engleski

One-step Mechanocynthesis of organopalladium Compounds Via Anion Replacement

Cyclopalladated complexes or palladacycles are successfully applied in organic synthesis and catalysis, as well as in many areas of material science and biological chemistry. The synthesis of palladacycles usually relies on solvent-based protocol which may require elevated temperatures and toxic solvents, and are often time-consuming. Recently, we have employed ball-milling methods for the synthesis of a series of mono- and/or dicyclopalladated azobenzenes via C–H bond activation, known as cyclopalladation, using common Pd(II) precursors. The desired products were obtained in high yields and in shorter reaction time than in the solution. Herein we describe the one-step mechanosynthesis of palladacycles by substitution of anionic ligands in the ball mill solvent-free conditions. The mutual exchange of chloride, acetate, tetrafluoroborate and acetylacetonate ligands in mono- and/or dicyclopalladated azobenzenes yielded desired products, some of which were inaccessible via direct C-H bond activation with Pd(II) precursors. The products were obtained in high yields with shorter reaction times than those under a solvent-based protocol. The starting compounds and products were characterised in the solid state by using PXRD, Raman and IR spectroscopies, and by 1H- NMR spectroscopy in solution.

organopalladium compounds ; anion replacement ; mechanochemistry

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