Fully Solvated, Monomeric Re Complexes: Insights into the Chemistry of [Re(NCCH)].

The oxidation of [Re(η-CH)] with Ag in acetonitrile yields [Re(NCCH)]. This fully solvated Re compound was characterized by spectroscopic methods and X-ray structure analyses. We show that [Re(NCCH)] acts as a precursor complex for a variety of substitution reactions. Treatment with monodentate triphenylphosphine (PPh) and bidentate 1,2-bis(diphenylphosphino)ethane (dppe) yields the complexes [-Re(PPh)(NCCH)] and [-Re(dppe)(NCCH)], respectively. [-Re(dppe)(NCCH)] is oxidized under mild conditions by Ag to its Re analogue [-Re(dppe)(NCCH)]. Reactions of [Re(NCCH)] with a halide mixture consisting of NaX and AgX (X = Cl, I) result in the formation of the corresponding Re complexes [-ReX(NCCH)]. [-ReBr(NCCH)] can be obtained directly from [Re(η-CH)] by oxidation with FeBr in acetonitrile. The title compound is thus a convenient starting material for Re and Re complexes by simple solvent exchange, which are otherwise difficult to access.