Isolation of kinetically-stabilised diarylchalcogenide radical cations.

Chalcogenide radical cations [RE] (E = S, Se, Te) are commonly short-lived intermediates of fundamental interest. Sulfide radical cations in particular are associated in vivo with oxidative stress and neuropathological processes. Having succeeded in the preparation of meta-terphenyl-based dichalcogenide radical cations [RE] (E = S, Se, Te), and a telluride analogue [RTe] in the past, we aimed to complete the series regarding sulfur and selenium.

Synthesis and Single-Electron Oxidation of Bulky Bis(m-terphenyl)chalcogenides: The Quest for Kinetically Stabilized Radical Cations.

Sterically encumbered bis(m-terphenyl)chalcogenides, (2,6-Mes C H ) E (E=S, Se, Te) were obtained by the reaction of the chalcogen tetrafluorides, EF , with three equivalents of m-terphenyl lithium, 2,6-Mes C H Li. The single-electron oxidation of (2,6-Mes C H ) Te using XeF /K[B(C F ) ] afforded the radical cation [(2,6-Mes C H ) Te][B(C F ) ] that was isolated and fully characterized. The electrochemical oxidation of the lighter homologs (2,6-Mes C H ) E (E=S, Se) was irreversible and impaired by rapid decomposition.

Donor Acceptor Complexes between the Chalcogen Fluorides SF , SeF , SeF and TeF and an N-Heterocyclic Carbene.

The majority of binary chalcogen fluorides are fiercely reactive and extremely difficult to handle. Here, we show that access to crystalline donor-acceptor complexes between chalcogen difluorides (sulfur, selenium) and tetrafluorides (selenium, tellurium) with the N-heterocyclic carbene (NHC) 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) is possible conveniently and safely without the need to generate the highly unstable EF (E=S, Se) or the very toxic and corrosive SeF .