Diacetonitrilebis(β-diketonato)ruthenium(II) Complexes. Their Preparation and Use as Intermediates for the Synthesis of Mixed-ligand β-Diketonato Ruthenium(III) Complexes

Diacetonitrilebis(β-diketonato)ruthenium(II) complexes were readily prepared by reducing the corresponding tris(β-diketonato)ruthenium(III) with zinc amalgam in an acetonitril–ethanol–water mixture. When a mixed-ligand β-diketonato complex [RuL2L′] is treated in this way, the more electron-donating ligand is preferentially displaced by two acetonitrile molecules. The diacetonitrile complexes are useful intermediates for the synthesis of mixed-ligand β-diketonato ruthenium( III) complexes of the type [RuL2L″].