On the nature of partially oxidised magnus green

Abstract

The complex [Pt(NH₃)₄][Pt(NH₃)₄Cl₂][HSO₄]₄ can be synthesised by the partial aerial oxidation of Magnus green in 50% sulphuric acid. It forms as highly dichroic, orange-red needles, which are shown to contain chlorine-bridged linear chains of the sort ⋯ Pt^II⋯ Cl–Pt^IV–Cl ⋯, the ammonia molecules being co-ordinated in the equatorial positions to each platinum atom. The resonance Raman spectrum of the complex at 80 K, obtained by irradiating within the contour of the intense Pt^IVâ†� Pt^II intervalence band, is dominated by a progression in ν₁ to 11 ν₁, where ν₁ is the symmetric Pt^IV–Cl chain-stretching mode. The thermochromism of the complex is discussed. The nature of the other products of partial oxidation of Magnus green is also discussed.