The Syntheses and Crystal Structures of cis-[Bis(diphenylphosphino)methane][1,2-bis(diphenylphosphlno)ethane] dicarbonylmolybdenum(O) and cis-[1,2-Bis(diphenylphosphino)ethane] [cis-1,2-bis(diphenylphosphino) ethylene]dicarbonylmolybdenum(0)

The title compounds, Mo(CO)₂(Ph₂PCH₂PPh₂)(Ph₂PCH₂CH₂PPh₂), Mo(CO)₂(dppm)(dppe) 1, and Mo(CO)₂(Ph₂PCH₂CH₂PPh₂)(Ph₂PCH = CHPPh₂), Mo(CO)₂(dppe)(cis-vpp) 2, were prepared from Mo(CO)₆ and the corresponding bidentate diphosphine ligands in n-decane under nitrogen atomosphere. Crystals of 1 are monoclinic, space group P 2₁/c, with a = 19.072(3), b = 11.348(3), c = 23.57(1) Å, β = 99.64(3)°, Z = 4, and the final residual R(F) = 0.044 for 4810 observed reflections; data of 2 are triclinic, space group P 1, with a = 12.091(3), b = 12.186(8), c = 18.934(5) Å, α = 96.93(4),β = 108.15(2), γ = 107.08(4)deg;, Z = 2, and the final residual R(F) = 0.058 for 4570 observed reflections. The distortion of compound 1 is more pronounced than that of compound 2, The two Mo-P lengths in the same bidentate chelate ligand for both compounds are different. Among them, the two larger Mo-P bond lengths for compound 2 are similar, but significantly different for 1.