Trisimidazole complexes of ruthenium and osmium

The preparation and characterisation of ruthenium(II) and osmium(II) complexes with the trisimidazole ligands tris(N-methylimidazol-2-yl)methanol (1a) ((mim)₃COH) and tris(N-ethoxymethylimidazol-2-yl)methanol (1b) ((emim)₃COH) are reported (mim = N-methylimidazol-2-yl, emim = N-ethoxymethylimidazol-2-yl). The complex [{RuCl(PPh₃)₂((mim)₃COH)}⁺Cl^-] (2) was formed by the reaction of (mim)₃COH with [RuCl₂(PPh₃)₄]. The complexes [{Ru(PPh₃)(CO)H((mim)₃COH)}⁺Cl^-] (3a) and [{Ru(PPh₃)(CO)H((emim)₃COH)}⁺Cl^-] (3b) were formed by the reaction of (mim)₃COH or (emim)₃COH (respectively) with [Ru(PPh₃)₃HCl(CO)]. Likewise, the reaction of (mim)₃COH or (emim)₃COH (respectively) with [Os(PPh₃)₃HCl(CO)] formed [{Os(PPh₃)(CO)H((mim)₃COH)}⁺Cl^-] (4a) and [{Os(PPh₃)(CO)H((emim)₃COH)}⁺Cl^-] (4b). The ruthenium monohydride complex [{Ru(PPh₃)(CO)H((mim)₃COH)}⁺Cl^-] (3a) adds to the terminal C-H bond of phenylacetylene to form the vinyl complex [{Ru(PPh₃)(CO)(CH=CHPh)((mim)₃COH)}⁺Cl^-] (5). The air-stable complexes were characterised by multinuclear NMR spectroscopy and 2 and 3b were characterised by X-ray crystallography. Crystals of 2, C₄₉H₄₆N₆OP₂RuCl₂, M 968.87, are triclinic, space group P1̄, a = 12.011(5), b = 13.342(3), c = 16.554(6) Å, α = 89.26(3)°, β = 76.94(3)°, γ = 77.43(3)°, Ζ = 2. Crystals of 3b, C₃₈H₄₄N₆O₅PRuCl, Μ 832.30, are triclinic, space group P1̄, a = 12.759(3), b= 13.017(2), c= 13.167(4) Å, α = 87.65(2)°, β = 64.09(2)°, γ = 88.82(2)°, Ζ =2.