Ab Initio Calculations Of Hydroxoplatinum Compounds: II. Binuclear Platinum(IV) Superoxo Complexes
![Equilibrium structure of the binuclear monobridged platinum superoxo complexes [(OH)5Pt(μ-O2)Pt(OH)5]3–](/images/redox-images/articles/2008_rjnc_2.gif "Equilibrium structure of the binuclear monobridged platinum superoxo complexes [(OH)5Pt(μ-O2)Pt(OH)5]3–")
Ab Initio Calculations Of Hydroxoplatinum Compounds: II. Binuclear Platinum(IV) Superoxo Complexes. Pankratov D.A., Dement'ev A.I., Kiselev Yu.M. //Russian Journal of Inorganic Chemistry. 2008. V.53. №2. P.247-253.
The structural and spectral data have been obtained by ab initio methods for the [(OH)4Pt(μ-O2)(μ-OH)Pt(OH)4]2-, [(OH)4Pt(μ-O2)(μ-OH)Pt(OH)4(OH)]3-, [(OH)5Pt(μ-O2)Pt(OH)5]3-, and [(H2O)(OH)4Pt(μ-O2)Pt(OH)4•(H2O)]- clusters, corresponding to binuclear platinum (IV) superoxo complexes with one and two bridges. The data obtained are in good agreement with experimental data and make it possible to judge the structure of available complexes.
Previously it was shown that in the conditions of oxidative synthesis platinum (IV) formed superoxocomplexes, whose composition is different for strongly basic mediums, and highly concentrated alkalis. These compounds mainly exist in solution (only one compound was synthesized in the solid state), and their structures were judged using the data of different physicochemical methods (e.g., infrared and Raman spectroscopy, or EPR spectroscopy).
This work deals with theoretical consideration of the possibility of the existence of similar platinum (IV) superoxo complexes and with the determination of their structural and spectral features. The applicability of this approach was shown in our previous work on clusters corresponding to the hexahydroxoplatinate (IV) ion.
A solution to the geometry optimization problem for the clusters corresponding to superoxo platinum derivatives should answer a number of questions, including (1) whether the formation of similar binuclear monoand dibridged superoxo complexes is theoretically possible, (2) whether conformational isomerism is possible for these complexes, (3) how close the resulting geometric parameters are to the parameters for other known superoxo complexes, (4) how stable mono- or dibridged complexes are, and (5) what effect the superoxo group will have in vibrational spectra.
Thus, our quantum-chemical calculations confirm the possibility of formation and stability of binuclear platinum (IV) superoxo complexes of different types and conformations, are in agreement with the known experimental data, and predict the high sensitivity of such complexes to external conditions.
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