I) in tmu with a half-life time of an hour. At the dissolution of Tl(CF3SO3)3 in N,N-dimethylpropyleneurea (dmpu) an immediate reduction to thallium(I) takes place. A stable colorless aqueous thallium (III) solution is obtained at the dissolution in acidic water. Stable dmso solutions and solid dmso solvates of thallium(III) perchlorate, nitrate and trifluormethanesulfonate can be prepared by adding dmso to concentrated acidic aqueous thallium(III) solutions. These experimental observations conclude that the pure solids Tl (CF3SO3)3 and Tl(CF3COO)3 play an essential role in the formation of the red-colored thallium complexes. 205Tl NMR data show that the red thallium complex contains equal amounts of thallium(III) and thallium(I). The structure of the red thallium complex in dmso, as determined by EXAFS, has Tl-O bond distances of 2.216(3) and 2.80(2) & ANGS;, which are in very close agreement with the bond distances obtained in the pure dmso solvates of the thallium(III) and thallium(I) ions, respectively, and a Tl...Tl distance of 3.49(1) & ANGS; bridged by oxygen atoms. From the EXAFS data it is impossible to distinguish if dmso molecules and/or trifluoromethanesulfonate ions act as bridges. DFT calculations could eliminate some structures due to the irrelevant structural parameters or the energetics of the proposed reactions.

Nyckelord

Mixed-valence thallium(III)-thallium(I) complex; Red-colored complex; Dimethylsulfoxide; N; N'N'-tetramethyl urea; Structure; Decomposition rate

Publicerad i

Journal of Molecular Liquids
2023, Volym: 385, artikelnummer: 122233
Utgivare: ELSEVIER

SLU författare

• Bajnóczi, Eva

  • Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
    
  • Hungarian Wigner Research Centre for Physics

• Persson, Ingmar

  • Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Atom- och molekylfysik och optik
Fysikalisk kemi


Publikationens identifierare

DOI: https://doi.org/10.1016/j.molliq.2023.122233

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/122997