The fragment bis(acetylacetonato)ruthenium: a meeting-point of coordination and organometallic chemistry

Abstract Reduction of [Ru(acac) 3 ] with zinc in THF/H 2 O provides a range of coordination and organometallic complexes containing Ru II (acac) 2 , whose chemistry is reviewed. Most of these compounds, including those containing alkenes, undergo reversible one-electron oxidation to their Ru III (acac) 2 counterparts, and the alkene–ruthenium(III) cations have been detected by spectroelectrochemistry. The cations derived from the chelate N-donor ligands o -CH 2 CHC 6 H 4 NMe 2 and o -PhC CC 6 H 4 NMe 2 have been isolated and structurally characterized. Comparison of the metrical data establishes that, whereas the alkene is less firmly bound to Ru III than to Ru II , the alkyne is bound about as strongly to Ru III as to Ru II . Some uncharged nucleophiles (pyridine, diethylamine, PPh 3 ) react with the cationic Ru III complexes to give unusual, paramagnetic Ru III –C σ-bonded chelate complexes.