Pressure-tuning infrared and Raman spectra of trans-dichloro-bis[(diperfluoroethyl)phenylphosphine]platinum(II), trans-Pt[PPh(CF3CF2)2]2Cl2

Infrared and Raman spectra of solid trans-dichloro-bisdiperfluoroethyl(phenyl)phosphine]platinum(II), trans-PtPPh(CF₃CF₂)₂]₂Cl₂, have been studied at high external pressures up to ∼50 kbar with the aid of a diamond-anvil cell. A gradual, pressure-induced phase transition, most probably second order, was observed in the 21-34 kbar pressure range. In the IR spectra, the bands assigned to the CF stretching modes of the CF₃ groups exhibit larger pressure sensitivities than do those associated with the CF stretching modes of the CF₂ groups, most probably because of their physical location on the outside in the molecules in the unit cell. The fairly high pressure sensitivities of the symmetric PtCl stretching mode in both the low and high pressure phases (0.46 and 37 cm⁻¹/kbar, respectively) are considered to reflect the low force constant associated with the long PtCl bond length thus making this vibration more susceptible to compression.