Preparation of the octahedral d6 amido complex TpRu(CO)(PPh3)(NHPh) (Tp = hydridotris(pyrazolyl)borate):: Solid-state structural characterization and reactivity

The reaction of TpRu(CO)(PPh3)(OTf) (2) with LiNHPh affords the amido complex TpRu(CO)(PPh3)(NHPh) (3) in 88% isolated yield. The amido complex 3 has been characterized by H-1 NMR, C-13 NMR, P-31 NMR, elemental analysis, cyclic voltammetry, and a solid-state X-ray diffraction study. Variable temperature NMR studies have revealed a rotational barrier around the ruthenium-amido nitrogen bond of 3 of 12 kcal/mol (transformation of the major isomer to the minor isomer). The solid-state structure of 3 discloses a pyramidal amido moiety. Heating benzene solutions of the amido complex 3 and 1,4-cyclohexadiene or 9,10-dihydroanthracene results in no observable reaction. Reaction of complex 2 with excess aniline yields [TpRu(CO)(PPh3)(NH2Ph)][OTf] (4).