Platin in seiner ungewöhnlichen Oxidationsstufe + III: Diplatin(III)-Komplexe der Modellnukleobase 1-Methyluracil / Platinum in its Unusual Oxidation State + III: Diplatinum(III) Complexes with the Model Nucleobase 1-Methyluracil

Lippert, Bernhard; Schöllhorn, Helmut; Thewalt, Ulf

Platin in seiner ungewöhnlichen Oxidationsstufe + III: Diplatin(III)-Komplexe der Modellnukleobase 1-Methyluracil / Platinum in its Unusual Oxidation State + III: Diplatinum(III) Complexes with the Model Nucleobase 1-Methyluracil

2014

Lippert, Bernhard | Schöllhorn, Helmut | Thewalt, Ulf

Oxidation of the head-tail dimer cis-[(NH₃)₂Pt(1-MeU)]₂(NO₃)₂ (1-MeU = 1-methyl - uracilato anion, C₅H₅N₂O₂) with a mixture of nitrous and nitric acid yields three crystalline species, [(NO₂)(NH₃)₂Pt(C₅H₅N₂O₂)₂Pt(]SrH₃)₂(NO₂)](NO₃)₂ · 3 H₂O (1), [(H₂O)(NH₃)₂Pt(C₅H₅N₂O₂)₂Pt(]SrH₃)₂(NO₂)](NO₃)₂ · 5 H₂O (2) and [(NO₃)(NH₃)₂Pt(C₅H₅N₂O₂)₂Pt(]SrH₃)₂(NO₃)](NO₃)₂ · 4.5 H₂O (3). The crystal structure of 2 has been determined. 2 crystallizes in the triclinic space group P1̄ with cell dimensions a= 11.959(4), b= 11.560(3), c= 11.261(2) Å, α = 89.16(2), β= 104.36(2), γ = 99.61(2)° and Z = 2. The structure was refined to R = 0.056, Rw = 0.061 on 4311 reflections. The Pt-Pt distance within the dinuclear cation of 2 is 2.574(1) Å and corresponds to a Pt-Pt single bond. The axial ligands are N̲O₂ (Ptl) and O̲H₂ (Pt2), the equatorial ligands two NH₃ groups, N 3 and O4 of 1-MeU for both Pt atoms. The oxidation state of Pt in 2 is +III. ¹H NMR and IR spectra of 1, 2, and 3 reveal a close structural similarity of the three compounds.

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