Geometry of palladium(II) and platinum(II) complexes of diethylchalcogens in solution

Abstract

Dipole-moment determinations coupled with n.m.r., i.r., and Raman spectroscopic investigations indicate that in solutions of [ML₂X₂](L = SEt₂, SeEt₂, or TeEt₂; M = Pd or Pt; X = Cl, Br, or I) the trans geometry predominates, often exclusively. The telluro-complexes [PdCl₂(TeEt₂)₂], [PtCl₂(TeEt₂)₂], and [PtBr₂(TeEt₂)₂] are isolated as the cis isomers in the solid state, but rapidly islmerize to their transforms in solution. The trend towards trans geometry in solution increases along the series Pt < Pd, Cl < Br < I, and S < Se < Te in these complexes.