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

ABSTRACT: Oxidation of [Re(NCCH₃)₆]²⁺ with the thianthrene 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 °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(η⁶-C₆H₆)(NCPh₃)₃]⁺ in NCPh. The same synthetic strategy is feasible for the synthesis of [Re(NCCH₃)₆]²⁺ as well. [Re(NCCH₃)₆]³⁺ reacts with 1,4,7-trithiacyclononane (C₆H₁₂S₃) to yield sevenfold-coordinated [Re(κ³-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 Re^III complexes.

SUBMITTER: Bolliger R 

PROVIDER: S-EPMC9682483 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature