Reactivity of the Ru-O bond in η2(O,P) -chelated mono(ether-phospine) (pentamethylcyclopentadienyl) ruthenium(II) complexes

Article abstract of DOI:10.1016/0022-328X(95)05817-9

By treatment of the 16-electron starting compound Cp * RuCl(P ～ O) (1) (Cp * = η⁵-C₅Me₅; P ～ O, ¹(P)-coordinated ether-phosphine ligand Cy₂PCH₂CH₂OCH₃) with L = CO (a) and P(OEt)₃ (b), the carbonyl and mixed bisphosphine ruthenium(II) complexes Cp * RuCl(L)(P ～ O) (2a, 2b) are accessible. Chloride abstraction from 2a, 2b with NaBPh₄ leads to the chelated complexes [Cp * Ru(L)(P ∩ O)][BPh₄] (3a, 3b) (P ∩ O, η²(O,P)-coordinated ligand). Cleavage of the Ru-O bond in 3a, 3b with sulphur dioxide results in the formation of the η¹-SO₂ complexes [Cp * Ru(L)(P ～ O)(η¹-SO₂)][BPh₄] (4a, 4b) in which the O₂SRu fragment adopts a trigonal planar geometry. In a similar way the Ru-O bond is easily ruptured when [Cp * Ru(CO)(P ∩ O)][BPh₄] (3a) is reacted with ethene and phenylacetylene to give the adduct [Cp * Ru(CO)(P ～ O)(η²-C₂H₄)][BPh₄] (5a) and the η¹ -vinylidene complex [Cp * Ru(CO)(P ～ O)(=C=CHPh)][BPh₄] (6a) respectively.