From AlCp*- and GaCp*-Ligated Ruthenium Hydrides to Zinc-Rich Heterometallic Complexes

The reactivity of ZnMe2 towards heteroleptic (poly)hydride ruthenium complexes was investigated. The Ru centers were coligated with different ligands including reactive low-valent ECp* (E = Ga, Al; Cp* = pentamethylcyclopentadienyl) ligands and nonreactive phosphane ligands (PCy3, PPh3, Cy = cyclohexyl, Ph = phenyl). The ECp* ligands undergo a redox reaction together with Cp*/Me group exchange when treated with ZnMe2 to form two equivalents of ZnR (R = Cp*, Me) units, and ER3 species are liberated. Similarly, Ru-H moieties react with ZnMe2 to form one equivalent of ZnMe and one equivalent of CH4. The 18-electron rule proved valid for the rationalization of the obtained compositions; one ECp* or phosphane ligand is equivalent to two one-electron ZnR or H ligands. The factors that control the exchange of phosphane or hydride ligands are discussed. All compounds were characterized by NMR and IR spectroscopy, liquid injection field desorption ionization (LIFDI) MS analysis, single-crystal X-ray diffraction, and elemental analysis.