The molecular structure of the dimer of bis(tetramethyldiphosphinoethane)ruthenium that results from paired oxidative additions of CH bonds to two metal atoms

Abstract The compound of stoichiometry (Me 2 PCH 2 CH 2 PMe 2 ) 2 Ru reported in 1965 and formulated as a mononuclear species containing an RuH bond and a three-membered RuPC ring has been shown by x-ray crystallography to be a dinuclear species. This is formed by union of two dmpe 2 Ru molecules, where dmpe = Me 2 PCH 2 CH 2 PMe 2 , so that one CH bond of a methyl group in one unit adds oxidatively to the Ru atom of the other unit. A central RuPCRuPC ring with a chair configuration is formed and each metal atom is octahedrally coordinated by four P atoms, one C atom and one H atom. Crystal data: Space group, P 1 ; Z = 4(dmpe 2 Ru); a = 10.028(4) A ; b = 13.880(6) A ; c = 15.018(6) A ; α = 95.87(3)°; β = 101.27(3)°; γ = 112.02(3)°; V = 1865(1) A 3 . There are two crystallographically independent dinuclear molecules, each located on an inversion center (at 0, 0, 0 and 1 2 , 1 2 , 1 2 ). Anisotropic refinement of all non-hydrogen atoms gave residuals of R 1 = 0.052 and R 2 = 0.076. Using data for which λ −1 sin Θ A −1 the ligate hydrogen atoms were then located; a mean RuH distance of 1.67(7) A was obtained after refinement of the hydride positions.