Reactivity of a cationic triruthenium hydridoalkenylcarbonyl cluster complex toward nucleophilic reagents. Carbonyl substitution versus alkene elimination reactions

Abstract The reactions of the cationic hydridoalkenyl cluster complex [Ru 3 ( μ -H)( μ 3 -PhCCHPh)(CO) 8 ][BF 4 ] ( 1 ) (Hampy = 2-amino-6-methylpyridine) with neutral and anionic nucleophiles have been studied. Complex 1 reacts with different amounts of triphenylphosphine to replace CO giving [Ru 3 ( μ -H)( μ 3 -ampy)( μ -PhCCHPh)(PPh 3 )(CO) 7 ][BF 4 ] (two isomers), [Ru 3 ( μ -H)( μ 3 -ampy)( μ -PhCCHPh)(PPh 3 ) 2 (CO) 6 ][BF 4 ] and [Ru 3 ( μ -H)( μ 3 -ampy)( μ -PhCCHPh)(PPh 3 ) 3 (CO) 5 ][BF 4 ] (two isomers). Analogous results are obtained using tri-4-tolyphosphine. The reaction of compound 1 with two equivalents of bis(diphenylphosphino)methane (dppm) induces the reductive elimination of cis -stilbene, yielding [Ru 3 ( μ 3 -ampy)( μ -dppm)(dppm)(CO) 7 ]BF 4 ]. Complex 1 undergoes deprotonation upon treatment with NaOMe to give [Ru 3 ( μ 3 -ampy)( μ -PhCCHPh)(CO) 8 ]. However, a similar reaction with NaOH yields cis -stilbene and the neutral hydride [Ru 3 ( μ -H)( μ 3 -ampy)(CO) 9 ].