The oxidative addition of a vinylic C-H bond of divinyl(phenyl)phosphine at M3(CO)12 carbonyls (M = RU, Os). Stepwise formation and crystal structure of [(μ-H)RU3(CO)8{PPh(CH=Ch2)2}{μ3-PPh(CH=CH2) (CH=CH)}]

Article abstract of DOI:10.1016/S0022-328X(97)00272-6

The metal carbonyls M₃(CO)₁₂ (M = Ru, Os) react with diphenylvinylphosphine (PPh2CH=CH₂) and divinylphenylphosphine (PPh(CH=CH₂)₂) in n-octane or toluene giving carbonyl substitution products of formulae M₃(CO)₁₁L (1, M = Ru; 1′, M = Os), M₃(CO)₁₀L (2; 2′) and M₃(CO)₁₀L₂ (3; 3′) (L = PPh₂CH = CH₂ or PPh(CH = CH₂)₂). When M = Os the reactions stop at this stage. When M = Ru oxidative addition of the vinylic C-H bond of one of the phosphinic ligands of complexes 3 occurs to form [(μ-H)Ru₃(CO)₈(PPh₂CH=CH₂) {μ₃-PPh₂(CH=CH)}] (4a) and [(μ-H)Ru₃(CO)₈{PPh(CH=CH₂)₂}{μ₃-PPh(CH=CH₂)(CH=CH)}] (4b), starting from PPh₂CH=CH₂ and PPh(CH=CH₂)₂ respectively; this process is favoured by the TLC material and is faster for PPh₂CH=CH₂ than for PPh(CH=CH₂)₂. The structure of 4b, determined by X-ray diffraction methods, consists of a triangle of Ru atoms bound to eight terminal carbonyls. The PPh(CH=CH₂)₂ ligand is σ-bound to one of the Ru atoms through the P atom, whilst the PPh(CH=CH₂)(CH=CH) moiety interacts with all of the three metals, being σ-bound to two Ru atoms through the P and C atoms and π-bound to the third Ru atom through the double bond.