Taming the stilbene radical anion

Abstract

Radical anions appear as intermediates in a variety of organic reductions and have recently garnered interest for their role as mediators for electron-driven catalysis as well as for organic electron...

Divergent Interaction of (Iso)nitriles with a Linear Iron(I) Silylamide─A Combined Structural, Spectroscopic, and Computational Study

“…Here, computational and experimental analysis of their magnetic properties gave virtually free-ion behavior with unquenched orbital angular momentum, which resembles the situation for lanthanide ions. Reports on the chemical properties of named linear complexes show their great versatility, such as C–halide bond cleavage and C–C cross-coupling, − platforms for high-spin imido metal species, , construction of small molecular chalcogenide/metal clusters, , or formation of metal stabilized radical anions. , For the latter, side-on bound radical anions of alkynes and even alkenes to metal(II) ions could be observed by us. , Together with a related report from coordination of an alkyne to a T-shaped iron(I) complex, it added a third resonance structure for the metal–C/C double and triple bond interaction that is widely described within the dichotomy of a π complex with π → d-donation/d → π*-backdonation, and a metallacyclopropane or metallacyclopropene, respectively. , The invoked metal stabilized radical character can be used in chemical transformations, , such as catalytic Z → E alkene isomerization or bismetalation of an alkyne.…”

“…Given the possibility of a metal-stabilized nitrile radical anion, we contemplated its direct formation and stabilization void of an interaction with a transition metal. For that, we resorted to a recent approach from our group, where a radical anion (e.g., stilbene) , was encapsulated between two K{18c6} moieties. As such, mesityl nitrile was treated at −30 °C with KC 8 in Et 2 O in the presence of 18-crown-6 as well as K{18c6}[Fe(hmds) 3 ] .…”

“…24,25 For the latter, side-on bound radical anions of alkynes and even alkenes to metal(II) ions could be observed by us. 26,27 Together with a related report from coordination of an alkyne to a T-shaped iron(I) complex, 28 it added a third resonance structure for the metal−C/C double and triple bond interaction that is widely described within the dichotomy of a π complex with π → ddonation/d → π*-backdonation, and a metallacyclopropane or metallacyclopropene, respectively. 29,30 The invoked metal stabilized radical character can be used in chemical transformations, 27,31 such as catalytic Z → E alkene isomerization or bismetalation of an alkyne.…”

Moisture-resistant radical anions of quinoxalin-2(1H)-ones in aerial dioxygen activation

“…3 Although radical anions show promise as visible light photocatalysts, 4 their persistent instability poses a challenge, 5 attributable to their intrinsic reactivity and vulnerability to environmental elements like air and moisture. 6 Despite persistent challenges in creating radical anions suitable for ambient chemical reactions, 7 such as molecular oxygen activation, 8 due to their reactivity, this study represents a significant advancement. Organic radical anions and dianions have been observed in moist environments, particularly in the context of visible light photocatalysis.…”

“…3 Although radical anions show promise as visible light photocatalysts, 4 their persistent instability poses a challenge, 5 attributable to their intrinsic reactivity and vulnerability to environmental elements like air and moisture. 6…”