Bridging and chelating diphosphine ligands in Ru3(μ-H)(μ-N=CPh2)(CO)8(P—P). X-ray diffraction structures of Ru3(μ-H)(μ-N=CPh2)(CO)8(dmpe) and Ru3(μ-H)(μ-N=CPh2)(CO)8(bpcd)

Abstract

Treatment of the azavinylidene-bridged cluster Ru3(μ-H)(μ-N=CPh2)(CO)10 (1) with the diphosphine ligand bis(dimethylphosphino)ethane (dmpe) gives Ru3( μ-H)(μ-N=CPh2)(CO)8(dmpe) (2) in moderate yield, while the ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) reacts with Ru3( μ-H)(μ-N=CPh2)(CO)10 in the presence of Me3NO to furnish Ru3( μ-H)(μ-N=CPh2)(CO)8(bpcd) (3) in low yield. Each new cluster has been isolated and characterized in solution by IR and NMR (1H and 31P) spectroscopies, and the coordination mode exhibited by the ancillary diphosphine ligand in 2 and 3 has been established by X-ray crystallography. Ru3( μ-H)(μ-N=CPh2)(CO)8(dmpe) crystallizes in the monoclinic space group P2(1)/c, a = 10.791(1) A, b = 16.377(1) A, c = 18.148(1) A, β = 96.675(2)°, V = 3185.3(4) A3, Z = 4, D cacl = 1.791 Mg/m3; R = 0.0360, R w = 0.0866 for 7522 observed reflections with I > 2σ(I). Ru3(μ-H)(μ-N=CPh2)(CO)8(bpcd) crystallizes, as the CH2Cl2 solvate, in the triclinic space group $$P\bar 1$$ , a = 11.956(1) A, b = 14.228(1) A, c = 31.409(3) A, α = 89.377(2)°, β = 79.344(2)°, γ = 77.235(2)°, V = 5118.4(8) A3, Z = 2, D calc = 1.670 Mg/m3; R = 0.0557, R w = 0.1069 for 10977 observed reflections with I > 2σ(I). The structural details of clusters 2 and 3 are contrasted with Ru3(μ-H)(μ-N=CPh2)(CO)7(μ-dppm)(η-dppm), which is the only known structurally characterized phosphine-substituted cluster of this genre.