Spectroscopic and theoretical study of [PdCl3(C2H4)]− and [PdCl3(C2D4)]− complexes

FTIR and FT-Raman spectra of [PdCl3(C2H4)]− and [PdCl3(C2D4)]− anions have been recorded at greater sensitivity than hitherto and assigned on the basis of the well-studied Zeise’s salt. Density functional theory (DFT) calculations were performed in order to obtain the optimised geometry, the vibrational frequencies and IR intensities of the Pd-complex. The comparison of the theoretical infrared spectra, the H/D isotopic shifts and the shifts in the CC stretching and CH scissoring frequencies upon coordination with those from experimental study show a remarkable agreement for the [PdCl3(C2H4)]− and [PdCl3(C2D4)]− species. The optimised PdC bond distance is 2.197 Å, indicating that the metal–ligand bond is weaker in [PdCl3(C2H4)]− than in Zeise’s salt but C2H4 seems to be more distorted in the Pd-analogue. The calculated force constants also confirm the lower stability of the Pd-complex.