Kinetic and mechanistic studies on the Pd–Cl cleavage of dichloro‐ [1‐alkyl‐2‐(naphthylazo)imidazole]palladium(II) complexes by 2,2′‐bipyridine

Abstract

The interaction of 2,2 -bipyridine with dichloro-[1-alkyl-2-(α-naphthylazo) imidazole]palladium(II) [Pd(α-NaiR )Cl 2 , 1] and dichloro-[1-alkyl-2-(β-naphthylazo) imidazole] palladium(II) [Pd(β-NaiR )Cl 2 , 2] complexes {where alkyl R = Me (a), Et (b) or Bz (c)} in acetonitrile medium to yield 4b, 4c) was studied. The products were characterized by microanalytical data and spectroscopic techniques (FT-IR, UV-vis, and NMR). The nucleophilic substitution reaction shows a first-order dependence of rate on each of the Pd(II) complex and 2,2 -bipyridine. Addition of LiCl to the reaction decreases the rate of reaction and has proved the cleavage of Pd-Cl bond at the rate-determining step. Thermodynamic parameters standard enthalpy of activation ( ‡ H • ), and standard entropy of activation ( ‡ S • ) were determined. The second-order rate constant k 2 corroborates with the experimental ‡ H • values. The negative values of ‡ S • indicate that the reaction proceeds through an associative inner sphere mechanism. C

Mechanism of the Formation of Palladium(II) Maleate Complex: A DFT Approach

“…Concerning the role of palladium as a catalyst in the synthesis of organic compounds, kinetic and mechanistic studies of complexes containing this element are of special importance .…”