Dicarbonyltetrahalogenoplatinate(I) salts

Abstract

The complex anions [Pt₂X₄(CO)₂]^2–(X = Cl or Br) are formed in solution by the reaction of CO with [PtX₄]^2– ions in concentrated aqueous HX. Their tetra-n-propylammonium salts have been isolated. Vibrational spectra indicate that the structure of the anions consists of two planar [PtX₂CO]^– units linked by a platinum–platinum bond. Two forms of the salt (Prⁿ₄N)₂[Pt₂Cl₄(CO)₂] have been crystallised, both apparently containing anions with the same symmetry but having different vibrational frequencies, suggesting that the two PtX₂CO planes are rotated 45° with respect to each other. The Pt–Pt bond is cleaved by Cl₂, HCl, H₂, and MeHgCl.