A Pt-195 NMR study of the oxidation of [PtCl4](2-) with chlorate, bromate, and hydrogen peroxide in acidic aqueous solution

作者：Murray Pieter; Koch Klaus R^*

来源：Journal of Coordination Chemistry, 2010, 63(14-16): 2561-2577.

DOI：10.1080/00958972.2010.493212

• Pt-195 NMR
• Oxidation of [PtCl4](2-) by NaClO3, H2O2, and NaBrO3
• cis-[PtCl4(H2O)(2)]
• Molecular structure of trans-K-2[PtCl4(OH)(2)](18-cr-6)(2)center dot 2H(2)O

Pt-195 NMR has been used to investigate the distribution of Pt(IV) products after oxidation of [PtCl4](2-) with sodium chlorate (NaClO3), sodium bromate (NaBrO3), and H2O2 in acidic solutions and, for comparison, with H2O2 in water. The relative rates of oxidation of [PtCl4](2-) with NaClO3 and H2O2 in 1 mol L-1 HClO4 at 50 degrees C are comparable, while that with NaBrO3 is significantly higher. Our Pt-195 NMR results confirm previous work on the oxidation of [PtCl4](2-) with H2O2 in water, which results in mainly trans-[PtCl4(OH)(2)](2-) as product. By contrast oxidation of [PtCl4](2-) with NaClO3 and NaBrO3 in acidic solutions results in the distribution of several [PtCln(H2O)(6-n)](4-n) (n=2-6) and [PtClnBrm(H2O)(6-n-m)](4-n-m) (n, m=2-6) species; notably the distribution of product species is dominated by cis-[PtCl4(H2O)(2)] in solution. This species can be unambiguously identified by the Cl-35/Cl-37-isotope-induced effects on the Pt-195 NMR resonance shape in solution. trans-[PtCl4(OH)(2)](2-) was co-crystallized with 18-crown-6 to form trans-K-2[PtCl4(OH)(2)](18-cr-6)(2)center dot 2H(2)O and the single crystal X-ray structure is reported. Oxidation of [PtCl4](2-) with H2O2 in various acidic solutions gives qualitatively similar Pt(IV) species distributions as found for NaClO3, and the implications of these results are discussed in the context of Pt(II)-> Pt(IV) oxidation reactions by these oxidants in aqueous solutions.

• 出版日期2010