Transformation of C2 units on a bimetallic tetranuclear cluster.: Reactivity of [Ru3Mo(μ3-η1-CC)(μ-CO)3(CO)2(η-C5H4R)3(η-C5H5)] (R = H, Me)

The reactivity of [Ru3Mo(μ4-η2-CC)(μ-CO)3(CO)2(η-C5H4R)3(η-C5H5)] (R = H; Me) have been investigated, initially to elucidate the nature of the starting material, and, latterly, to define the reactivity of an interesting ethane-1,2-bis(ylidyne) species. While the mixed RuMo clusters were unreactive towards simple electrophiles and carbonyl substitution by phosphine ligands they did react with atmospheric oxygen or carbon monoxide to give substantially different products. In all instances oxygen was incorporated either at the metal centre or at the C2 fragment. High-pressure carbonylations yielded [Ru3(μ-CO)3(η-C5H5)3(μ3-C-C(O)O{Ru(CO)2(η-C5H5)})] and [{Ru2(μ-CO)(CO)2(η-C5H4Me)2}(μ4-η2-Cdouble bond; length as m-dashC){Ru(CO)(η-C5H4Me)Mo(η-C5H5)(=O)(μ-O)}], an ethane-1,2-bis(ylidene) complex, this exemplifying a relatively rare raft geometry which further reacted with Cl2Cdouble bond; length as m-dashCCl2 to give [Mo3(μ4-C2(Ru(CO)2(η-C5H4Me))(CO)(μ-CO)(η-C5H5)3(Cl)2] having a similar geometry and undergone halogenation. In order to extend the extant examples of these raft clusters we explored the reaction of [{Ru(CO)2(η-C5H4R)2}2(μ-C2)] with [{Ru(CO)2(η-C5H5)2}2] to provide a rational synthetic pathway leading to very reactive [Ru(μ4-η2-CC)(μ2-CO)2(CO)4(η-C5H4Me)2(η-C5H4R)2] rafts.