Displacement of organic sulphides by amines in trans-dichlorobis(organic sulphide)palladium(II) complexes

Abstract

The kinetics of nucleophilic displacement of a variety of organic sulphides RSR′ from complexes of the type trans-[Pd(RSR′)₂Cl₂] by amines of different basicity and steric hindrance have been measured in 1,2-dimethoxyethane at 25 °C. The overall reaction occurs in two separate stages, the first being much faster than the second. The investigated processes correspond to the reaction: trans-[Pd(RSR′)₂Cl₂]+ amine →trans-[Pd(RSR′)(amine)-Cl₂]+ RSR′(amine = pyridine or substituted pyridine). The nucleophilic substitutions obey the usual two-term rate equation. The rate of the reactions, the discrimination of one complex against the individual entering amines, and the lability of the individual sulphides when they are displaced by a given amine are compared and discussed.