One Electron Changes Everything: Synthesis, Characterization, and Reactivity Studies of [Re(NCCH(3))(6)](3+)

[Image: see text] Oxidation of [Re(NCCH(3))(6)](2+) with the thianthrene radical cation results in the formation of [Re(NCCH(3))(6)](3+), one of the very rare cases of a fully solvated +3 complex. It was fully characterized by spectroscopy and X-ray structure analysis. In contrast to its reduced analogue, [Re(NCCH(3))(6)](3+) exhibits a much faster CH(3)CN exchange. Hence, substitution reactions proceed at 20 °C within minutes. Its potential as a versatile precursor for Re(III) chemistry was examined with a series of substitution reactions. The more lipophilic analogue [Re(NCPh)(6)](3+) was synthesized by nitrile exchange in benzonitrile (NCPh). The Re(II) analogue of [Re(NCPh)(6)](3+), [Re(NCPh)(6)](2+), forms by Ag(I)-mediated oxidation of in situ formed [Re(η(6)-C(6)H(6))(NCPh(3))(3)](+) in NCPh. The same synthetic strategy is feasible for the synthesis of [Re(NCCH(3))(6)](2+) as well. [Re(NCCH(3))(6)](3+) reacts with 1,4,7-trithiacyclononane (C(6)H(12)S(3)) to yield sevenfold-coordinated [Re(κ(3)-C(6)H(12)S(3))(2)(NCCH(3))](3+). The reaction of [Re(NCCH(3))(6)](3+) with 1 equiv of (NBu(4))X produces the Re(III) monohalide complexes [ReX(NCCH(3))(5)](2+) (X = Cl, Br, I). Mixed Re(III) dihalides (trans-[ReXY(NCCH(3))(4)](+)) were obtained by treating [ReX(NCCH(3))(5)](2+) with a second equivalent of (NBu(4))Y (if X = Cl, Y = Br, I; if X = Br, Y = I). Because of this fast CH(3)CN exchange, [Re(NCCH(3))(6)](3+) is a very suitable precursor for new Re(III) complexes.