VIBRATIONAL SPECTRA OF SEVERAL PLATINUM-ETHYLENE COMPLEXES - K[PTCL3(C2H4)].H2O (ZEISES SALT) K[PTCL3(C2D4)].H2O AND [PTCL2(C2H4)]2

Raman and infrared spectra have been obtained for K[PtCl3(C2H4)]·H2O (Zeise's salt), K[PtCl3(C2D4)]·H2O, and [PtCl2(C2H4)]2. The Raman results are for both solids and aqueous solutions, and include depolarizations for the latter. Infrared data cover the range 35-4000 cm-1, and are mainly for the solids. The C-C stretching frequency in Zeise's salt, which has heretofore always been taken as the weak infrared band near 1520 cm-1, is instead believed to be a strong, polarized Raman band at 1243 cm-1. It seems to be mixed with a CH2 scissoring mode, and as a result moves up by 110 cm-1 upon deuteration of the ethylene. The assignments, and the unusual shift on deuteration, are supported by a normal coordinate calculation for the a1 and b1 modes. The C2H4 group has many similarities to the C2H4 group in ethylene oxide. The two Pt-C stretches are thought to be 405 cm-1 (symmetric) and 493 cm-1 (antisymmetric). These results indicate that the ethylene is tightly bound to the Pt(II) atom, in sharp contrast to most previous conclusions. Assignments are suggested for most of the fundamentals of all three substances. Those for the dimer are only tentative. © 1969.