Nucleophilic attack on (eta)^3-allyl and (eta)^2-tetrahydroborate complexes of ruthenium(II)

Reaction of [Ru(CO)((eta)^3-C3H5)Cl(PMe2Ph)2], 1, with CO and Ag+ yielded 2A and 2B, isomers of [Ru(CO)2((eta)^3-C3H5)(PMe2Ph) 2]+. Treatment of 2B with BH4- gave [Ru(CO)2(CH2CH2CH2)(PMe2Ph)2], 7, and [Ru((eta)^2-BH4)(CO)H(PMe2Ph)2], 6, subsequently obtained from [Ru2(CO)2Cl4(PMe2Ph)4] and NaBH4. Chloride attacked the metal in 2B, yielding [Ru(CO)2((eta)^1-C3H5)Cl(PMe2Ph)2], 8, which then reformed 1. Lability of the Ru-HB bond trans to hydride allowed nucleophilic access to the metal in 6, with lowtemperature formation of [Ru((eta)^1-BH4)(CO)H(L)(PMe2Ph)2](11, 12, 13, L = PMe2Ph, CO, 4-methylpyridine, respectively). On warming with excess L, these gave H3B·L and [Ru(CO)(H)2L(PMe2Ph)2](5, 4, 14, respectively). For L = C2H4, low-temperature NMR studies revealed a rapid equilibrium between 6, C2H4 and [Ru((eta)^1-BH4)(CO)((eta)^2-C2H4)H(PMe2Ph)2], 16, with slower conversion to [Ru((eta)^2-BH4)(CO)Et(PMe2Ph)2], 17.