Effect of high external pressures on the vibrational spectra of Zeise’s complexes, K[Pt(η2-C2H4)Cl3] and [Pt(η2-C2H4)Cl2]2

The pressure dependences (dν/dP) of the main IR and Raman bands of Zeise’s complexes, K[Pt(η2-C2H4)Cl3] and [Pt(η2-C2H4)Cl2]2, have been determined for the first time for selected pressures up to ∼33 kbar with the aid of diamond-anvil cells. Neither complex undergoes a pressure-induced structural change throughout the pressure range investigated. The dν/dP values range from −0.13 to 0.79 cm−1 kbar−1. The negative values have proved particularly informative in identifying the location of the Cdouble bond; length as m-dashC stretching modes of the Pt–ethylene groups, a topic of considerable disagreement in the literature.