Double complex salts [M(NH3)5Cl][M′Br4] (M = Rh, Ir, Co, Cr, Ru; M′ = Pt, Pd): Synthesis, x-ray diffraction characterization, and thermal properties

Abstract

Double complex salts (DCSs) with [M(NH3)5Cl]2+ (M = Rh, Ir, Co, Cr, Ru) cations and [PtBr4]2− anions were prepared in high yields. The salts were two-phase mixtures of the anhydrous and monohydro DCSs. Anhydrous analogues containing [PdBr4]2− anions with M = Cr or Ru were synthesized. All the compounds were characterized using a set of physicochemical methods. The crystal structure of chloropentaamminechromium(III) tetrabromopalladate(II) was solved: space group Pnma, Z = 4, a = 17.068(2) A, b = 8.315(12) A, c = 9.653(14) A. The [M(NH3)5Cl][M′X4] (M = Rh, Ir, Co, Cr, Ru; M′ = Pd, Pt; X = Cl, Br) compounds were shown to be isostructural. The [M(NH3)5Cl][PtBr4] · H2O monohydrates are isostructural to the [M(NH3)5Cl][PdCl4] · H2O monohydrates (space group P21/c, z = 4). The properties of the compounds were comparatively analyzed. The tendencies of the thermal stability of the complexes were elucidated. The thermolysis products of the double complex salts obtained under a helium or hydrogen atmosphere were studied.