One Electron Changes Everything: Synthesis, Characterization, and Reactivity Studies of [Re(NCCH3)6]3+

Oxidation of [Re(NCCH3)(6)](2+) with the thinathrene radical cation results in the formation of [Re(NCCH3)(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(NCCH3)(6)](3+) exhibits a much faster CH3CN exchange. Hence, substitution reactions proceed at 20 degrees C within minutes. Its potential as a versatile precursor for Rem 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 Agi-mediated oxidation of in situ formed [Re(eta(6)-C6H6)(NCPh3)(3)](+) in NCPh The same synthetic strategy is feasible for the synthesis of [Re(NCCH3)(6)](3+) as well. [Re(NCCH3)(6)](3+) reacts with 1,4,7-trithiacyclononane (C6H12S3) to yield sevenfold-coordinated [Re(kappa(3)-C6H12S3)(2)(NCCH3)](3+). The reaction of [Re(NCCH3)(6)](3+) with 1 equiv of (NBu4)X produces the Re-III monohalide complexes [ReX(NCCH3)(5)](2+) (X = Cl, Br, I). Mixed Re-III dihalides (trans-[ReXY(NCCH3)(4)](+)) were obtained by treating [ReX(NCCH3)(5)](2+) with a second equivalent of (NBu4)Y (if X = Cl, Y = Br, I; if X = Br, Y = I). Because of this fast CH3CN exchange, [Re(NCCH3)(6)](3+) is a very suitable precursor for new Rem complexes.

Automated summary

The oxidation of [Re(NCCH3)(6)](2+) with the thinathrene radical cation leads to the formation of [Re(NCCH3)(6)](3+), which is a fully solvated +3 complex. This complex demonstrates a faster CH3CN exchange rate, making it a suitable precursor for new Rem complexes.