NIR-FT-Raman studies of square-planar palladium(II) and platinum(II) complexes

Solid state NIR-FT-Raman and far IR spectra of K(2)MX(4) and [M(NH3)(4)]Y-2 (where M = Pd(II) or Pt(II), X = Cl- or Br-, and Y = Cl- or NO3-) from 100 to 700 cm(-1) are measured. The crystal structures of the samples are investigated by X-ray powder diffraction. Anhydrous compounds with the general formula K(2)MX(4) have isomorphous structures with the complex ions in a site symmetry of D-4h. Extra peaks found in the Raman spectrum of a reddish brown form of K2PtBr4 are due to the presence of some dihydrate K2PtBr4 . 2H(2)O, and not to crystalline K2PtBr6. Based on the revised assignments of the bromo-compounds and reliable frequency data for all compounds, the valence force constants (GVFF) of the MX(4)(2-) (X = Cl-, Br-) ions, the M(NH3)(4)(2+) ions are calculated and compared.