TRISIMIDAZOLE COMPLEXES OF RUTHENIUM AND OSMIUM

The preparation and characterisation of ruthenium(II) and osmium(II) c omplexes with the trisimidazole ligands tris(N-methylimidazol-2-yl)met hanol (1a) ((mim)(3)COH) and tris(N-ethoxymethylimidazol-2-yl)methanol (1b) ((emim)(3)COH) are reported (mim = N-methylimidazol-2-yl, emim = N-ethoxymethylimidazol-2-yl). The complex [{RuCl(PPh3)(2)((mim)(3)COH )}Cl-+(-)] (2) was formed by the reaction of (mim)(3)COH with [RuCl2(P Ph3)(4)]. The complexes [{Ru(PPh3)(Co)H((mim)(3)COH)}Cl-+(-)] (3a) and [{Ru(PPh3)(CO)H((emim)(3)COH)}Cl-+(-)] (3b) were formed by the reacti on of (mim)(3)COH or (emim)(3)COH (respectively) with [Ru(PPh3)(3)HCl( CO)]. Likewise, the reaction of (mim)(3)COH or (emim)(3)COH (respectiv ely) with [Os(PPh3)(3)HCl(CO)] formed [{Os(PPh3)(CO)H((mim)(3)COH)}Cl- +(-)] (4a) and [{Os(PPh3)(CO)H((emim)(3)COH)}Cl-+(-)] (4b). The ruthen ium monohydride complex [{Ru(PPh3)(CO)H((mim)(3)COH)}Cl-+(-)] (3a) add s to the terminal C-H bond of phenylacetylene to form the vinyl comple x [{Ru(PPh3)(CO)(CH = CHPh)((mim)(3)COH)}Cl-+(-)] (5). The air-stable complexes were characterised by multinuclear NMR spectroscopy and 2 an d 3b were characterised by X-ray crystallography. Crystals of 2, C49H4 6N6OP2RuCl2, M 968.87, are triclinic, space group <P(1)over bar>, c = 12.011(5), b = 13.342(3), c = 16.554(6)Angstrom, alpha = 89.26(3)degre es, beta = 76.94(3)degrees, gamma = 77.43(3)degrees, Z = 2. Crystals o f 3b, C38H44N6O5PRuCl, M 832.30, are triclinic, space group <P(1)over bar>, a = 12.759(3), b = 13.017(2), c = 13.167(4)Angstrom, alpha = 87. 65(2)degrees, beta = 64.09(2)degrees, gamma = 88.82(2)degrees, Z = 2.