EQUILIBRIUM STUDIES OF THE REACTION BETWEEN TETRACHLOROPALLADIUM(II) ANION AND SULFOXIDES. THE FORMATION OF THE MONO-S-SULFOXIDE COMPLEXES

Abstract

The equilibrium coefficient, K₁, for the reaction [PdCl₄]^2- + RR′ SO ⇆ [Pd(RR′ SO)Cl]⁻ + Cl⁻, has been determined for dimethylsulfoxide, tetramethylensulfoxide, and phenylmethylsulfoxide and found to be 67, 46 and 8.8 respectively at 25°C, ü= 1.0 in 95:5 methanol-water. Values for the equilibrium constants for the dimethylsulfoxide complex are also reported at other ionic strengths. The equilibrium constants for the second stage, [Pd(Me₂SO)Cl₃]- + Me₂SO)⇆-[Pd(Me₂SO)₂Cl₂] + Cl⁻, has been determined for dimethylsulfoxide only, K₂=2.5 × 10⁻² at 25°C (μ not controlled). The causes of the mutual destabilisation of two dimethylsulfoxides are discussed.