Pressure-tuning infrared spectra of the three Magnus’ Green salts, [Pt(NH3)4][PtCl4], [Pt(ND3)4][PtCl4] and [Pt(NH3)4][PtBr4]

Pressure-tuning infrared spectra (up to ca. 40 kbar) are reported for Magnus’ Green salt, [Pt(NH3)4][PtCl4] and two of its derivatives, [Pt(ND3)4][PtCl4] and [Pt(NH3)4][PtBr4]. The spectroscopic data indicate that there is restricted rotation of the coordinated ammonia groups about the Pt–N bonds in the complexes. It is possible that this restricted rotation is due to the presence of weak hydrogen bonding to the halogens, i.e., N–H⋯X (X = Cl, Br) interactions.