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001-es BibID:BIBFORM114075
035-os BibID:(cikkazonosító)122233 (WoS)001024543100001 (Scopus)85162926390
Első szerző:Łyczko, Krzysztof
Cím:Striking stability of a mixed-valence thallium(III)-thallium(I) complex in some solvents / Łyczko, Krzysztof; Wiȩckowska, Agnieszka; Bajnoczi, Éva G.; Csupász, Tibor; Purgel, Mihály; Sigfridsson Clauss, Kajsa G. V.; Tóth, Imre; Persson, Ingmar
Megjegyzések: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 red-colored 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) ?A, 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) ?A 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.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Mixed-valence thallium(III)-thallium(I) complex
Red-colored complex
N, N, N'N'-tetramethyl urea
Decomposition rate
Megjelenés:Journal Of Molecular Liquids. - 385 (2023), p. 1-9. -
További szerzők:Wiȩckowska, Agnieszka Bajnoczi Éva G. Csupász Tibor (1991-) (vegyész) Purgel Mihály (1982-) (vegyész) Sigfridsson Clauss, Kajsa G. V. Tóth Imre (1950-) (vegyész) Persson, Ingmar
Pályázati támogatás:TAMOP-4.2.2.C-11/1/KONV-2012-0010
NKFIH K-128201
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001-es BibID:BIBFORM018853
Első szerző:Purgel Mihály (vegyész)
Cím:Binuclear Pt-Tl Bonded Complex with Square Pyramidal Coordination around Pt : A Combined Multinuclear NMR, EXAFS, UV-Vis, and DFT/TDDFT Study in Dimethylsulfoxide Solution / Mihály Purgel, Mikhail Maliarik, Julius Glaser, Carlos Platas-Iglesias, Ingmar Persson, Imre Tóth
Megjegyzések:The structure and bonding of a new Pt-Tl bonded complex formed in dimethylsulfoxide (dmso), (CN)4Pt?Tl(dmso)5+, have been studied by multinuclear NMR and UV?vis spectroscopies, and EXAFS measurements in combination with density functional theory (DFT) and time dependent density functional theory (TDDFT) calculations. This complex is formed following the equilibrium reaction Pt(CN)42? + Tl(dmso)63+ (CN)4Pt?Tl(dmso)5+ + dmso. The stability constant of the Pt?Tl bonded species, as determined using 13C NMR spectroscopy, amounts to log K = 2.9 ? 0.2. The (NC)4Pt?Tl(dmso)5+ species constitutes the first example of a Pt?Tl bonded cyanide complex in which the sixth coordination position around Pt (in trans with respect to the Tl atom) is not occupied. The spectral parameters confirm the formation of the metal?metal bond, but differ substantially from those measured earlier in aqueous solution for complexes (CN)5Pt?Tl(CN)n(H2O)xn? (n = 0?3). The 205 Tl NMR chemical shift, ? = 75 ppm, is at extraordinary high field, while spin?spin coupling constant, 1JPt?Tl = 93 kHz, is the largest measured to date for a Pt?Tl bond in the absence of supporting bridging ligands. The absorption spectrum is dominated by two strong absorption bands in the UV region that are assigned to MMCT (Pt-Tl) and LMCT (dmso ? Tl) bands, respectively, on the basis of MO and TDDFT calculations. The solution of the complex has a bright yellow color as a result of a shoulder present on the low energy side of the band at 355 nm. The geometry of the (CN)4Pt?Tl core can be elucidated from NMR data, but the particular stoichiometry and structure involving the dmso ligands are established by using Tl and Pt LIII-edge EXAFS measurements. The Pt?Tl bond distance is 2.67(1) Å, the Tl?O bond distance is 2.282(6) Å, and the Pt?C?N entity is linear with Pt?C and Pt???N distances amounting to 1.969(6) and 3.096(6) Å, respectively. Geometry optimizations on the (CN)4Pt?Tl(dmso)5+ system by using DFT calculations (B3LYP model) provide bond distances in excellent agreement with the EXAFS data. The four cyanide ligands are located in a square around the Pt atom, while the Tl atom is coordinated in a distorted octahedral fashion with the metal being located 0.40 Å above the equatorial plane described by four oxygen atoms of dmso ligands. The four equatorial Tl?O bonds and the four cyano ligands around the Pt atom are arranged in an alternate geometry. The coordination environment around Pt may be considered as being square pyramidal, where the apical position is occupied by the Tl atom. The optimized geometry of (CN)4Pt?Tl(dmso)5+ is asymmetrical (C1 point group). This low symmetry might be responsible for the unusually large NMR linewidths observed due to intramolecular chemical exchange processes. The nature of the Pt?Tl bond has been studied by MO analysis. The metal?metal bond formation in (CN)4Pt?Tl(dmso)5+ can be simply interpreted as the result of a Pt(5dz2)2 ? Tl(6s)0 donation. This bonding scheme may rationalize the smaller thermodynamic stability of this adduct compared to the related complexes with (CN)5Pt?Tl entity, where the linear C?Pt?Tl unit constitutes a very stable bonding system.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganic Chemistry. - 50 : 13 (2011), p. 6163-6173. -
További szerzők:Maliarik, Mikhail Glaser, Julius Platas-Iglesias, Carlos Persson, Ingmar Tóth Imre (1950-) (vegyész)
Pályázati támogatás:OTKA 63388)
Internet cím:Szerző által megadott URL
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