Reactions of Dihydridotetrakis(triphenylphosphine)ruthenium(II) with Olefins and Isolation of New Ruthenium–Olefin Complexes

Dihydridotetrakis(triphenylphosphine)ruthenium(II), RuH2(PPh3)4, reacts with olefins (ethylene, propylene, styrene and butadiene) to give olefin-coordinated complexes of the type, Ru(olefin)(PPh3)3 and equimolar amounts of their hydrogenation products per mol of the dihydride complex. The olefin coordinated with ruthenium can be exchanged with other olefins. Olefin-coordinated complexes easily react with molecular hydrogen to afford tetrahydridotris(triphenylphosphine)ruthenium, RuH4(PPh3)3, releasing alkane at room temperature. Under hydrogen atmosphere, catalytic hydrogenation of the olefins smoothly takes place with RuH2(PPh3)4. (Ethylene) tris(triphenylphosphine) ruthenium (0) reacts with methyl iodide to give propylene and a trace of bu adiere along with methane, ethylene, and small amounts of ethane and butenes. The formation of propylene suggests that oxidative addition involving cleavage of the C–H bond of ethylene to ruthenium giving a hydridovinyl complex may be taking place. Reactions of Ru(C2H4)(PPh3)3 with methyl-d3 iodide and ethyl iodide, and of Ru(C3H6)(PPh3)3 with methyl iodide were examined to test the generality of this type of reaction. The reaction of Ru(C2H4)(PPh3)3 with CD3I released CD4 and CD2H2 together with CD3H suggesting the involvement of α-hydrogen abstraction.