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Abstract Herein, the first report on the isolated and unambiguously proven benzene radical trianion is presented. This unprecedented radical oxidation state of benzene is stabilized through two trivalent rare earth (RE) metal cations each supported by a bis(guanidinate) scaffold. Specifically, the one‐electron chemical reduction of the neutral inverse‐sandwich yttrium complex [[{(Me3Si)2NC(NiPr)2}2Y]2(μ–ƞ6:ƞ6–C6H6)]1, containing a benzene dianion, with potassium graphite (KC8) in the presence of [2.2.2]‐cryptand yielded the title complex [K([2.2.2]‐cryptand)][[{(Me3Si)2NC(NiPr)2}2Y]2(μ–ƞ6:ƞ6–C6H6•)]2, featuring a benzene radical trianion. Analyses through single‐crystal X‐ray diffraction, EPR and UV–vis spectroscopy, elucidated its molecular structure and revealed strong [YIII–(C6H6)3–•–YIII] metal–radical interactions. Although the Y centers remain in the +3 oxidation state, the spin density of the unpaired electron resides primarily on the benzene trianion moiety and extends toward the YIIIions. Density functional theory (DFT) calculations on2corroborate this assignment and further suggest weak aromaticity for the benzene radical trianion.
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Synthesis of a “Masked” Terminal Zinc Sulfide and Its Reactivity with Brønsted and Lewis Acids
Abstract The “masked” terminal Zn sulfide, [K(2.2.2‐cryptand)][MeLZn(S)] (2) (MeL={(2,6‐iPr2C6H3)NC(Me)}2CH), was isolated via reaction of [MeLZnSCPh3] (1) with 2.3 equivalents of KC8in THF, in the presence of 2.2.2‐cryptand, at −78 °C. Complex2reacts readily with PhCCH and N2O to form [K(2.2.2‐cryptand)][MeLZn(SH)(CCPh)] (4) and [K(2.2.2‐cryptand)][MeLZn(SNNO)] (5), respectively, displaying both Brønsted and Lewis basicity. In addition, the electronic structure of2was examined computationally and compared with the previously reported Ni congener, [K(2.2.2‐cryptand)][tBuLNi(S)] (tBuL={(2,6‐iPr2C6H3)NC(tBu)}2CH).
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- Award ID(s):
- 1764345
- PAR ID:
- 10156019
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 59
- Issue:
- 23
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 8947-8951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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