Double oxidative addition of C-H bonds on a triruthenium cluster complex; synthesis and characterization of Ru33-C(OEt)=C(H)>(CO)9 and Ru33-C(OEt)N(Me)C(H)>(CO)9

Article abstract of DOI:10.1016/0022-328X(87)80283-8

Titration of Ru3<μ-H,μ-O=C(CH3)>(CO)10 (1) with LiCH3 in diethyl ether at -30 degC leads to its instantaneous conversion into

1-C(O)CH3><μ-H,μ-O=C(CH3)>(CO)9>.Alkylation with C2H5OSO2CF3 at 25 degC leads after 48 h to Ru3<μ-H2,η²,μ3-C(OEt)=C(H)>(CO)9 (3) in 80percent yield; acetaldehyde is obtained as a by-product.Use of LiCD3 in the first step of this sequence gives unlabeled acetaldehyde and the trinuclear product Ru3<μ-D2,η²,μ3-C(OEt)=C(D)>(CO)9.Starting with Ru3<μ-H,μ-C(O)CD3>(CO)10 and LiCH3, the reaction gives CD3C(O)H and no deuterium incorporation into the triruthenium product.Under an atmosphere of CO, acetaldehyde is still eliminated from the initial alkylation product but oxidative addition is prevented; IR spectroscopy indicates that a new complex is present, but this has eluded characterization owing to its rapid conversion to 3 under conditions used in attempts to isolate or purify it.Reaction of 1 with LiPh or LiCMe3 followed by alkylation with C2H5OSO2CF3 also gives 3, along with the corresponding aldehyde RC(O)H.Reaction of 1 with HNMe2 followed by alkylation with C2H5OSO2CF3 gives Ru3<μ-H2,Η²,μ-3C(OEt)N(Me)C(H)>(CO)9 (45percent yield).