An X-ray absorption spectroscopic investigation of the geometry of Pt(IV) in H2PtCl6 ammonia solution

• The local structure around the Pt(IV) in H2PtCl6 ammonia solution was investigated.
• The chlorine ligands around Pt are completely replaced by NH3 instead of OH−.
• The octahedral geometry of Pt(IV) in solution is retained after the substitution.
• A ‘hybridization peak’ can be assigned to Cl and N d-states contributions.

The geometrical structure of noble metal cations has an important impact in many areas. Therefore, the structure of some noble cations in solution has been investigated in order to understand the relationship between the structure and property of noble metal cations in solution. In this contribution, the coordination chemistry of H2PtCl6 in ammonia solution was investigated by X-ray absorption spectroscopy (XAS). We found that Cl ligands around Pt with a Pt–Cl bond length of 2.32 Å are completely replaced by NH3 ligands with a Pt–N distance of 2.05 Å. Theoretical calculations point out the occurrence of both a Pt–Cl and a Pt–N orbital hybridization. The observed ‘hybridization peak’ and the post-edge feature have been assigned to the contribution of Cl and N d-states.

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