Syntheses and characterization of the cyclopalladated complexes of benzyl butyl sulphides

Abstract

Reactions of benzyl t- and iso-butyl sulphides with palladium(II) acetate result in the formation of the acetato-bridged binuclear cyclopalladated complexes, [{Pd(C₆H₄CH₂SR)(O₂CMe)}₂](R = Bu^t or Buⁱ). These complexes are easily converted into the chloro-bridged analogues, [{Pd(C₆H₄CH₂SR)Cl}₂], by metathetical reaction with LiCl. The chloro-bridged complexes undergo bridge cleavage with 3,5-dimethylpyridine (dmpy) and thallium(I) acetylacetonate, Tl[acac], to give the corresponding mononuclear cyclopalladated complexes, [Pd(C₆H₄CH₂SR)Cl-(dmpy)] and [Pd(C₆H₄CH₂SR)(acac)] respectively. All complexes are characterized by means of elemental analysis, i.r., n.m.r., and mass spectroscopy. Temperature-dependent ¹H n.m.r. spectra are observed for all the cyclopalladated complexes and are attributed to the inversion of the butyl group at the sulphur atom.