Trisimidazole complexes of ruthenium and osmium

Abstract

Abstract 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 P1¯, a = 12.011(5), b = 13.342(3), c = 16.554(6) A, α = 89.26(3)°, β = 76.94(3)°, γ = 77.43(3)°, Z = 2. Crystals of 3b, C38H44N6O5PRuCl, M 832.30, are triclinic, space group P1¯, a = 12.759(3), b = 13.017(2), c = 13.167(4) A, α = 87.65(2)°, β = 64.09(2)°, γ = 88.82(2)°, Z = 2.